Add a security hook that allows an LSM to rule on whether a notification
message is allowed to be inserted into a particular watch queue.
The hook is given the following information:
(1) The credentials of the triggerer (which may be init_cred for a system
notification, eg. a hardware error).
(2) The credentials of the whoever set the watch.
(3) The notification message.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
cc: Stephen Smalley <sds@xxxxxxxxxxxxx>
cc: linux-security-module@xxxxxxxxxxxxxxx
---
include/linux/lsm_hooks.h | 10 ++++++++++
include/linux/security.h | 10 ++++++++++
security/security.c | 6 ++++++
3 files changed, 26 insertions(+)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 19108185b254..e9f1f69cd04d 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1426,6 +1426,12 @@
* from devices (as a global set).
* @watch: The watch object
*
+ * @post_notification:
+ * Check to see if a watch notification can be posted to a particular
+ * queue.
+ * @w_cred: The credentials of the whoever set the watch.
+ * @cred: The event-triggerer's credentials
+ * @n: The notification being posted
*
* Security hooks for using the eBPF maps and programs functionalities through
* eBPF syscalls.
@@ -1705,6 +1711,9 @@ union security_list_options {
#ifdef CONFIG_WATCH_QUEUE
int (*watch_key)(struct watch *watch, struct key *key);
int (*watch_devices)(struct watch *watch);
+ int (*post_notification)(const struct cred *w_cred,
+ const struct cred *cred,
+ struct watch_notification *n);
#endif /* CONFIG_WATCH_QUEUE */
#ifdef CONFIG_SECURITY_NETWORK
@@ -1985,6 +1994,7 @@ struct security_hook_heads {
#ifdef CONFIG_WATCH_QUEUE
struct hlist_head watch_key;
struct hlist_head watch_devices;
+ struct hlist_head post_notification;
#endif /* CONFIG_WATCH_QUEUE */
#ifdef CONFIG_SECURITY_NETWORK
struct hlist_head unix_stream_connect;
diff --git a/include/linux/security.h b/include/linux/security.h
index feeade454308..003437714eee 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -58,6 +58,7 @@ struct fs_context;
struct fs_parameter;
enum fs_value_type;
struct watch;
+struct watch_notification;
/* Default (no) options for the capable function */
#define CAP_OPT_NONE 0x0
@@ -396,6 +397,9 @@ int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen);
#ifdef CONFIG_WATCH_QUEUE
int security_watch_key(struct watch *watch, struct key *key);
int security_watch_devices(struct watch *watch);
+int security_post_notification(const struct cred *w_cred,
+ const struct cred *cred,
+ struct watch_notification *n);
#endif /* CONFIG_WATCH_QUEUE */
#else /* CONFIG_SECURITY */
@@ -1218,6 +1222,12 @@ static inline int security_watch_devices(struct watch *watch)
{
return 0;
}
+static inline int security_post_notification(const struct cred *w_cred,
+ const struct cred *cred,
+ struct watch_notification *n)
+{
+ return 0;
+}
#endif /* CONFIG_WATCH_QUEUE */
#endif /* CONFIG_SECURITY */
diff --git a/security/security.c b/security/security.c
index 1ebd2c936a57..5afe966aea4e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1927,6 +1927,12 @@ int security_watch_devices(struct watch *watch)
return call_int_hook(watch_devices, 0, watch);
}
+int security_post_notification(const struct cred *w_cred,
+ const struct cred *cred,
+ struct watch_notification *n)
+{
+ return call_int_hook(post_notification, 0, w_cred, cred, n);
+}
#endif /* CONFIG_WATCH_QUEUE */
#ifdef CONFIG_SECURITY_NETWORK
