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From: David Howells <dhowells@redhat.com>
To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk
Cc: Casey Schaufler <casey@schaufler-ca.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	linux-security-module@vger.kernel.org, dhowells@redhat.com,
	casey@schaufler-ca.com, sds@tycho.nsa.gov,
	nicolas.dichtel@6wind.com, raven@themaw.net,
	christian@brauner.io, andres@anarazel.de, jlayton@redhat.com,
	dray@redhat.com, kzak@redhat.com, keyrings@vger.kernel.org,
	linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 03/17] security: Add a hook for the point of notification insertion [ver #5]
Date: Wed, 18 Mar 2020 15:03:41 +0000	[thread overview]
Message-ID: <158454382138.2863966.4611034029343321389.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <158454378820.2863966.10496767254293183123.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  |   14 ++++++++++++++
 security/security.c       |    9 +++++++++
 3 files changed, 37 insertions(+)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 79d7c73676d7..16530255dc11 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,
@@ -2009,6 +2020,9 @@ 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 7a36064a64ea..910a1efa9a79 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
@@ -1292,6 +1294,18 @@ 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
 
diff --git a/security/security.c b/security/security.c
index 22877f47cf62..db7b574c9c70 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1988,6 +1988,15 @@ 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:[~2020-03-18 15:03 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18 15:03 [PATCH 00/17] pipe: Keyrings, mount and superblock notifications " David Howells
2020-03-18 15:03 ` [PATCH 01/17] uapi: General notification queue definitions " David Howells
2020-03-18 15:03 ` [PATCH 02/17] security: Add hooks to rule on setting a watch " David Howells
2020-03-18 18:56   ` James Morris
2020-03-18 15:03 ` David Howells [this message]
2020-03-18 18:57   ` [PATCH 03/17] security: Add a hook for the point of notification insertion " James Morris
2020-03-18 15:03 ` [PATCH 04/17] pipe: Add O_NOTIFICATION_PIPE " David Howells
2020-03-18 15:03 ` [PATCH 05/17] pipe: Add general notification queue support " David Howells
2020-03-18 15:04 ` [PATCH 06/17] watch_queue: Add a key/keyring notification facility " David Howells
2020-03-18 19:04   ` James Morris
2020-03-18 15:04 ` [PATCH 07/17] Add sample notification program " David Howells
2020-03-18 15:04 ` [PATCH 08/17] pipe: Allow buffers to be marked read-whole-or-error for notifications " David Howells
2020-03-18 15:04 ` [PATCH 09/17] pipe: Add notification lossage handling " David Howells
2020-03-18 15:04 ` [PATCH 10/17] selinux: Implement the watch_key security hook " David Howells
2020-03-18 19:06   ` James Morris
2020-03-18 15:04 ` [PATCH 11/17] smack: Implement the watch_key and post_notification hooks " David Howells
2020-03-18 15:05 ` [PATCH 12/17] watch_queue: Add security hooks to rule on setting mount and sb watches " David Howells
2020-03-18 19:07   ` James Morris
2020-03-18 15:05 ` [PATCH 13/17] watch_queue: Implement mount topology and attribute change notifications " David Howells
2020-04-02 15:19   ` Miklos Szeredi
2020-06-14  3:07     ` Ian Kent
2020-06-15  8:44       ` Miklos Szeredi
2020-07-23 10:48   ` David Howells
2020-08-03  9:29     ` Miklos Szeredi
2020-08-04 11:38       ` Ian Kent
2020-08-04 13:19         ` Miklos Szeredi
2020-08-05  1:53           ` Ian Kent
2020-08-05  7:43             ` Miklos Szeredi
2020-08-05 11:36               ` Ian Kent
2020-08-05 11:56                 ` Miklos Szeredi
2020-07-24 10:19   ` David Howells
2020-07-24 10:44     ` Ian Kent
2020-07-24 11:36     ` David Howells
2020-08-03 10:02       ` Miklos Szeredi
2020-08-03 10:08       ` David Howells
2020-08-03 10:18       ` David Howells
2020-08-03 11:17         ` Miklos Szeredi
2020-08-03 11:49         ` David Howells
2020-08-03 12:01           ` Ian Kent
2020-08-03 12:31           ` David Howells
2020-08-03 14:30             ` Ian Kent
2020-03-18 15:05 ` [PATCH 14/17] watch_queue: sample: Display mount tree " David Howells
2020-03-18 15:05 ` [PATCH 15/17] watch_queue: Introduce a non-repeating system-unique superblock ID " David Howells
2020-03-18 15:05 ` [PATCH 16/17] watch_queue: Add superblock notifications " David Howells
2020-03-18 15:05 ` [PATCH 17/17] watch_queue: sample: Display " David Howells

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