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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 EE6E7C4361B for ; Wed, 9 Dec 2020 09:07:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADD2123B85 for ; Wed, 9 Dec 2020 09:07:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728820AbgLIJHo (ORCPT ); Wed, 9 Dec 2020 04:07:44 -0500 Received: from mx2.suse.de ([195.135.220.15]:47324 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728814AbgLIJHm (ORCPT ); Wed, 9 Dec 2020 04:07:42 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 78D9BAB63; Wed, 9 Dec 2020 09:07:00 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 26FBD1E133E; Wed, 9 Dec 2020 10:07:00 +0100 (CET) Date: Wed, 9 Dec 2020 10:07:00 +0100 From: Jan Kara To: Anant Thazhemadam Cc: Jan Kara , linux-kernel@vger.kernel.org, syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com Subject: Re: [PATCH] fs: quota: fix array-index-out-of-bounds bug by passing correct argument to vfs_cleanup_quota_inode() Message-ID: <20201209090700.GA18595@quack2.suse.cz> References: <20201208194338.7064-1-anant.thazhemadam@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201208194338.7064-1-anant.thazhemadam@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 09-12-20 01:13:38, Anant Thazhemadam wrote: > When dquot_resume() was last updated, the argument that got passed > to vfs_cleanup_quota_inode was incorrectly set. > > If type = -1 and dquot_load_quota_sb() returns a negative value, > then vfs_cleanup_quota_inode() gets called with -1 passed as an > argument, and this leads to an array-index-out-of-bounds bug. > > Fix this issue by correctly passing the arguments. > > Fixes: ae45f07d47cc ("quota: Simplify dquot_resume()") > Reported-by: syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com > Tested-by: syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com > Signed-off-by: Anant Thazhemadam Thanks for the fix! I've just queued the very same fix I wrote yesterday to my tree. But yours has better changelog so let me pick your patch instead ;) For next time, how can we avoid collisions like this? Did you work on the fix based on the syzbot email sent to the list so if I actually reply to the syzbot email that I'm working on / already have a fix you'd see it? Honza > --- > If type = -1 is passed as an argument to vfs_cleanup_quota_inode(), > it causes an array-index-out-of-bounds error since dqopt->files[-1] > can be potentially attempted to be accessed. > Before the bisected commit introduced this bug, vfs_load_quota_inode() > was being directly called in dquot_resume(), and subsequently > vfs_cleanup_quota_inode() was called with the cnt value as argument. > > fs/quota/dquot.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c > index bb02989d92b6..4f1373463766 100644 > --- a/fs/quota/dquot.c > +++ b/fs/quota/dquot.c > @@ -2455,7 +2455,7 @@ int dquot_resume(struct super_block *sb, int type) > ret = dquot_load_quota_sb(sb, cnt, dqopt->info[cnt].dqi_fmt_id, > flags); > if (ret < 0) > - vfs_cleanup_quota_inode(sb, type); > + vfs_cleanup_quota_inode(sb, cnt); > } > > return ret; > -- > 2.25.1 > -- Jan Kara SUSE Labs, CR