Return-Path: Received: from mx2.suse.de ([195.135.220.15]:44272 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730050AbeK0UMK (ORCPT ); Tue, 27 Nov 2018 15:12:10 -0500 Date: Tue, 27 Nov 2018 10:14:53 +0100 From: Jan Kara To: Pan Bian Cc: Theodore Ts'o , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ext4: fix possible use after free in ext4_quota_enable Message-ID: <20181127091453.GA16301@quack2.suse.cz> References: <1543202466-68277-1-git-send-email-bianpan2016@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1543202466-68277-1-git-send-email-bianpan2016@163.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon 26-11-18 11:21:06, Pan Bian wrote: > The function frees qf_inode via iput but then pass qf_inode to > lockdep_set_quota_inode on the failure path. This may result in a > use-after-free bug. The patch frees df_inode only when it is never used. > > Signed-off-by: Pan Bian > Fixes: daf647d2dd5("ext4: add lockdep annotations for i_data_sem") Thanks for the fix! The patch looks good. You can add: Reviewed-by: Jan Kara Honza > --- > fs/ext4/super.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 53ff6c2..35689eb 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -5690,9 +5690,9 @@ static int ext4_quota_enable(struct super_block *sb, int type, int format_id, > qf_inode->i_flags |= S_NOQUOTA; > lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA); > err = dquot_enable(qf_inode, type, format_id, flags); > - iput(qf_inode); > if (err) > lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL); > + iput(qf_inode); > > return err; > } > -- > 2.7.4 > > -- Jan Kara SUSE Labs, CR