integrity: Fix memory leakage in keyring allocation error path

Key restriction is allocated in integrity_init_keyring(). However, if
keyring allocation failed, it is not freed, causing memory leaks.

Fixes: 2b6aa412ff ("KEYS: Use structure to capture key restriction function and data")
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

security/integrity/digsig.c

@@ -126,6 +126,7 @@ int __init integrity_init_keyring(const unsigned int id)
 {
 	struct key_restriction *restriction;
 	key_perm_t perm;
+	int ret;
 
 	perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW
 		| KEY_USR_READ | KEY_USR_SEARCH;
@@ -154,7 +155,10 @@ int __init integrity_init_keyring(const unsigned int id)
 		perm |= KEY_USR_WRITE;
 
 out:
-	return __integrity_init_keyring(id, perm, restriction);
+	ret = __integrity_init_keyring(id, perm, restriction);
+	if (ret)
+		kfree(restriction);
+	return ret;
 }
 
 static int __init integrity_add_key(const unsigned int id, const void *data,