From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765579AbXHIUkU (ORCPT ); Thu, 9 Aug 2007 16:40:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755173AbXHIUkE (ORCPT ); Thu, 9 Aug 2007 16:40:04 -0400 Received: from sandeen.net ([209.173.210.139]:13595 "EHLO sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754370AbXHIUkC (ORCPT ); Thu, 9 Aug 2007 16:40:02 -0400 Message-ID: <46BB7BA0.70107@sandeen.net> Date: Thu, 09 Aug 2007 15:40:00 -0500 From: Eric Sandeen User-Agent: Thunderbird 2.0.0.6 (Macintosh/20070728) MIME-Version: 1.0 To: linux-kernel Mailing List CC: linux-fsdevel Subject: [PATCH V2] limit minixfs printks on corrupted dir i_size, CVE-2006-6058 References: <46BB6101.4030307@redhat.com> In-Reply-To: <46BB6101.4030307@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Perhaps this is simpler, and preferable. Thanks to adilger for reminding me about printk_ratelimit. :) ---- This attempts to address CVE-2006-6058 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-6058 first reported at http://projects.info-pull.com/mokb/MOKB-17-11-2006.html Essentially a corrupted minix dir inode reporting a very large i_size will loop for a very long time in minix_readdir, minix_find_entry, etc, because on EIO they just move on to try the next page. This is under the BKL, printk-storming as well. This can lock up the machine for a very long time. Simply ratelimiting the printks gets things back under control. Signed-off-by: Eric Sandeen Index: linux-2.6.22-rc4/fs/minix/itree_v1.c =================================================================== --- linux-2.6.22-rc4.orig/fs/minix/itree_v1.c +++ linux-2.6.22-rc4/fs/minix/itree_v1.c @@ -27,7 +27,8 @@ static int block_to_path(struct inode * if (block < 0) { printk("minix_bmap: block<0\n"); } else if (block >= (minix_sb(inode->i_sb)->s_max_size/BLOCK_SIZE)) { - printk("minix_bmap: block>big\n"); + if (printk_ratelimit()) + printk("minix_bmap: block>big\n"); } else if (block < 7) { offsets[n++] = block; } else if ((block -= 7) < 512) { Index: linux-2.6.22-rc4/fs/minix/itree_v2.c =================================================================== --- linux-2.6.22-rc4.orig/fs/minix/itree_v2.c +++ linux-2.6.22-rc4/fs/minix/itree_v2.c @@ -28,7 +28,8 @@ static int block_to_path(struct inode * if (block < 0) { printk("minix_bmap: block<0\n"); } else if (block >= (minix_sb(inode->i_sb)->s_max_size/sb->s_blocksize)) { - printk("minix_bmap: block>big\n"); + if (printk_ratelimit()) + printk("minix_bmap: block>big\n"); } else if (block < 7) { offsets[n++] = block; } else if ((block -= 7) < 256) {