Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261318AbVC1ITS (ORCPT ); Mon, 28 Mar 2005 03:19:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261354AbVC1ITS (ORCPT ); Mon, 28 Mar 2005 03:19:18 -0500 Received: from yue.linux-ipv6.org ([203.178.140.15]:8966 "EHLO yue.st-paulia.net") by vger.kernel.org with ESMTP id S261318AbVC1ITM (ORCPT ); Mon, 28 Mar 2005 03:19:12 -0500 Date: Mon, 28 Mar 2005 17:21:08 +0900 (JST) Message-Id: <20050328.172108.30349253.yoshfuji@linux-ipv6.org> To: from-linux-kernel@I-love.sakura.ne.jp Cc: linux-kernel@vger.kernel.org, netdev@oss.sgi.com Subject: Re: Off-by-one bug at unix_mkname ? From: YOSHIFUJI Hideaki / =?iso-2022-jp?B?GyRCNUhGIzFRTEAbKEI=?= In-Reply-To: <200503281700.HHE91205.FtVLOStGOSPMYJFMN@I-love.sakura.ne.jp> References: <200503281700.HHE91205.FtVLOStGOSPMYJFMN@I-love.sakura.ne.jp> Organization: USAGI Project X-URL: http://www.yoshifuji.org/%7Ehideaki/ X-Fingerprint: 9022 65EB 1ECF 3AD1 0BDF 80D8 4807 F894 E062 0EEA X-PGP-Key-URL: http://www.yoshifuji.org/%7Ehideaki/hideaki@yoshifuji.org.asc X-Face: "5$Al-.M>NJ%a'@hhZdQm:."qn~PA^gq4o*>iCFToq*bAi#4FRtx}enhuQKz7fNqQz\BYU] $~O_5m-9'}MIs`XGwIEscw;e5b>n"B_?j/AkL~i/MEaZBLP X-Mailer: Mew version 2.2 on Emacs 20.7 / Mule 4.1 (AOI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1743 Lines: 45 In article <200503281700.HHE91205.FtVLOStGOSPMYJFMN@I-love.sakura.ne.jp> (at Mon, 28 Mar 2005 17:00:05 +0900), Tetsuo Handa says: > It seems to me that the following code is off-by-one bug. > > http://lxr.linux.no/source/net/unix/af_unix.c#L191 > http://lxr.linux.no/source/net/unix/af_unix.c?v=2.4.28#L182 > > I think > ((char *)sunaddr)[len]=0; > should be > ((char *)sunaddr)[len-1]=0; Well, 2.2 has some comment on this: static int unix_mkname(struct sockaddr_un * sunaddr, int len, unsigned *hashp) { if (len <= sizeof(short) || len > sizeof(*sunaddr)) return -EINVAL; : if (sunaddr->sun_path[0]) { /* * This may look like an off by one error but it is * a bit more subtle. 108 is the longest valid AF_UNIX * path for a binding. sun_path[108] doesnt as such * exist. However in kernel space we are guaranteed that * it is a valid memory location in our kernel * address buffer. */ if (len > sizeof(*sunaddr)) len = sizeof(*sunaddr); ((char *)sunaddr)[len]=0; len = strlen(sunaddr->sun_path)+1+sizeof(short); return len; } : -- Hideaki YOSHIFUJI @ USAGI Project GPG FP: 9022 65EB 1ECF 3AD1 0BDF 80D8 4807 F894 E062 0EEA - 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/