security: Add a hook for the point of notification insertion

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@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
This commit is contained in:
David Howells 2020-02-12 13:58:35 +00:00
parent 0858caa419
commit 344fa64ef8
4 changed files with 38 additions and 0 deletions

View File

@ -253,6 +253,11 @@ LSM_HOOK(int, 0, inode_setsecctx, struct dentry *dentry, void *ctx, u32 ctxlen)
LSM_HOOK(int, 0, inode_getsecctx, struct inode *inode, void **ctx,
u32 *ctxlen)
#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_KEY_NOTIFICATIONS */
#ifdef CONFIG_SECURITY_NETWORK
LSM_HOOK(int, 0, unix_stream_connect, struct sock *sock, struct sock *other,
struct sock *newsk)

View File

@ -1437,6 +1437,15 @@
* @ctx is a pointer in which to place the allocated security context.
* @ctxlen points to the place to put the length of @ctx.
*
* Security hooks for the general notification queue:
*
* @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.
*

View File

@ -56,6 +56,8 @@ struct mm_struct;
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
@ -1275,6 +1277,19 @@ static inline int security_locked_down(enum lockdown_reason what)
}
#endif /* CONFIG_SECURITY */
#if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE)
int security_post_notification(const struct cred *w_cred,
const struct cred *cred,
struct watch_notification *n);
#else
static inline int security_post_notification(const struct cred *w_cred,
const struct cred *cred,
struct watch_notification *n)
{
return 0;
}
#endif
#ifdef CONFIG_SECURITY_NETWORK
int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk);

View File

@ -2007,6 +2007,15 @@ int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
}
EXPORT_SYMBOL(security_inode_getsecctx);
#ifdef CONFIG_WATCH_QUEUE
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
int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk)