userns: Convert security/keys to the new userns infrastructure

- Replace key_user ->user_ns equality checks with kuid_has_mapping checks.
- Use from_kuid to generate key descriptions
- Use kuid_t and kgid_t and the associated helpers instead of uid_t and gid_t
- Avoid potential problems with file descriptor passing by displaying
  keys in the user namespace of the opener of key status proc files.

Cc: linux-security-module@vger.kernel.org
Cc: keyrings@linux-nfs.org
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 4 insertions, 10 deletions

diff --git a/security/keys/permission.c b/security/keys/permission.c
index 0b4d019..efcc0c8 100644
--- a/security/keys/permission.c
+++ b/security/keys/permission.c
@@ -36,33 +36,27 @@ int key_task_permission(const key_ref_t key_ref, const struct cred *cred,
 
 	key = key_ref_to_ptr(key_ref);
 
-	if (key->user->user_ns != cred->user_ns)
-		goto use_other_perms;
-
 	/* use the second 8-bits of permissions for keys the caller owns */
-	if (key->uid == cred->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 == cred->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;
 		}
 
-		ret = groups_search(cred->group_info,
-				    make_kgid(current_user_ns(), key->gid));
+		ret = groups_search(cred->group_info, key->gid);
 		if (ret) {
 			kperm = key->perm >> 8;
 			goto use_these_perms;
 		}
 	}
 
-use_other_perms:
-
 	/* otherwise use the least-significant 8-bits */
 	kperm = key->perm;