[linux-cifs-client] [PATCH] cifs: sanity check version in spnego upcall response

[Jeff Layton]

Currently, we don't check the version in the SPNEGO upcall response
even though one is provided. Do so and bail out with -EKEYREJECTED
if the check fails.

Signed-off-by: Jeff Layton <jlayton at redhat.com>
---
 fs/cifs/sess.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 3188e4d..4cd2343 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -516,6 +516,13 @@ CIFS_SessSetup(unsigned int xid, struct cifsSesInfo *ses, int first_time,
 		}
 
 		msg = spnego_key->payload.data;
+		/* sanity check version */
+		if (msg->version != CIFS_SPNEGO_UPCALL_VERSION)	{
+			cERROR(1, ("Bad upcall version: expected %d, got %d",
+				CIFS_SPNEGO_UPCALL_VERSION, msg->version));
+			rc = -EKEYREJECTED;
+			goto ssetup_exit;
+		}
 		/* bail out if key is too long */
 		if (msg->sesskey_len >
 		    sizeof(ses->server->mac_signing_key.data.krb5)) {
-- 
1.5.5.1