[PATCH 4.9 056/101] libceph: weaken sizeof check in ceph_x_verify_authorizer_reply()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ilya Dryomov <idryomov@xxxxxxxxx>

commit f1d10e04637924f2b00a0fecdd2ca4565f5cfc3f upstream.

Allow for extending ceph_x_authorize_reply in the future.

Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: Sage Weil <sage@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ceph/auth_x.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/ceph/auth_x.c
+++ b/net/ceph/auth_x.c
@@ -733,8 +733,10 @@ static int ceph_x_verify_authorizer_repl
 	ret = ceph_x_decrypt(&au->session_key, &p, p + CEPHX_AU_ENC_BUF_LEN);
 	if (ret < 0)
 		return ret;
-	if (ret != sizeof(*reply))
-		return -EPERM;
+	if (ret < sizeof(*reply)) {
+		pr_err("bad size %d for ceph_x_authorize_reply\n", ret);
+		return -EINVAL;
+	}
 
 	if (au->nonce + 1 != le64_to_cpu(reply->nonce_plus_one))
 		ret = -EPERM;