security: Add hooks to rule on setting a watch

Add security hooks that will allow an LSM to rule on whether or not a watch
may be set.  More than one hook is required as the watches watch different
types of object.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: Stephen Smalley <sds@tycho.nsa.gov>
cc: linux-security-module@vger.kernel.org

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index e0def45..a54f49e 100644 (file)
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -256,6 +256,10 @@ LSM_HOOK(int, 0, inode_getsecctx, struct inode *inode, void **ctx,
 #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
 LSM_HOOK(int, 0, post_notification, const struct cred *w_cred,
         const struct cred *cred, struct watch_notification *n)
+#endif /* CONFIG_SECURITY && CONFIG_WATCH_QUEUE */
+
+#if defined(CONFIG_SECURITY) && defined(CONFIG_KEY_NOTIFICATIONS)
+LSM_HOOK(int, 0, watch_key, struct key *key)
 #endif /* CONFIG_SECURITY && CONFIG_KEY_NOTIFICATIONS */
 
 #ifdef CONFIG_SECURITY_NETWORK

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 0b5e576..3f1374c 100644 (file)
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1446,6 +1446,11 @@
  *     @cred: The event-triggerer's credentials
  *     @n: The notification being posted
  *
+ * @watch_key:
+ *     Check to see if a process is allowed to watch for event notifications
+ *     from a key or keyring.
+ *     @key: The key to watch.
+ *
  * Security hooks for using the eBPF maps and programs functionalities through
  * eBPF syscalls.
  *

diff --git a/include/linux/security.h b/include/linux/security.h
index 9a5d12a..e7914e4 100644 (file)
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1290,6 +1290,15 @@ static inline int security_post_notification(const struct cred *w_cred,
 }
 #endif
 
+#if defined(CONFIG_SECURITY) && defined(CONFIG_KEY_NOTIFICATIONS)
+int security_watch_key(struct key *key);
+#else
+static inline int security_watch_key(struct key *key)
+{
+       return 0;
+}
+#endif
+
 #ifdef CONFIG_SECURITY_NETWORK
 
 int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk);

diff --git a/security/security.c b/security/security.c
index 7d55607..c73334a 100644 (file)
--- a/security/security.c
+++ b/security/security.c
@@ -2016,6 +2016,13 @@ int security_post_notification(const struct cred *w_cred,
 }
 #endif /* CONFIG_WATCH_QUEUE */
 
+#ifdef CONFIG_KEY_NOTIFICATIONS
+int security_watch_key(struct key *key)
+{
+       return call_int_hook(watch_key, 0, key);
+}
+#endif
+
 #ifdef CONFIG_SECURITY_NETWORK
 
 int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk)