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From: David Howells <dhowells@redhat.com>
To: torvalds@linux-foundation.org
Cc: dhowells@redhat.com, Casey Schaufler <casey@schaufler-ca.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	nicolas.dichtel@6wind.com, raven@themaw.net,
	Christian Brauner <christian@brauner.io>,
	dhowells@redhat.com, keyrings@vger.kernel.org,
	linux-usb@vger.kernel.org, linux-block@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH 11/21] security: Add a hook for the point of notification insertion
Date: Tue, 15 Oct 2019 22:49:27 +0100	[thread overview]
Message-ID: <157117616761.15019.7679238411987421969.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <157117606853.15019.15459271147790470307.stgit@warthog.procyon.org.uk>

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>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: Stephen Smalley <sds@tycho.nsa.gov>
cc: linux-security-module@vger.kernel.org
---

 include/linux/lsm_hooks.h |   14 ++++++++++++++
 include/linux/security.h  |   15 ++++++++++++++-
 security/security.c       |    9 +++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d62e92b768c4..8e1cbc27fc62 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1427,6 +1427,12 @@
  *	Check to see if a process is allowed to watch for event notifications
  *	from devices (as a global set).
  *
+ * @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.
@@ -1716,6 +1722,11 @@ union security_list_options {
 #ifdef CONFIG_DEVICE_NOTIFICATIONS
 	int (*watch_devices)(void);
 #endif
+#ifdef CONFIG_WATCH_QUEUE
+	int (*post_notification)(const struct cred *w_cred,
+				 const struct cred *cred,
+				 struct watch_notification *n);
+#endif
 
 #ifdef CONFIG_SECURITY_NETWORK
 	int (*unix_stream_connect)(struct sock *sock, struct sock *other,
@@ -2001,6 +2012,9 @@ struct security_hook_heads {
 #ifdef CONFIG_DEVICE_NOTIFICATIONS
 	struct hlist_head watch_devices;
 #endif
+#ifdef CONFIG_WATCH_QUEUE
+	struct hlist_head post_notification;
+#endif /* CONFIG_WATCH_QUEUE */
 #ifdef CONFIG_SECURITY_NETWORK
 	struct hlist_head unix_stream_connect;
 	struct hlist_head unix_may_send;
diff --git a/include/linux/security.h b/include/linux/security.h
index 5d1867772022..ee98e020c749 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -57,6 +57,8 @@ 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
@@ -1287,6 +1289,18 @@ static inline int security_watch_devices(void)
 	return 0;
 }
 #endif
+#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
 
@@ -1912,4 +1926,3 @@ static inline void security_bpf_prog_free(struct bpf_prog_aux *aux)
 #endif /* CONFIG_BPF_SYSCALL */
 
 #endif /* ! __LINUX_SECURITY_H */
-
diff --git a/security/security.c b/security/security.c
index 4f970716fa6c..c9d5c3d5472a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1956,6 +1956,15 @@ 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_KEY_NOTIFICATIONS
 int security_watch_key(struct key *key)
 {


  parent reply	other threads:[~2019-10-15 21:49 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-15 21:47 [RFC PATCH 00/21] pipe: Keyrings, Block and USB notifications David Howells
2019-10-15 21:47 ` [RFC PATCH 01/21] pipe: Reduce #inclusion of pipe_fs_i.h David Howells
2019-10-15 21:48 ` [RFC PATCH 02/21] Add a prelocked wake-up David Howells
2019-10-15 22:14   ` Linus Torvalds
2019-10-16 17:02     ` Tim Chen
2019-10-15 22:33   ` David Howells
2019-10-16 14:26   ` David Howells
2019-10-16 15:31     ` Linus Torvalds
2019-10-15 21:48 ` [RFC PATCH 03/21] pipe: Use head and tail pointers for the ring, not cursor and length David Howells
2019-10-16  7:46   ` Rasmus Villemoes
2019-10-17 10:53   ` David Howells
2019-10-15 21:48 ` [RFC PATCH 04/21] pipe: Advance tail pointer inside of wait spinlock in pipe_read() David Howells
2019-10-15 21:48 ` [RFC PATCH 05/21] pipe: Conditionalise wakeup " David Howells
2019-10-15 21:48 ` [RFC PATCH 06/21] pipe: Rearrange sequence in pipe_write() to preallocate slot David Howells
2019-10-15 21:48 ` [RFC PATCH 07/21] pipe: Remove redundant wakeup from pipe_write() David Howells
2019-10-15 21:49 ` [RFC PATCH 08/21] pipe: Check for ring full inside of the spinlock in pipe_write() David Howells
2019-10-15 22:20   ` Linus Torvalds
2019-10-15 21:49 ` [RFC PATCH 09/21] uapi: General notification queue definitions David Howells
2019-10-15 21:49 ` [RFC PATCH 10/21] security: Add hooks to rule on setting a watch David Howells
2019-10-15 21:49 ` David Howells [this message]
2019-10-15 21:49 ` [RFC PATCH 12/21] pipe: Add general notification queue support David Howells
2019-10-15 21:49 ` [RFC PATCH 13/21] keys: Add a notification facility David Howells
2019-10-15 21:49 ` [RFC PATCH 14/21] Add sample notification program David Howells
2019-10-15 21:50 ` [RFC PATCH 15/21] pipe: Allow buffers to be marked read-whole-or-error for notifications David Howells
2019-10-15 21:50 ` [RFC PATCH 16/21] pipe: Add notification lossage handling David Howells
2019-10-15 21:50 ` [RFC PATCH 17/21] Add a general, global device notification watch list David Howells
2019-10-15 21:50 ` [RFC PATCH 18/21] block: Add block layer notifications David Howells
2019-10-15 21:50 ` [RFC PATCH 19/21] usb: Add USB subsystem notifications David Howells
2019-10-15 21:50 ` [RFC PATCH 20/21] selinux: Implement the watch_key security hook David Howells
2019-10-15 21:50 ` [RFC PATCH 21/21] smack: Implement the watch_key and post_notification hooks David Howells
2019-10-15 22:11 ` [RFC PATCH 00/21] pipe: Keyrings, Block and USB notifications James Morris
2019-10-15 22:32 ` Linus Torvalds

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