From: Philipp Reisner <philipp.reisner@linbit.com>
Date: Wed, 28 Mar 2012 08:17:32 +0000 (+0200)
Subject: drbd: Ensure that data_size is not 0 before using data_size-1 as index
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=5de738272e38f7051c7a44c42631b71a0e2a1e80;p=openwrt%2Fstaging%2Fblogic.git

drbd: Ensure that data_size is not 0 before using data_size-1 as index

This could be exploited by a peer which runs modified code.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 9db93ff11c02..017eeb745ed9 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2837,10 +2837,10 @@ static int receive_SyncParam(struct drbd_conf *mdev, enum drbd_packets cmd, unsi
 
 	if (apv >= 88) {
 		if (apv == 88) {
-			if (data_size > SHARED_SECRET_MAX) {
-				dev_err(DEV, "verify-alg too long, "
-				    "peer wants %u, accepting only %u byte\n",
-						data_size, SHARED_SECRET_MAX);
+			if (data_size > SHARED_SECRET_MAX || data_size == 0) {
+				dev_err(DEV, "verify-alg of wrong size, "
+					"peer wants %u, accepting only up to %u byte\n",
+					data_size, SHARED_SECRET_MAX);
 				return false;
 			}