keys: skip keys from another user namespace

When listing keys, do not return keys belonging to the
same uid in another user namespace.  Otherwise uid 500
in another user namespace will return keyrings called
uid.500 for another user namespace.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index ed851574d073..3dba81c2eba3 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -539,6 +539,9 @@ struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
                                     &keyring_name_hash[bucket],
                                     type_data.link
                                     ) {
+                        if (keyring->user->user_ns != current_user_ns())
+                                continue;
+
                         if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
                                 continue;