From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCH] vhost-net: fix range checking in mrg bufs case Date: Tue, 14 Sep 2010 15:15:52 +0200 Message-ID: <20100914131552.GA1937@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: "Michael S. Tsirkin" , kvm@vger.kernel.org, virtualization@lists.osdl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org In mergeable buffer case, we use headcount, log_num and seg as indexes in same-size arrays, and we know that headcount <= seg and log_num equals either 0 or seg. Therefore, the right thing to do is range-check seg, not headcount as we do now: these will be different if guest chains s/g descriptors (this does not happen now, but we can not trust the guest). Long term, we should add BUG_ON checks to verify two other indexes are what we think they should be. Reported-by: Jason Wang Signed-off-by: Michael S. Tsirkin --- Dave, I'll queue this on my tree, no need to bother. drivers/vhost/net.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 6400cd5..f095de6 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -245,7 +245,7 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, int r, nlogs = 0; while (datalen > 0) { - if (unlikely(headcount >= VHOST_NET_MAX_SG)) { + if (unlikely(seg >= VHOST_NET_MAX_SG)) { r = -ENOBUFS; goto err; } -- 1.7.3.rc1.5.ge5969