eCryptfs: Validate global auth tok keys

When searching through the global authentication tokens for a given key
signature, verify that a matching key has not been revoked and has not
expired.  This allows the `keyctl revoke` command to be properly used on
keys in use by eCryptfs.

Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Cc: stable <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 17164e483ab1..a0a7847567e9 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -416,7 +416,9 @@ ecryptfs_find_global_auth_tok_for_sig(
                             &mount_crypt_stat->global_auth_tok_list,
                             mount_crypt_stat_list) {
                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX) == 0) {
-                        (*global_auth_tok) = walker;
+                        rc = key_validate(walker->global_auth_tok_key);
+                        if (!rc)
+                                (*global_auth_tok) = walker;
                         goto out;
                 }
         }