From 34bba27d0399bee3cf65b030f2f43dde77d92248 Mon Sep 17 00:00:00 2001 From: Pan Bian Date: Mon, 3 Dec 2018 23:28:02 -0500 Subject: [PATCH] ext4: fix possible use after free in ext4_quota_enable commit 61157b24e60fb3cd1f85f2c76a7b1d628f970144 upstream. 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. Fixes: daf647d2dd5 ("ext4: add lockdep annotations for i_data_sem") Cc: stable@kernel.org # 4.6 Reviewed-by: Jan Kara Signed-off-by: Pan Bian Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- 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 675f425..fb5ed94 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5636,9 +5636,9 @@ 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