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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id h4sm450668pji.24.2019.06.18.22.11.09 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 18 Jun 2019 22:11:09 -0700 (PDT) Date: Tue, 18 Jun 2019 22:11:08 -0700 From: Kees Cook To: Casey Schaufler Cc: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov Subject: Re: [PATCH v2 13/25] LSM: Use lsmblob in security_cred_getsecid Message-ID: <201906182210.8765003E11@keescook> References: <20190618230551.7475-1-casey@schaufler-ca.com> <20190618230551.7475-14-casey@schaufler-ca.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190618230551.7475-14-casey@schaufler-ca.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Tue, Jun 18, 2019 at 04:05:39PM -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. Cool, cool. I'm digging the clean conversions all the way through this patch. I didn't see patch 14/25 for some reason, though... -Kees > > Signed-off-by: Casey Schaufler > --- > include/linux/security.h | 2 +- > kernel/audit.c | 14 +++++------- > kernel/audit.h | 5 +++-- > kernel/auditsc.c | 37 +++++++++++-------------------- > security/integrity/ima/ima_main.c | 6 ++--- > security/security.c | 9 +++++--- > 6 files changed, 32 insertions(+), 41 deletions(-) > > diff --git a/include/linux/security.h b/include/linux/security.h > index b28d4f9c7714..07a239292e02 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 *l); > int security_kernel_act_as(struct cred *new, struct lsmblob *l); > 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 3ab2a1c0ba61..a52f8772477f 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 le; > - > - lsmblob_init(&le, audit_sig_sid); > - err = security_secid_to_secctx(&le, &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 > #include > #include > +#include > #include > #include > > @@ -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 cdd1dd9e0eec..ebdd7eab9247 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; > }; > @@ -937,14 +937,14 @@ 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 *l, char *comm) > { > struct audit_buffer *ab; > char *ctx = NULL; > u32 len; > int rc = 0; > - struct lsmblob le; > > ab = audit_log_start(context, GFP_KERNEL, AUDIT_OBJ_PID); > if (!ab) > @@ -953,9 +953,8 @@ 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(&le, sid); > - if (security_secid_to_secctx(&le, &ctx, &len)) { > + if (lsmblob_is_set(l)) { > + if (security_secid_to_secctx(l, &ctx, &len)) { > audit_log_format(ab, " obj=(none)"); > rc = 1; > } else { > @@ -1525,7 +1524,7 @@ 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; > } > @@ -1534,7 +1533,7 @@ 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) { > @@ -1711,7 +1710,7 @@ 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; > @@ -2365,15 +2364,12 @@ int __audit_sockaddr(int len, void *a) > void __audit_ptrace(struct task_struct *t) > { > struct audit_context *context = audit_context(); > - struct lsmblob le; > > 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, &le); > - /* scaffolding - until target_sid is converted */ > - context->target_sid = le.secid[1]; > + security_task_getsecid(t, &context->target_lsm); > memcpy(context->target_comm, t->comm, TASK_COMM_LEN); > } > > @@ -2390,7 +2386,6 @@ 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 le; > > if (auditd_test_task(t) && > (sig == SIGTERM || sig == SIGHUP || > @@ -2401,9 +2396,7 @@ int audit_signal_info(int sig, struct task_struct *t) > audit_sig_uid = auid; > else > audit_sig_uid = uid; > - security_task_getsecid(current, &le); > - /* scaffolding until audit_sig_sid is converted */ > - audit_sig_sid = le.secid[1]; > + security_task_getsecid(current, &audit_sig_lsm); > } > > if (!audit_signals || audit_dummy_context()) > @@ -2416,9 +2409,7 @@ 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, &le); > - /* scaffolding until target_sid is converted */ > - ctx->target_sid = le.secid[1]; > + security_task_getsecid(t, &ctx->target_lsm); > memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN); > return 0; > } > @@ -2439,9 +2430,7 @@ 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, &le); > - /* scaffolding until target_sid is converted */ > - axp->target_sid[axp->pid_count] = le.secid[1]; > + 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 99870a6286a9..9959d7cbe42e 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 le; > > security_task_getsecid(current, &le); > @@ -373,8 +372,9 @@ 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, > + security_cred_getsecid(bprm->cred, &le); > + /* scaffolding until process_measurement changes */ > + return process_measurement(bprm->file, bprm->cred, le.secid[1], NULL, 0, > MAY_EXEC, CREDS_CHECK); > } > > diff --git a/security/security.c b/security/security.c > index e82994667263..46f6cf21d33c 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -1638,10 +1638,13 @@ 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 *l) > { > - *secid = 0; > - call_void_hook(cred_getsecid, c, secid); > + struct security_hook_list *hp; > + > + lsmblob_init(l, 0); > + hlist_for_each_entry(hp, &security_hook_heads.cred_getsecid, list) > + hp->hook.cred_getsecid(c, &l->secid[hp->slot]); > } > EXPORT_SYMBOL(security_cred_getsecid); > > -- > 2.20.1 > -- Kees Cook