1 files changed, 13 insertions, 11 deletions

diff --git a/security/keys/permission.c b/security/keys/permission.c
index 13c36164f28..5d9fc7b93f2 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -14,24 +14,27 @@
 #include "internal.h"
 
 /*****************************************************************************/
-/*
- * check to see whether permission is granted to use a key in the desired way,
- * but permit the security modules to override
+/**
+ * key_task_permission - Check a key can be used
+ * @key_ref: The key to check
+ * @cred: The credentials to use
+ * @perm: The permissions to check for
+ *
+ * Check to see whether permission is granted to use a key in the desired way,
+ * but permit the security modules to override.
+ *
+ * The caller must hold either a ref on cred or must hold the RCU readlock or a
+ * spinlock.
  */
-int key_task_permission(const key_ref_t key_ref,
-                        struct task_struct *context,
+int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
                         key_perm_t perm)
 {
-        const struct cred *cred;
         struct key *key;
         key_perm_t kperm;
         int ret;
 
         key = key_ref_to_ptr(key_ref);
 
-        rcu_read_lock();
-        cred = __task_cred(context);
-
         /* use the second 8-bits of permissions for keys the caller owns */
         if (key->uid == cred->fsuid) {
                 kperm = key->perm >> 16;
@@ -57,7 +60,6 @@ int key_task_permission(const key_ref_t key_ref,
         kperm = key->perm;
 
 use_these_perms:
-        rcu_read_lock();
 
         /* use the top 8-bits of permissions for keys the caller possesses
          * - possessor permissions are additive with other permissions
@@ -71,7 +73,7 @@ use_these_perms:
                 return -EACCES;
 
         /* let LSM be the final arbiter */
-        return security_key_permission(key_ref, context, perm);
+        return security_key_permission(key_ref, cred, perm);
 
 } /* end key_task_permission() */