* Re: [PATCH v3 19/24] LSM: Use lsmcontext in security_inode_getsecctx
From: Kees Cook @ 2019-06-22 22:56 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-20-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:28AM -0700, Casey Schaufler wrote:
> Change the security_inode_getsecctx() interface to fill
> a lsmcontext structure instead of data and length pointers.
> This provides the information about which LSM created the
> context so that security_release_secctx() can use the
> correct hook. A lsmcontext is used within kernfs to store
> the security information as well.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> fs/kernfs/dir.c | 8 ++------
> fs/kernfs/inode.c | 34 ++++++++++++----------------------
> fs/kernfs/kernfs-internal.h | 3 +--
> fs/nfsd/nfs4xdr.c | 23 +++++++++--------------
> include/linux/security.h | 5 +++--
> security/security.c | 13 +++++++++++--
> 6 files changed, 38 insertions(+), 48 deletions(-)
>
> diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
> index 92afad387237..1d000289d8b7 100644
> --- a/fs/kernfs/dir.c
> +++ b/fs/kernfs/dir.c
> @@ -532,12 +532,8 @@ void kernfs_put(struct kernfs_node *kn)
> kfree_const(kn->name);
>
> if (kn->iattr) {
> - struct lsmcontext scaff; /* scaffolding */
> - if (kn->iattr->ia_secdata) {
> - lsmcontext_init(&scaff, kn->iattr->ia_secdata,
> - kn->iattr->ia_secdata_len, 0);
> - security_release_secctx(&scaff);
> - }
> + if (kn->iattr->ia_context.context)
> + security_release_secctx(&kn->iattr->ia_context);
> simple_xattrs_free(&kn->iattr->xattrs);
> kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
> }
> diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
> index 02cde9dac5ee..ffbf7863306d 100644
> --- a/fs/kernfs/inode.c
> +++ b/fs/kernfs/inode.c
> @@ -135,21 +135,14 @@ int kernfs_iop_setattr(struct dentry *dentry, struct iattr *iattr)
> return error;
> }
>
> -static int kernfs_node_setsecdata(struct kernfs_iattrs *attrs, void **secdata,
> - u32 *secdata_len)
> +static void kernfs_node_setsecdata(struct kernfs_iattrs *attrs,
> + struct lsmcontext *cp)
> {
> - void *old_secdata;
> - size_t old_secdata_len;
> + struct lsmcontext old_context;
>
> - old_secdata = attrs->ia_secdata;
> - old_secdata_len = attrs->ia_secdata_len;
> -
> - attrs->ia_secdata = *secdata;
> - attrs->ia_secdata_len = *secdata_len;
> -
> - *secdata = old_secdata;
> - *secdata_len = old_secdata_len;
> - return 0;
> + old_context = attrs->ia_context;
> + attrs->ia_context = *cp;
> + *cp = old_context;
> }
>
> ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
> @@ -192,8 +185,8 @@ static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)
> * persistent copy in kernfs_node.
> */
> set_inode_attr(inode, &attrs->ia_iattr);
> - security_inode_notifysecctx(inode, attrs->ia_secdata,
> - attrs->ia_secdata_len);
> + security_inode_notifysecctx(inode, attrs->ia_context.context,
> + attrs->ia_context.len);
> }
>
> if (kernfs_type(kn) == KERNFS_DIR)
> @@ -350,8 +343,6 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
> struct kernfs_node *kn = inode->i_private;
> struct kernfs_iattrs *attrs;
> struct lsmcontext context;
> - void *secdata;
> - u32 secdata_len = 0;
> int error;
>
> attrs = kernfs_iattrs(kn);
> @@ -361,18 +352,17 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
> error = security_inode_setsecurity(inode, suffix, value, size, flags);
> if (error)
> return error;
> - error = security_inode_getsecctx(inode, &secdata, &secdata_len);
> + error = security_inode_getsecctx(inode, &context);
> if (error)
> return error;
>
> mutex_lock(&kernfs_mutex);
> - error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len);
> + kernfs_node_setsecdata(attrs, &context);
> mutex_unlock(&kernfs_mutex);
>
> - if (secdata) {
> - lsmcontext_init(&context, secdata, secdata_len, 0);
> + if (context.context)
> security_release_secctx(&context);
> - }
> +
> return error;
> }
>
> diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
> index 0b7d197a904c..844a028d282f 100644
> --- a/fs/kernfs/kernfs-internal.h
> +++ b/fs/kernfs/kernfs-internal.h
> @@ -21,8 +21,7 @@
>
> struct kernfs_iattrs {
> struct iattr ia_iattr;
> - void *ia_secdata;
> - u32 ia_secdata_len;
> + struct lsmcontext ia_context;
>
> struct simple_xattrs xattrs;
> };
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index bb3db033e144..1209083565dd 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2304,11 +2304,11 @@ nfsd4_encode_layout_types(struct xdr_stream *xdr, u32 layout_types)
> #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
> static inline __be32
> nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
> - void *context, int len)
> + struct lsmcontext *context)
> {
> __be32 *p;
>
> - p = xdr_reserve_space(xdr, len + 4 + 4 + 4);
> + p = xdr_reserve_space(xdr, context->len + 4 + 4 + 4);
> if (!p)
> return nfserr_resource;
>
> @@ -2318,13 +2318,13 @@ nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
> */
> *p++ = cpu_to_be32(0); /* lfs */
> *p++ = cpu_to_be32(0); /* pi */
> - p = xdr_encode_opaque(p, context, len);
> + p = xdr_encode_opaque(p, context->context, context->len);
> return 0;
> }
> #else
> static inline __be32
> nfsd4_encode_security_label(struct xdr_stream *xdr, struct svc_rqst *rqstp,
> - void *context, int len)
> + struct lsmcontext *context)
> { return 0; }
> #endif
>
> @@ -2420,9 +2420,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> __be32 status;
> int err;
> struct nfs4_acl *acl = NULL;
> - struct lsmcontext scaff; /* scaffolding */
> - void *context = NULL;
> - int contextlen;
> + struct lsmcontext context;
> bool contextsupport = false;
> struct nfsd4_compoundres *resp = rqstp->rq_resp;
> u32 minorversion = resp->cstate.minorversion;
> @@ -2479,7 +2477,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) {
> if (exp->ex_flags & NFSEXP_SECURITY_LABEL)
> err = security_inode_getsecctx(d_inode(dentry),
> - &context, &contextlen);
> + &context);
> else
> err = -EOPNOTSUPP;
> contextsupport = (err == 0);
> @@ -2908,8 +2906,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> }
>
> if (bmval2 & FATTR4_WORD2_SECURITY_LABEL) {
> - status = nfsd4_encode_security_label(xdr, rqstp, context,
> - contextlen);
> + status = nfsd4_encode_security_label(xdr, rqstp, &context);
> if (status)
> goto out;
> }
> @@ -2920,10 +2917,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>
> out:
> #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
> - if (context) {
> - lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
> - security_release_secctx(&scaff);
> - }
> + if (context.context)
> + security_release_secctx(&context);
> #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
> kfree(acl);
> if (tempfh) {
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 2a2785a4e752..bfdb06bc5466 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -485,7 +485,7 @@ void security_release_secctx(struct lsmcontext *cp);
> void security_inode_invalidate_secctx(struct inode *inode);
> int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
> int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
> -int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
> +int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp);
> #else /* CONFIG_SECURITY */
>
> static inline int call_lsm_notifier(enum lsm_event event, void *data)
> @@ -1286,7 +1286,8 @@ static inline int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32
> {
> return -EOPNOTSUPP;
> }
> -static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
> +static inline int security_inode_getsecctx(struct inode *inode,
> + struct lsmcontext *cp)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/security/security.c b/security/security.c
> index 842ac65abc08..b2ffcd1f3057 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2139,9 +2139,18 @@ int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
> }
> EXPORT_SYMBOL(security_inode_setsecctx);
>
> -int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
> +int security_inode_getsecctx(struct inode *inode, struct lsmcontext *cp)
> {
> - return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen);
> + int *display = current->security;
> + struct security_hook_list *hp;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.inode_getsecctx, list)
> + if (*display == 0 || *display == hp->slot) {
> + cp->slot = hp->slot;
> + return hp->hook.inode_getsecctx(inode,
> + (void **)&cp->context, &cp->len);
> + }
> + return -EOPNOTSUPP;
> }
> EXPORT_SYMBOL(security_inode_getsecctx);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 18/24] LSM: Use lsmcontext in security_dentry_init_security
From: Kees Cook @ 2019-06-22 22:54 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-19-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:27AM -0700, Casey Schaufler wrote:
> Change the security_dentry_init_security() interface to
> fill an lsmcontext structure instead of a void * data area
> and a length. The lone caller of this interface is NFS4,
> which may make copies of the data using its own mechanisms.
> A rework of the nfs4 code to use the lsmcontext properly
> is a significant project, so the coward's way out is taken,
> and the lsmcontext data from security_dentry_init_security()
> is copied, then released directly.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
> fs/nfs/nfs4proc.c | 26 ++++++++++++++++----------
> include/linux/security.h | 7 +++----
> security/security.c | 20 ++++++++++++++++----
> 3 files changed, 35 insertions(+), 18 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index af1c0db29c39..952f805965bb 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -113,6 +113,7 @@ static inline struct nfs4_label *
> nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
> struct iattr *sattr, struct nfs4_label *label)
> {
> + struct lsmcontext context;
> int err;
>
> if (label == NULL)
> @@ -122,21 +123,26 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
> return NULL;
>
> err = security_dentry_init_security(dentry, sattr->ia_mode,
> - &dentry->d_name, (void **)&label->label, &label->len);
> - if (err == 0)
> - return label;
> + &dentry->d_name, &context);
> +
> + if (err)
> + return NULL;
> +
> + label->label = kmemdup(context.context, context.len, GFP_KERNEL);
> + if (label->label == NULL)
> + label = NULL;
> + else
> + label->len = context.len;
> +
> + security_release_secctx(&context);
> +
> + return label;
>
> - return NULL;
> }
> static inline void
> nfs4_label_release_security(struct nfs4_label *label)
> {
> - struct lsmcontext scaff; /* scaffolding */
> -
> - if (label) {
> - lsmcontext_init(&scaff, label->label, label->len, 0);
> - security_release_secctx(&scaff);
> - }
> + kfree(label->label);
> }
> static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
> {
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 3cbe43db16f5..2a2785a4e752 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -348,8 +348,8 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb,
> int security_add_mnt_opt(const char *option, const char *val,
> int len, void **mnt_opts);
> int security_dentry_init_security(struct dentry *dentry, int mode,
> - const struct qstr *name, void **ctx,
> - u32 *ctxlen);
> + const struct qstr *name,
> + struct lsmcontext *ctx);
> int security_dentry_create_files_as(struct dentry *dentry, int mode,
> struct qstr *name,
> const struct cred *old,
> @@ -720,8 +720,7 @@ static inline void security_inode_free(struct inode *inode)
> static inline int security_dentry_init_security(struct dentry *dentry,
> int mode,
> const struct qstr *name,
> - void **ctx,
> - u32 *ctxlen)
> + struct lsmcontext *ctx)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/security/security.c b/security/security.c
> index f461ab3fb9c4..842ac65abc08 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -453,6 +453,8 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
> * secid in the lsmblob structure.
> */
> if (hooks[i].head == &security_hook_heads.audit_rule_match ||
> + hooks[i].head ==
> + &security_hook_heads.dentry_init_security ||
> hooks[i].head == &security_hook_heads.kernel_act_as ||
> hooks[i].head ==
> &security_hook_heads.socket_getpeersec_dgram ||
> @@ -1040,11 +1042,21 @@ void security_inode_free(struct inode *inode)
> }
>
> int security_dentry_init_security(struct dentry *dentry, int mode,
> - const struct qstr *name, void **ctx,
> - u32 *ctxlen)
> + const struct qstr *name,
> + struct lsmcontext *cp)
> {
> - return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode,
> - name, ctx, ctxlen);
> + int *display = current->security;
> + struct security_hook_list *hp;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.dentry_init_security,
> + list)
> + if (*display == 0 || *display == hp->slot) {
Is this supposed to be == -1 not 0? Isn't 0 an assigned slot?
Otherwise:
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> + cp->slot = hp->slot;
> + return hp->hook.dentry_init_security(dentry, mode,
> + name, (void **)&cp->context, &cp->len);
> + }
> +
> + return -EOPNOTSUPP;
> }
> EXPORT_SYMBOL(security_dentry_init_security);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 17/24] LSM: Use lsmcontext in security_secid_to_secctx
From: Kees Cook @ 2019-06-22 22:52 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-18-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:26AM -0700, Casey Schaufler wrote:
> Replace the (secctx,seclen) pointer pair with a single
> lsmcontext pointer to allow return of the LSM identifier
> along with the context and context length. This allows
> security_release_secctx() to know how to release the
> context. Callers have been modified to use or save the
> returned data from the new structure.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> drivers/android/binder.c | 24 ++++++---------
> include/linux/security.h | 4 +--
> include/net/scm.h | 9 ++----
> kernel/audit.c | 29 +++++++-----------
> kernel/auditsc.c | 31 +++++++------------
> net/ipv4/ip_sockglue.c | 7 ++---
> net/netfilter/nf_conntrack_netlink.c | 14 +++++----
> net/netfilter/nf_conntrack_standalone.c | 7 ++---
> net/netfilter/nfnetlink_queue.c | 5 +++-
> net/netlabel/netlabel_unlabeled.c | 40 ++++++++-----------------
> net/netlabel/netlabel_user.c | 7 ++---
> security/security.c | 9 +++---
> 12 files changed, 71 insertions(+), 115 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 89e574be34cc..5d417a7b9bb3 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -2874,9 +2874,7 @@ static void binder_transaction(struct binder_proc *proc,
> binder_size_t last_fixup_min_off = 0;
> struct binder_context *context = proc->context;
> int t_debug_id = atomic_inc_return(&binder_last_id);
> - char *secctx = NULL;
> - u32 secctx_sz = 0;
> - struct lsmcontext scaff; /* scaffolding */
> + struct lsmcontext lsmctx;
>
> e = binder_transaction_log_add(&binder_transaction_log);
> e->debug_id = t_debug_id;
> @@ -3123,14 +3121,14 @@ static void binder_transaction(struct binder_proc *proc,
> struct lsmblob blob;
>
> security_task_getsecid(proc->tsk, &blob);
> - ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
> + ret = security_secid_to_secctx(&blob, &lsmctx);
> if (ret) {
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> return_error_line = __LINE__;
> goto err_get_secctx_failed;
> }
> - extra_buffers_size += ALIGN(secctx_sz, sizeof(u64));
> + extra_buffers_size += ALIGN(lsmctx.len, sizeof(u64));
> }
>
> trace_binder_transaction(reply, t, target_node);
> @@ -3149,19 +3147,17 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer = NULL;
> goto err_binder_alloc_buf_failed;
> }
> - if (secctx) {
> + if (lsmctx.context) {
> size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) +
> ALIGN(tr->offsets_size, sizeof(void *)) +
> ALIGN(extra_buffers_size, sizeof(void *)) -
> - ALIGN(secctx_sz, sizeof(u64));
> + ALIGN(lsmctx.len, sizeof(u64));
>
> t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
> binder_alloc_copy_to_buffer(&target_proc->alloc,
> t->buffer, buf_offset,
> - secctx, secctx_sz);
> - lsmcontext_init(&scaff, secctx, secctx_sz, 0);
> - security_release_secctx(&scaff);
> - secctx = NULL;
> + lsmctx.context, lsmctx.len);
> + security_release_secctx(&lsmctx);
> }
> t->buffer->debug_id = t->debug_id;
> t->buffer->transaction = t;
> @@ -3481,10 +3477,8 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer->transaction = NULL;
> binder_alloc_free_buf(&target_proc->alloc, t->buffer);
> err_binder_alloc_buf_failed:
> - if (secctx) {
> - lsmcontext_init(&scaff, secctx, secctx_sz, 0);
> - security_release_secctx(&scaff);
> - }
> + if (lsmctx.context)
> + security_release_secctx(&lsmctx);
> err_get_secctx_failed:
> kfree(tcomplete);
> binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
> diff --git a/include/linux/security.h b/include/linux/security.h
> index ddf6d7cb23f1..3cbe43db16f5 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -477,7 +477,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
> size_t size);
> int security_netlink_send(struct sock *sk, struct sk_buff *skb);
> int security_ismaclabel(const char *name);
> -int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
> +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp);
> int security_secctx_to_secid(const char *secdata, u32 seclen,
> struct lsmblob *blob);
> void security_release_secctx(struct lsmcontext *cp);
> @@ -1259,7 +1259,7 @@ static inline int security_ismaclabel(const char *name)
> }
>
> static inline int security_secid_to_secctx(struct lsmblob *blob,
> - char **secdata, u32 *seclen)
> + struct lsmcontext *cp)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/include/net/scm.h b/include/net/scm.h
> index 6c7c3c229e4a..4a6ad8caf423 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -93,17 +93,14 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
> static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
> {
> struct lsmcontext context;
> - char *secdata;
> - u32 seclen;
> int err;
>
> if (test_bit(SOCK_PASSSEC, &sock->flags)) {
> - err = security_secid_to_secctx(&scm->lsmblob, &secdata,
> - &seclen);
> + err = security_secid_to_secctx(&scm->lsmblob, &context);
>
> if (!err) {
> - put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
> - lsmcontext_init(&context, secdata, seclen, 0);/*scaffolding*/
> + put_cmsg(msg, SOL_SOCKET, SCM_SECURITY,
> + context.len, context.context);
> security_release_secctx(&context);
> }
> }
> diff --git a/kernel/audit.c b/kernel/audit.c
> index f844a2a642e6..436c23429319 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1191,9 +1191,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> struct audit_buffer *ab;
> u16 msg_type = nlh->nlmsg_type;
> struct audit_sig_info *sig_data;
> - char *ctx = NULL;
> u32 len;
> - struct lsmcontext scaff; /* scaffolding */
> + struct lsmcontext context;
>
> err = audit_netlink_ok(skb, msg_type);
> if (err)
> @@ -1431,25 +1430,22 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> case AUDIT_SIGNAL_INFO:
> len = 0;
> if (lsmblob_is_set(&audit_sig_lsm)) {
> - err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
> - &len);
> + err = security_secid_to_secctx(&audit_sig_lsm,
> + &context);
> if (err)
> return err;
> }
> sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
> if (!sig_data) {
> - if (lsmblob_is_set(&audit_sig_lsm)) {
> - lsmcontext_init(&scaff, ctx, len, 0);
> - security_release_secctx(&scaff);
> - }
> + if (lsmblob_is_set(&audit_sig_lsm))
> + security_release_secctx(&context);
> return -ENOMEM;
> }
> sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
> sig_data->pid = audit_sig_pid;
> if (lsmblob_is_set(&audit_sig_lsm)) {
> - memcpy(sig_data->ctx, ctx, len);
> - lsmcontext_init(&scaff, ctx, len, 0);
> - security_release_secctx(&scaff);
> + memcpy(sig_data->ctx, context.context, context.len);
> + security_release_secctx(&context);
> }
> audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
> sig_data, sizeof(*sig_data) + len);
> @@ -2074,26 +2070,23 @@ void audit_log_key(struct audit_buffer *ab, char *key)
>
> int audit_log_task_context(struct audit_buffer *ab)
> {
> - char *ctx = NULL;
> - unsigned len;
> int error;
> struct lsmblob blob;
> - struct lsmcontext scaff; /* scaffolding */
> + struct lsmcontext context;
>
> security_task_getsecid(current, &blob);
> if (!lsmblob_is_set(&blob))
> return 0;
>
> - error = security_secid_to_secctx(&blob, &ctx, &len);
> + error = security_secid_to_secctx(&blob, &context);
> if (error) {
> if (error != -EINVAL)
> goto error_path;
> return 0;
> }
>
> - audit_log_format(ab, " subj=%s", ctx);
> - lsmcontext_init(&scaff, ctx, len, 0);
> - security_release_secctx(&scaff);
> + audit_log_format(ab, " subj=%s", context.context);
> + security_release_secctx(&context);
> return 0;
>
> error_path:
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 9fab0e7d90c3..0478680cd0a8 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -943,9 +943,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> struct lsmblob *blob, char *comm)
> {
> struct audit_buffer *ab;
> - struct lsmcontext lsmcxt;
> - char *ctx = NULL;
> - u32 len;
> + struct lsmcontext lsmctx;
> int rc = 0;
>
> ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
> @@ -956,13 +954,12 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> from_kuid(&init_user_ns, auid),
> from_kuid(&init_user_ns, uid), sessionid);
> if (lsmblob_is_set(blob)) {
> - if (security_secid_to_secctx(blob, &ctx, &len)) {
> + if (security_secid_to_secctx(blob, &lsmctx)) {
> audit_log_format(ab, " obj=(none)");
> rc = 1;
> } else {
> - audit_log_format(ab, " obj=%s", ctx);
> - lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
> - security_release_secctx(&lsmcxt);
> + audit_log_format(ab, " obj=%s", lsmctx.context);
> + security_release_secctx(&lsmctx);
> }
> }
> audit_log_format(ab, " ocomm=");
> @@ -1174,7 +1171,6 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
>
> static void show_special(struct audit_context *context, int *call_panic)
> {
> - struct lsmcontext lsmcxt;
> struct audit_buffer *ab;
> int i;
>
> @@ -1198,17 +1194,15 @@ static void show_special(struct audit_context *context, int *call_panic)
> from_kgid(&init_user_ns, context->ipc.gid),
> context->ipc.mode);
> if (osid) {
> - char *ctx = NULL;
> - u32 len;
> + struct lsmcontext lsmcxt;
> struct lsmblob blob;
>
> lsmblob_init(&blob, osid);
> - if (security_secid_to_secctx(&blob, &ctx, &len)) {
> + if (security_secid_to_secctx(&blob, &lsmcxt)) {
> audit_log_format(ab, " osid=%u", osid);
> *call_panic = 1;
> } else {
> - audit_log_format(ab, " obj=%s", ctx);
> - lsmcontext_init(&lsmcxt, ctx, len, 0);
> + audit_log_format(ab, " obj=%s", lsmcxt.context);
> security_release_secctx(&lsmcxt);
> }
> }
> @@ -1353,20 +1347,17 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> MAJOR(n->rdev),
> MINOR(n->rdev));
> if (n->osid != 0) {
> - char *ctx = NULL;
> - u32 len;
> struct lsmblob blob;
> - struct lsmcontext lsmcxt;
> + struct lsmcontext lsmctx;
>
> lsmblob_init(&blob, n->osid);
> - if (security_secid_to_secctx(&blob, &ctx, &len)) {
> + if (security_secid_to_secctx(&blob, &lsmctx)) {
> audit_log_format(ab, " osid=%u", n->osid);
> if (call_panic)
> *call_panic = 2;
> } else {
> - audit_log_format(ab, " obj=%s", ctx);
> - lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
> - security_release_secctx(&lsmcxt);
> + audit_log_format(ab, " obj=%s", lsmctx.context);
> + security_release_secctx(&lsmctx);
> }
> }
>
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index 7834c357b60b..80ae0c5a1301 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -132,20 +132,17 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> {
> struct lsmcontext context;
> struct lsmblob lb;
> - char *secdata;
> - u32 seclen;
> int err;
>
> err = security_socket_getpeersec_dgram(NULL, skb, &lb);
> if (err)
> return;
>
> - err = security_secid_to_secctx(&lb, &secdata, &seclen);
> + err = security_secid_to_secctx(&lb, &context);
> if (err)
> return;
>
> - put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
> - lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
> + put_cmsg(msg, SOL_IP, SCM_SECURITY, context.len, context.context);
> security_release_secctx(&context);
> }
>
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index 6954e6600583..403307ff0fff 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -328,13 +328,12 @@ static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
> static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
> {
> struct nlattr *nest_secctx;
> - int len, ret;
> - char *secctx;
> + int ret;
> struct lsmblob blob;
> struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> - ret = security_secid_to_secctx(&blob, &secctx, &len);
> + ret = security_secid_to_secctx(&blob, &context);
> if (ret)
> return 0;
>
> @@ -343,13 +342,12 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
> if (!nest_secctx)
> goto nla_put_failure;
>
> - if (nla_put_string(skb, CTA_SECCTX_NAME, secctx))
> + if (nla_put_string(skb, CTA_SECCTX_NAME, context.context))
> goto nla_put_failure;
> nla_nest_end(skb, nest_secctx);
>
> ret = 0;
> nla_put_failure:
> - lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
> security_release_secctx(&context);
> return ret;
> }
> @@ -620,12 +618,16 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
> #ifdef CONFIG_NF_CONNTRACK_SECMARK
> int len, ret;
> struct lsmblob blob;
> + struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> - ret = security_secid_to_secctx(&blob, NULL, &len);
> + ret = security_secid_to_secctx(&blob, &context);
> if (ret)
> return 0;
>
> + len = context.len;
> + security_release_secctx(&context);
> +
> return nla_total_size(0) /* CTA_SECCTX */
> + nla_total_size(sizeof(char) * len); /* CTA_SECCTX_NAME */
> #else
> diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
> index 79158ad0486e..fcb51ab2bb8b 100644
> --- a/net/netfilter/nf_conntrack_standalone.c
> +++ b/net/netfilter/nf_conntrack_standalone.c
> @@ -173,19 +173,16 @@ static void ct_seq_stop(struct seq_file *s, void *v)
> static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> {
> int ret;
> - u32 len;
> - char *secctx;
> struct lsmblob blob;
> struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> - ret = security_secid_to_secctx(&blob, &secctx, &len);
> + ret = security_secid_to_secctx(&blob, &context);
> if (ret)
> return;
>
> - seq_printf(s, "secctx=%s ", secctx);
> + seq_printf(s, "secctx=%s ", context.context);
>
> - lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
> security_release_secctx(&context);
> }
> #else
> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index fe8403ef4e89..6da00c7add5b 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -310,6 +310,7 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
> u32 seclen = 0;
> #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
> struct lsmblob blob;
> + struct lsmcontext context;
>
> if (!skb || !sk_fullsock(skb->sk))
> return 0;
> @@ -318,10 +319,12 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
>
> if (skb->secmark) {
> lsmblob_init(&blob, skb->secmark);
> - security_secid_to_secctx(&blob, secdata, &seclen);
> + security_secid_to_secctx(&blob, &context);
> + *secdata = context.context;
> }
>
> read_unlock_bh(&skb->sk->sk_callback_lock);
> + seclen = context.len;
> #endif
> return seclen;
> }
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index 15b1945853be..4716e0011ba5 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -388,8 +388,6 @@ int netlbl_unlhsh_add(struct net *net,
> struct netlbl_unlhsh_iface *iface;
> struct audit_buffer *audit_buf = NULL;
> struct lsmcontext context;
> - char *secctx = NULL;
> - u32 secctx_len;
> struct lsmblob blob;
>
> if (addr_len != sizeof(struct in_addr) &&
> @@ -454,12 +452,9 @@ int netlbl_unlhsh_add(struct net *net,
> rcu_read_unlock();
> if (audit_buf != NULL) {
> lsmblob_init(&blob, secid);
> - if (security_secid_to_secctx(&blob,
> - &secctx,
> - &secctx_len) == 0) {
> - audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - /* scaffolding */
> - lsmcontext_init(&context, secctx, secctx_len, 0);
> + if (security_secid_to_secctx(&blob, &context) == 0) {
> + audit_log_format(audit_buf, " sec_obj=%s",
> + context.context);
> security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
> @@ -492,8 +487,6 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> struct lsmcontext context;
> - char *secctx;
> - u32 secctx_len;
> struct lsmblob blob;
>
> spin_lock(&netlbl_unlhsh_lock);
> @@ -517,11 +510,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> if (entry != NULL)
> lsmblob_init(&blob, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(&blob,
> - &secctx, &secctx_len) == 0) {
> - audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - /* scaffolding */
> - lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_secid_to_secctx(&blob, &context) == 0) {
> + audit_log_format(audit_buf, " sec_obj=%s",
> + context.context);
> security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
> @@ -560,8 +551,6 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> struct lsmcontext context;
> - char *secctx;
> - u32 secctx_len;
> struct lsmblob blob;
>
> spin_lock(&netlbl_unlhsh_lock);
> @@ -584,10 +573,9 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> if (entry != NULL)
> lsmblob_init(&blob, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(&blob,
> - &secctx, &secctx_len) == 0) {
> - audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_secid_to_secctx(&blob, &context) == 0) {
> + audit_log_format(audit_buf, " sec_obj=%s",
> + context.context);
> security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
> @@ -1105,8 +1093,6 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> struct lsmcontext context;
> void *data;
> u32 secid;
> - char *secctx;
> - u32 secctx_len;
> struct lsmblob blob;
>
> data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
> @@ -1163,15 +1149,13 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> }
>
> lsmblob_init(&blob, secid);
> - ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
> + ret_val = security_secid_to_secctx(&blob, &context);
> if (ret_val != 0)
> goto list_cb_failure;
> ret_val = nla_put(cb_arg->skb,
> NLBL_UNLABEL_A_SECCTX,
> - secctx_len,
> - secctx);
> - /* scaffolding */
> - lsmcontext_init(&context, secctx, secctx_len, 0);
> + context.len,
> + context.context);
> security_release_secctx(&context);
> if (ret_val != 0)
> goto list_cb_failure;
> diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
> index 94aea4985b74..2d1307f65250 100644
> --- a/net/netlabel/netlabel_user.c
> +++ b/net/netlabel/netlabel_user.c
> @@ -99,8 +99,6 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> {
> struct audit_buffer *audit_buf;
> struct lsmcontext context;
> - char *secctx;
> - u32 secctx_len;
> struct lsmblob blob;
>
> if (audit_enabled == AUDIT_OFF)
> @@ -116,9 +114,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
>
> lsmblob_init(&blob, audit_info->secid);
> if (audit_info->secid != 0 &&
> - security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
> - audit_log_format(audit_buf, " subj=%s", secctx);
> - lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
> + security_secid_to_secctx(&blob, &context) == 0) {
> + audit_log_format(audit_buf, " subj=%s", context.context);
> security_release_secctx(&context);
> }
>
> diff --git a/security/security.c b/security/security.c
> index d5f173e85393..f461ab3fb9c4 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -459,7 +459,6 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
> hooks[i].head == &security_hook_heads.getprocattr ||
> hooks[i].head == &security_hook_heads.setprocattr ||
> hooks[i].head == &security_hook_heads.secctx_to_secid ||
> - hooks[i].head == &security_hook_heads.secid_to_secctx ||
> hooks[i].head == &security_hook_heads.release_secctx ||
> hooks[i].head == &security_hook_heads.ipc_getsecid ||
> hooks[i].head == &security_hook_heads.task_getsecid ||
> @@ -2064,15 +2063,17 @@ int security_ismaclabel(const char *name)
> }
> EXPORT_SYMBOL(security_ismaclabel);
>
> -int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
> +int security_secid_to_secctx(struct lsmblob *blob, struct lsmcontext *cp)
> {
> struct security_hook_list *hp;
> int *display = current->security;
>
> hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list)
> - if (*display == LSMBLOB_INVALID || *display == hp->slot)
> + if (*display == LSMBLOB_INVALID || *display == hp->slot) {
> + cp->slot = hp->slot;
> return hp->hook.secid_to_secctx(blob->secid[hp->slot],
> - secdata, seclen);
> + &cp->context, &cp->len);
> + }
> return 0;
> }
> EXPORT_SYMBOL(security_secid_to_secctx);
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 16/24] LSM: Ensure the correct LSM context releaser
From: Kees Cook @ 2019-06-22 22:52 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-17-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:25AM -0700, Casey Schaufler wrote:
> Add a new lsmcontext data structure to hold all the information
> about a "security context", including the string, its size and
> which LSM allocated the string. The allocation information is
> necessary because LSMs have different policies regarding the
> lifecycle of these strings. SELinux allocates and destroys
> them on each use, whereas Smack provides a pointer to an entry
> in a list that never goes away.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> drivers/android/binder.c | 10 +++++--
> fs/kernfs/dir.c | 9 ++++--
> fs/kernfs/inode.c | 7 +++--
> fs/nfs/nfs4proc.c | 8 +++--
> fs/nfsd/nfs4xdr.c | 7 +++--
> include/linux/security.h | 39 +++++++++++++++++++++++--
> include/net/scm.h | 4 ++-
> kernel/audit.c | 14 ++++++---
> kernel/auditsc.c | 12 ++++++--
> net/ipv4/ip_sockglue.c | 4 ++-
> net/netfilter/nf_conntrack_netlink.c | 4 ++-
> net/netfilter/nf_conntrack_standalone.c | 4 ++-
> net/netfilter/nfnetlink_queue.c | 13 ++++++---
> net/netlabel/netlabel_unlabeled.c | 19 +++++++++---
> net/netlabel/netlabel_user.c | 4 ++-
> security/security.c | 12 +++++---
> security/smack/smack_lsm.c | 14 ++++++---
> 17 files changed, 142 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 144ac4f1c24f..89e574be34cc 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -2876,6 +2876,7 @@ static void binder_transaction(struct binder_proc *proc,
> int t_debug_id = atomic_inc_return(&binder_last_id);
> char *secctx = NULL;
> u32 secctx_sz = 0;
> + struct lsmcontext scaff; /* scaffolding */
>
> e = binder_transaction_log_add(&binder_transaction_log);
> e->debug_id = t_debug_id;
> @@ -3158,7 +3159,8 @@ static void binder_transaction(struct binder_proc *proc,
> binder_alloc_copy_to_buffer(&target_proc->alloc,
> t->buffer, buf_offset,
> secctx, secctx_sz);
> - security_release_secctx(secctx, secctx_sz);
> + lsmcontext_init(&scaff, secctx, secctx_sz, 0);
> + security_release_secctx(&scaff);
> secctx = NULL;
> }
> t->buffer->debug_id = t->debug_id;
> @@ -3479,8 +3481,10 @@ static void binder_transaction(struct binder_proc *proc,
> t->buffer->transaction = NULL;
> binder_alloc_free_buf(&target_proc->alloc, t->buffer);
> err_binder_alloc_buf_failed:
> - if (secctx)
> - security_release_secctx(secctx, secctx_sz);
> + if (secctx) {
> + lsmcontext_init(&scaff, secctx, secctx_sz, 0);
> + security_release_secctx(&scaff);
> + }
> err_get_secctx_failed:
> kfree(tcomplete);
> binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
> diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
> index b84d635567d3..92afad387237 100644
> --- a/fs/kernfs/dir.c
> +++ b/fs/kernfs/dir.c
> @@ -532,9 +532,12 @@ void kernfs_put(struct kernfs_node *kn)
> kfree_const(kn->name);
>
> if (kn->iattr) {
> - if (kn->iattr->ia_secdata)
> - security_release_secctx(kn->iattr->ia_secdata,
> - kn->iattr->ia_secdata_len);
> + struct lsmcontext scaff; /* scaffolding */
> + if (kn->iattr->ia_secdata) {
> + lsmcontext_init(&scaff, kn->iattr->ia_secdata,
> + kn->iattr->ia_secdata_len, 0);
> + security_release_secctx(&scaff);
> + }
> simple_xattrs_free(&kn->iattr->xattrs);
> kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
> }
> diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
> index 0c1fd945ce42..02cde9dac5ee 100644
> --- a/fs/kernfs/inode.c
> +++ b/fs/kernfs/inode.c
> @@ -349,6 +349,7 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
> {
> struct kernfs_node *kn = inode->i_private;
> struct kernfs_iattrs *attrs;
> + struct lsmcontext context;
> void *secdata;
> u32 secdata_len = 0;
> int error;
> @@ -368,8 +369,10 @@ static int kernfs_security_xattr_set(const struct xattr_handler *handler,
> error = kernfs_node_setsecdata(attrs, &secdata, &secdata_len);
> mutex_unlock(&kernfs_mutex);
>
> - if (secdata)
> - security_release_secctx(secdata, secdata_len);
> + if (secdata) {
> + lsmcontext_init(&context, secdata, secdata_len, 0);
> + security_release_secctx(&context);
> + }
> return error;
> }
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 4dbb0ee23432..af1c0db29c39 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -131,8 +131,12 @@ nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
> static inline void
> nfs4_label_release_security(struct nfs4_label *label)
> {
> - if (label)
> - security_release_secctx(label->label, label->len);
> + struct lsmcontext scaff; /* scaffolding */
> +
> + if (label) {
> + lsmcontext_init(&scaff, label->label, label->len, 0);
> + security_release_secctx(&scaff);
> + }
> }
> static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
> {
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index 3de42a729093..bb3db033e144 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2420,6 +2420,7 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
> __be32 status;
> int err;
> struct nfs4_acl *acl = NULL;
> + struct lsmcontext scaff; /* scaffolding */
> void *context = NULL;
> int contextlen;
> bool contextsupport = false;
> @@ -2919,8 +2920,10 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
>
> out:
> #ifdef CONFIG_NFSD_V4_SECURITY_LABEL
> - if (context)
> - security_release_secctx(context, contextlen);
> + if (context) {
> + lsmcontext_init(&scaff, context, contextlen, 0); /*scaffolding*/
> + security_release_secctx(&scaff);
> + }
> #endif /* CONFIG_NFSD_V4_SECURITY_LABEL */
> kfree(acl);
> if (tempfh) {
> diff --git a/include/linux/security.h b/include/linux/security.h
> index c712fc72b7bd..ddf6d7cb23f1 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -76,6 +76,41 @@ enum lsm_event {
> LSM_POLICY_CHANGE,
> };
>
> +/*
> + * A "security context" is the text representation of
> + * the information used by LSMs.
> + * This structure contains the string, its length, and which LSM
> + * it is useful for.
> + */
> +struct lsmcontext {
> + char *context; /* Provided by the module */
> + u32 len;
> + int slot; /* Identifies the module */
> +};
> +
> +/**
> + * lsmcontext_init - initialize an lsmcontext structure.
> + * @cp: Pointer to the context to initialize
> + * @context: Initial context, or NULL
> + * @size: Size of context, or 0
> + * @slot: Which LSM provided the context
> + *
> + * Fill in the lsmcontext from the provided information.
> + * This is a scaffolding function that will be removed when
> + * lsmcontext integration is complete.
> + */
> +static inline void lsmcontext_init(struct lsmcontext *cp, char *context,
> + u32 size, int slot)
> +{
> + cp->slot = slot;
> + cp->context = context;
> +
> + if (context == NULL || size == 0)
> + cp->len = 0;
> + else
> + cp->len = strlen(context);
> +}
> +
> /*
> * Data exported by the security modules
> */
> @@ -445,7 +480,7 @@ int security_ismaclabel(const char *name);
> int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
> int security_secctx_to_secid(const char *secdata, u32 seclen,
> struct lsmblob *blob);
> -void security_release_secctx(char *secdata, u32 seclen);
> +void security_release_secctx(struct lsmcontext *cp);
>
> void security_inode_invalidate_secctx(struct inode *inode);
> int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
> @@ -1236,7 +1271,7 @@ static inline int security_secctx_to_secid(const char *secdata,
> return -EOPNOTSUPP;
> }
>
> -static inline void security_release_secctx(char *secdata, u32 seclen)
> +static inline void security_release_secctx(struct lsmcontext *cp)
> {
> }
>
> diff --git a/include/net/scm.h b/include/net/scm.h
> index 31ae605fcc0a..6c7c3c229e4a 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -92,6 +92,7 @@ static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
> #ifdef CONFIG_SECURITY_NETWORK
> static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm)
> {
> + struct lsmcontext context;
> char *secdata;
> u32 seclen;
> int err;
> @@ -102,7 +103,8 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
>
> if (!err) {
> put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
> - security_release_secctx(secdata, seclen);
> + lsmcontext_init(&context, secdata, seclen, 0);/*scaffolding*/
> + security_release_secctx(&context);
> }
> }
> }
> diff --git a/kernel/audit.c b/kernel/audit.c
> index 1b51e907f131..f844a2a642e6 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1193,6 +1193,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> struct audit_sig_info *sig_data;
> char *ctx = NULL;
> u32 len;
> + struct lsmcontext scaff; /* scaffolding */
>
> err = audit_netlink_ok(skb, msg_type);
> if (err)
> @@ -1437,15 +1438,18 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> }
> sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
> if (!sig_data) {
> - if (lsmblob_is_set(&audit_sig_lsm))
> - security_release_secctx(ctx, len);
> + if (lsmblob_is_set(&audit_sig_lsm)) {
> + lsmcontext_init(&scaff, ctx, len, 0);
> + security_release_secctx(&scaff);
> + }
> return -ENOMEM;
> }
> sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
> sig_data->pid = audit_sig_pid;
> if (lsmblob_is_set(&audit_sig_lsm)) {
> memcpy(sig_data->ctx, ctx, len);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&scaff, ctx, len, 0);
> + security_release_secctx(&scaff);
> }
> audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
> sig_data, sizeof(*sig_data) + len);
> @@ -2074,6 +2078,7 @@ int audit_log_task_context(struct audit_buffer *ab)
> unsigned len;
> int error;
> struct lsmblob blob;
> + struct lsmcontext scaff; /* scaffolding */
>
> security_task_getsecid(current, &blob);
> if (!lsmblob_is_set(&blob))
> @@ -2087,7 +2092,8 @@ int audit_log_task_context(struct audit_buffer *ab)
> }
>
> audit_log_format(ab, " subj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&scaff, ctx, len, 0);
> + security_release_secctx(&scaff);
> return 0;
>
> error_path:
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index c7aa39bda5cc..9fab0e7d90c3 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -943,6 +943,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> struct lsmblob *blob, char *comm)
> {
> struct audit_buffer *ab;
> + struct lsmcontext lsmcxt;
> char *ctx = NULL;
> u32 len;
> int rc = 0;
> @@ -960,7 +961,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> rc = 1;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&lsmcxt, ctx, len, 0); /*scaffolding*/
> + security_release_secctx(&lsmcxt);
> }
> }
> audit_log_format(ab, " ocomm=");
> @@ -1172,6 +1174,7 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
>
> static void show_special(struct audit_context *context, int *call_panic)
> {
> + struct lsmcontext lsmcxt;
> struct audit_buffer *ab;
> int i;
>
> @@ -1205,7 +1208,8 @@ static void show_special(struct audit_context *context, int *call_panic)
> *call_panic = 1;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&lsmcxt, ctx, len, 0);
> + security_release_secctx(&lsmcxt);
> }
> }
> if (context->ipc.has_perm) {
> @@ -1352,6 +1356,7 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> char *ctx = NULL;
> u32 len;
> struct lsmblob blob;
> + struct lsmcontext lsmcxt;
>
> lsmblob_init(&blob, n->osid);
> if (security_secid_to_secctx(&blob, &ctx, &len)) {
> @@ -1360,7 +1365,8 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> *call_panic = 2;
> } else {
> audit_log_format(ab, " obj=%s", ctx);
> - security_release_secctx(ctx, len);
> + lsmcontext_init(&lsmcxt, ctx, len, 0); /* scaffolding */
> + security_release_secctx(&lsmcxt);
> }
> }
>
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index e05f4ef68bd8..7834c357b60b 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -130,6 +130,7 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
>
> static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> {
> + struct lsmcontext context;
> struct lsmblob lb;
> char *secdata;
> u32 seclen;
> @@ -144,7 +145,8 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> return;
>
> put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);
> - security_release_secctx(secdata, seclen);
> + lsmcontext_init(&context, secdata, seclen, 0); /* scaffolding */
> + security_release_secctx(&context);
> }
>
> static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index ca0968f13240..6954e6600583 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -331,6 +331,7 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
> int len, ret;
> char *secctx;
> struct lsmblob blob;
> + struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> ret = security_secid_to_secctx(&blob, &secctx, &len);
> @@ -348,7 +349,8 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
>
> ret = 0;
> nla_put_failure:
> - security_release_secctx(secctx, len);
> + lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
> + security_release_secctx(&context);
> return ret;
> }
> #else
> diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
> index c793103f3cd7..79158ad0486e 100644
> --- a/net/netfilter/nf_conntrack_standalone.c
> +++ b/net/netfilter/nf_conntrack_standalone.c
> @@ -176,6 +176,7 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> u32 len;
> char *secctx;
> struct lsmblob blob;
> + struct lsmcontext context;
>
> lsmblob_init(&blob, ct->secmark);
> ret = security_secid_to_secctx(&blob, &secctx, &len);
> @@ -184,7 +185,8 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
>
> seq_printf(s, "secctx=%s ", secctx);
>
> - security_release_secctx(secctx, len);
> + lsmcontext_init(&context, secctx, len, 0); /* scaffolding */
> + security_release_secctx(&context);
> }
> #else
> static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index 59211bff90ab..fe8403ef4e89 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -399,6 +399,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
> enum ip_conntrack_info uninitialized_var(ctinfo);
> struct nfnl_ct_hook *nfnl_ct;
> bool csum_verify;
> + struct lsmcontext scaff; /* scaffolding */
> char *secdata = NULL;
> u32 seclen = 0;
>
> @@ -629,8 +630,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
> }
>
> nlh->nlmsg_len = skb->len;
> - if (seclen)
> - security_release_secctx(secdata, seclen);
> + if (seclen) {
> + lsmcontext_init(&scaff, secdata, seclen, 0);
> + security_release_secctx(&scaff);
> + }
> return skb;
>
> nla_put_failure:
> @@ -638,8 +641,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
> kfree_skb(skb);
> net_err_ratelimited("nf_queue: error creating packet message\n");
> nlmsg_failure:
> - if (seclen)
> - security_release_secctx(secdata, seclen);
> + if (seclen) {
> + lsmcontext_init(&scaff, secdata, seclen, 0);
> + security_release_secctx(&scaff);
> + }
> return NULL;
> }
>
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index 2294aa9471e6..15b1945853be 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -387,6 +387,7 @@ int netlbl_unlhsh_add(struct net *net,
> struct net_device *dev;
> struct netlbl_unlhsh_iface *iface;
> struct audit_buffer *audit_buf = NULL;
> + struct lsmcontext context;
> char *secctx = NULL;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -457,7 +458,9 @@ int netlbl_unlhsh_add(struct net *net,
> &secctx,
> &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + /* scaffolding */
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", ret_val == 0 ? 1 : 0);
> audit_log_end(audit_buf);
> @@ -488,6 +491,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> struct netlbl_unlhsh_addr4 *entry;
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> + struct lsmcontext context;
> char *secctx;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -516,7 +520,9 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> security_secid_to_secctx(&blob,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + /* scaffolding */
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
> audit_log_end(audit_buf);
> @@ -553,6 +559,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> struct netlbl_unlhsh_addr6 *entry;
> struct audit_buffer *audit_buf;
> struct net_device *dev;
> + struct lsmcontext context;
> char *secctx;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -580,7 +587,8 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> security_secid_to_secctx(&blob,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> }
> audit_log_format(audit_buf, " res=%u", entry != NULL ? 1 : 0);
> audit_log_end(audit_buf);
> @@ -1094,6 +1102,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> int ret_val = -ENOMEM;
> struct netlbl_unlhsh_walk_arg *cb_arg = arg;
> struct net_device *dev;
> + struct lsmcontext context;
> void *data;
> u32 secid;
> char *secctx;
> @@ -1161,7 +1170,9 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> NLBL_UNLABEL_A_SECCTX,
> secctx_len,
> secctx);
> - security_release_secctx(secctx, secctx_len);
> + /* scaffolding */
> + lsmcontext_init(&context, secctx, secctx_len, 0);
> + security_release_secctx(&context);
> if (ret_val != 0)
> goto list_cb_failure;
>
> diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
> index 2ccc6567e2a2..94aea4985b74 100644
> --- a/net/netlabel/netlabel_user.c
> +++ b/net/netlabel/netlabel_user.c
> @@ -98,6 +98,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> struct netlbl_audit *audit_info)
> {
> struct audit_buffer *audit_buf;
> + struct lsmcontext context;
> char *secctx;
> u32 secctx_len;
> struct lsmblob blob;
> @@ -117,7 +118,8 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> if (audit_info->secid != 0 &&
> security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " subj=%s", secctx);
> - security_release_secctx(secctx, secctx_len);
> + lsmcontext_init(&context, secctx, secctx_len, 0);/*scaffolding*/
> + security_release_secctx(&context);
> }
>
> return audit_buf;
> diff --git a/security/security.c b/security/security.c
> index 92c5aa427b53..d5f173e85393 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -460,6 +460,7 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
> hooks[i].head == &security_hook_heads.setprocattr ||
> hooks[i].head == &security_hook_heads.secctx_to_secid ||
> hooks[i].head == &security_hook_heads.secid_to_secctx ||
> + hooks[i].head == &security_hook_heads.release_secctx ||
> hooks[i].head == &security_hook_heads.ipc_getsecid ||
> hooks[i].head == &security_hook_heads.task_getsecid ||
> hooks[i].head == &security_hook_heads.inode_getsecid ||
> @@ -2091,16 +2092,19 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
> }
> EXPORT_SYMBOL(security_secctx_to_secid);
>
> -void security_release_secctx(char *secdata, u32 seclen)
> +void security_release_secctx(struct lsmcontext *cp)
> {
> struct security_hook_list *hp;
> - int *display = current->security;
>
> hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
> - if (*display == LSMBLOB_INVALID || *display == hp->slot) {
> - hp->hook.release_secctx(secdata, seclen);
> + if (cp->slot == hp->slot) {
> + hp->hook.release_secctx(cp->context, cp->len);
> + memset(cp, 0, sizeof(*cp));
> return;
> }
> +
> + pr_warn("%s context \"%s\" from slot %d not released\n", __func__,
> + cp->context, cp->slot);
> }
> EXPORT_SYMBOL(security_release_secctx);
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index e9560b078efe..3834b751d1e9 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -4439,11 +4439,16 @@ static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
> return 0;
> }
>
> -/*
> - * There used to be a smack_release_secctx hook
> - * that did nothing back when hooks were in a vector.
> - * Now that there's a list such a hook adds cost.
> +/**
> + * smack_release_secctx - do everything necessary to free a context
> + * @secdata: Unused
> + * @seclen: Unused
> + *
> + * Do nothing but hold a slot in the hooks list.
> */
> +static void smack_release_secctx(char *secdata, u32 seclen)
> +{
> +}
>
> static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
> {
> @@ -4683,6 +4688,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
> LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
> LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
> LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
> + LSM_HOOK_INIT(release_secctx, smack_release_secctx),
> LSM_HOOK_INIT(inode_notifysecctx, smack_inode_notifysecctx),
> LSM_HOOK_INIT(inode_setsecctx, smack_inode_setsecctx),
> LSM_HOOK_INIT(inode_getsecctx, smack_inode_getsecctx),
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 15/24] LSM: Specify which LSM to display
From: Kees Cook @ 2019-06-22 22:51 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-16-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:24AM -0700, Casey Schaufler wrote:
> Create a new entry "display" in /proc/.../attr for controlling
> which LSM security information is displayed for a process.
> The name of an active LSM that supplies hooks for human readable
> data may be written to "display" to set the value. The name of
> the LSM currently in use can be read from "display".
> At this point there can only be one LSM capable of display
> active.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> fs/proc/base.c | 1 +
> security/security.c | 110 +++++++++++++++++++++++++++++++++++---------
> 2 files changed, 90 insertions(+), 21 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index ddef482f1334..7bf70e041315 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2618,6 +2618,7 @@ static const struct pid_entry attr_dir_stuff[] = {
> ATTR(NULL, "fscreate", 0666),
> ATTR(NULL, "keycreate", 0666),
> ATTR(NULL, "sockcreate", 0666),
> + ATTR(NULL, "display", 0666),
> #ifdef CONFIG_SECURITY_SMACK
> DIR("smack", 0555,
> proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
> diff --git a/security/security.c b/security/security.c
> index aa8e1c73a062..92c5aa427b53 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -46,7 +46,9 @@ static struct kmem_cache *lsm_file_cache;
> static struct kmem_cache *lsm_inode_cache;
>
> char *lsm_names;
> -static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init;
> +static struct lsm_blob_sizes blob_sizes __lsm_ro_after_init = {
> + .lbs_task = sizeof(int), /* slot number for the "display" LSM */
> +};
>
> /* Boot-time LSM user choice */
> static __initdata const char *chosen_lsm_order;
> @@ -583,6 +585,8 @@ int lsm_inode_alloc(struct inode *inode)
> */
> static int lsm_task_alloc(struct task_struct *task)
> {
> + int *display;
> +
> if (blob_sizes.lbs_task == 0) {
> task->security = NULL;
> return 0;
> @@ -591,6 +595,15 @@ static int lsm_task_alloc(struct task_struct *task)
> task->security = kzalloc(blob_sizes.lbs_task, GFP_KERNEL);
> if (task->security == NULL)
> return -ENOMEM;
> +
> + /*
> + * The start of the task blob contains the "display" LSM slot number.
> + * Start with it set to the invalid slot number, indicating that the
> + * default first registered LSM be displayed.
> + */
> + display = task->security;
> + *display = LSMBLOB_INVALID;
> +
> return 0;
> }
>
> @@ -1579,14 +1592,24 @@ int security_file_open(struct file *file)
>
> int security_task_alloc(struct task_struct *task, unsigned long clone_flags)
> {
> + int *odisplay = current->security;
> + int *ndisplay;
> int rc = lsm_task_alloc(task);
>
> - if (rc)
> + if (unlikely(rc))
> return rc;
> +
> rc = call_int_hook(task_alloc, 0, task, clone_flags);
> - if (unlikely(rc))
> + if (unlikely(rc)) {
> security_task_free(task);
> - return rc;
> + return rc;
> + }
> +
> + ndisplay = task->security;
> + if (ndisplay && odisplay)
> + *ndisplay = *odisplay;
> +
> + return 0;
> }
>
> void security_task_free(struct task_struct *task)
> @@ -1972,10 +1995,28 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
> char **value)
> {
> struct security_hook_list *hp;
> + int *display = current->security;
> +
> + if (!strcmp(name, "display")) {
> + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx,
> + list) {
> + if (*display == LSMBLOB_INVALID ||
> + hp->slot == *display) {
> + *value = kstrdup(hp->lsm, GFP_KERNEL);
> + if (*value)
> + return strlen(hp->lsm);
> + return -ENOMEM;
> + }
> + }
> + return -EINVAL;
> + }
>
> hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
> if (lsm != NULL && strcmp(lsm, hp->lsm))
> continue;
> + if (lsm == NULL && *display != LSMBLOB_INVALID &&
> + *display != hp->slot)
> + continue;
> return hp->hook.getprocattr(p, name, value);
> }
> return -EINVAL;
> @@ -1985,10 +2026,27 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
> size_t size)
> {
> struct security_hook_list *hp;
> + int *display = current->security;
> + int len;
> +
> + if (!strcmp(name, "display")) {
> + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx,
> + list) {
> + len = strlen(hp->lsm);
> + if (size >= len && !strncmp(value, hp->lsm, len)) {
> + *display = hp->slot;
> + return size;
> + }
> + }
> + return -EINVAL;
> + }
>
> hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
> if (lsm != NULL && strcmp(lsm, hp->lsm))
> continue;
> + if (lsm == NULL && *display != LSMBLOB_INVALID &&
> + *display != hp->slot)
> + continue;
> return hp->hook.setprocattr(name, value, size);
> }
> return -EINVAL;
> @@ -2008,14 +2066,12 @@ EXPORT_SYMBOL(security_ismaclabel);
> int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
> {
> struct security_hook_list *hp;
> - int rc;
> + int *display = current->security;
>
> - hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
> - rc = hp->hook.secid_to_secctx(blob->secid[hp->slot],
> - secdata, seclen);
> - if (rc != 0)
> - return rc;
> - }
> + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list)
> + if (*display == LSMBLOB_INVALID || *display == hp->slot)
> + return hp->hook.secid_to_secctx(blob->secid[hp->slot],
> + secdata, seclen);
> return 0;
> }
> EXPORT_SYMBOL(security_secid_to_secctx);
> @@ -2024,22 +2080,27 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
> struct lsmblob *blob)
> {
> struct security_hook_list *hp;
> - int rc;
> + int *display = current->security;
>
> lsmblob_init(blob, 0);
> - hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
> - rc = hp->hook.secctx_to_secid(secdata, seclen,
> - &blob->secid[hp->slot]);
> - if (rc != 0)
> - return rc;
> - }
> + hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list)
> + if (*display == LSMBLOB_INVALID || *display == hp->slot)
> + return hp->hook.secctx_to_secid(secdata, seclen,
> + &blob->secid[hp->slot]);
> return 0;
> }
> EXPORT_SYMBOL(security_secctx_to_secid);
>
> void security_release_secctx(char *secdata, u32 seclen)
> {
> - call_void_hook(release_secctx, secdata, seclen);
> + struct security_hook_list *hp;
> + int *display = current->security;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.release_secctx, list)
> + if (*display == LSMBLOB_INVALID || *display == hp->slot) {
> + hp->hook.release_secctx(secdata, seclen);
> + return;
> + }
> }
> EXPORT_SYMBOL(security_release_secctx);
>
> @@ -2164,8 +2225,15 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
> int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
> int __user *optlen, unsigned len)
> {
> - return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
> - optval, optlen, len);
> + int *display = current->security;
> + struct security_hook_list *hp;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
> + list)
> + if (*display == LSMBLOB_INVALID || *display == hp->slot)
> + return hp->hook.socket_getpeersec_stream(sock, optval,
> + optlen, len);
> + return -ENOPROTOOPT;
> }
>
> int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 14/24] IMA: Change internal interfaces to use lsmblobs
From: Kees Cook @ 2019-06-22 22:51 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-15-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:23AM -0700, Casey Schaufler wrote:
> The IMA interfaces ima_get_action() and ima_match_policy()
> call LSM functions that use lsmblobs. Change the IMA functions
> to pass the lsmblob to be compatible with the LSM functions.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
> security/integrity/ima/ima.h | 10 ++++++----
> security/integrity/ima/ima_api.c | 9 +++++----
> security/integrity/ima/ima_appraise.c | 4 +---
> security/integrity/ima/ima_main.c | 27 +++++++++++----------------
> security/integrity/ima/ima_policy.c | 12 ++++++------
> 5 files changed, 29 insertions(+), 33 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 5a337239d9e4..73b3b15dec5c 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -192,8 +192,9 @@ enum ima_hooks {
> };
>
> /* LIM API function definitions */
> -int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
> - int mask, enum ima_hooks func, int *pcr);
> +int ima_get_action(struct inode *inode, const struct cred *cred,
> + struct lsmblob *blob, int mask, enum ima_hooks func,
> + int *pcr);
> int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
> int ima_collect_measurement(struct integrity_iint_cache *iint,
> struct file *file, void *buf, loff_t size,
> @@ -213,8 +214,9 @@ void ima_free_template_entry(struct ima_template_entry *entry);
> const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);
>
> /* IMA policy related functions */
> -int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
> - enum ima_hooks func, int mask, int flags, int *pcr);
> +int ima_match_policy(struct inode *inode, const struct cred *cred,
> + struct lsmblob *blob, enum ima_hooks func, int mask,
> + int flags, int *pcr);
> void ima_init_policy(void);
> void ima_update_policy(void);
> void ima_update_policy_flag(void);
> diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
> index c7505fb122d4..03a2392852de 100644
> --- a/security/integrity/ima/ima_api.c
> +++ b/security/integrity/ima/ima_api.c
> @@ -159,7 +159,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
> * ima_get_action - appraise & measure decision based on policy.
> * @inode: pointer to inode to measure
> * @cred: pointer to credentials structure to validate
> - * @secid: secid of the task being validated
> + * @blob: LAM data of the task being validated
typo: LAM -> LSM
with that fixed:
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC,
> * MAY_APPEND)
> * @func: caller identifier
> @@ -175,14 +175,15 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
> * Returns IMA_MEASURE, IMA_APPRAISE mask.
> *
> */
> -int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
> - int mask, enum ima_hooks func, int *pcr)
> +int ima_get_action(struct inode *inode, const struct cred *cred,
> + struct lsmblob *blob, int mask, enum ima_hooks func,
> + int *pcr)
> {
> int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH;
>
> flags &= ima_policy_flag;
>
> - return ima_match_policy(inode, cred, secid, func, mask, flags, pcr);
> + return ima_match_policy(inode, cred, blob, func, mask, flags, pcr);
> }
>
> /*
> diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
> index 85c7692fc4a3..3ff7aae81829 100644
> --- a/security/integrity/ima/ima_appraise.c
> +++ b/security/integrity/ima/ima_appraise.c
> @@ -50,15 +50,13 @@ bool is_ima_appraise_enabled(void)
> */
> int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
> {
> - u32 secid;
> struct lsmblob blob;
>
> if (!ima_appraise)
> return 0;
>
> security_task_getsecid(current, &blob);
> - lsmblob_secid(&blob, &secid);
> - return ima_match_policy(inode, current_cred(), secid, func, mask,
> + return ima_match_policy(inode, current_cred(), &blob, func, mask,
> IMA_APPRAISE | IMA_HASH, NULL);
> }
>
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 1afb75a893af..0588dd9a88db 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -169,8 +169,8 @@ void ima_file_free(struct file *file)
> }
>
> static int process_measurement(struct file *file, const struct cred *cred,
> - u32 secid, char *buf, loff_t size, int mask,
> - enum ima_hooks func)
> + struct lsmblob *blob, char *buf, loff_t size,
> + int mask, enum ima_hooks func)
> {
> struct inode *inode = file_inode(file);
> struct integrity_iint_cache *iint = NULL;
> @@ -192,7 +192,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
> * bitmask based on the appraise/audit/measurement policy.
> * Included is the appraise submask.
> */
> - action = ima_get_action(inode, cred, secid, mask, func, &pcr);
> + action = ima_get_action(inode, cred, blob, mask, func, &pcr);
> violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
> (ima_policy_flag & IMA_MEASURE));
> if (!action && !violation_check)
> @@ -339,8 +339,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)
>
> if (file && (prot & PROT_EXEC)) {
> security_task_getsecid(current, &blob);
> - /* scaffolding - until process_measurement changes */
> - return process_measurement(file, current_cred(), blob.secid[0],
> + return process_measurement(file, current_cred(), &blob,
> NULL, 0, MAY_EXEC, MMAP_CHECK);
> }
>
> @@ -366,16 +365,14 @@ int ima_bprm_check(struct linux_binprm *bprm)
> struct lsmblob blob;
>
> security_task_getsecid(current, &blob);
> - /* scaffolding until process_measurement changes */
> - ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
> - NULL, 0, MAY_EXEC, BPRM_CHECK);
> + ret = process_measurement(bprm->file, current_cred(), &blob, NULL, 0,
> + MAY_EXEC, BPRM_CHECK);
> if (ret)
> return ret;
>
> security_cred_getsecid(bprm->cred, &blob);
> - /* scaffolding until process_measurement changes */
> - return process_measurement(bprm->file, bprm->cred, blob.secid[0],
> - NULL, 0, MAY_EXEC, CREDS_CHECK);
> + return process_measurement(bprm->file, bprm->cred, &blob, NULL, 0,
> + MAY_EXEC, CREDS_CHECK);
> }
>
> /**
> @@ -393,8 +390,7 @@ int ima_file_check(struct file *file, int mask)
> struct lsmblob blob;
>
> security_task_getsecid(current, &blob);
> - /* scaffolding until process_measurement changes */
> - return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
> + return process_measurement(file, current_cred(), &blob, NULL, 0,
> mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
> MAY_APPEND), FILE_CHECK);
> }
> @@ -526,9 +522,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
>
> func = read_idmap[read_id] ?: FILE_CHECK;
> security_task_getsecid(current, &blob);
> - /* scaffolding until process_measurement changes */
> - return process_measurement(file, current_cred(), blob.secid[0], buf,
> - size, MAY_READ, func);
> + return process_measurement(file, current_cred(), &blob, buf, size,
> + MAY_READ, func);
> }
>
> /**
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 92ee3d984c73..dbad256aa7b4 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -286,7 +286,7 @@ static void ima_lsm_update_rules(void)
> * Returns true on rule match, false on failure.
> */
> static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> - const struct cred *cred, u32 secid,
> + const struct cred *cred, struct lsmblob *blob,
> enum ima_hooks func, int mask)
> {
> int i;
> @@ -345,7 +345,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> case LSM_SUBJ_USER:
> case LSM_SUBJ_ROLE:
> case LSM_SUBJ_TYPE:
> - lsmblob_init(&blob, secid);
> rc = security_filter_rule_match(&blob,
> rule->lsm[i].type,
> Audit_equal,
> @@ -394,7 +393,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
> * @inode: pointer to an inode for which the policy decision is being made
> * @cred: pointer to a credentials structure for which the policy decision is
> * being made
> - * @secid: LSM secid of the task to be validated
> + * @blob: LSM data of the task to be validated
> * @func: IMA hook identifier
> * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
> * @pcr: set the pcr to extend
> @@ -406,8 +405,9 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
> * list when walking it. Reads are many orders of magnitude more numerous
> * than writes so ima_match_policy() is classical RCU candidate.
> */
> -int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
> - enum ima_hooks func, int mask, int flags, int *pcr)
> +int ima_match_policy(struct inode *inode, const struct cred *cred,
> + struct lsmblob *blob, enum ima_hooks func, int mask,
> + int flags, int *pcr)
> {
> struct ima_rule_entry *entry;
> int action = 0, actmask = flags | (flags << 1);
> @@ -418,7 +418,7 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
> if (!(entry->action & actmask))
> continue;
>
> - if (!ima_match_rules(entry, inode, cred, secid, func, mask))
> + if (!ima_match_rules(entry, inode, cred, blob, func, mask))
> continue;
>
> action |= entry->flags & IMA_ACTION_FLAGS;
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 13/24] LSM: Use lsmblob in security_cred_getsecid
From: Kees Cook @ 2019-06-22 22:50 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-14-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:22AM -0700, Casey Schaufler wrote:
> Change the security_cred_getsecid() interface to fill in a
> lsmblob instead of a u32 secid. The associated data elements
> in the audit sub-system are changed from a secid to a lsmblob
> to accomodate multiple possible LSM audit users.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/security.h | 2 +-
> kernel/audit.c | 14 +++++-------
> kernel/audit.h | 5 +++--
> kernel/auditsc.c | 37 +++++++++++--------------------
> security/integrity/ima/ima_main.c | 8 +++----
> security/security.c | 9 +++++---
> 6 files changed, 33 insertions(+), 42 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 6eb64b7f878a..c712fc72b7bd 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -383,7 +383,7 @@ int security_cred_alloc_blank(struct cred *cred, gfp_t gfp);
> void security_cred_free(struct cred *cred);
> int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
> void security_transfer_creds(struct cred *new, const struct cred *old);
> -void security_cred_getsecid(const struct cred *c, u32 *secid);
> +void security_cred_getsecid(const struct cred *c, struct lsmblob *blob);
> int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
> int security_kernel_create_files_as(struct cred *new, struct inode *inode);
> int security_kernel_module_request(char *kmod_name);
> diff --git a/kernel/audit.c b/kernel/audit.c
> index a0205f3c23c7..1b51e907f131 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -137,7 +137,7 @@ static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
> /* The identity of the user shutting down the audit system. */
> kuid_t audit_sig_uid = INVALID_UID;
> pid_t audit_sig_pid = -1;
> -u32 audit_sig_sid = 0;
> +struct lsmblob audit_sig_lsm;
>
> /* Records can be lost in several ways:
> 0) [suppressed in audit_alloc]
> @@ -1429,23 +1429,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> }
> case AUDIT_SIGNAL_INFO:
> len = 0;
> - if (audit_sig_sid) {
> - struct lsmblob blob;
> -
> - lsmblob_init(&blob, audit_sig_sid);
> - err = security_secid_to_secctx(&blob, &ctx, &len);
> + if (lsmblob_is_set(&audit_sig_lsm)) {
> + err = security_secid_to_secctx(&audit_sig_lsm, &ctx,
> + &len);
> if (err)
> return err;
> }
> sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
> if (!sig_data) {
> - if (audit_sig_sid)
> + if (lsmblob_is_set(&audit_sig_lsm))
> security_release_secctx(ctx, len);
> return -ENOMEM;
> }
> sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
> sig_data->pid = audit_sig_pid;
> - if (audit_sig_sid) {
> + if (lsmblob_is_set(&audit_sig_lsm)) {
> memcpy(sig_data->ctx, ctx, len);
> security_release_secctx(ctx, len);
> }
> diff --git a/kernel/audit.h b/kernel/audit.h
> index 958d5b8fc1b3..29e29c6f4afb 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -22,6 +22,7 @@
> #include <linux/fs.h>
> #include <linux/audit.h>
> #include <linux/skbuff.h>
> +#include <linux/security.h>
> #include <uapi/linux/mqueue.h>
> #include <linux/tty.h>
>
> @@ -147,7 +148,7 @@ struct audit_context {
> kuid_t target_auid;
> kuid_t target_uid;
> unsigned int target_sessionid;
> - u32 target_sid;
> + struct lsmblob target_lsm;
> char target_comm[TASK_COMM_LEN];
>
> struct audit_tree_refs *trees, *first_trees;
> @@ -338,7 +339,7 @@ extern char *audit_unpack_string(void **bufp, size_t *remain, size_t len);
>
> extern pid_t audit_sig_pid;
> extern kuid_t audit_sig_uid;
> -extern u32 audit_sig_sid;
> +extern struct lsmblob audit_sig_lsm;
>
> extern int audit_filter(int msgtype, unsigned int listtype);
>
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 54797c0fc3b7..c7aa39bda5cc 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -112,7 +112,7 @@ struct audit_aux_data_pids {
> kuid_t target_auid[AUDIT_AUX_PIDS];
> kuid_t target_uid[AUDIT_AUX_PIDS];
> unsigned int target_sessionid[AUDIT_AUX_PIDS];
> - u32 target_sid[AUDIT_AUX_PIDS];
> + struct lsmblob target_lsm[AUDIT_AUX_PIDS];
> char target_comm[AUDIT_AUX_PIDS][TASK_COMM_LEN];
> int pid_count;
> };
> @@ -938,14 +938,14 @@ static inline void audit_free_context(struct audit_context *context)
> }
>
> static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> - kuid_t auid, kuid_t uid, unsigned int sessionid,
> - u32 sid, char *comm)
> + kuid_t auid, kuid_t uid,
> + unsigned int sessionid,
> + struct lsmblob *blob, char *comm)
> {
> struct audit_buffer *ab;
> char *ctx = NULL;
> u32 len;
> int rc = 0;
> - struct lsmblob blob;
>
> ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
> if (!ab)
> @@ -954,9 +954,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> audit_log_format(ab, "opid=%d oauid=%d ouid=%d oses=%d", pid,
> from_kuid(&init_user_ns, auid),
> from_kuid(&init_user_ns, uid), sessionid);
> - if (sid) {
> - lsmblob_init(&blob, sid);
> - if (security_secid_to_secctx(&blob, &ctx, &len)) {
> + if (lsmblob_is_set(blob)) {
> + if (security_secid_to_secctx(blob, &ctx, &len)) {
> audit_log_format(ab, " obj=(none)");
> rc = 1;
> } else {
> @@ -1527,7 +1526,7 @@ static void audit_log_exit(void)
> axs->target_auid[i],
> axs->target_uid[i],
> axs->target_sessionid[i],
> - axs->target_sid[i],
> + &axs->target_lsm[i],
> axs->target_comm[i]))
> call_panic = 1;
> }
> @@ -1536,7 +1535,7 @@ static void audit_log_exit(void)
> audit_log_pid_context(context, context->target_pid,
> context->target_auid, context->target_uid,
> context->target_sessionid,
> - context->target_sid, context->target_comm))
> + &context->target_lsm, context->target_comm))
> call_panic = 1;
>
> if (context->pwd.dentry && context->pwd.mnt) {
> @@ -1713,7 +1712,7 @@ void __audit_syscall_exit(int success, long return_code)
> context->aux = NULL;
> context->aux_pids = NULL;
> context->target_pid = 0;
> - context->target_sid = 0;
> + lsmblob_init(&context->target_lsm, 0);
> context->sockaddr_len = 0;
> context->type = 0;
> context->fds[0] = -1;
> @@ -2367,15 +2366,12 @@ int __audit_sockaddr(int len, void *a)
> void __audit_ptrace(struct task_struct *t)
> {
> struct audit_context *context = audit_context();
> - struct lsmblob blob;
>
> context->target_pid = task_tgid_nr(t);
> context->target_auid = audit_get_loginuid(t);
> context->target_uid = task_uid(t);
> context->target_sessionid = audit_get_sessionid(t);
> - security_task_getsecid(t, &blob);
> - /* scaffolding - until target_sid is converted */
> - context->target_sid = blob.secid[0];
> + security_task_getsecid(t, &context->target_lsm);
> memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
> }
>
> @@ -2392,7 +2388,6 @@ int audit_signal_info(int sig, struct task_struct *t)
> struct audit_aux_data_pids *axp;
> struct audit_context *ctx = audit_context();
> kuid_t uid = current_uid(), auid, t_uid = task_uid(t);
> - struct lsmblob blob;
>
> if (auditd_test_task(t) &&
> (sig == SIGTERM || sig == SIGHUP ||
> @@ -2403,9 +2398,7 @@ int audit_signal_info(int sig, struct task_struct *t)
> audit_sig_uid = auid;
> else
> audit_sig_uid = uid;
> - security_task_getsecid(current, &blob);
> - /* scaffolding until audit_sig_sid is converted */
> - audit_sig_sid = blob.secid[0];
> + security_task_getsecid(current, &audit_sig_lsm);
> }
>
> if (!audit_signals || audit_dummy_context())
> @@ -2418,9 +2411,7 @@ int audit_signal_info(int sig, struct task_struct *t)
> ctx->target_auid = audit_get_loginuid(t);
> ctx->target_uid = t_uid;
> ctx->target_sessionid = audit_get_sessionid(t);
> - security_task_getsecid(t, &blob);
> - /* scaffolding until target_sid is converted */
> - ctx->target_sid = blob.secid[0];
> + security_task_getsecid(t, &ctx->target_lsm);
> memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
> return 0;
> }
> @@ -2441,9 +2432,7 @@ int audit_signal_info(int sig, struct task_struct *t)
> axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
> axp->target_uid[axp->pid_count] = t_uid;
> axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
> - security_task_getsecid(t, &blob);
> - /* scaffolding until target_sid is converted */
> - axp->target_sid[axp->pid_count] = blob.secid[0];
> + security_task_getsecid(t, &axp->target_lsm[axp->pid_count]);
> memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
> axp->pid_count++;
>
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index fefa848cf0c7..1afb75a893af 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -363,7 +363,6 @@ int ima_file_mmap(struct file *file, unsigned long prot)
> int ima_bprm_check(struct linux_binprm *bprm)
> {
> int ret;
> - u32 secid;
> struct lsmblob blob;
>
> security_task_getsecid(current, &blob);
> @@ -373,9 +372,10 @@ int ima_bprm_check(struct linux_binprm *bprm)
> if (ret)
> return ret;
>
> - security_cred_getsecid(bprm->cred, &secid);
> - return process_measurement(bprm->file, bprm->cred, secid, NULL, 0,
> - MAY_EXEC, CREDS_CHECK);
> + security_cred_getsecid(bprm->cred, &blob);
> + /* scaffolding until process_measurement changes */
> + return process_measurement(bprm->file, bprm->cred, blob.secid[0],
> + NULL, 0, MAY_EXEC, CREDS_CHECK);
> }
>
> /**
> diff --git a/security/security.c b/security/security.c
> index 6f0635b51180..aa8e1c73a062 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1643,10 +1643,13 @@ void security_transfer_creds(struct cred *new, const struct cred *old)
> call_void_hook(cred_transfer, new, old);
> }
>
> -void security_cred_getsecid(const struct cred *c, u32 *secid)
> +void security_cred_getsecid(const struct cred *c, struct lsmblob *blob)
> {
> - *secid = 0;
> - call_void_hook(cred_getsecid, c, secid);
> + struct security_hook_list *hp;
> +
> + lsmblob_init(blob, 0);
> + hlist_for_each_entry(hp, &security_hook_heads.cred_getsecid, list)
> + hp->hook.cred_getsecid(c, &blob->secid[hp->slot]);
> }
> EXPORT_SYMBOL(security_cred_getsecid);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 12/24] LSM: Use lsmblob in security_inode_getsecid
From: Kees Cook @ 2019-06-22 22:49 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-13-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:21AM -0700, Casey Schaufler wrote:
> Change the security_inode_getsecid() interface to fill in a
> lsmblob structure instead of a u32 secid. This allows for its
> callers to gather data from all registered LSMs. Data is provided
> for IMA and audit.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/security.h | 7 ++++---
> kernel/auditsc.c | 6 +++++-
> security/integrity/ima/ima_policy.c | 4 +---
> security/security.c | 8 ++++++--
> 4 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index c5fdaaff8806..6eb64b7f878a 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -358,7 +358,7 @@ int security_inode_killpriv(struct dentry *dentry);
> int security_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc);
> int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
> int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
> -void security_inode_getsecid(struct inode *inode, u32 *secid);
> +void security_inode_getsecid(struct inode *inode, struct lsmblob *blob);
> int security_inode_copy_up(struct dentry *src, struct cred **new);
> int security_inode_copy_up_xattr(const char *name);
> int security_file_permission(struct file *file, int mask);
> @@ -854,9 +854,10 @@ static inline int security_inode_listsecurity(struct inode *inode, char *buffer,
> return 0;
> }
>
> -static inline void security_inode_getsecid(struct inode *inode, u32 *secid)
> +static inline void security_inode_getsecid(struct inode *inode,
> + struct lsmblob *blob)
> {
> - *secid = 0;
> + lsmblob_init(blob, 0);
> }
>
> static inline int security_inode_copy_up(struct dentry *src, struct cred **new)
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 7112fe31684d..54797c0fc3b7 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -1910,13 +1910,17 @@ static inline int audit_copy_fcaps(struct audit_names *name,
> void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
> struct inode *inode, unsigned int flags)
> {
> + struct lsmblob blob;
> +
> name->ino = inode->i_ino;
> name->dev = inode->i_sb->s_dev;
> name->mode = inode->i_mode;
> name->uid = inode->i_uid;
> name->gid = inode->i_gid;
> name->rdev = inode->i_rdev;
> - security_inode_getsecid(inode, &name->osid);
> + security_inode_getsecid(inode, &blob);
> + /* scaffolding until osid is updated */
> + name->osid = blob.secid[0];
> if (flags & AUDIT_INODE_NOEVAL) {
> name->fcap_ver = -1;
> return;
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index e7b8ce942950..92ee3d984c73 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -326,7 +326,6 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> return false;
> for (i = 0; i < MAX_LSM_RULES; i++) {
> int rc = 0;
> - u32 osid;
> struct lsmblob blob;
> int retried = 0;
>
> @@ -337,8 +336,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> case LSM_OBJ_USER:
> case LSM_OBJ_ROLE:
> case LSM_OBJ_TYPE:
> - security_inode_getsecid(inode, &osid);
> - lsmblob_init(&blob, osid);
> + security_inode_getsecid(inode, &blob);
> rc = security_filter_rule_match(&blob,
> rule->lsm[i].type,
> Audit_equal,
> diff --git a/security/security.c b/security/security.c
> index 1184ef092bce..6f0635b51180 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1423,9 +1423,13 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer
> }
> EXPORT_SYMBOL(security_inode_listsecurity);
>
> -void security_inode_getsecid(struct inode *inode, u32 *secid)
> +void security_inode_getsecid(struct inode *inode, struct lsmblob *blob)
> {
> - call_void_hook(inode_getsecid, inode, secid);
> + struct security_hook_list *hp;
> +
> + lsmblob_init(blob, 0);
> + hlist_for_each_entry(hp, &security_hook_heads.inode_getsecid, list)
> + hp->hook.inode_getsecid(inode, &blob->secid[hp->slot]);
> }
>
> int security_inode_copy_up(struct dentry *src, struct cred **new)
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 11/24] LSM: Use lsmblob in security_task_getsecid
From: Kees Cook @ 2019-06-22 22:49 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-12-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:20AM -0700, Casey Schaufler wrote:
> Change the security_task_getsecid() interface to fill in
> a lsmblob structure instead of a u32 secid in support of
> LSM stacking. Audit interfaces will need to collect all
> possible secids for possible reporting.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> drivers/android/binder.c | 4 +---
> include/linux/security.h | 7 +++---
> kernel/audit.c | 6 ++---
> kernel/auditfilter.c | 4 +---
> kernel/auditsc.c | 22 ++++++++++++------
> net/netlabel/netlabel_unlabeled.c | 5 +++-
> net/netlabel/netlabel_user.h | 6 ++++-
> security/integrity/ima/ima_appraise.c | 4 +++-
> security/integrity/ima/ima_main.c | 33 +++++++++++++++------------
> security/security.c | 9 +++++---
> 10 files changed, 60 insertions(+), 40 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 1962f6b8abd0..144ac4f1c24f 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3119,11 +3119,9 @@ static void binder_transaction(struct binder_proc *proc,
> t->priority = task_nice(current);
>
> if (target_node && target_node->txn_security_ctx) {
> - u32 secid;
> struct lsmblob blob;
>
> - security_task_getsecid(proc->tsk, &secid);
> - lsmblob_init(&blob, secid);
> + security_task_getsecid(proc->tsk, &blob);
> ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
> if (ret) {
> return_error = BR_FAILED_REPLY;
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 0d5e172341fc..c5fdaaff8806 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -396,7 +396,7 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old,
> int security_task_setpgid(struct task_struct *p, pid_t pgid);
> int security_task_getpgid(struct task_struct *p);
> int security_task_getsid(struct task_struct *p);
> -void security_task_getsecid(struct task_struct *p, u32 *secid);
> +void security_task_getsecid(struct task_struct *p, struct lsmblob *blob);
> int security_task_setnice(struct task_struct *p, int nice);
> int security_task_setioprio(struct task_struct *p, int ioprio);
> int security_task_getioprio(struct task_struct *p);
> @@ -1025,9 +1025,10 @@ static inline int security_task_getsid(struct task_struct *p)
> return 0;
> }
>
> -static inline void security_task_getsecid(struct task_struct *p, u32 *secid)
> +static inline void security_task_getsecid(struct task_struct *p,
> + struct lsmblob *blob)
> {
> - *secid = 0;
> + lsmblob_init(blob, 0);
> }
>
> static inline int security_task_setnice(struct task_struct *p, int nice)
> diff --git a/kernel/audit.c b/kernel/audit.c
> index d0338411d75d..a0205f3c23c7 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -2075,14 +2075,12 @@ int audit_log_task_context(struct audit_buffer *ab)
> char *ctx = NULL;
> unsigned len;
> int error;
> - u32 sid;
> struct lsmblob blob;
>
> - security_task_getsecid(current, &sid);
> - if (!sid)
> + security_task_getsecid(current, &blob);
> + if (!lsmblob_is_set(&blob))
> return 0;
>
> - lsmblob_init(&blob, sid);
> error = security_secid_to_secctx(&blob, &ctx, &len);
> if (error) {
> if (error != -EINVAL)
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index da211065160f..76b4c0ca4fd2 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -1323,7 +1323,6 @@ int audit_filter(int msgtype, unsigned int listtype)
> for (i = 0; i < e->rule.field_count; i++) {
> struct audit_field *f = &e->rule.fields[i];
> pid_t pid;
> - u32 sid;
> struct lsmblob blob;
>
> switch (f->type) {
> @@ -1354,8 +1353,7 @@ int audit_filter(int msgtype, unsigned int listtype)
> case AUDIT_SUBJ_SEN:
> case AUDIT_SUBJ_CLR:
> if (f->lsm_rule) {
> - security_task_getsecid(current, &sid);
> - lsmblob_init(&blob, sid);
> + security_task_getsecid(current, &blob);
> result = security_audit_rule_match(&blob,
> f->type, f->op, f->lsm_rule);
> }
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 148733ec3c72..7112fe31684d 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -444,7 +444,6 @@ static int audit_filter_rules(struct task_struct *tsk,
> {
> const struct cred *cred;
> int i, need_sid = 1;
> - u32 sid;
> struct lsmblob blob;
> unsigned int sessionid;
>
> @@ -628,10 +627,9 @@ static int audit_filter_rules(struct task_struct *tsk,
> logged upon error */
> if (f->lsm_rule) {
> if (need_sid) {
> - security_task_getsecid(tsk, &sid);
> + security_task_getsecid(tsk, &blob);
> need_sid = 0;
> }
> - lsmblob_init(&blob, sid);
> result = security_audit_rule_match(&blob,
> f->type,
> f->op,
> @@ -2365,12 +2363,15 @@ int __audit_sockaddr(int len, void *a)
> void __audit_ptrace(struct task_struct *t)
> {
> struct audit_context *context = audit_context();
> + struct lsmblob blob;
>
> context->target_pid = task_tgid_nr(t);
> context->target_auid = audit_get_loginuid(t);
> context->target_uid = task_uid(t);
> context->target_sessionid = audit_get_sessionid(t);
> - security_task_getsecid(t, &context->target_sid);
> + security_task_getsecid(t, &blob);
> + /* scaffolding - until target_sid is converted */
> + context->target_sid = blob.secid[0];
> memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
> }
>
> @@ -2387,6 +2388,7 @@ int audit_signal_info(int sig, struct task_struct *t)
> struct audit_aux_data_pids *axp;
> struct audit_context *ctx = audit_context();
> kuid_t uid = current_uid(), auid, t_uid = task_uid(t);
> + struct lsmblob blob;
>
> if (auditd_test_task(t) &&
> (sig == SIGTERM || sig == SIGHUP ||
> @@ -2397,7 +2399,9 @@ int audit_signal_info(int sig, struct task_struct *t)
> audit_sig_uid = auid;
> else
> audit_sig_uid = uid;
> - security_task_getsecid(current, &audit_sig_sid);
> + security_task_getsecid(current, &blob);
> + /* scaffolding until audit_sig_sid is converted */
> + audit_sig_sid = blob.secid[0];
> }
>
> if (!audit_signals || audit_dummy_context())
> @@ -2410,7 +2414,9 @@ int audit_signal_info(int sig, struct task_struct *t)
> ctx->target_auid = audit_get_loginuid(t);
> ctx->target_uid = t_uid;
> ctx->target_sessionid = audit_get_sessionid(t);
> - security_task_getsecid(t, &ctx->target_sid);
> + security_task_getsecid(t, &blob);
> + /* scaffolding until target_sid is converted */
> + ctx->target_sid = blob.secid[0];
> memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
> return 0;
> }
> @@ -2431,7 +2437,9 @@ int audit_signal_info(int sig, struct task_struct *t)
> axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
> axp->target_uid[axp->pid_count] = t_uid;
> axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
> - security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
> + security_task_getsecid(t, &blob);
> + /* scaffolding until target_sid is converted */
> + axp->target_sid[axp->pid_count] = blob.secid[0];
> memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);
> axp->pid_count++;
>
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index 2d8dd5b84457..2294aa9471e6 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -1552,11 +1552,14 @@ int __init netlbl_unlabel_defconf(void)
> int ret_val;
> struct netlbl_dom_map *entry;
> struct netlbl_audit audit_info;
> + struct lsmblob blob;
>
> /* Only the kernel is allowed to call this function and the only time
> * it is called is at bootup before the audit subsystem is reporting
> * messages so don't worry to much about these values. */
> - security_task_getsecid(current, &audit_info.secid);
> + security_task_getsecid(current, &blob);
> + /* scaffolding until audit_info.secid is converted */
> + audit_info.secid = blob.secid[0];
> audit_info.loginuid = GLOBAL_ROOT_UID;
> audit_info.sessionid = 0;
>
> diff --git a/net/netlabel/netlabel_user.h b/net/netlabel/netlabel_user.h
> index 4a397cde1a48..ab88baaaa50d 100644
> --- a/net/netlabel/netlabel_user.h
> +++ b/net/netlabel/netlabel_user.h
> @@ -48,7 +48,11 @@
> static inline void netlbl_netlink_auditinfo(struct sk_buff *skb,
> struct netlbl_audit *audit_info)
> {
> - security_task_getsecid(current, &audit_info->secid);
> + struct lsmblob blob;
> +
> + security_task_getsecid(current, &blob);
> + /* scaffolding until secid is converted */
> + audit_info->secid = blob.secid[0];
> audit_info->loginuid = audit_get_loginuid(current);
> audit_info->sessionid = audit_get_sessionid(current);
> }
> diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
> index 5fb7127bbe68..85c7692fc4a3 100644
> --- a/security/integrity/ima/ima_appraise.c
> +++ b/security/integrity/ima/ima_appraise.c
> @@ -51,11 +51,13 @@ bool is_ima_appraise_enabled(void)
> int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
> {
> u32 secid;
> + struct lsmblob blob;
>
> if (!ima_appraise)
> return 0;
>
> - security_task_getsecid(current, &secid);
> + security_task_getsecid(current, &blob);
> + lsmblob_secid(&blob, &secid);
> return ima_match_policy(inode, current_cred(), secid, func, mask,
> IMA_APPRAISE | IMA_HASH, NULL);
> }
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index 357edd140c09..fefa848cf0c7 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -335,12 +335,13 @@ static int process_measurement(struct file *file, const struct cred *cred,
> */
> int ima_file_mmap(struct file *file, unsigned long prot)
> {
> - u32 secid;
> + struct lsmblob blob;
>
> if (file && (prot & PROT_EXEC)) {
> - security_task_getsecid(current, &secid);
> - return process_measurement(file, current_cred(), secid, NULL,
> - 0, MAY_EXEC, MMAP_CHECK);
> + security_task_getsecid(current, &blob);
> + /* scaffolding - until process_measurement changes */
> + return process_measurement(file, current_cred(), blob.secid[0],
> + NULL, 0, MAY_EXEC, MMAP_CHECK);
> }
>
> return 0;
> @@ -363,10 +364,12 @@ int ima_bprm_check(struct linux_binprm *bprm)
> {
> int ret;
> u32 secid;
> + struct lsmblob blob;
>
> - security_task_getsecid(current, &secid);
> - ret = process_measurement(bprm->file, current_cred(), secid, NULL, 0,
> - MAY_EXEC, BPRM_CHECK);
> + security_task_getsecid(current, &blob);
> + /* scaffolding until process_measurement changes */
> + ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
> + NULL, 0, MAY_EXEC, BPRM_CHECK);
> if (ret)
> return ret;
>
> @@ -387,10 +390,11 @@ int ima_bprm_check(struct linux_binprm *bprm)
> */
> int ima_file_check(struct file *file, int mask)
> {
> - u32 secid;
> + struct lsmblob blob;
>
> - security_task_getsecid(current, &secid);
> - return process_measurement(file, current_cred(), secid, NULL, 0,
> + security_task_getsecid(current, &blob);
> + /* scaffolding until process_measurement changes */
> + return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
> mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
> MAY_APPEND), FILE_CHECK);
> }
> @@ -499,7 +503,7 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
> enum kernel_read_file_id read_id)
> {
> enum ima_hooks func;
> - u32 secid;
> + struct lsmblob blob;
>
> if (!file && read_id == READING_FIRMWARE) {
> if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
> @@ -521,9 +525,10 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
> }
>
> func = read_idmap[read_id] ?: FILE_CHECK;
> - security_task_getsecid(current, &secid);
> - return process_measurement(file, current_cred(), secid, buf, size,
> - MAY_READ, func);
> + security_task_getsecid(current, &blob);
> + /* scaffolding until process_measurement changes */
> + return process_measurement(file, current_cred(), blob.secid[0], buf,
> + size, MAY_READ, func);
> }
>
> /**
> diff --git a/security/security.c b/security/security.c
> index d55f01041f05..1184ef092bce 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1729,10 +1729,13 @@ int security_task_getsid(struct task_struct *p)
> return call_int_hook(task_getsid, 0, p);
> }
>
> -void security_task_getsecid(struct task_struct *p, u32 *secid)
> +void security_task_getsecid(struct task_struct *p, struct lsmblob *blob)
> {
> - *secid = 0;
> - call_void_hook(task_getsecid, p, secid);
> + struct security_hook_list *hp;
> +
> + lsmblob_init(blob, 0);
> + hlist_for_each_entry(hp, &security_hook_heads.task_getsecid, list)
> + hp->hook.task_getsecid(p, &blob->secid[hp->slot]);
> }
> EXPORT_SYMBOL(security_task_getsecid);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 10/24] Use lsmblob in security_ipc_getsecid
From: Kees Cook @ 2019-06-22 22:48 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-11-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:19AM -0700, Casey Schaufler wrote:
> There may be more than one LSM that provides IPC data
> for auditing. Change security_ipc_getsecid() to fill in
> a lsmblob structure instead of the u32 secid. The
> audit data structure containing the secid will be updated
> later, so there is a bit of scaffolding here.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
One thought below...
> ---
> include/linux/security.h | 7 ++++---
> kernel/auditsc.c | 5 ++++-
> security/security.c | 9 ++++++---
> 3 files changed, 14 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index c6cddeff8a17..0d5e172341fc 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -413,7 +413,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> unsigned long arg4, unsigned long arg5);
> void security_task_to_inode(struct task_struct *p, struct inode *inode);
> int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag);
> -void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid);
> +void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob);
> int security_msg_msg_alloc(struct msg_msg *msg);
> void security_msg_msg_free(struct msg_msg *msg);
> int security_msg_queue_alloc(struct kern_ipc_perm *msq);
> @@ -1098,9 +1098,10 @@ static inline int security_ipc_permission(struct kern_ipc_perm *ipcp,
> return 0;
> }
>
> -static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
> +static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp,
> + struct lsmblob *blob)
> {
> - *secid = 0;
> + lsmblob_init(blob, 0);
> }
>
> static inline int security_msg_msg_alloc(struct msg_msg *msg)
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index d31914088a82..148733ec3c72 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2268,11 +2268,14 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
> void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
> {
> struct audit_context *context = audit_context();
> + struct lsmblob blob;
> context->ipc.uid = ipcp->uid;
> context->ipc.gid = ipcp->gid;
> context->ipc.mode = ipcp->mode;
> context->ipc.has_perm = 0;
> - security_ipc_getsecid(ipcp, &context->ipc.osid);
> + security_ipc_getsecid(ipcp, &blob);
> + /* scaffolding on the [0] - change "osid" to a lsmblob */
> + context->ipc.osid = blob.secid[0];
> context->type = AUDIT_IPC;
> }
>
> diff --git a/security/security.c b/security/security.c
> index 5ab07631df75..d55f01041f05 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1812,10 +1812,13 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
> return call_int_hook(ipc_permission, 0, ipcp, flag);
> }
>
> -void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
> +void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob)
> {
> - *secid = 0;
> - call_void_hook(ipc_getsecid, ipcp, secid);
> + struct security_hook_list *hp;
> +
> + lsmblob_init(blob, 0);
> + hlist_for_each_entry(hp, &security_hook_heads.ipc_getsecid, list)
> + hp->hook.ipc_getsecid(ipcp, &blob->secid[hp->slot]);
Just for sanity when using hp->slot, it might be good to do something
like this in the places it gets used. Like for here:
if (!WARN_ON(hp->slot < 0 || hp->slot >= LSMBLOB_COUNT))
hp->hook.ipc_getsecid(ipcp, &blob->secid[hp->slot]);
This _should_ be overkill, but since lists of hooks that trigger slot
assignment is hardcoded, it seems nice to cover any future problems or
mismatches.
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 09/24] LSM: Use lsmblob in security_secid_to_secctx
From: Kees Cook @ 2019-06-22 22:44 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-10-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:18AM -0700, Casey Schaufler wrote:
> Change security_secid_to_secctx() to take a lsmblob as input
> instead of a u32 secid. It will then call the LSM hooks
> using the lsmblob element allocated for that module. The
> callers have been updated as well. This allows for the
> possibility that more than one module may called upon
> to translate a secid to a string, as can occur in the
> audit code.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> drivers/android/binder.c | 4 +++-
> include/linux/security.h | 5 +++--
> include/net/scm.h | 5 ++---
> kernel/audit.c | 9 +++++++--
> kernel/auditsc.c | 14 ++++++++++----
> net/ipv4/ip_sockglue.c | 3 +--
> net/netfilter/nf_conntrack_netlink.c | 8 ++++++--
> net/netfilter/nf_conntrack_standalone.c | 4 +++-
> net/netfilter/nfnetlink_queue.c | 8 ++++++--
> net/netlabel/netlabel_unlabeled.c | 18 ++++++++++++++----
> net/netlabel/netlabel_user.c | 6 +++---
> security/security.c | 14 +++++++++++---
> 12 files changed, 69 insertions(+), 29 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 8685882da64c..1962f6b8abd0 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3120,9 +3120,11 @@ static void binder_transaction(struct binder_proc *proc,
>
> if (target_node && target_node->txn_security_ctx) {
> u32 secid;
> + struct lsmblob blob;
>
> security_task_getsecid(proc->tsk, &secid);
> - ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
> + lsmblob_init(&blob, secid);
> + ret = security_secid_to_secctx(&blob, &secctx, &secctx_sz);
> if (ret) {
> return_error = BR_FAILED_REPLY;
> return_error_param = ret;
> diff --git a/include/linux/security.h b/include/linux/security.h
> index b0395d224c43..c6cddeff8a17 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -442,7 +442,7 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
> size_t size);
> int security_netlink_send(struct sock *sk, struct sk_buff *skb);
> int security_ismaclabel(const char *name);
> -int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
> +int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen);
> int security_secctx_to_secid(const char *secdata, u32 seclen,
> struct lsmblob *blob);
> void security_release_secctx(char *secdata, u32 seclen);
> @@ -1220,7 +1220,8 @@ static inline int security_ismaclabel(const char *name)
> return 0;
> }
>
> -static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
> +static inline int security_secid_to_secctx(struct lsmblob *blob,
> + char **secdata, u32 *seclen)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/include/net/scm.h b/include/net/scm.h
> index e2e71c4bf9d0..31ae605fcc0a 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -97,9 +97,8 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
> int err;
>
> if (test_bit(SOCK_PASSSEC, &sock->flags)) {
> - /* Scaffolding - it has to be element 0 for now */
> - err = security_secid_to_secctx(scm->lsmblob.secid[0],
> - &secdata, &seclen);
> + err = security_secid_to_secctx(&scm->lsmblob, &secdata,
> + &seclen);
>
> if (!err) {
> put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
> diff --git a/kernel/audit.c b/kernel/audit.c
> index c89ea48c70a6..d0338411d75d 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -1430,7 +1430,10 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
> case AUDIT_SIGNAL_INFO:
> len = 0;
> if (audit_sig_sid) {
> - err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
> + struct lsmblob blob;
> +
> + lsmblob_init(&blob, audit_sig_sid);
> + err = security_secid_to_secctx(&blob, &ctx, &len);
> if (err)
> return err;
> }
> @@ -2073,12 +2076,14 @@ int audit_log_task_context(struct audit_buffer *ab)
> unsigned len;
> int error;
> u32 sid;
> + struct lsmblob blob;
>
> security_task_getsecid(current, &sid);
> if (!sid)
> return 0;
>
> - error = security_secid_to_secctx(sid, &ctx, &len);
> + lsmblob_init(&blob, sid);
> + error = security_secid_to_secctx(&blob, &ctx, &len);
> if (error) {
> if (error != -EINVAL)
> goto error_path;
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 18ee5556c086..d31914088a82 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -947,6 +947,7 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> char *ctx = NULL;
> u32 len;
> int rc = 0;
> + struct lsmblob blob;
>
> ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID);
> if (!ab)
> @@ -956,7 +957,8 @@ static int audit_log_pid_context(struct audit_context *context, pid_t pid,
> from_kuid(&init_user_ns, auid),
> from_kuid(&init_user_ns, uid), sessionid);
> if (sid) {
> - if (security_secid_to_secctx(sid, &ctx, &len)) {
> + lsmblob_init(&blob, sid);
> + if (security_secid_to_secctx(&blob, &ctx, &len)) {
> audit_log_format(ab, " obj=(none)");
> rc = 1;
> } else {
> @@ -1198,7 +1200,10 @@ static void show_special(struct audit_context *context, int *call_panic)
> if (osid) {
> char *ctx = NULL;
> u32 len;
> - if (security_secid_to_secctx(osid, &ctx, &len)) {
> + struct lsmblob blob;
> +
> + lsmblob_init(&blob, osid);
> + if (security_secid_to_secctx(&blob, &ctx, &len)) {
> audit_log_format(ab, " osid=%u", osid);
> *call_panic = 1;
> } else {
> @@ -1349,9 +1354,10 @@ static void audit_log_name(struct audit_context *context, struct audit_names *n,
> if (n->osid != 0) {
> char *ctx = NULL;
> u32 len;
> + struct lsmblob blob;
>
> - if (security_secid_to_secctx(
> - n->osid, &ctx, &len)) {
> + lsmblob_init(&blob, n->osid);
> + if (security_secid_to_secctx(&blob, &ctx, &len)) {
> audit_log_format(ab, " osid=%u", n->osid);
> if (call_panic)
> *call_panic = 2;
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index 2a5c868ce135..e05f4ef68bd8 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -139,8 +139,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> if (err)
> return;
>
> - /* Scaffolding - it has to be element 0 */
> - err = security_secid_to_secctx(lb.secid[0], &secdata, &seclen);
> + err = security_secid_to_secctx(&lb, &secdata, &seclen);
> if (err)
> return;
>
> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
> index 66c596d287a5..ca0968f13240 100644
> --- a/net/netfilter/nf_conntrack_netlink.c
> +++ b/net/netfilter/nf_conntrack_netlink.c
> @@ -330,8 +330,10 @@ static int ctnetlink_dump_secctx(struct sk_buff *skb, const struct nf_conn *ct)
> struct nlattr *nest_secctx;
> int len, ret;
> char *secctx;
> + struct lsmblob blob;
>
> - ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
> + lsmblob_init(&blob, ct->secmark);
> + ret = security_secid_to_secctx(&blob, &secctx, &len);
> if (ret)
> return 0;
>
> @@ -615,8 +617,10 @@ static inline int ctnetlink_secctx_size(const struct nf_conn *ct)
> {
> #ifdef CONFIG_NF_CONNTRACK_SECMARK
> int len, ret;
> + struct lsmblob blob;
>
> - ret = security_secid_to_secctx(ct->secmark, NULL, &len);
> + lsmblob_init(&blob, ct->secmark);
> + ret = security_secid_to_secctx(&blob, NULL, &len);
> if (ret)
> return 0;
>
> diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
> index c2ae14c720b4..c793103f3cd7 100644
> --- a/net/netfilter/nf_conntrack_standalone.c
> +++ b/net/netfilter/nf_conntrack_standalone.c
> @@ -175,8 +175,10 @@ static void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
> int ret;
> u32 len;
> char *secctx;
> + struct lsmblob blob;
>
> - ret = security_secid_to_secctx(ct->secmark, &secctx, &len);
> + lsmblob_init(&blob, ct->secmark);
> + ret = security_secid_to_secctx(&blob, &secctx, &len);
> if (ret)
> return;
>
> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index 0dcc3592d053..59211bff90ab 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -309,13 +309,17 @@ static u32 nfqnl_get_sk_secctx(struct sk_buff *skb, char **secdata)
> {
> u32 seclen = 0;
> #if IS_ENABLED(CONFIG_NETWORK_SECMARK)
> + struct lsmblob blob;
> +
> if (!skb || !sk_fullsock(skb->sk))
> return 0;
>
> read_lock_bh(&skb->sk->sk_callback_lock);
>
> - if (skb->secmark)
> - security_secid_to_secctx(skb->secmark, secdata, &seclen);
> + if (skb->secmark) {
> + lsmblob_init(&blob, skb->secmark);
> + security_secid_to_secctx(&blob, secdata, &seclen);
> + }
>
> read_unlock_bh(&skb->sk->sk_callback_lock);
> #endif
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index 2976370e41aa..2d8dd5b84457 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -389,6 +389,7 @@ int netlbl_unlhsh_add(struct net *net,
> struct audit_buffer *audit_buf = NULL;
> char *secctx = NULL;
> u32 secctx_len;
> + struct lsmblob blob;
>
> if (addr_len != sizeof(struct in_addr) &&
> addr_len != sizeof(struct in6_addr))
> @@ -451,7 +452,8 @@ int netlbl_unlhsh_add(struct net *net,
> unlhsh_add_return:
> rcu_read_unlock();
> if (audit_buf != NULL) {
> - if (security_secid_to_secctx(secid,
> + lsmblob_init(&blob, secid);
> + if (security_secid_to_secctx(&blob,
> &secctx,
> &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> @@ -488,6 +490,7 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> struct net_device *dev;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob blob;
>
> spin_lock(&netlbl_unlhsh_lock);
> list_entry = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
> @@ -507,8 +510,10 @@ static int netlbl_unlhsh_remove_addr4(struct net *net,
> addr->s_addr, mask->s_addr);
> if (dev != NULL)
> dev_put(dev);
> + if (entry != NULL)
> + lsmblob_init(&blob, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(entry->secid,
> + security_secid_to_secctx(&blob,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> security_release_secctx(secctx, secctx_len);
> @@ -550,6 +555,7 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> struct net_device *dev;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob blob;
>
> spin_lock(&netlbl_unlhsh_lock);
> list_entry = netlbl_af6list_remove(addr, mask, &iface->addr6_list);
> @@ -568,8 +574,10 @@ static int netlbl_unlhsh_remove_addr6(struct net *net,
> addr, mask);
> if (dev != NULL)
> dev_put(dev);
> + if (entry != NULL)
> + lsmblob_init(&blob, entry->secid);
> if (entry != NULL &&
> - security_secid_to_secctx(entry->secid,
> + security_secid_to_secctx(&blob,
> &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " sec_obj=%s", secctx);
> security_release_secctx(secctx, secctx_len);
> @@ -1090,6 +1098,7 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> u32 secid;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob blob;
>
> data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).portid,
> cb_arg->seq, &netlbl_unlabel_gnl_family,
> @@ -1144,7 +1153,8 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd,
> secid = addr6->secid;
> }
>
> - ret_val = security_secid_to_secctx(secid, &secctx, &secctx_len);
> + lsmblob_init(&blob, secid);
> + ret_val = security_secid_to_secctx(&blob, &secctx, &secctx_len);
> if (ret_val != 0)
> goto list_cb_failure;
> ret_val = nla_put(cb_arg->skb,
> diff --git a/net/netlabel/netlabel_user.c b/net/netlabel/netlabel_user.c
> index 4676f5bb16ae..2ccc6567e2a2 100644
> --- a/net/netlabel/netlabel_user.c
> +++ b/net/netlabel/netlabel_user.c
> @@ -100,6 +100,7 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> struct audit_buffer *audit_buf;
> char *secctx;
> u32 secctx_len;
> + struct lsmblob blob;
>
> if (audit_enabled == AUDIT_OFF)
> return NULL;
> @@ -112,10 +113,9 @@ struct audit_buffer *netlbl_audit_start_common(int type,
> from_kuid(&init_user_ns, audit_info->loginuid),
> audit_info->sessionid);
>
> + lsmblob_init(&blob, audit_info->secid);
> if (audit_info->secid != 0 &&
> - security_secid_to_secctx(audit_info->secid,
> - &secctx,
> - &secctx_len) == 0) {
> + security_secid_to_secctx(&blob, &secctx, &secctx_len) == 0) {
> audit_log_format(audit_buf, " subj=%s", secctx);
> security_release_secctx(secctx, secctx_len);
> }
> diff --git a/security/security.c b/security/security.c
> index cb1545bfe8c5..5ab07631df75 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1992,10 +1992,18 @@ int security_ismaclabel(const char *name)
> }
> EXPORT_SYMBOL(security_ismaclabel);
>
> -int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
> +int security_secid_to_secctx(struct lsmblob *blob, char **secdata, u32 *seclen)
> {
> - return call_int_hook(secid_to_secctx, -EOPNOTSUPP, secid, secdata,
> - seclen);
> + struct security_hook_list *hp;
> + int rc;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.secid_to_secctx, list) {
> + rc = hp->hook.secid_to_secctx(blob->secid[hp->slot],
> + secdata, seclen);
> + if (rc != 0)
> + return rc;
> + }
> + return 0;
> }
> EXPORT_SYMBOL(security_secid_to_secctx);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 08/24] LSM: Use lsmblob in security_secctx_to_secid
From: Kees Cook @ 2019-06-22 22:44 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-9-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:17AM -0700, Casey Schaufler wrote:
> Change security_secctx_to_secid() to fill in a lsmblob instead
> of a u32 secid. Multiple LSMs may be able to interpret the
> string, and this allows for setting whichever secid is
> appropriate. In some cases there is scaffolding where other
> interfaces have yet to be converted.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/security.h | 5 +++--
> kernel/cred.c | 4 +---
> net/netfilter/nft_meta.c | 13 ++++++-------
> net/netfilter/xt_SECMARK.c | 5 ++++-
> net/netlabel/netlabel_unlabeled.c | 14 ++++++++------
> security/security.c | 16 +++++++++++++---
> 6 files changed, 35 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 905830a90745..b0395d224c43 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -443,7 +443,8 @@ int security_setprocattr(const char *lsm, const char *name, void *value,
> int security_netlink_send(struct sock *sk, struct sk_buff *skb);
> int security_ismaclabel(const char *name);
> int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
> -int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
> +int security_secctx_to_secid(const char *secdata, u32 seclen,
> + struct lsmblob *blob);
> void security_release_secctx(char *secdata, u32 seclen);
>
> void security_inode_invalidate_secctx(struct inode *inode);
> @@ -1226,7 +1227,7 @@ static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *secle
>
> static inline int security_secctx_to_secid(const char *secdata,
> u32 seclen,
> - u32 *secid)
> + struct lsmblob *blob)
> {
> return -EOPNOTSUPP;
> }
> diff --git a/kernel/cred.c b/kernel/cred.c
> index 71c14dda107e..d70a2c02ced4 100644
> --- a/kernel/cred.c
> +++ b/kernel/cred.c
> @@ -725,14 +725,12 @@ EXPORT_SYMBOL(set_security_override);
> int set_security_override_from_ctx(struct cred *new, const char *secctx)
> {
> struct lsmblob blob;
> - u32 secid;
> int ret;
>
> - ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
> + ret = security_secctx_to_secid(secctx, strlen(secctx), &blob);
> if (ret < 0)
> return ret;
>
> - lsmblob_init(&blob, secid);
> return set_security_override(new, &blob);
> }
> EXPORT_SYMBOL(set_security_override_from_ctx);
> diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c
> index 987d2d6ce624..91973d3a5f6a 100644
> --- a/net/netfilter/nft_meta.c
> +++ b/net/netfilter/nft_meta.c
> @@ -576,21 +576,20 @@ static const struct nla_policy nft_secmark_policy[NFTA_SECMARK_MAX + 1] = {
>
> static int nft_secmark_compute_secid(struct nft_secmark *priv)
> {
> - u32 tmp_secid = 0;
> + struct lsmblob blob;
> int err;
>
> - err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &tmp_secid);
> + err = security_secctx_to_secid(priv->ctx, strlen(priv->ctx), &blob);
> if (err)
> return err;
>
> - if (!tmp_secid)
> - return -ENOENT;
> -
> - err = security_secmark_relabel_packet(tmp_secid);
> + /* Using le[0] is scaffolding */
> + err = security_secmark_relabel_packet(blob.secid[0]);
> if (err)
> return err;
>
> - priv->secid = tmp_secid;
> + /* Using le[1] is scaffolding */
> + priv->secid = blob.secid[0];
> return 0;
> }
>
> diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c
> index f16202d26c20..8081fadc30e9 100644
> --- a/net/netfilter/xt_SECMARK.c
> +++ b/net/netfilter/xt_SECMARK.c
> @@ -49,13 +49,14 @@ secmark_tg(struct sk_buff *skb, const struct xt_action_param *par)
>
> static int checkentry_lsm(struct xt_secmark_target_info *info)
> {
> + struct lsmblob blob;
> int err;
>
> info->secctx[SECMARK_SECCTX_MAX - 1] = '\0';
> info->secid = 0;
>
> err = security_secctx_to_secid(info->secctx, strlen(info->secctx),
> - &info->secid);
> + &blob);
> if (err) {
> if (err == -EINVAL)
> pr_info_ratelimited("invalid security context \'%s\'\n",
> @@ -63,6 +64,8 @@ static int checkentry_lsm(struct xt_secmark_target_info *info)
> return err;
> }
>
> + /* scaffolding during the transition */
> + info->secid = blob.secid[0];
> if (!info->secid) {
> pr_info_ratelimited("unable to map security context \'%s\'\n",
> info->secctx);
> diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
> index c92894c3e40a..2976370e41aa 100644
> --- a/net/netlabel/netlabel_unlabeled.c
> +++ b/net/netlabel/netlabel_unlabeled.c
> @@ -895,7 +895,7 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
> void *addr;
> void *mask;
> u32 addr_len;
> - u32 secid;
> + struct lsmblob blob;
> struct netlbl_audit audit_info;
>
> /* Don't allow users to add both IPv4 and IPv6 addresses for a
> @@ -919,12 +919,13 @@ static int netlbl_unlabel_staticadd(struct sk_buff *skb,
> ret_val = security_secctx_to_secid(
> nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> - &secid);
> + &blob);
> if (ret_val != 0)
> return ret_val;
>
> + /* scaffolding with the [0] */
> return netlbl_unlhsh_add(&init_net,
> - dev_name, addr, mask, addr_len, secid,
> + dev_name, addr, mask, addr_len, blob.secid[0],
> &audit_info);
> }
>
> @@ -946,7 +947,7 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
> void *addr;
> void *mask;
> u32 addr_len;
> - u32 secid;
> + struct lsmblob blob;
> struct netlbl_audit audit_info;
>
> /* Don't allow users to add both IPv4 and IPv6 addresses for a
> @@ -968,12 +969,13 @@ static int netlbl_unlabel_staticadddef(struct sk_buff *skb,
> ret_val = security_secctx_to_secid(
> nla_data(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> nla_len(info->attrs[NLBL_UNLABEL_A_SECCTX]),
> - &secid);
> + &blob);
> if (ret_val != 0)
> return ret_val;
>
> + /* scaffolding with the [0] */
> return netlbl_unlhsh_add(&init_net,
> - NULL, addr, mask, addr_len, secid,
> + NULL, addr, mask, addr_len, blob.secid[0],
> &audit_info);
> }
>
> diff --git a/security/security.c b/security/security.c
> index c7b3d1a294ad..cb1545bfe8c5 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1999,10 +1999,20 @@ int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
> }
> EXPORT_SYMBOL(security_secid_to_secctx);
>
> -int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
> +int security_secctx_to_secid(const char *secdata, u32 seclen,
> + struct lsmblob *blob)
> {
> - *secid = 0;
> - return call_int_hook(secctx_to_secid, 0, secdata, seclen, secid);
> + struct security_hook_list *hp;
> + int rc;
> +
> + lsmblob_init(blob, 0);
> + hlist_for_each_entry(hp, &security_hook_heads.secctx_to_secid, list) {
> + rc = hp->hook.secctx_to_secid(secdata, seclen,
> + &blob->secid[hp->slot]);
> + if (rc != 0)
> + return rc;
> + }
> + return 0;
> }
> EXPORT_SYMBOL(security_secctx_to_secid);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 07/24] net: Prepare UDS for secuirty module stacking
From: Kees Cook @ 2019-06-22 22:43 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-8-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:16AM -0700, Casey Schaufler wrote:
> Change the data used in UDS SO_PEERSEC processing from a
> secid to a more general struct lsmblob. Update the
> security_socket_getpeersec_dgram() interface to use the
> lsmblob. There is a small amount of scaffolding code
> that will come out when the security_secid_to_secctx()
> code is brought in line with the lsmblob.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/security.h | 7 +++++--
> include/net/af_unix.h | 2 +-
> include/net/scm.h | 8 +++++---
> net/ipv4/ip_sockglue.c | 8 +++++---
> net/unix/af_unix.c | 6 +++---
> security/security.c | 16 +++++++++++++---
> 6 files changed, 32 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 4a78516cc74a..905830a90745 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -1276,7 +1276,8 @@ int security_socket_shutdown(struct socket *sock, int how);
> int security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb);
> int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
> int __user *optlen, unsigned len);
> -int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid);
> +int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
> + struct lsmblob *blob);
> int security_sk_alloc(struct sock *sk, int family, gfp_t priority);
> void security_sk_free(struct sock *sk);
> void security_sk_clone(const struct sock *sk, struct sock *newsk);
> @@ -1414,7 +1415,9 @@ static inline int security_socket_getpeersec_stream(struct socket *sock, char __
> return -ENOPROTOOPT;
> }
>
> -static inline int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
> +static inline int security_socket_getpeersec_dgram(struct socket *sock,
> + struct sk_buff *skb,
> + struct lsmblob *blob)
> {
> return -ENOPROTOOPT;
> }
> diff --git a/include/net/af_unix.h b/include/net/af_unix.h
> index 3426d6dacc45..933492c08b8c 100644
> --- a/include/net/af_unix.h
> +++ b/include/net/af_unix.h
> @@ -36,7 +36,7 @@ struct unix_skb_parms {
> kgid_t gid;
> struct scm_fp_list *fp; /* Passed files */
> #ifdef CONFIG_SECURITY_NETWORK
> - u32 secid; /* Security ID */
> + struct lsmblob lsmblob; /* Security LSM data */
> #endif
> u32 consumed;
> } __randomize_layout;
> diff --git a/include/net/scm.h b/include/net/scm.h
> index 1ce365f4c256..e2e71c4bf9d0 100644
> --- a/include/net/scm.h
> +++ b/include/net/scm.h
> @@ -33,7 +33,7 @@ struct scm_cookie {
> struct scm_fp_list *fp; /* Passed files */
> struct scm_creds creds; /* Skb credentials */
> #ifdef CONFIG_SECURITY_NETWORK
> - u32 secid; /* Passed security ID */
> + struct lsmblob lsmblob; /* Passed LSM data */
> #endif
> };
>
> @@ -46,7 +46,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl);
> #ifdef CONFIG_SECURITY_NETWORK
> static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
> {
> - security_socket_getpeersec_dgram(sock, NULL, &scm->secid);
> + security_socket_getpeersec_dgram(sock, NULL, &scm->lsmblob);
> }
> #else
> static __inline__ void unix_get_peersec_dgram(struct socket *sock, struct scm_cookie *scm)
> @@ -97,7 +97,9 @@ static inline void scm_passec(struct socket *sock, struct msghdr *msg, struct sc
> int err;
>
> if (test_bit(SOCK_PASSSEC, &sock->flags)) {
> - err = security_secid_to_secctx(scm->secid, &secdata, &seclen);
> + /* Scaffolding - it has to be element 0 for now */
> + err = security_secid_to_secctx(scm->lsmblob.secid[0],
> + &secdata, &seclen);
>
> if (!err) {
> put_cmsg(msg, SOL_SOCKET, SCM_SECURITY, seclen, secdata);
> diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
> index 82f341e84fae..2a5c868ce135 100644
> --- a/net/ipv4/ip_sockglue.c
> +++ b/net/ipv4/ip_sockglue.c
> @@ -130,15 +130,17 @@ static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
>
> static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
> {
> + struct lsmblob lb;
> char *secdata;
> - u32 seclen, secid;
> + u32 seclen;
> int err;
>
> - err = security_socket_getpeersec_dgram(NULL, skb, &secid);
> + err = security_socket_getpeersec_dgram(NULL, skb, &lb);
> if (err)
> return;
>
> - err = security_secid_to_secctx(secid, &secdata, &seclen);
> + /* Scaffolding - it has to be element 0 */
> + err = security_secid_to_secctx(lb.secid[0], &secdata, &seclen);
> if (err)
> return;
>
> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
> index ddb838a1b74c..c50a004a1389 100644
> --- a/net/unix/af_unix.c
> +++ b/net/unix/af_unix.c
> @@ -143,17 +143,17 @@ static struct hlist_head *unix_sockets_unbound(void *addr)
> #ifdef CONFIG_SECURITY_NETWORK
> static void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
> {
> - UNIXCB(skb).secid = scm->secid;
> + UNIXCB(skb).lsmblob = scm->lsmblob;
> }
>
> static inline void unix_set_secdata(struct scm_cookie *scm, struct sk_buff *skb)
> {
> - scm->secid = UNIXCB(skb).secid;
> + scm->lsmblob = UNIXCB(skb).lsmblob;
> }
>
> static inline bool unix_secdata_eq(struct scm_cookie *scm, struct sk_buff *skb)
> {
> - return (scm->secid == UNIXCB(skb).secid);
> + return lsmblob_equal(&scm->lsmblob, &(UNIXCB(skb).lsmblob));
> }
> #else
> static inline void unix_get_secdata(struct scm_cookie *scm, struct sk_buff *skb)
> diff --git a/security/security.c b/security/security.c
> index 43f8018b9e13..c7b3d1a294ad 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2137,10 +2137,20 @@ int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
> optval, optlen, len);
> }
>
> -int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
> +int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
> + struct lsmblob *blob)
> {
> - return call_int_hook(socket_getpeersec_dgram, -ENOPROTOOPT, sock,
> - skb, secid);
> + struct security_hook_list *hp;
> + int rc = -ENOPROTOOPT;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_dgram,
> + list) {
> + rc = hp->hook.socket_getpeersec_dgram(sock, skb,
> + &blob->secid[hp->slot]);
> + if (rc != 0)
> + break;
> + }
> + return rc;
> }
> EXPORT_SYMBOL(security_socket_getpeersec_dgram);
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 06/24] LSM: Use lsmblob in security_kernel_act_as
From: Kees Cook @ 2019-06-22 22:43 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-7-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:15AM -0700, Casey Schaufler wrote:
> Change the security_kernel_act_as interface to use a lsmblob
> structure in place of the single u32 secid in support of
> module stacking. Change it's only caller, set_security_override,
> to do the same. Change that one's only caller,
> set_security_override_from_ctx, to call it with the new
> parameter type.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/cred.h | 3 ++-
> include/linux/security.h | 5 +++--
> kernel/cred.c | 10 ++++++----
> security/security.c | 12 ++++++++++--
> 4 files changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/cred.h b/include/linux/cred.h
> index efb6edf32de7..9a21c376ed97 100644
> --- a/include/linux/cred.h
> +++ b/include/linux/cred.h
> @@ -22,6 +22,7 @@
>
> struct cred;
> struct inode;
> +struct lsmblob;
>
> /*
> * COW Supplementary groups list
> @@ -165,7 +166,7 @@ extern const struct cred *override_creds(const struct cred *);
> extern void revert_creds(const struct cred *);
> extern struct cred *prepare_kernel_cred(struct task_struct *);
> extern int change_create_files_as(struct cred *, struct inode *);
> -extern int set_security_override(struct cred *, u32);
> +extern int set_security_override(struct cred *, struct lsmblob *);
> extern int set_security_override_from_ctx(struct cred *, const char *);
> extern int set_create_files_as(struct cred *, struct inode *);
> extern int cred_fscmp(const struct cred *, const struct cred *);
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 52d89c4a9594..4a78516cc74a 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -384,7 +384,7 @@ void security_cred_free(struct cred *cred);
> int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp);
> void security_transfer_creds(struct cred *new, const struct cred *old);
> void security_cred_getsecid(const struct cred *c, u32 *secid);
> -int security_kernel_act_as(struct cred *new, u32 secid);
> +int security_kernel_act_as(struct cred *new, struct lsmblob *blob);
> int security_kernel_create_files_as(struct cred *new, struct inode *inode);
> int security_kernel_module_request(char *kmod_name);
> int security_kernel_load_data(enum kernel_load_data_id id);
> @@ -967,7 +967,8 @@ static inline void security_transfer_creds(struct cred *new,
> {
> }
>
> -static inline int security_kernel_act_as(struct cred *cred, u32 secid)
> +static inline int security_kernel_act_as(struct cred *cred,
> + struct lsmblob *blob)
> {
> return 0;
> }
> diff --git a/kernel/cred.c b/kernel/cred.c
> index 45d77284aed0..71c14dda107e 100644
> --- a/kernel/cred.c
> +++ b/kernel/cred.c
> @@ -701,14 +701,14 @@ EXPORT_SYMBOL(prepare_kernel_cred);
> /**
> * set_security_override - Set the security ID in a set of credentials
> * @new: The credentials to alter
> - * @secid: The LSM security ID to set
> + * @blob: The LSM security information to set
> *
> * Set the LSM security ID in a set of credentials so that the subjective
> * security is overridden when an alternative set of credentials is used.
> */
> -int set_security_override(struct cred *new, u32 secid)
> +int set_security_override(struct cred *new, struct lsmblob *blob)
> {
> - return security_kernel_act_as(new, secid);
> + return security_kernel_act_as(new, blob);
> }
> EXPORT_SYMBOL(set_security_override);
>
> @@ -724,6 +724,7 @@ EXPORT_SYMBOL(set_security_override);
> */
> int set_security_override_from_ctx(struct cred *new, const char *secctx)
> {
> + struct lsmblob blob;
> u32 secid;
> int ret;
>
> @@ -731,7 +732,8 @@ int set_security_override_from_ctx(struct cred *new, const char *secctx)
> if (ret < 0)
> return ret;
>
> - return set_security_override(new, secid);
> + lsmblob_init(&blob, secid);
> + return set_security_override(new, &blob);
> }
> EXPORT_SYMBOL(set_security_override_from_ctx);
>
> diff --git a/security/security.c b/security/security.c
> index 4692f44718c6..43f8018b9e13 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1646,9 +1646,17 @@ void security_cred_getsecid(const struct cred *c, u32 *secid)
> }
> EXPORT_SYMBOL(security_cred_getsecid);
>
> -int security_kernel_act_as(struct cred *new, u32 secid)
> +int security_kernel_act_as(struct cred *new, struct lsmblob *blob)
> {
> - return call_int_hook(kernel_act_as, 0, new, secid);
> + struct security_hook_list *hp;
> + int rc;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.kernel_act_as, list) {
> + rc = hp->hook.kernel_act_as(new, blob->secid[hp->slot]);
> + if (rc != 0)
> + return rc;
> + }
> + return 0;
> }
>
> int security_kernel_create_files_as(struct cred *new, struct inode *inode)
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 05/24] Use lsmblob in security_audit_rule_match
From: Kees Cook @ 2019-06-22 22:43 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-6-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:14AM -0700, Casey Schaufler wrote:
> Change the secid parameter of security_audit_rule_match
> to a lsmblob structure pointer. Pass the entry from the
> lsmblob structure for the approprite slot to the LSM hook.
>
> Change the users of security_audit_rule_match to use the
> lsmblob instead of a u32. In some cases this requires a
> temporary conversion using lsmblob_init() that will go
> away when other interfaces get converted.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/security.h | 7 ++++---
> kernel/auditfilter.c | 4 +++-
> kernel/auditsc.c | 14 ++++++++++----
> security/integrity/ima/ima.h | 4 ++--
> security/integrity/ima/ima_policy.c | 7 +++++--
> security/security.c | 14 ++++++++++++--
> 6 files changed, 36 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 0aa9417a5762..52d89c4a9594 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -1757,7 +1757,8 @@ static inline int security_key_getsecurity(struct key *key, char **_buffer)
> #ifdef CONFIG_SECURITY
> int security_audit_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
> int security_audit_rule_known(struct audit_krule *krule);
> -int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule);
> +int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
> + void *lsmrule);
> void security_audit_rule_free(void *lsmrule);
>
> #else
> @@ -1773,8 +1774,8 @@ static inline int security_audit_rule_known(struct audit_krule *krule)
> return 0;
> }
>
> -static inline int security_audit_rule_match(u32 secid, u32 field, u32 op,
> - void *lsmrule)
> +static inline int security_audit_rule_match(struct lsmblob *blob, u32 field,
> + u32 op, void *lsmrule)
> {
> return 0;
> }
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index 63f8b3f26fab..da211065160f 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -1324,6 +1324,7 @@ int audit_filter(int msgtype, unsigned int listtype)
> struct audit_field *f = &e->rule.fields[i];
> pid_t pid;
> u32 sid;
> + struct lsmblob blob;
>
> switch (f->type) {
> case AUDIT_PID:
> @@ -1354,7 +1355,8 @@ int audit_filter(int msgtype, unsigned int listtype)
> case AUDIT_SUBJ_CLR:
> if (f->lsm_rule) {
> security_task_getsecid(current, &sid);
> - result = security_audit_rule_match(sid,
> + lsmblob_init(&blob, sid);
> + result = security_audit_rule_match(&blob,
> f->type, f->op, f->lsm_rule);
> }
> break;
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index d1eab1d4a930..18ee5556c086 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -445,6 +445,7 @@ static int audit_filter_rules(struct task_struct *tsk,
> const struct cred *cred;
> int i, need_sid = 1;
> u32 sid;
> + struct lsmblob blob;
> unsigned int sessionid;
>
> cred = rcu_dereference_check(tsk->cred, tsk == current || task_creation);
> @@ -630,7 +631,9 @@ static int audit_filter_rules(struct task_struct *tsk,
> security_task_getsecid(tsk, &sid);
> need_sid = 0;
> }
> - result = security_audit_rule_match(sid, f->type,
> + lsmblob_init(&blob, sid);
> + result = security_audit_rule_match(&blob,
> + f->type,
> f->op,
> f->lsm_rule);
> }
> @@ -645,15 +648,17 @@ static int audit_filter_rules(struct task_struct *tsk,
> if (f->lsm_rule) {
> /* Find files that match */
> if (name) {
> + lsmblob_init(&blob, name->osid);
> result = security_audit_rule_match(
> - name->osid,
> + &blob,
> f->type,
> f->op,
> f->lsm_rule);
> } else if (ctx) {
> list_for_each_entry(n, &ctx->names_list, list) {
> + lsmblob_init(&blob, n->osid);
> if (security_audit_rule_match(
> - n->osid,
> + &blob,
> f->type,
> f->op,
> f->lsm_rule)) {
> @@ -665,7 +670,8 @@ static int audit_filter_rules(struct task_struct *tsk,
> /* Find ipc objects that match */
> if (!ctx || ctx->type != AUDIT_IPC)
> break;
> - if (security_audit_rule_match(ctx->ipc.osid,
> + lsmblob_init(&blob, ctx->ipc.osid);
> + if (security_audit_rule_match(&blob,
> f->type, f->op,
> f->lsm_rule))
> ++result;
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index d213e835c498..5a337239d9e4 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -307,8 +307,8 @@ static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
> return -EINVAL;
> }
>
> -static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
> - void *lsmrule)
> +static inline int security_filter_rule_match(struct lsmblob *blob, u32 field,
> + u32 op, void *lsmrule)
> {
> return -EINVAL;
> }
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index e0cc323f948f..e7b8ce942950 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -327,6 +327,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> for (i = 0; i < MAX_LSM_RULES; i++) {
> int rc = 0;
> u32 osid;
> + struct lsmblob blob;
> int retried = 0;
>
> if (!rule->lsm[i].rule)
> @@ -337,7 +338,8 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> case LSM_OBJ_ROLE:
> case LSM_OBJ_TYPE:
> security_inode_getsecid(inode, &osid);
> - rc = security_filter_rule_match(osid,
> + lsmblob_init(&blob, osid);
> + rc = security_filter_rule_match(&blob,
> rule->lsm[i].type,
> Audit_equal,
> rule->lsm[i].rule);
> @@ -345,7 +347,8 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
> case LSM_SUBJ_USER:
> case LSM_SUBJ_ROLE:
> case LSM_SUBJ_TYPE:
> - rc = security_filter_rule_match(secid,
> + lsmblob_init(&blob, secid);
> + rc = security_filter_rule_match(&blob,
> rule->lsm[i].type,
> Audit_equal,
> rule->lsm[i].rule);
> diff --git a/security/security.c b/security/security.c
> index 7618c761060d..4692f44718c6 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2452,9 +2452,19 @@ void security_audit_rule_free(void *lsmrule)
> call_void_hook(audit_rule_free, lsmrule);
> }
>
> -int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
> +int security_audit_rule_match(struct lsmblob *blob, u32 field, u32 op,
> + void *lsmrule)
> {
> - return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule);
> + struct security_hook_list *hp;
> + int rc;
> +
> + hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) {
> + rc = hp->hook.audit_rule_match(blob->secid[hp->slot], field,
> + op, lsmrule);
> + if (rc != 0)
> + return rc;
> + }
> + return 0;
> }
> #endif /* CONFIG_AUDIT */
>
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH v3 04/24] LSM: Create and manage the lsmblob data structure.
From: Kees Cook @ 2019-06-22 22:42 UTC (permalink / raw)
To: Casey Schaufler
Cc: casey.schaufler, jmorris, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <20190621185233.6766-5-casey@schaufler-ca.com>
On Fri, Jun 21, 2019 at 11:52:13AM -0700, Casey Schaufler wrote:
> When more than one security module is exporting data to
> audit and networking sub-systems a single 32 bit integer
> is no longer sufficient to represent the data. Add a
> structure to be used instead.
>
> The lsmblob structure is currently an array of
> u32 "secids". There is an entry for each of the
> security modules built into the system that would
> use secids if active. The system assigns the module
> a "slot" when it registers hooks. If modules are
> compiled in but not registered there will be unused
> slots.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> include/linux/lsm_hooks.h | 1 +
> include/linux/security.h | 62 +++++++++++++++++++++++++++++++++++++++
> security/security.c | 36 +++++++++++++++++++++++
> 3 files changed, 99 insertions(+)
>
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 3fe39abccc8f..4d1ddf1a2aa6 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -2038,6 +2038,7 @@ struct security_hook_list {
> struct hlist_head *head;
> union security_list_options hook;
> char *lsm;
> + int slot;
> } __randomize_layout;
>
> /*
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 49f2685324b0..0aa9417a5762 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -76,6 +76,68 @@ enum lsm_event {
> LSM_POLICY_CHANGE,
> };
>
> +/*
> + * Data exported by the security modules
> + */
> +#define LSMBLOB_ENTRIES ( \
> + (IS_ENABLED(CONFIG_SECURITY_SELINUX) ? 1 : 0) + \
> + (IS_ENABLED(CONFIG_SECURITY_SMACK) ? 1 : 0) + \
> + (IS_ENABLED(CONFIG_SECURITY_APPARMOR) ? 1 : 0))
> +
> +struct lsmblob {
> + u32 secid[LSMBLOB_ENTRIES];
> +};
> +
> +#define LSMBLOB_INVALID -1
> +
> +/**
> + * lsmblob_init - initialize an lsmblob structure.
> + * @blob: Pointer to the data to initialize
> + * @secid: The initial secid value
> + *
> + * Set all secid for all modules to the specified value.
> + */
> +static inline void lsmblob_init(struct lsmblob *blob, u32 secid)
> +{
> + int i;
> +
> + for (i = 0; i < LSMBLOB_ENTRIES; i++)
> + blob->secid[i] = secid;
> +}
> +
> +/**
> + * lsmblob_is_set - report if there is an value in the lsmblob
> + * @blob: Pointer to the exported LSM data
> + *
> + * Returns true if there is a secid set, false otherwise
> + */
> +static inline bool lsmblob_is_set(struct lsmblob *blob)
> +{
> + int i;
> +
> + for (i = 0; i < LSMBLOB_ENTRIES; i++)
> + if (blob->secid[i] != 0)
> + return true;
> + return false;
> +}
> +
> +/**
> + * lsmblob_equal - report if the two lsmblob's are equal
> + * @bloba: Pointer to one LSM data
> + * @blobb: Pointer to the other LSM data
> + *
> + * Returns true if all entries in the two are equal, false otherwise
> + */
> +static inline bool lsmblob_equal(struct lsmblob *bloba, struct lsmblob *blobb)
> +{
> + int i;
> +
> + for (i = 0; i < LSMBLOB_ENTRIES; i++)
> + if (bloba->secid[i] != blobb->secid[i])
> + return false;
> + return true;
> +}
> +
> /* These functions are in security/commoncap.c */
> extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
> int cap, unsigned int opts);
> diff --git a/security/security.c b/security/security.c
> index d05f00a40e82..7618c761060d 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -317,6 +317,7 @@ static void __init ordered_lsm_init(void)
> init_debug("sock blob size = %d\n", blob_sizes.lbs_sock);
> init_debug("superblock blob size = %d\n", blob_sizes.lbs_superblock);
> init_debug("task blob size = %d\n", blob_sizes.lbs_task);
> + init_debug("lsmblob size = %lu\n", sizeof(struct lsmblob));
>
> /*
> * Create any kmem_caches needed for blobs
> @@ -420,6 +421,11 @@ static int lsm_append(char *new, char **result)
> return 0;
> }
>
> +/*
> + * Current index to use while initializing the lsmblob secid list.
> + */
> +static int lsm_slot __initdata;
> +
> /**
> * security_add_hooks - Add a modules hooks to the hook lists.
> * @hooks: the hooks to add
> @@ -427,15 +433,45 @@ static int lsm_append(char *new, char **result)
> * @lsm: the name of the security module
> *
> * Each LSM has to register its hooks with the infrastructure.
> + * If the LSM is using hooks that export secids allocate a slot
> + * for it in the lsmblob.
> */
> void __init security_add_hooks(struct security_hook_list *hooks, int count,
> char *lsm)
> {
> + int slot = LSMBLOB_INVALID;
> int i;
>
> for (i = 0; i < count; i++) {
> hooks[i].lsm = lsm;
> hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
> + /*
> + * If this is one of the hooks that uses a secid
> + * note it so that a slot can in allocated for the
> + * secid in the lsmblob structure.
> + */
> + if (hooks[i].head == &security_hook_heads.audit_rule_match ||
> + hooks[i].head == &security_hook_heads.kernel_act_as ||
> + hooks[i].head ==
> + &security_hook_heads.socket_getpeersec_dgram ||
> + hooks[i].head == &security_hook_heads.getprocattr ||
> + hooks[i].head == &security_hook_heads.setprocattr ||
> + hooks[i].head == &security_hook_heads.secctx_to_secid ||
> + hooks[i].head == &security_hook_heads.secid_to_secctx ||
> + hooks[i].head == &security_hook_heads.ipc_getsecid ||
> + hooks[i].head == &security_hook_heads.task_getsecid ||
> + hooks[i].head == &security_hook_heads.inode_getsecid ||
> + hooks[i].head == &security_hook_heads.cred_getsecid) {
> + if (slot == LSMBLOB_INVALID) {
> + slot = lsm_slot++;
> + if (slot >= LSMBLOB_ENTRIES)
> + panic("%s Too many LSMs registered.\n",
> + __func__);
> + init_debug("%s assigned lsmblob slot %d\n",
> + hooks[i].lsm, slot);
> + }
> + }
> + hooks[i].slot = slot;
> }
> if (lsm_append(lsm, &lsm_names) < 0)
> panic("%s - Cannot get early memory.\n", __func__);
> --
> 2.20.1
>
--
Kees Cook
^ permalink raw reply
* Re: [PATCH] structleak: disable BYREF_ALL in combination with KASAN_STACK
From: Kees Cook @ 2019-06-22 20:26 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: Arnd Bergmann, Andrey Ryabinin, Alexander Potapenko,
Dmitry Vyukov, kasan-dev, Alexander Popov, James Morris,
Serge E. Hallyn, Masahiro Yamada, LSM List,
Linux Kernel Mailing List
In-Reply-To: <CAKv+Gu9p017iPva85dPMdnKW_MSOUcthqcy7KDhGEYCN7=C_SA@mail.gmail.com>
On Fri, Jun 21, 2019 at 03:50:02PM +0200, Ard Biesheuvel wrote:
> On Fri, 21 Jun 2019 at 15:44, Arnd Bergmann <arnd@arndb.de> wrote:
> > One pattern I have seen here is temporary variables from macros or
> > inline functions whose lifetime now extends over the entire function
> > rather than just the basic block in which they are defined, see e.g.
> > lpfc_debug_dump_qe() being inlined multiple times into
> > lpfc_debug_dump_all_queues(). Each instance of the local
> > "char line_buf[LPFC_LBUF_SZ];" seems to add on to the previous
> > one now, where the behavior without the structleak plugin is that
> > they don't.
Ewww.
> Right, that seems to be due to the fact that this code
>
> /* split the first bb where we can put the forced initializers */
> gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
> bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
> if (!single_pred_p(bb)) {
> split_edge(single_succ_edge(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
> gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
> }
>
> puts all the initializers at the beginning of the function rather than
> inside the scope of the definition.
Do you see a sane way to improve this? I hadn't noticed that this
actually moved it up to the start of the function. :(
--
Kees Cook
^ permalink raw reply
* Re: [PATCH V34 10/29] hibernate: Disable when the kernel is locked down
From: Pavel Machek @ 2019-06-22 17:52 UTC (permalink / raw)
To: Matthew Garrett
Cc: jmorris, linux-security-module, linux-kernel, linux-api,
Josh Boyer, David Howells, Matthew Garrett, rjw, linux-pm, jikos
In-Reply-To: <20190622000358.19895-11-matthewgarrett@google.com>
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On Fri 2019-06-21 17:03:39, Matthew Garrett wrote:
> From: Josh Boyer <jwboyer@fedoraproject.org>
>
> There is currently no way to verify the resume image when returning
> from hibernate. This might compromise the signed modules trust model,
> so until we can work with signed hibernate images we disable it when the
> kernel is locked down.
I keep getting these...
IIRC suse has patches to verify the images.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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^ permalink raw reply
* Re: Stacked LSMs (was Re: [PATCH v2 00/25] LSM: Module stacking for AppArmor)
From: Mickaël Salaün @ 2019-06-22 14:15 UTC (permalink / raw)
To: Kees Cook, Salvatore Mesoraca, James Morris
Cc: Casey Schaufler, casey.schaufler, linux-security-module, selinux,
john.johansen, penguin-kernel, paul, sds
In-Reply-To: <201906201029.0476F14A@keescook>
On June 20, 2019 7:33:25 PM GMT+02:00, Kees Cook <keescook@chromium.org> wrote:
> On Thu, Jun 20, 2019 at 06:08:03AM +1000, James Morris wrote:
> > We extended stacking support in March to allow Landlock and SARA to
> be
> > merged and have not seen anything from them since.
>
> Salvatore and Mickaël, have you had a chance to look at the stacking
> changes? I'd love to see work progress on your LSMs now that the
> stacking prerequisites have landed.
>
> Thanks!
Yes, I successfully updated Landlock as a stackable LSM. I also worked on removing some code (and related features, for now) to get smaller patches for the next round, and I tried to get rid of the VFS modifications. I still need to update the tests, rebase a last time and review everything before sending a new patch set, hopefully next week.
Mickaël
^ permalink raw reply
* [PATCH v2] tomoyo: Don't check open/getattr permission on sockets.
From: Tetsuo Handa @ 2019-06-22 4:45 UTC (permalink / raw)
To: Al Viro
Cc: linux-fsdevel, syzbot, jmorris, linux-kernel,
linux-security-module, serge, syzkaller-bugs, takedakn,
David S. Miller
In-Reply-To: <20190618204933.GE17978@ZenIV.linux.org.uk>
On 2019/06/19 5:49, Al Viro wrote:
> On Sun, Jun 16, 2019 at 03:49:00PM +0900, Tetsuo Handa wrote:
>> Hello, Al.
>>
>> Q1: Do you agree that we should fix TOMOYO side rather than SOCKET_I()->sk
>> management.
>
> You do realize that sockets are not unique in that respect, right?
> All kinds of interesting stuff can be accessed via /proc/*/fd/*, and
> it _can_ be closed under you. So I'd suggest checking how your code
> copes with similar for pipes, FIFOs, epoll, etc., accessed that way...
I know all kinds of interesting stuff can be accessed via /proc/*/fd/*,
and it _can_ be closed under me.
Regarding sockets, I was accessing "struct socket" memory and
"struct sock" memory which are outside of "struct inode" memory.
But regarding other objects, I am accessing "struct dentry" memory,
"struct super_block" memory and "struct inode" memory. I'm expecting
that these memory can't be kfree()d as long as "struct path" holds
a reference. Is my expectation correct?
>
> We are _not_ going to be checking that in fs/open.c - the stuff found
> via /proc/*/fd/* can have the associated file closed by the time
> we get to calling ->open() and we won't know that until said call.
OK. Then, fixing TOMOYO side is the correct way.
>
>> Q2: Do you see any problem with using f->f_path.dentry->d_inode ?
>> Do we need to use d_backing_inode() or d_inode() ?
>
> Huh? What's wrong with file_inode(f), in the first place? And
> just when can that be NULL, while we are at it?
Oh, I was not aware of file_inode(). Thanks.
>
>>> static int tomoyo_inode_getattr(const struct path *path)
>>> {
>>> + /* It is not safe to call tomoyo_get_socket_name(). */
>>> + if (path->dentry->d_inode && S_ISSOCK(path->dentry->d_inode->i_mode))
>>> + return 0;
>
> Can that be called for a negative?
>
I check for NULL when I'm not sure it is guaranteed to hold a valid pointer.
You meant "we are sure that path->dentry->d_inode is valid", don't you?
By the way, "negative" associates with IS_ERR() range. I guess that
"NULL" is the better name...
Anyway, here is V2 patch.
From c63c4074300921d6d1c33c3b8dc9c84ebfededf5 Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Sat, 22 Jun 2019 13:14:26 +0900
Subject: [PATCH v2] tomoyo: Don't check open/getattr permission on sockets.
syzbot is reporting that use of SOCKET_I()->sk from open() can result in
use after free problem [1], for socket's inode is still reachable via
/proc/pid/fd/n despite destruction of SOCKET_I()->sk already completed.
But there is no point with calling security_file_open() on sockets
because open("/proc/pid/fd/n", !O_PATH) on sockets fails with -ENXIO.
There is some point with calling security_inode_getattr() on sockets
because stat("/proc/pid/fd/n") and fstat(open("/proc/pid/fd/n", O_PATH))
are valid. If we want to access "struct sock"->sk_{family,type,protocol}
fields, we will need to use security_socket_post_create() hook and
security_inode_free() hook in order to remember these fields because
security_sk_free() hook is called before the inode is destructed. But
since information which can be protected by checking
security_inode_getattr() on sockets is trivial, let's not be bothered by
"struct inode"->i_security management.
There is point with calling security_file_ioctl() on sockets. Since
ioctl(open("/proc/pid/fd/n", O_PATH)) is invalid, security_file_ioctl()
on sockets should remain safe.
[1] https://syzkaller.appspot.com/bug?id=73d590010454403d55164cca23bd0565b1eb3b74
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+0341f6a4d729d4e0acf1@syzkaller.appspotmail.com>
---
security/tomoyo/tomoyo.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c
index 716c92e..8ea3f5d 100644
--- a/security/tomoyo/tomoyo.c
+++ b/security/tomoyo/tomoyo.c
@@ -126,6 +126,9 @@ static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
*/
static int tomoyo_inode_getattr(const struct path *path)
{
+ /* It is not safe to call tomoyo_get_socket_name(). */
+ if (S_ISSOCK(d_inode(path->dentry)->i_mode))
+ return 0;
return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, path, NULL);
}
@@ -316,6 +319,9 @@ static int tomoyo_file_open(struct file *f)
/* Don't check read permission here if called from do_execve(). */
if (current->in_execve)
return 0;
+ /* Sockets can't be opened by open(). */
+ if (S_ISSOCK(file_inode(f)->i_mode))
+ return 0;
return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path,
f->f_flags);
}
--
1.8.3.1
^ permalink raw reply related
* [PATCH V34 01/29] security: Support early LSMs
From: Matthew Garrett @ 2019-06-22 0:03 UTC (permalink / raw)
To: jmorris
Cc: linux-security-module, linux-kernel, linux-api, Matthew Garrett,
Matthew Garrett
In-Reply-To: <20190622000358.19895-1-matthewgarrett@google.com>
The lockdown module is intended to allow for kernels to be locked down
early in boot - sufficiently early that we don't have the ability to
kmalloc() yet. Add support for early initialisation of some LSMs, and
then add them to the list of names when we do full initialisation later.
Early LSMs are initialised in link order and cannot be overridden via
boot parameters, and cannot make use of kmalloc() (since the allocator
isn't initialised yet).
Signed-off-by: Matthew Garrett <mjg59@google.com>
---
include/asm-generic/vmlinux.lds.h | 8 ++++-
include/linux/lsm_hooks.h | 6 ++++
include/linux/security.h | 1 +
init/main.c | 1 +
security/security.c | 50 ++++++++++++++++++++++++++-----
5 files changed, 57 insertions(+), 9 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index f8f6f04c4453..e1963352fdb6 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -208,8 +208,13 @@
__start_lsm_info = .; \
KEEP(*(.lsm_info.init)) \
__end_lsm_info = .;
+#define EARLY_LSM_TABLE() . = ALIGN(8); \
+ __start_early_lsm_info = .; \
+ KEEP(*(.early_lsm_info.init)) \
+ __end_early_lsm_info = .;
#else
#define LSM_TABLE()
+#define EARLY_LSM_TABLE()
#endif
#define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name)
@@ -610,7 +615,8 @@
ACPI_PROBE_TABLE(irqchip) \
ACPI_PROBE_TABLE(timer) \
EARLYCON_TABLE() \
- LSM_TABLE()
+ LSM_TABLE() \
+ EARLY_LSM_TABLE()
#define INIT_TEXT \
*(.init.text .init.text.*) \
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index a240a3fc5fc4..66fd1eac7a32 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -2085,12 +2085,18 @@ struct lsm_info {
};
extern struct lsm_info __start_lsm_info[], __end_lsm_info[];
+extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[];
#define DEFINE_LSM(lsm) \
static struct lsm_info __lsm_##lsm \
__used __section(.lsm_info.init) \
__aligned(sizeof(unsigned long))
+#define DEFINE_EARLY_LSM(lsm) \
+ static struct lsm_info __early_lsm_##lsm \
+ __used __section(.early_lsm_info.init) \
+ __aligned(sizeof(unsigned long))
+
#ifdef CONFIG_SECURITY_SELINUX_DISABLE
/*
* Assuring the safety of deleting a security module is up to
diff --git a/include/linux/security.h b/include/linux/security.h
index 49f2685324b0..1bb6fb2f1523 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -194,6 +194,7 @@ int unregister_lsm_notifier(struct notifier_block *nb);
/* prototypes */
extern int security_init(void);
+extern int early_security_init(void);
/* Security operations */
int security_binder_set_context_mgr(struct task_struct *mgr);
diff --git a/init/main.c b/init/main.c
index 598e278b46f7..f3faeb89c75f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -563,6 +563,7 @@ asmlinkage __visible void __init start_kernel(void)
boot_cpu_init();
page_address_init();
pr_notice("%s", linux_banner);
+ early_security_init();
setup_arch(&command_line);
/*
* Set up the the initial canary and entropy after arch
diff --git a/security/security.c b/security/security.c
index 23cbb1a295a3..487e1f3eb2df 100644
--- a/security/security.c
+++ b/security/security.c
@@ -37,6 +37,7 @@
/* How many LSMs were built into the kernel? */
#define LSM_COUNT (__end_lsm_info - __start_lsm_info)
+#define EARLY_LSM_COUNT (__end_early_lsm_info - __start_early_lsm_info)
struct security_hook_heads security_hook_heads __lsm_ro_after_init;
static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
@@ -281,6 +282,8 @@ static void __init ordered_lsm_parse(const char *order, const char *origin)
static void __init lsm_early_cred(struct cred *cred);
static void __init lsm_early_task(struct task_struct *task);
+static int lsm_append(const char *new, char **result);
+
static void __init ordered_lsm_init(void)
{
struct lsm_info **lsm;
@@ -327,6 +330,26 @@ static void __init ordered_lsm_init(void)
kfree(ordered_lsms);
}
+int __init early_security_init(void)
+{
+ int i;
+ struct hlist_head *list = (struct hlist_head *) &security_hook_heads;
+ struct lsm_info *lsm;
+
+ for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct hlist_head);
+ i++)
+ INIT_HLIST_HEAD(&list[i]);
+
+ for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) {
+ if (!lsm->enabled)
+ lsm->enabled = &lsm_enabled_true;
+ prepare_lsm(lsm);
+ initialize_lsm(lsm);
+ }
+
+ return 0;
+}
+
/**
* security_init - initializes the security framework
*
@@ -334,14 +357,18 @@ static void __init ordered_lsm_init(void)
*/
int __init security_init(void)
{
- int i;
- struct hlist_head *list = (struct hlist_head *) &security_hook_heads;
+ struct lsm_info *lsm;
pr_info("Security Framework initializing\n");
- for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct hlist_head);
- i++)
- INIT_HLIST_HEAD(&list[i]);
+ /*
+ * Append the names of the early LSM modules now that kmalloc() is
+ * available
+ */
+ for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) {
+ if (lsm->enabled)
+ lsm_append(lsm->name, &lsm_names);
+ }
/* Load LSMs in specified order. */
ordered_lsm_init();
@@ -388,7 +415,7 @@ static bool match_last_lsm(const char *list, const char *lsm)
return !strcmp(last, lsm);
}
-static int lsm_append(char *new, char **result)
+static int lsm_append(const char *new, char **result)
{
char *cp;
@@ -426,8 +453,15 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
hooks[i].lsm = lsm;
hlist_add_tail_rcu(&hooks[i].list, hooks[i].head);
}
- if (lsm_append(lsm, &lsm_names) < 0)
- panic("%s - Cannot get early memory.\n", __func__);
+
+ /*
+ * Don't try to append during early_security_init(), we'll come back
+ * and fix this up afterwards.
+ */
+ if (slab_is_available()) {
+ if (lsm_append(lsm, &lsm_names) < 0)
+ panic("%s - Cannot get early memory.\n", __func__);
+ }
}
int call_lsm_notifier(enum lsm_event event, void *data)
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related
* [PATCH V34 02/29] security: Add a "locked down" LSM hook
From: Matthew Garrett @ 2019-06-22 0:03 UTC (permalink / raw)
To: jmorris
Cc: linux-security-module, linux-kernel, linux-api, Matthew Garrett,
Matthew Garrett
In-Reply-To: <20190622000358.19895-1-matthewgarrett@google.com>
Add a mechanism to allow LSMs to make a policy decision around whether
kernel functionality that would allow tampering with or examining the
runtime state of the kernel should be permitted.
Signed-off-by: Matthew Garrett <mjg59@google.com>
---
include/linux/lsm_hooks.h | 2 ++
include/linux/security.h | 11 +++++++++++
security/security.c | 6 ++++++
3 files changed, 19 insertions(+)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 66fd1eac7a32..df2aebc99838 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1790,6 +1790,7 @@ union security_list_options {
int (*bpf_prog_alloc_security)(struct bpf_prog_aux *aux);
void (*bpf_prog_free_security)(struct bpf_prog_aux *aux);
#endif /* CONFIG_BPF_SYSCALL */
+ int (*locked_down)(enum lockdown_reason what);
};
struct security_hook_heads {
@@ -2027,6 +2028,7 @@ struct security_hook_heads {
struct hlist_head bpf_prog_alloc_security;
struct hlist_head bpf_prog_free_security;
#endif /* CONFIG_BPF_SYSCALL */
+ struct hlist_head locked_down;
} __randomize_layout;
/*
diff --git a/include/linux/security.h b/include/linux/security.h
index 1bb6fb2f1523..9eaf02e70707 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -76,6 +76,12 @@ enum lsm_event {
LSM_POLICY_CHANGE,
};
+enum lockdown_reason {
+ LOCKDOWN_NONE,
+ LOCKDOWN_INTEGRITY_MAX,
+ LOCKDOWN_CONFIDENTIALITY_MAX,
+};
+
/* These functions are in security/commoncap.c */
extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
int cap, unsigned int opts);
@@ -389,6 +395,7 @@ void security_inode_invalidate_secctx(struct inode *inode);
int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen);
int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
+int security_locked_down(enum lockdown_reason what);
#else /* CONFIG_SECURITY */
static inline int call_lsm_notifier(enum lsm_event event, void *data)
@@ -1189,6 +1196,10 @@ static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32
{
return -EOPNOTSUPP;
}
+static inline int security_locked_down(enum lockdown_reason what)
+{
+ return 0;
+}
#endif /* CONFIG_SECURITY */
#ifdef CONFIG_SECURITY_NETWORK
diff --git a/security/security.c b/security/security.c
index 487e1f3eb2df..553f50e9a106 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2382,3 +2382,9 @@ void security_bpf_prog_free(struct bpf_prog_aux *aux)
call_void_hook(bpf_prog_free_security, aux);
}
#endif /* CONFIG_BPF_SYSCALL */
+
+int security_locked_down(enum lockdown_reason what)
+{
+ return call_int_hook(locked_down, 0, what);
+}
+EXPORT_SYMBOL(security_locked_down);
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related
* [PATCH V34 03/29] security: Add a static lockdown policy LSM
From: Matthew Garrett @ 2019-06-22 0:03 UTC (permalink / raw)
To: jmorris
Cc: linux-security-module, linux-kernel, linux-api, Matthew Garrett,
Matthew Garrett, David Howells
In-Reply-To: <20190622000358.19895-1-matthewgarrett@google.com>
While existing LSMs can be extended to handle lockdown policy,
distributions generally want to be able to apply a straightforward
static policy. This patch adds a simple LSM that can be configured to
reject either integrity or all lockdown queries, and can be configured
at runtime (through securityfs), boot time (via a kernel parameter) or
build time (via a kconfig option). Based on initial code by David
Howells.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: David Howells <dhowells@redhat.com>
---
.../admin-guide/kernel-parameters.txt | 9 +
include/linux/security.h | 4 +
security/Kconfig | 3 +-
security/Makefile | 2 +
security/lockdown/Kconfig | 47 +++++
security/lockdown/Makefile | 1 +
security/lockdown/lockdown.c | 172 ++++++++++++++++++
7 files changed, 237 insertions(+), 1 deletion(-)
create mode 100644 security/lockdown/Kconfig
create mode 100644 security/lockdown/Makefile
create mode 100644 security/lockdown/lockdown.c
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2b8ee90bb644..fa336f6cd5bc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2239,6 +2239,15 @@
lockd.nlm_udpport=M [NFS] Assign UDP port.
Format: <integer>
+ lockdown= [SECURITY]
+ { integrity | confidentiality }
+ Enable the kernel lockdown feature. If set to
+ integrity, kernel features that allow userland to
+ modify the running kernel are disabled. If set to
+ confidentiality, kernel features that allow userland
+ to extract confidential information from the kernel
+ are also disabled.
+
locktorture.nreaders_stress= [KNL]
Set the number of locking read-acquisition kthreads.
Defaults to being automatically set based on the
diff --git a/include/linux/security.h b/include/linux/security.h
index 9eaf02e70707..c808d344ec75 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -76,6 +76,10 @@ enum lsm_event {
LSM_POLICY_CHANGE,
};
+/*
+ * If you add to this, remember to extend lockdown_reasons in
+ * security/lockdown/lockdown.c.
+ */
enum lockdown_reason {
LOCKDOWN_NONE,
LOCKDOWN_INTEGRITY_MAX,
diff --git a/security/Kconfig b/security/Kconfig
index 1d6463fb1450..c35aa72103df 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -236,12 +236,13 @@ source "security/apparmor/Kconfig"
source "security/loadpin/Kconfig"
source "security/yama/Kconfig"
source "security/safesetid/Kconfig"
+source "security/lockdown/Kconfig"
source "security/integrity/Kconfig"
config LSM
string "Ordered list of enabled LSMs"
- default "yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
+ default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"
help
A comma-separated list of LSMs, in initialization order.
Any LSMs left off this list will be ignored. This can be
diff --git a/security/Makefile b/security/Makefile
index c598b904938f..be1dd9d2cb2f 100644
--- a/security/Makefile
+++ b/security/Makefile
@@ -11,6 +11,7 @@ subdir-$(CONFIG_SECURITY_APPARMOR) += apparmor
subdir-$(CONFIG_SECURITY_YAMA) += yama
subdir-$(CONFIG_SECURITY_LOADPIN) += loadpin
subdir-$(CONFIG_SECURITY_SAFESETID) += safesetid
+subdir-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown
# always enable default capabilities
obj-y += commoncap.o
@@ -27,6 +28,7 @@ obj-$(CONFIG_SECURITY_APPARMOR) += apparmor/
obj-$(CONFIG_SECURITY_YAMA) += yama/
obj-$(CONFIG_SECURITY_LOADPIN) += loadpin/
obj-$(CONFIG_SECURITY_SAFESETID) += safesetid/
+obj-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown/
obj-$(CONFIG_CGROUP_DEVICE) += device_cgroup.o
# Object integrity file lists
diff --git a/security/lockdown/Kconfig b/security/lockdown/Kconfig
new file mode 100644
index 000000000000..7374ba76d8eb
--- /dev/null
+++ b/security/lockdown/Kconfig
@@ -0,0 +1,47 @@
+config SECURITY_LOCKDOWN_LSM
+ bool "Basic module for enforcing kernel lockdown"
+ depends on SECURITY
+ help
+ Build support for an LSM that enforces a coarse kernel lockdown
+ behaviour.
+
+config SECURITY_LOCKDOWN_LSM_EARLY
+ bool "Enable lockdown LSM early in init"
+ depends on SECURITY_LOCKDOWN_LSM
+ help
+ Enable the lockdown LSM early in boot. This is necessary in order
+ to ensure that lockdown enforcement can be carried out on kernel
+ boot parameters that are otherwise parsed before the security
+ subsystem is fully initialised. If enabled, lockdown will
+ unconditionally be called before any other LSMs.
+
+choice
+ prompt "Kernel default lockdown mode"
+ default LOCK_DOWN_KERNEL_FORCE_NONE
+ depends on SECURITY_LOCKDOWN_LSM
+ help
+ The kernel can be configured to default to differing levels of
+ lockdown.
+
+config LOCK_DOWN_KERNEL_FORCE_NONE
+ bool "None"
+ help
+ No lockdown functionality is enabled by default. Lockdown may be
+ enabled via the kernel commandline or /sys/kernel/security/lockdown.
+
+config LOCK_DOWN_KERNEL_FORCE_INTEGRITY
+ bool "Integrity"
+ help
+ The kernel runs in integrity mode by default. Features that allow
+ the kernel to be modified at runtime are disabled.
+
+config LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY
+ bool "Confidentiality"
+ help
+ The kernel runs in confidentiality mode by default. Features that
+ allow the kernel to be modified at runtime or that permit userland
+ code to read confidential material held inside the kernel are
+ disabled.
+
+endchoice
+
diff --git a/security/lockdown/Makefile b/security/lockdown/Makefile
new file mode 100644
index 000000000000..e3634b9017e7
--- /dev/null
+++ b/security/lockdown/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SECURITY_LOCKDOWN_LSM) += lockdown.o
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
new file mode 100644
index 000000000000..8e39b36b8f33
--- /dev/null
+++ b/security/lockdown/lockdown.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Lock down the kernel
+ *
+ * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/security.h>
+#include <linux/export.h>
+#include <linux/lsm_hooks.h>
+
+static enum lockdown_reason kernel_locked_down;
+
+static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
+ [LOCKDOWN_NONE] = "none",
+ [LOCKDOWN_INTEGRITY_MAX] = "integrity",
+ [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
+};
+
+static enum lockdown_reason lockdown_levels[] = {LOCKDOWN_NONE,
+ LOCKDOWN_INTEGRITY_MAX,
+ LOCKDOWN_CONFIDENTIALITY_MAX};
+
+/*
+ * Put the kernel into lock-down mode.
+ */
+static int lock_kernel_down(const char *where, enum lockdown_reason level)
+{
+ if (kernel_locked_down >= level)
+ return -EPERM;
+
+ kernel_locked_down = level;
+ pr_notice("Kernel is locked down from %s; see man kernel_lockdown.7\n",
+ where);
+ return 0;
+}
+
+static int __init lockdown_param(char *level)
+{
+ if (!level)
+ return -EINVAL;
+
+ if (strcmp(level, "integrity") == 0)
+ lock_kernel_down("command line", LOCKDOWN_INTEGRITY_MAX);
+ else if (strcmp(level, "confidentiality") == 0)
+ lock_kernel_down("command line", LOCKDOWN_CONFIDENTIALITY_MAX);
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+early_param("lockdown", lockdown_param);
+
+/**
+ * lockdown_is_locked_down - Find out if the kernel is locked down
+ * @what: Tag to use in notice generated if lockdown is in effect
+ */
+static int lockdown_is_locked_down(enum lockdown_reason what)
+{
+ if ((kernel_locked_down >= what)) {
+ if (lockdown_reasons[what])
+ pr_notice("Lockdown: %s is restricted; see man kernel_lockdown.7\n",
+ lockdown_reasons[what]);
+ return -EPERM;
+ }
+
+ return 0;
+}
+
+static struct security_hook_list lockdown_hooks[] __lsm_ro_after_init = {
+ LSM_HOOK_INIT(locked_down, lockdown_is_locked_down),
+};
+
+static int __init lockdown_lsm_init(void)
+{
+#if defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_INTEGRITY)
+ lock_kernel_down("Kernel configuration", LOCKDOWN_INTEGRITY_MAX);
+#elif defined(CONFIG_LOCK_DOWN_KERNEL_FORCE_CONFIDENTIALITY)
+ lock_kernel_down("Kernel configuration", LOCKDOWN_CONFIDENTIALITY_MAX);
+#endif
+ security_add_hooks(lockdown_hooks, ARRAY_SIZE(lockdown_hooks),
+ "lockdown");
+ return 0;
+}
+
+static ssize_t lockdown_read(struct file *filp, char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ char temp[80];
+ int i, offset=0;
+
+ for (i = 0; i < ARRAY_SIZE(lockdown_levels); i++) {
+ enum lockdown_reason level = lockdown_levels[i];
+
+ if (lockdown_reasons[level]) {
+ const char *label = lockdown_reasons[level];
+
+ if (kernel_locked_down == level)
+ offset += sprintf(temp+offset, "[%s] ", label);
+ else
+ offset += sprintf(temp+offset, "%s ", label);
+ }
+ }
+
+ /* Convert the last space to a newline if needed. */
+ if (offset > 0)
+ temp[offset-1] = '\n';
+
+ return simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
+}
+
+static ssize_t lockdown_write(struct file *file, const char __user *buf,
+ size_t n, loff_t *ppos)
+{
+ char *state;
+ int i, len, err = -EINVAL;
+
+ state = memdup_user_nul(buf, n);
+ if (IS_ERR(state))
+ return PTR_ERR(state);
+
+ len = strlen(state);
+ if (len && state[len-1] == '\n') {
+ state[len-1] = '\0';
+ len--;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(lockdown_levels); i++) {
+ enum lockdown_reason level = lockdown_levels[i];
+ const char *label = lockdown_reasons[level];
+
+ if (label && !strcmp(state, label))
+ err = lock_kernel_down("securityfs", level);
+ }
+
+ kfree(state);
+ return err ? err : n;
+}
+
+static const struct file_operations lockdown_ops = {
+ .read = lockdown_read,
+ .write = lockdown_write,
+};
+
+static int __init lockdown_secfs_init(void)
+{
+ struct dentry *dentry;
+
+ dentry = securityfs_create_file("lockdown", 0600, NULL, NULL,
+ &lockdown_ops);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+
+ return 0;
+}
+
+core_initcall(lockdown_secfs_init);
+
+#ifdef CONFIG_SECURITY_LOCKDOWN_LSM_EARLY
+DEFINE_EARLY_LSM(lockdown) = {
+#else
+DEFINE_LSM(lockdown) = {
+#endif
+ .name = "lockdown",
+ .init = lockdown_lsm_init,
+};
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related
* [PATCH V34 05/29] Restrict /dev/{mem,kmem,port} when the kernel is locked down
From: Matthew Garrett @ 2019-06-22 0:03 UTC (permalink / raw)
To: jmorris
Cc: linux-security-module, linux-kernel, linux-api, Matthew Garrett,
David Howells, Matthew Garrett, x86
In-Reply-To: <20190622000358.19895-1-matthewgarrett@google.com>
From: Matthew Garrett <mjg59@srcf.ucam.org>
Allowing users to read and write to core kernel memory makes it possible
for the kernel to be subverted, avoiding module loading restrictions, and
also to steal cryptographic information.
Disallow /dev/mem and /dev/kmem from being opened this when the kernel has
been locked down to prevent this.
Also disallow /dev/port from being opened to prevent raw ioport access and
thus DMA from being used to accomplish the same thing.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Cc: x86@kernel.org
---
drivers/char/mem.c | 6 +++++-
include/linux/security.h | 1 +
security/lockdown/lockdown.c | 1 +
3 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index b08dc50f9f26..93c02493f0fa 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -29,8 +29,8 @@
#include <linux/export.h>
#include <linux/io.h>
#include <linux/uio.h>
-
#include <linux/uaccess.h>
+#include <linux/security.h>
#ifdef CONFIG_IA64
# include <linux/efi.h>
@@ -786,6 +786,10 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
static int open_port(struct inode *inode, struct file *filp)
{
+ int ret = security_locked_down(LOCKDOWN_DEV_MEM);
+
+ if (ret)
+ return ret;
return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
}
diff --git a/include/linux/security.h b/include/linux/security.h
index 46d85cd63b06..200175c8605a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -83,6 +83,7 @@ enum lsm_event {
enum lockdown_reason {
LOCKDOWN_NONE,
LOCKDOWN_MODULE_SIGNATURE,
+ LOCKDOWN_DEV_MEM,
LOCKDOWN_INTEGRITY_MAX,
LOCKDOWN_CONFIDENTIALITY_MAX,
};
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index 25a3a5b0aa9c..565c87451f0f 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -19,6 +19,7 @@ static enum lockdown_reason kernel_locked_down;
static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
[LOCKDOWN_NONE] = "none",
[LOCKDOWN_MODULE_SIGNATURE] = "unsigned module loading",
+ [LOCKDOWN_DEV_MEM] = "/dev/mem,kmem,port",
[LOCKDOWN_INTEGRITY_MAX] = "integrity",
[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
};
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related
* [PATCH V34 09/29] kexec_file: Restrict at runtime if the kernel is locked down
From: Matthew Garrett @ 2019-06-22 0:03 UTC (permalink / raw)
To: jmorris
Cc: linux-security-module, linux-kernel, linux-api, Jiri Bohac,
David Howells, Matthew Garrett, kexec
In-Reply-To: <20190622000358.19895-1-matthewgarrett@google.com>
From: Jiri Bohac <jbohac@suse.cz>
When KEXEC_SIG is not enabled, kernel should not load images through
kexec_file systemcall if the kernel is locked down.
[Modified by David Howells to fit with modifications to the previous patch
and to return -EPERM if the kernel is locked down for consistency with
other lockdowns. Modified by Matthew Garrett to remove the IMA
integration, which will be replaced by integrating with the IMA
architecture policy patches.]
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Jiri Bohac <jbohac@suse.cz>
cc: kexec@lists.infradead.org
---
kernel/kexec_file.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index eec7e5bb2a08..27adb4312b03 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -237,7 +237,10 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
goto out;
}
- ret = 0;
+ ret = security_locked_down(LOCKDOWN_KEXEC);
+ if (ret)
+ goto out;
+
break;
/* All other errors are fatal, including nomem, unparseable
--
2.22.0.410.gd8fdbe21b5-goog
^ permalink raw reply related
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