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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 03/11] security: Add a hook for the point of notification insertion [ver #6] From: David Howells To: viro@zeniv.linux.org.uk Cc: dhowells@redhat.com, Casey Schaufler , Stephen Smalley , Greg Kroah-Hartman , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , dhowells@redhat.com, keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-block@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 29 Aug 2019 19:30:16 +0100 Message-ID: <156710341641.10009.9324038712143541997.stgit@warthog.procyon.org.uk> In-Reply-To: <156710338860.10009.12524626894838499011.stgit@warthog.procyon.org.uk> References: <156710338860.10009.12524626894838499011.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.69]); Thu, 29 Aug 2019 18:30:20 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: 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 cc: Casey Schaufler cc: Stephen Smalley 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 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