From patchwork Thu Mar 3 18:38:35 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Miller X-Patchwork-Id: 85325 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 66794B715A for ; Fri, 4 Mar 2011 05:38:04 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758664Ab1CCSh6 (ORCPT ); Thu, 3 Mar 2011 13:37:58 -0500 Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:57055 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758443Ab1CCSh6 (ORCPT ); Thu, 3 Mar 2011 13:37:58 -0500 Received: from localhost (localhost [127.0.0.1]) by sunset.davemloft.net (Postfix) with ESMTP id 5622524C08A; Thu, 3 Mar 2011 10:38:35 -0800 (PST) Date: Thu, 03 Mar 2011 10:38:35 -0800 (PST) Message-Id: <20110303.103835.226796504.davem@davemloft.net> To: eric.dumazet@gmail.com Cc: netdev@vger.kernel.org Subject: Re: [BUG net-next-2.6] dst_release() crash From: David Miller In-Reply-To: <1299169686.2983.129.camel@edumazet-laptop> References: <1299169686.2983.129.camel@edumazet-laptop> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Date: Thu, 03 Mar 2011 17:28:06 +0100 > We could add a sanity test in dst_release(), or fix callers ? Callers are responsible for not passing garbage pointers around :-) Thanks for the report. I just checked in the following fix. -------------------- ipv4: Fix crash in dst_release when udp_sendmsg route lookup fails. As reported by Eric: [11483.697233] IP: [] dst_release+0x18/0x60 ... [11483.697741] Call Trace: [11483.697764] [] udp_sendmsg+0x282/0x6e0 [11483.697790] [] ? memcpy_toiovec+0x51/0x70 [11483.697818] [] ? ip_generic_getfrag+0x0/0xb0 The pointer passed to dst_release() is -EINVAL, that's because we leave an error pointer in the local variable "rt" by accident. NULL it out to fix the bug. Reported-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/udp.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 95e0c2c..c9a73e5 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -925,6 +925,7 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, rt = ip_route_output_flow(net, &fl, sk); if (IS_ERR(rt)) { err = PTR_ERR(rt); + rt = NULL; if (err == -ENETUNREACH) IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES); goto out;