Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756701Ab3CYBUx (ORCPT ); Sun, 24 Mar 2013 21:20:53 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34130 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756340Ab3CYBQg (ORCPT ); Sun, 24 Mar 2013 21:16:36 -0400 Message-Id: <20130325010526.795498363@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 25 Mar 2013 01:05:49 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, "Michael S. Tsirkin" , Rusty Russell , "David S. Miller" Subject: [ 025/104] vhost/net: fix heads usage of ubuf_info Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In-Reply-To: <20130325010524.240972766@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:f137:78a:b654:affb X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1362 Lines: 40 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" commit 46aa92d1ba162b4b3d6b7102440e459d4e4ee255 upstream. ubuf info allocator uses guest controlled head as an index, so a malicious guest could put the same head entry in the ring twice, and we will get two callbacks on the same value. To fix use upend_idx which is guaranteed to be unique. Reported-by: Rusty Russell Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -234,7 +234,8 @@ static void handle_tx(struct vhost_net * msg.msg_controllen = 0; ubufs = NULL; } else { - struct ubuf_info *ubuf = &vq->ubuf_info[head]; + struct ubuf_info *ubuf; + ubuf = vq->ubuf_info + vq->upend_idx; vq->heads[vq->upend_idx].len = len; ubuf->callback = vhost_zerocopy_callback; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/