[PATCH] Keys: Possessor permissions should be additive

This patch makes the possessor permissions on a key additive with
user/group/other permissions on the same key.

This permits extra rights to be granted to the possessor of a key without
taking away any rights conferred by them owning the key or having common group
membership.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/security/keys/permission.c b/security/keys/permission.c
index 1c3651670ce9..03db073ba45c 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -27,12 +27,6 @@ int key_task_permission(const key_ref_t key_ref,
 
         key = key_ref_to_ptr(key_ref);
 
-        /* use the top 8-bits of permissions for keys the caller possesses */
-        if (is_key_possessed(key_ref)) {
-                kperm = key->perm >> 24;
-                goto use_these_perms;
-        }
-
         /* use the second 8-bits of permissions for keys the caller owns */
         if (key->uid == context->fsuid) {
                 kperm = key->perm >> 16;
@@ -61,6 +55,12 @@ 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;