1 files changed, 59 insertions, 19 deletions

diff --git a/security/keys/permission.c b/security/keys/permission.c
index 03db073ba45..732cc0beffd 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -1,4 +1,4 @@
-/* permission.c: key permission determination
+/* Key permission checking
  *
  * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
@@ -10,16 +10,25 @@
  */
 
 #include <linux/module.h>
+#include <linux/security.h>
 #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.
+ *
+ * Returns 0 if successful, -EACCES if access is denied based on the
+ * permissions bits or the LSM check.
  */
-int key_task_permission(const key_ref_t key_ref,
-			struct task_struct *context,
-			key_perm_t perm)
+int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
+			unsigned perm)
 {
 	struct key *key;
 	key_perm_t kperm;
@@ -28,23 +37,20 @@ int key_task_permission(const key_ref_t key_ref,
 	key = key_ref_to_ptr(key_ref);
 
 	/* use the second 8-bits of permissions for keys the caller owns */
-	if (key->uid == context->fsuid) {
+	if (uid_eq(key->uid, cred->fsuid)) {
 		kperm = key->perm >> 16;
 		goto use_these_perms;
 	}
 
 	/* use the third 8-bits of permissions for keys the caller has a group
 	 * membership in common with */
-	if (key->gid != -1 && key->perm & KEY_GRP_ALL) {
-		if (key->gid == context->fsgid) {
+	if (gid_valid(key->gid) && key->perm & KEY_GRP_ALL) {
+		if (gid_eq(key->gid, cred->fsgid)) {
 			kperm = key->perm >> 8;
 			goto use_these_perms;
 		}
 
-		task_lock(context);
-		ret = groups_search(context->group_info, key->gid);
-		task_unlock(context);
-
+		ret = groups_search(cred->group_info, key->gid);
 		if (ret) {
 			kperm = key->perm >> 8;
 			goto use_these_perms;
@@ -55,16 +61,50 @@ int key_task_permission(const key_ref_t key_ref,
 	kperm = key->perm;
 
 use_these_perms:
+
 	/* use the top 8-bits of permissions for keys the caller possesses
 	 * - possessor permissions are additive with other permissions
 	 */
 	if (is_key_possessed(key_ref))
 		kperm |= key->perm >> 24;
 
-	kperm = kperm & perm & KEY_ALL;
-
-	return kperm == perm;
+	kperm = kperm & perm & KEY_NEED_ALL;
 
-} /* end key_task_permission() */
+	if (kperm != perm)
+		return -EACCES;
 
+	/* let LSM be the final arbiter */
+	return security_key_permission(key_ref, cred, perm);
+}
 EXPORT_SYMBOL(key_task_permission);
+
+/**
+ * key_validate - Validate a key.
+ * @key: The key to be validated.
+ *
+ * Check that a key is valid, returning 0 if the key is okay, -ENOKEY if the
+ * key is invalidated, -EKEYREVOKED if the key's type has been removed or if
+ * the key has been revoked or -EKEYEXPIRED if the key has expired.
+ */
+int key_validate(const struct key *key)
+{
+	unsigned long flags = key->flags;
+
+	if (flags & (1 << KEY_FLAG_INVALIDATED))
+		return -ENOKEY;
+
+	/* check it's still accessible */
+	if (flags & ((1 << KEY_FLAG_REVOKED) |
+		     (1 << KEY_FLAG_DEAD)))
+		return -EKEYREVOKED;
+
+	/* check it hasn't expired */
+	if (key->expiry) {
+		struct timespec now = current_kernel_time();
+		if (now.tv_sec >= key->expiry)
+			return -EKEYEXPIRED;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(key_validate);