From: Casey Schaufler <casey@schaufler-ca.com>
To: Sebastien Buisson <sbuisson.ddn@gmail.com>,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, selinux@tycho.nsa.gov
Cc: serge@hallyn.com, james.l.morris@oracle.com,
eparis@parisplace.org, sds@tycho.nsa.gov, paul@paul-moore.com,
danielj@mellanox.com, Sebastien Buisson <sbuisson@ddn.com>
Subject: Re: [PATCH 1/3] selinux: Implement LSM notification system
Date: Wed, 26 Apr 2017 08:38:22 -0700 [thread overview]
Message-ID: <8d4c5ab6-8c15-312a-398b-c3ee9d7e8cb6@schaufler-ca.com> (raw)
In-Reply-To: <1493218936-18522-1-git-send-email-sbuisson@ddn.com>
On 4/26/2017 8:02 AM, Sebastien Buisson wrote:
> From: Daniel Jurgens <danielj@mellanox.com>
>
> Add a generic notification mechanism in the LSM. Interested consumers
> can register a callback with the LSM and security modules can produce
> events.
Why is this a generic mechanism? Do you ever see anyone
other than SELinux using it?
> Add a call to the notification mechanism from SELinux when the AVC
> cache changes.
This seems like a whole lot of mechanism for
something you could accomplish with a log message.
What am I missing?
>
> Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
> Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
> ---
> include/linux/security.h | 23 +++++++++++++++++++++++
> security/security.c | 20 ++++++++++++++++++++
> security/selinux/hooks.c | 12 ++++++++++++
> 3 files changed, 55 insertions(+)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index af675b5..73a9c93 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -68,6 +68,10 @@
> struct user_namespace;
> struct timezone;
>
> +enum lsm_event {
> + LSM_POLICY_CHANGE,
> +};
> +
> /* These functions are in security/commoncap.c */
> extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
> int cap, int audit);
> @@ -163,6 +167,10 @@ struct security_mnt_opts {
> int num_mnt_opts;
> };
>
> +int call_lsm_notifier(enum lsm_event event, void *data);
> +int register_lsm_notifier(struct notifier_block *nb);
> +int unregister_lsm_notifier(struct notifier_block *nb);
> +
> static inline void security_init_mnt_opts(struct security_mnt_opts *opts)
> {
> opts->mnt_opts = NULL;
> @@ -381,6 +389,21 @@ int security_sem_semop(struct sem_array *sma, struct sembuf *sops,
> struct security_mnt_opts {
> };
>
> +static inline int call_lsm_notifier(enum lsm_event event, void *data)
> +{
> + return 0;
> +}
> +
> +static inline int register_lsm_notifier(struct notifier_block *nb)
> +{
> + return 0;
> +}
> +
> +static inline int unregister_lsm_notifier(struct notifier_block *nb)
> +{
> + return 0;
> +}
> +
> static inline void security_init_mnt_opts(struct security_mnt_opts *opts)
> {
> }
> diff --git a/security/security.c b/security/security.c
> index b9fea39..ef9d9e1 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -32,6 +32,8 @@
> /* Maximum number of letters for an LSM name string */
> #define SECURITY_NAME_MAX 10
>
> +static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
> +
> struct security_hook_heads security_hook_heads __lsm_ro_after_init;
> char *lsm_names;
> /* Boot-time LSM user choice */
> @@ -146,6 +148,24 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
> panic("%s - Cannot get early memory.\n", __func__);
> }
>
> +int call_lsm_notifier(enum lsm_event event, void *data)
> +{
> + return atomic_notifier_call_chain(&lsm_notifier_chain, event, data);
> +}
> +EXPORT_SYMBOL(call_lsm_notifier);
> +
> +int register_lsm_notifier(struct notifier_block *nb)
> +{
> + return atomic_notifier_chain_register(&lsm_notifier_chain, nb);
> +}
> +EXPORT_SYMBOL(register_lsm_notifier);
> +
> +int unregister_lsm_notifier(struct notifier_block *nb)
> +{
> + return atomic_notifier_chain_unregister(&lsm_notifier_chain, nb);
> +}
> +EXPORT_SYMBOL(unregister_lsm_notifier);
> +
> /*
> * Hook list operation macros.
> *
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index e67a526..a4d36f8 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -171,6 +171,14 @@ static int selinux_netcache_avc_callback(u32 event)
> return 0;
> }
>
> +static int selinux_lsm_notifier_avc_callback(u32 event)
> +{
> + if (event == AVC_CALLBACK_RESET)
> + call_lsm_notifier(LSM_POLICY_CHANGE, NULL);
> +
> + return 0;
> +}
> +
> /*
> * initialise the security for the init task
> */
> @@ -6379,6 +6387,10 @@ static __init int selinux_init(void)
> if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
> panic("SELinux: Unable to register AVC netcache callback\n");
>
> + if (avc_add_callback(selinux_lsm_notifier_avc_callback,
> + AVC_CALLBACK_RESET))
> + panic("SELinux: Unable to register AVC LSM notifier callback\n");
> +
> if (selinux_enforcing)
> printk(KERN_DEBUG "SELinux: Starting in enforcing mode\n");
> else
next prev parent reply other threads:[~2017-04-26 15:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-26 15:02 [PATCH 1/3] selinux: Implement LSM notification system Sebastien Buisson
2017-04-26 15:02 ` [PATCH 2/3] selinux: add checksum to policydb Sebastien Buisson
2017-04-26 18:30 ` Stephen Smalley
2017-04-27 8:41 ` Sebastien Buisson
2017-04-27 15:18 ` Stephen Smalley
2017-04-27 17:12 ` Sebastien Buisson
2017-04-27 18:47 ` Stephen Smalley
2017-04-28 15:16 ` Sebastien Buisson
2017-04-28 15:50 ` Stephen Smalley
2017-04-28 16:08 ` Sebastien Buisson
2017-04-28 16:38 ` Stephen Smalley
2017-04-26 15:02 ` [PATCH 3/3] selinux: expose policy SHA256 checksum via selinuxfs Sebastien Buisson
2017-04-26 18:31 ` Stephen Smalley
2017-04-27 1:08 ` James Morris
2017-04-26 15:38 ` Casey Schaufler [this message]
2017-04-26 15:48 ` [PATCH 1/3] selinux: Implement LSM notification system Daniel Jurgens
2017-04-26 15:57 ` Sebastien Buisson
2017-04-26 16:11 ` Casey Schaufler
2017-04-26 17:36 ` Stephen Smalley
2017-04-26 17:47 ` Casey Schaufler
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