[v3,3/9] selinux lsm IB/core: Implement LSM notification system
diff mbox

Message ID 1469800416-125043-4-git-send-email-danielj@mellanox.com
State New
Headers show

Commit Message

Daniel Jurgens July 29, 2016, 1:53 p.m. UTC
From: Daniel Jurgens <danielj@mellanox.com>

Add a generic notificaiton mechanism in the LSM. Interested consumers
can register a callback with the LSM and security modules can produce
events.

Because access to Infiniband QPs are enforced in the setup phase of a
connection security should be enforced again if the policy changes.
Register infiniband devices for policy change notification and check all
QPs on that device when the notification is received.

Add a call to the notification mechanism from SELinux when the AVC
cache changes or setenforce is cleared.

Signed-off-by: Daniel Jurgens <danielj@mellanox.com>

---
v2:
- new patch that has the generic notification, replaces selinux and
  IB/core patches related to the ib_flush callback. Yuval Shaia and Paul
  Moore

v3:
- use notifier chains. Paul Moore

 drivers/infiniband/core/device.c | 53 ++++++++++++++++++++++++++++++++++++++++
 include/linux/security.h         |  8 ++++++
 security/security.c              | 20 +++++++++++++++
 security/selinux/hooks.c         |  5 ++--
 security/selinux/selinuxfs.c     |  2 ++
 5 files changed, 86 insertions(+), 2 deletions(-)

Comments

kernel test robot July 29, 2016, 10:40 p.m. UTC | #1
Hi,

[auto build test ERROR on next-20160729]
[cannot apply to pcmoore-selinux/next rdma/master linus/master v4.7-rc7 v4.7-rc6 v4.7-rc5 v4.7]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Dan-Jurgens/SELinux-support-for-Infiniband-RDMA/20160729-220959
config: ia64-defconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 4.9.0
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=ia64 

All errors (new ones prefixed by >>):

>> ERROR: "unregister_lsm_notifier" [drivers/infiniband/core/ib_core.ko] undefined!
>> ERROR: "register_lsm_notifier" [drivers/infiniband/core/ib_core.ko] undefined!

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
Paul Moore Sept. 1, 2016, 1:35 a.m. UTC | #2
On Fri, Jul 29, 2016 at 9:53 AM, Dan Jurgens <danielj@mellanox.com> wrote:
> From: Daniel Jurgens <danielj@mellanox.com>
>
> Add a generic notificaiton mechanism in the LSM. Interested consumers
> can register a callback with the LSM and security modules can produce
> events.
>
> Because access to Infiniband QPs are enforced in the setup phase of a
> connection security should be enforced again if the policy changes.
> Register infiniband devices for policy change notification and check all
> QPs on that device when the notification is received.
>
> Add a call to the notification mechanism from SELinux when the AVC
> cache changes or setenforce is cleared.
>
> Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
>
> ---
> v2:
> - new patch that has the generic notification, replaces selinux and
>   IB/core patches related to the ib_flush callback. Yuval Shaia and Paul
>   Moore
>
> v3:
> - use notifier chains. Paul Moore
>
>  drivers/infiniband/core/device.c | 53 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/security.h         |  8 ++++++
>  security/security.c              | 20 +++++++++++++++
>  security/selinux/hooks.c         |  5 ++--
>  security/selinux/selinuxfs.c     |  2 ++
>  5 files changed, 86 insertions(+), 2 deletions(-)

One small comment below, I also assume you've seen the test robot's
email regarding build problems on IA64?

> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index a86d537..7c22703 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -159,13 +159,14 @@ static int selinux_peerlbl_enabled(void)
>         return (selinux_policycap_alwaysnetwork || netlbl_enabled() || selinux_xfrm_enabled());
>  }
>
> -static int selinux_netcache_avc_callback(u32 event)
> +static int selinux_cache_avc_callback(u32 event)
>  {
>         if (event == AVC_CALLBACK_RESET) {
>                 sel_netif_flush();
>                 sel_netnode_flush();
>                 sel_netport_flush();
>                 synchronize_net();
> +               call_lsm_notifier(LSM_POLICY_CHANGE, NULL);
>         }
>         return 0;
>  }

We are getting down to the small details now ... I think I would
prefer if the "call_lsm_notifier(...)" call was done from its own AVC
callback instead of hanging off the existing netcache callback.

Patch
diff mbox

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 5b42e83..7b6fd06 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -39,6 +39,8 @@ 
 #include <linux/init.h>
 #include <linux/mutex.h>
 #include <linux/netdevice.h>
+#include <linux/security.h>
+#include <linux/notifier.h>
 #include <rdma/rdma_netlink.h>
 #include <rdma/ib_addr.h>
 #include <rdma/ib_cache.h>
@@ -82,6 +84,14 @@  static LIST_HEAD(client_list);
 static DEFINE_MUTEX(device_mutex);
 static DECLARE_RWSEM(lists_rwsem);
 
+static int ib_security_change(struct notifier_block *nb, unsigned long event,
+			      void *lsm_data);
+static void ib_policy_change_task(struct work_struct *work);
+static DECLARE_WORK(ib_policy_change_work, ib_policy_change_task);
+
+static struct notifier_block ibdev_lsm_nb = {
+	.notifier_call = ib_security_change,
+};
 
 static int ib_device_check_mandatory(struct ib_device *device)
 {
@@ -344,6 +354,40 @@  static int setup_port_pkey_list(struct ib_device *device)
 	return 0;
 }
 
+static void ib_policy_change_task(struct work_struct *work)
+{
+	struct ib_device *dev;
+
+	down_read(&lists_rwsem);
+	list_for_each_entry(dev, &device_list, core_list) {
+		int i;
+
+		for (i = rdma_start_port(dev); i <= rdma_end_port(dev); i++) {
+			u64 sp;
+			int ret = ib_get_cached_subnet_prefix(dev,
+							      i,
+							      &sp);
+
+			WARN_ONCE(ret,
+				  "ib_get_cached_subnet_prefix err: %d, this should never happen here\n",
+				  ret);
+			ib_security_cache_change(dev, i, sp);
+		}
+	}
+	up_read(&lists_rwsem);
+}
+
+static int ib_security_change(struct notifier_block *nb, unsigned long event,
+			      void *lsm_data)
+{
+	if (event != LSM_POLICY_CHANGE)
+		return NOTIFY_DONE;
+
+	schedule_work(&ib_policy_change_work);
+
+	return NOTIFY_OK;
+}
+
 /**
  * ib_register_device - Register an IB device with IB core
  * @device:Device to register
@@ -1075,10 +1119,18 @@  static int __init ib_core_init(void)
 		goto err_sa;
 	}
 
+	ret = register_lsm_notifier(&ibdev_lsm_nb);
+	if (ret) {
+		pr_warn("Couldn't register LSM notifier. ret %d\n", ret);
+		goto err_ibnl_clients;
+	}
+
 	ib_cache_setup();
 
 	return 0;
 
+err_ibnl_clients:
+	ib_remove_ibnl_clients();
 err_sa:
 	ib_sa_cleanup();
 err_mad:
@@ -1098,6 +1150,7 @@  err:
 
 static void __exit ib_core_cleanup(void)
 {
+	unregister_lsm_notifier(&ibdev_lsm_nb);
 	ib_cache_cleanup();
 	ib_remove_ibnl_clients();
 	ib_sa_cleanup();
diff --git a/include/linux/security.h b/include/linux/security.h
index 0bd8319..84abc05 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -69,6 +69,14 @@  struct audit_krule;
 struct user_namespace;
 struct timezone;
 
+enum lsm_event {
+	LSM_POLICY_CHANGE,
+};
+
+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);
+
 /* These functions are in security/commoncap.c */
 extern int cap_capable(const struct cred *cred, struct user_namespace *ns,
 		       int cap, int audit);
diff --git a/security/security.c b/security/security.c
index 45b6dc0..8b8ddb2 100644
--- a/security/security.c
+++ b/security/security.c
@@ -33,6 +33,8 @@ 
 /* Maximum number of letters for an LSM name string */
 #define SECURITY_NAME_MAX	10
 
+static ATOMIC_NOTIFIER_HEAD(lsm_notifier_chain);
+
 /* Boot-time LSM user choice */
 static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
 	CONFIG_DEFAULT_SECURITY;
@@ -98,6 +100,24 @@  int __init security_module_enable(const char *module)
 	return !strcmp(module, chosen_lsm);
 }
 
+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 a86d537..7c22703 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -159,13 +159,14 @@  static int selinux_peerlbl_enabled(void)
 	return (selinux_policycap_alwaysnetwork || netlbl_enabled() || selinux_xfrm_enabled());
 }
 
-static int selinux_netcache_avc_callback(u32 event)
+static int selinux_cache_avc_callback(u32 event)
 {
 	if (event == AVC_CALLBACK_RESET) {
 		sel_netif_flush();
 		sel_netnode_flush();
 		sel_netport_flush();
 		synchronize_net();
+		call_lsm_notifier(LSM_POLICY_CHANGE, NULL);
 	}
 	return 0;
 }
@@ -6235,7 +6236,7 @@  static __init int selinux_init(void)
 
 	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks));
 
-	if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
+	if (avc_add_callback(selinux_cache_avc_callback, AVC_CALLBACK_RESET))
 		panic("SELinux: Unable to register AVC netcache callback\n");
 
 	if (selinux_enforcing)
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 1b1fd27..983bf2a 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -177,6 +177,8 @@  static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
 			avc_ss_reset(0);
 		selnl_notify_setenforce(selinux_enforcing);
 		selinux_status_update_setenforce(selinux_enforcing);
+		if (!selinux_enforcing)
+			call_lsm_notifier(LSM_POLICY_CHANGE, NULL);
 	}
 	length = count;
 out: