Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754199AbaDRJay (ORCPT ); Fri, 18 Apr 2014 05:30:54 -0400 Received: from ip4-83-240-18-248.cust.nbox.cz ([83.240.18.248]:46020 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372AbaDRJWt (ORCPT ); Fri, 18 Apr 2014 05:22:49 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, "Michael S. Tsirkin" , "David S. Miller" , Jiri Slaby Subject: [PATCH 3.12 60/72] vhost: fix total length when packets are too short Date: Fri, 18 Apr 2014 11:22:33 +0200 Message-Id: X-Mailer: git-send-email 1.9.2 In-Reply-To: <3389f243c528afc7c7300c83b8f296290cd3656d.1397812482.git.jslaby@suse.cz> References: <3389f243c528afc7c7300c83b8f296290cd3656d.1397812482.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Michael S. Tsirkin" 3.12-stable review patch. If anyone has any objections, please let me know. =============== [ Upstream commit d8316f3991d207fe32881a9ac20241be8fa2bad0 ] When mergeable buffers are disabled, and the incoming packet is too large for the rx buffer, get_rx_bufs returns success. This was intentional in order for make recvmsg truncate the packet and then handle_rx would detect err != sock_len and drop it. Unfortunately we pass the original sock_len to recvmsg - which means we use parts of iov not fully validated. Fix this up by detecting this overrun and doing packet drop immediately. CVE-2014-0077 Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Jiri Slaby --- drivers/vhost/net.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b12176f2013c..e5522d9f59e8 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -528,6 +528,12 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, *iovcount = seg; if (unlikely(log)) *log_num = nlogs; + + /* Detect overrun */ + if (unlikely(datalen > 0)) { + r = UIO_MAXIOV + 1; + goto err; + } return headcount; err: vhost_discard_vq_desc(vq, headcount); @@ -583,6 +589,14 @@ static void handle_rx(struct vhost_net *net) /* On error, stop handling until the next kick. */ if (unlikely(headcount < 0)) break; + /* On overrun, truncate and discard */ + if (unlikely(headcount > UIO_MAXIOV)) { + msg.msg_iovlen = 1; + err = sock->ops->recvmsg(NULL, sock, &msg, + 1, MSG_DONTWAIT | MSG_TRUNC); + pr_debug("Discarded rx packet: len %zd\n", sock_len); + continue; + } /* OK, now we need to know about added descriptors. */ if (!headcount) { if (unlikely(vhost_enable_notify(&net->dev, vq))) { -- 1.9.2 -- 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/