From patchwork Fri Jun 6 15:42:31 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Jones X-Patchwork-Id: 356897 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 3D2B814008F for ; Sat, 7 Jun 2014 01:42:58 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752116AbaFFPml (ORCPT ); Fri, 6 Jun 2014 11:42:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53878 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752107AbaFFPmk (ORCPT ); Fri, 6 Jun 2014 11:42:40 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s56Fgc8g011433 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 6 Jun 2014 11:42:38 -0400 Received: from gelk.kernelslacker.org (ovpn-113-169.phx2.redhat.com [10.3.113.169]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s56FgWDx019914 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 6 Jun 2014 11:42:38 -0400 Received: from gelk.kernelslacker.org (localhost [127.0.0.1]) by gelk.kernelslacker.org (8.14.8/8.14.7) with ESMTP id s56FgVk4031003; Fri, 6 Jun 2014 11:42:31 -0400 Received: (from davej@localhost) by gelk.kernelslacker.org (8.14.8/8.14.8/Submit) id s56FgVnJ031002; Fri, 6 Jun 2014 11:42:31 -0400 X-Authentication-Warning: gelk.kernelslacker.org: davej set sender to davej@redhat.com using -f Date: Fri, 6 Jun 2014 11:42:31 -0400 From: Dave Jones To: Sasha Levin Cc: Arnaldo Carvalho de Melo , "David S. Miller" , "netdev@vger.kernel.org" , LKML Subject: Re: net: llc: NULL ptr deref in llc_ui_sendmsg Message-ID: <20140606154231.GA7629@redhat.com> Mail-Followup-To: Dave Jones , Sasha Levin , Arnaldo Carvalho de Melo , "David S. Miller" , "netdev@vger.kernel.org" , LKML References: <5391D971.4030001@oracle.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5391D971.4030001@oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jun 06, 2014 at 11:08:33AM -0400, Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools guest running the latest -next > kernel I've stumbled on the following spew: > > [ 269.531162] BUG: unable to handle kernel NULL pointer dereference at 000000000000021e > [ 269.531217] IP: llc_ui_sendmsg (net/llc/af_llc.c:912) 905 /* must bind connection to sap if user hasn't done it. */ 906 if (sock_flag(sk, SOCK_ZAPPED)) { 907 /* bind to sap with null dev, exclusive. */ 908 rc = llc_ui_autobind(sock, addr); 909 if (rc) 910 goto release; 911 } 912 hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr); looks like llc->dev was null, (understandable, given Trinity doesn't really know how to set up llc beyond random socket()/setsockopt() calls). llc_ui_autobind returns -ENODEV in that case, so it looks like the SOCK_ZAPPED test was false. Something like the patch below maybe ? It feels ugly to be duplicating that test there, but if this is agreed upon I'll resubmit this properly. Dave --- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index 0080d2b0a8ae..9b192db9883b 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -908,6 +908,11 @@ static int llc_ui_sendmsg(struct kiocb *iocb, struct socket *sock, rc = llc_ui_autobind(sock, addr); if (rc) goto release; + } else { + if (!llc->dev) { + rc = -ENODEV; + goto release; + } } hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr); size = hdrlen + len;