From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rusty Russell , "Michael S. Tsirkin" , "David S. Miller" , stable@kernel.org Subject: [ 19/98] vhost/net: fix heads usage of ubuf_info Date: Tue, 26 Mar 2013 15:42:08 -0700 Message-Id: <20130326224244.465447193@linuxfoundation.org> In-Reply-To: <20130326224242.449070940@linuxfoundation.org> References: <20130326224242.449070940@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" [ Upstream commit 46aa92d1ba162b4b3d6b7102440e459d4e4ee255 ] 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 Cc: stable@kernel.org Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -339,7 +339,8 @@ 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 = VHOST_DMA_IN_PROGRESS;