1 files changed, 32 insertions, 0 deletions

diff --git a/security/keys/permission.c b/security/keys/permission.c
index e7f579c0eaf5..3b41f9b52537 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -73,3 +73,35 @@ use_these_perms:
 } /* end key_task_permission() */
 
 EXPORT_SYMBOL(key_task_permission);
+
+/*****************************************************************************/
+/*
+ * validate a key
+ */
+int key_validate(struct key *key)
+{
+        struct timespec now;
+        int ret = 0;
+
+        if (key) {
+                /* check it's still accessible */
+                ret = -EKEYREVOKED;
+                if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
+                    test_bit(KEY_FLAG_DEAD, &key->flags))
+                        goto error;
+
+                /* check it hasn't expired */
+                ret = 0;
+                if (key->expiry) {
+                        now = current_kernel_time();
+                        if (now.tv_sec >= key->expiry)
+                                ret = -EKEYEXPIRED;
+                }
+        }
+
+ error:
+        return ret;
+
+} /* end key_validate() */
+
+EXPORT_SYMBOL(key_validate);