[PATCH v3 22/24] LSM: Return the lsmblob slot on initialization

[Casey Schaufler <casey@xxxxxxxxxxxxxxxx>]

Return the slot allocated to the calling LSM in the lsmblob
structure. This can be used to set lsmblobs explicitly for
netlabel interfaces.

Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
---
 include/linux/lsm_hooks.h  | 4 ++--
 security/apparmor/lsm.c    | 8 ++++++--
 security/security.c        | 9 +++++++--
 security/selinux/hooks.c   | 5 ++++-
 security/smack/smack_lsm.c | 5 ++++-
 5 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 4d1ddf1a2aa6..ce341bcbce5d 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -2068,8 +2068,8 @@ struct lsm_blob_sizes {
 extern struct security_hook_heads security_hook_heads;
 extern char *lsm_names;
 
-extern void security_add_hooks(struct security_hook_list *hooks, int count,
-				char *lsm);
+extern int security_add_hooks(struct security_hook_list *hooks, int count,
+			      char *lsm);
 
 #define LSM_FLAG_LEGACY_MAJOR	BIT(0)
 #define LSM_FLAG_EXCLUSIVE	BIT(1)
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 2716e7731279..dcbbefbd95ff 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -47,6 +47,9 @@
 /* Flag indicating whether initialization completed */
 int apparmor_initialized;
 
+/* Slot for the AppArmor secid in the lsmblob structure */
+int apparmor_lsmblob_slot;
+
 DEFINE_PER_CPU(struct aa_buffers, aa_buffers);
 
 
@@ -1678,8 +1681,9 @@ static int __init apparmor_init(void)
 		aa_free_root_ns();
 		goto buffers_out;
 	}
-	security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
-				"apparmor");
+	apparmor_lsmblob_slot = security_add_hooks(apparmor_hooks,
+						   ARRAY_SIZE(apparmor_hooks),
+						   "apparmor");
 
 	/* Report that AppArmor successfully initialized */
 	apparmor_initialized = 1;
diff --git a/security/security.c b/security/security.c
index b2ffcd1f3057..c93a368b697b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -437,9 +437,12 @@ static int lsm_slot __initdata;
  * Each LSM has to register its hooks with the infrastructure.
  * If the LSM is using hooks that export secids allocate a slot
  * for it in the lsmblob.
+ *
+ * Returns the slot number in the lsmblob structure if one is
+ * allocated or LSMBLOB_INVALID if one was not allocated.
  */
-void __init security_add_hooks(struct security_hook_list *hooks, int count,
-				char *lsm)
+int __init security_add_hooks(struct security_hook_list *hooks, int count,
+			      char *lsm)
 {
 	int slot = LSMBLOB_INVALID;
 	int i;
@@ -479,6 +482,8 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count,
 	}
 	if (lsm_append(lsm, &lsm_names) < 0)
 		panic("%s - Cannot get early memory.\n", __func__);
+
+	return slot;
 }
 
 int call_lsm_notifier(enum lsm_event event, void *data)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ee840fecfebb..1e09acbf9630 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -103,6 +103,7 @@
 #include "avc_ss.h"
 
 struct selinux_state selinux_state;
+int selinux_lsmblob_slot;
 
 /* SECMARK reference count */
 static atomic_t selinux_secmark_refcount = ATOMIC_INIT(0);
@@ -6877,7 +6878,9 @@ static __init int selinux_init(void)
 
 	hashtab_cache_init();
 
-	security_add_hooks(selinux_hooks, ARRAY_SIZE(selinux_hooks), "selinux");
+	selinux_lsmblob_slot = security_add_hooks(selinux_hooks,
+						  ARRAY_SIZE(selinux_hooks),
+						  "selinux");
 
 	if (avc_add_callback(selinux_netcache_avc_callback, AVC_CALLBACK_RESET))
 		panic("SELinux: Unable to register AVC netcache callback\n");
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 3834b751d1e9..273f311fb153 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -60,6 +60,7 @@ static LIST_HEAD(smk_ipv6_port_list);
 #endif
 static struct kmem_cache *smack_inode_cache;
 int smack_enabled;
+int smack_lsmblob_slot;
 
 #define A(s) {"smack"#s, sizeof("smack"#s) - 1, Opt_##s}
 static struct {
@@ -4749,7 +4750,9 @@ static __init int smack_init(void)
 	/*
 	 * Register with LSM
 	 */
-	security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), "smack");
+	smack_lsmblob_slot = security_add_hooks(smack_hooks,
+						ARRAY_SIZE(smack_hooks),
+						"smack");
 	smack_enabled = 1;
 
 	pr_info("Smack:  Initializing.\n");
-- 
2.20.1