[PATCH v15 07/23] LSM: Use lsmblob in security_secid_to_secctx

Casey Schaufler
2020-02-22T00:05:13Z

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 be called upon
to translate a secid to a string, as can occur in the
audit code.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
cc: netdev@vger.kernel.org
---
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 | 16 +++++++++++++---
12 files changed, 71 insertions(+), 29 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index a6b2082c24f8..a9d9b69d5596 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3107,10 +3107,12 @@ static void binder_transaction(struct binder_proc *proc,

if (target_node && target_node->txn_security_ctx) {
u32 secid;
+ struct lsmblob blob;
size_t added_size;

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 65adcffafee9..fdcba6e8d242 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -497,7 +497,7 @@ 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);
@@ -1298,7 +1298,8 @@ 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 17b0d523afb3..0fdd51d03598 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1418,7 +1418,10 @@ 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;
}
@@ -2061,12 +2064,14 @@ 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 ef2f5e7eec7b..d6723c225c7e 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -966,6 +966,7 @@ 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)
@@ -975,7 +976,8 @@ 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 {
@@ -1218,7 +1220,10 @@ 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 {
@@ -1368,9 +1373,10 @@ 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 6cf57d5ac899..1ca97d0cb4a9 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 6a1c8f1f6171..68c74c28eae9 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -331,8 +331,10 @@ 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;

@@ -643,8 +645,10 @@ 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 410809c669e1..183a85412155 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 76535fd9278c..b7b296fe0c0b 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -305,13 +305,17 @@ 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 7a5a87f15736..0cda17cb44a0 100644
--- a/net/netlabel/netlabel_unlabeled.c
+++ b/net/netlabel/netlabel_unlabeled.c
@@ -375,6 +375,7 @@ 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))
@@ -437,7 +438,8 @@ 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);
@@ -474,6 +476,7 @@ 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,
@@ -493,8 +496,10 @@ 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);
@@ -536,6 +541,7 @@ 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);
@@ -554,8 +560,10 @@ 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);
@@ -1076,6 +1084,7 @@ 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,
@@ -1130,7 +1139,8 @@ 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 3ed4fea2a2de..893301ae0131 100644
--- a/net/netlabel/netlabel_user.c
+++ b/net/netlabel/netlabel_user.c
@@ -86,6 +86,7 @@ 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;
@@ -98,10 +99,9 @@ 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 e0f9287483aa..dae86629a2f6 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1995,10 +1995,20 @@ 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) {
+ if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+ continue;
+ rc = hp->hook.secid_to_secctx(blob->secid[hp->lsmid->slot],
+ secdata, seclen);
+ if (rc != 0)
+ return rc;
+ }
+ return 0;
}
EXPORT_SYMBOL(security_secid_to_secctx);