[PATCH 04/13] security: Add a hook for the point of notification insertion [ver #4]
From: David Howells <dhowells@redhat.com>
Date: 2019-06-07 14:18:17
Also in:
keyrings, linux-block, linux-fsdevel, linux-security-module, lkml
Subsystem:
security subsystem, the rest · Maintainers:
Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
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 creator of the watch buffer.
(3) The notification message.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: Stephen Smalley <redacted>
cc: linux-security-module@vger.kernel.org
---
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 0543449c0f6e..94fb6067fed5 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h@@ -1445,6 +1445,12 @@ * 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. + * @q_cred: The credentials of the target watch queue. + * @cred: The event-triggerer's credentials + * @n: The notification being posted * * Security hooks for using the eBPF maps and programs functionalities through * eBPF syscalls.
@@ -1729,6 +1735,9 @@ union security_list_options { int (*watch_sb)(struct watch *watch, struct super_block *sb); int (*watch_key)(struct watch *watch, struct key *key); int (*watch_devices)(struct watch *watch); + int (*post_notification)(const struct cred *q_cred, + const struct cred *cred, + struct watch_notification *n); #endif /* CONFIG_WATCH_QUEUE */ #ifdef CONFIG_SECURITY_NETWORK
@@ -2014,6 +2023,7 @@ struct security_hook_heads { struct hlist_head watch_sb; 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 ac3bf6b5f87b..ed301edeaa19 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h@@ -59,6 +59,7 @@ struct fs_parameter; enum fs_value_type; struct fsinfo_kparams; struct watch; +struct watch_notification; /* Default (no) options for the capable function */ #define CAP_OPT_NONE 0x0
@@ -402,6 +403,9 @@ int security_watch_mount(struct watch *watch, struct path *path); int security_watch_sb(struct watch *watch, struct super_block *sb); int security_watch_key(struct watch *watch, struct key *key); int security_watch_devices(struct watch *watch); +int security_post_notification(const struct cred *q_cred, + const struct cred *cred, + struct watch_notification *n); #endif /* CONFIG_WATCH_QUEUE */ #else /* CONFIG_SECURITY */
@@ -1239,6 +1243,12 @@ static inline int security_watch_devices(struct watch *watch) { return 0; } +static inline int security_post_notification(const struct cred *q_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 ee2f8539a0d5..8a04ac74b4fe 100644
--- a/security/security.c
+++ b/security/security.c@@ -1950,6 +1950,12 @@ int security_watch_devices(struct watch *watch) return call_int_hook(watch_devices, 0, watch); } +int security_post_notification(const struct cred *q_cred, + const struct cred *cred, + struct watch_notification *n) +{ + return call_int_hook(post_notification, 0, q_cred, cred, n); +} #endif /* CONFIG_WATCH_QUEUE */ #ifdef CONFIG_SECURITY_NETWORK