lsm: infrastructure management of the infiniband blob

Move management of the infiniband security blob out of the individual
security modules and into the LSM infrastructure.  The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the ib_free() hook.
The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>

include/linux/lsm_hook_defs.h

@@ -373,8 +373,7 @@ LSM_HOOK(int, 0, mptcp_add_subflow, struct sock *sk, struct sock *ssk)
 LSM_HOOK(int, 0, ib_pkey_access, void *sec, u64 subnet_prefix, u16 pkey)
 LSM_HOOK(int, 0, ib_endport_manage_subnet, void *sec, const char *dev_name,
 	 u8 port_num)
-LSM_HOOK(int, 0, ib_alloc_security, void **sec)
-LSM_HOOK(void, LSM_RET_VOID, ib_free_security, void *sec)
+LSM_HOOK(int, 0, ib_alloc_security, void *sec)
 #endif /* CONFIG_SECURITY_INFINIBAND */
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM

include/linux/lsm_hooks.h

@@ -72,6 +72,7 @@ struct security_hook_list {
 struct lsm_blob_sizes {
 	int	lbs_cred;
 	int	lbs_file;
+	int	lbs_ib;
 	int	lbs_inode;
 	int	lbs_sock;
 	int	lbs_superblock;

security/security.c

@@ -219,6 +219,7 @@ static void __init lsm_set_blob_sizes(struct lsm_blob_sizes *needed)
 
 	lsm_set_blob_size(&needed->lbs_cred, &blob_sizes.lbs_cred);
 	lsm_set_blob_size(&needed->lbs_file, &blob_sizes.lbs_file);
+	lsm_set_blob_size(&needed->lbs_ib, &blob_sizes.lbs_ib);
 	/*
 	 * The inode blob gets an rcu_head in addition to
 	 * what the modules might need.
@@ -402,6 +403,7 @@ static void __init ordered_lsm_init(void)
 
 	init_debug("cred blob size       = %d\n", blob_sizes.lbs_cred);
 	init_debug("file blob size       = %d\n", blob_sizes.lbs_file);
+	init_debug("ib blob size         = %d\n", blob_sizes.lbs_ib);
 	init_debug("inode blob size      = %d\n", blob_sizes.lbs_inode);
 	init_debug("ipc blob size        = %d\n", blob_sizes.lbs_ipc);
 #ifdef CONFIG_KEYS
@@ -5096,7 +5098,18 @@ EXPORT_SYMBOL(security_ib_endport_manage_subnet);
  */
 int security_ib_alloc_security(void **sec)
 {
-	return call_int_hook(ib_alloc_security, sec);
+	int rc;
+
+	rc = lsm_blob_alloc(sec, blob_sizes.lbs_ib, GFP_KERNEL);
+	if (rc)
+		return rc;
+
+	rc = call_int_hook(ib_alloc_security, *sec);
+	if (rc) {
+		kfree(*sec);
+		*sec = NULL;
+	}
+	return rc;
 }
 EXPORT_SYMBOL(security_ib_alloc_security);
 
@@ -5108,7 +5121,7 @@ EXPORT_SYMBOL(security_ib_alloc_security);
  */
 void security_ib_free_security(void *sec)
 {
-	call_void_hook(ib_free_security, sec);
+	kfree(sec);
 }
 EXPORT_SYMBOL(security_ib_free_security);
 #endif	/* CONFIG_SECURITY_INFINIBAND */

security/selinux/hooks.c

@@ -6781,23 +6781,13 @@ static int selinux_ib_endport_manage_subnet(void *ib_sec, const char *dev_name,
 			    INFINIBAND_ENDPORT__MANAGE_SUBNET, &ad);
 }
 
-static int selinux_ib_alloc_security(void **ib_sec)
+static int selinux_ib_alloc_security(void *ib_sec)
 {
-	struct ib_security_struct *sec;
+	struct ib_security_struct *sec = selinux_ib(ib_sec);
 
-	sec = kzalloc(sizeof(*sec), GFP_KERNEL);
-	if (!sec)
-		return -ENOMEM;
 	sec->sid = current_sid();
-
-	*ib_sec = sec;
 	return 0;
 }
-
-static void selinux_ib_free_security(void *ib_sec)
-{
-	kfree(ib_sec);
-}
 #endif
 
 #ifdef CONFIG_BPF_SYSCALL
@@ -6969,6 +6959,7 @@ struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = {
 	.lbs_superblock = sizeof(struct superblock_security_struct),
 	.lbs_xattr_count = SELINUX_INODE_INIT_XATTRS,
 	.lbs_tun_dev = sizeof(struct tun_security_struct),
+	.lbs_ib = sizeof(struct ib_security_struct),
 };
 
 #ifdef CONFIG_PERF_EVENTS
@@ -7288,7 +7279,6 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(ib_pkey_access, selinux_ib_pkey_access),
 	LSM_HOOK_INIT(ib_endport_manage_subnet,
 		      selinux_ib_endport_manage_subnet),
-	LSM_HOOK_INIT(ib_free_security, selinux_ib_free_security),
 #endif
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
 	LSM_HOOK_INIT(xfrm_policy_free_security, selinux_xfrm_policy_free),

security/selinux/include/objsec.h

@@ -212,4 +212,9 @@ static inline struct tun_security_struct *selinux_tun_dev(void *security)
 	return security + selinux_blob_sizes.lbs_tun_dev;
 }
 
+static inline struct ib_security_struct *selinux_ib(void *ib_sec)
+{
+	return ib_sec + selinux_blob_sizes.lbs_ib;
+}
+
 #endif /* _SELINUX_OBJSEC_H_ */