From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEBE2C33CA1 for ; Wed, 8 Jan 2020 19:48:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0C3D2070E for ; Wed, 8 Jan 2020 19:48:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728704AbgAHTsG (ORCPT ); Wed, 8 Jan 2020 14:48:06 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43708 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730462AbgAHTqE (ORCPT ); Wed, 8 Jan 2020 14:46:04 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ipHHD-0006oj-RA; Wed, 08 Jan 2020 19:45:59 +0000 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1ipHHD-007dp2-D8; Wed, 08 Jan 2020 19:45:59 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , syzbot+33d7ea72e47de3bdf4e1@syzkaller.appspotmail.com, "Theodore Ts'o" , syzbot+f8d6f8386ceacdbfff57@syzkaller.appspotmail.com, syzbot+44b6763edfc17144296f@syzkaller.appspotmail.com Date: Wed, 08 Jan 2020 19:43:55 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 57/63] ext4: add more paranoia checking in ext4_expand_extra_isize handling In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.81-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 4ea99936a1630f51fc3a2d61a58ec4a1c4b7d55a upstream. It's possible to specify a non-zero s_want_extra_isize via debugging option, and this can cause bad things(tm) to happen when using a file system with an inode size of 128 bytes. Add better checking when the file system is mounted, as well as when we are actually doing the trying to do the inode expansion. Link: https://lore.kernel.org/r/20191110121510.GH23325@mit.edu Reported-by: syzbot+f8d6f8386ceacdbfff57@syzkaller.appspotmail.com Reported-by: syzbot+33d7ea72e47de3bdf4e1@syzkaller.appspotmail.com Reported-by: syzbot+44b6763edfc17144296f@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o [bwh: Backported to 3.16: - Use EIO instead of EFSCORRUPTED - Adjust context] Signed-off-by: Ben Hutchings --- --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5094,10 +5094,25 @@ static int ext4_expand_extra_isize(struc { struct ext4_inode *raw_inode; struct ext4_xattr_ibody_header *header; + unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb); + struct ext4_inode_info *ei = EXT4_I(inode); if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) return 0; + /* this was checked at iget time, but double check for good measure */ + if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) || + (ei->i_extra_isize & 3)) { + EXT4_ERROR_INODE(inode, "bad extra_isize %u (inode size %u)", + ei->i_extra_isize, + EXT4_INODE_SIZE(inode->i_sb)); + return -EIO; + } + if ((new_extra_isize < ei->i_extra_isize) || + (new_extra_isize < 4) || + (new_extra_isize > inode_size - EXT4_GOOD_OLD_INODE_SIZE)) + return -EINVAL; /* Should never happen */ + raw_inode = ext4_raw_inode(&iloc); header = IHDR(inode, raw_inode); --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3427,11 +3427,15 @@ static void ext4_clamp_want_extra_isize( { struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_super_block *es = sbi->s_es; + unsigned def_extra_isize = sizeof(struct ext4_inode) - + EXT4_GOOD_OLD_INODE_SIZE; - /* determine the minimum size of new large inodes, if present */ - if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) { - sbi->s_want_extra_isize = sizeof(struct ext4_inode) - - EXT4_GOOD_OLD_INODE_SIZE; + if (sbi->s_inode_size == EXT4_GOOD_OLD_INODE_SIZE) { + sbi->s_want_extra_isize = 0; + return; + } + if (sbi->s_want_extra_isize < 4) { + sbi->s_want_extra_isize = def_extra_isize; if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE)) { if (sbi->s_want_extra_isize < @@ -3445,10 +3449,10 @@ static void ext4_clamp_want_extra_isize( } } /* Check if enough inode space is available */ - if (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize > - sbi->s_inode_size) { - sbi->s_want_extra_isize = sizeof(struct ext4_inode) - - EXT4_GOOD_OLD_INODE_SIZE; + if ((sbi->s_want_extra_isize > sbi->s_inode_size) || + (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize > + sbi->s_inode_size)) { + sbi->s_want_extra_isize = def_extra_isize; ext4_msg(sb, KERN_INFO, "required extra inode space not available"); }