ext4: fix possible use after free in ext4_quota_enable

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: daf647d2dd ("ext4: add lockdep annotations for i_data_sem")
Cc: stable@kernel.org # 4.6
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Pan Bian 2018-12-03 23:28:02 -05:00 committed by Theodore Ts'o
parent 96f1e09745
commit 61157b24e6

View File

@ -5713,9 +5713,9 @@ 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;
}