Return-Path: Received: from m12-17.163.com ([220.181.12.17]:35171 "EHLO m12-17.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726116AbeKZOOZ (ORCPT ); Mon, 26 Nov 2018 09:14:25 -0500 From: Pan Bian To: "Theodore Ts\'o" , Andreas Dilger Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Pan Bian Subject: [PATCH] ext4: fix possible use after free in ext4_quota_enable Date: Mon, 26 Nov 2018 11:21:06 +0800 Message-Id: <1543202466-68277-1-git-send-email-bianpan2016@163.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: 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") --- 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