diff options
| author | Dennis Lam <dennis.lamerice@gmail.com> | 2024-12-17 21:39:25 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-01-17 13:34:48 +0100 |
| commit | 2d431192486367eee03cc28d0b53b97dafcb8e63 (patch) | |
| tree | 93625c9db25598f1242c3afdaf1cb7924fc33fda | |
| parent | 18a1cd923b562f359f482c3c550a7f5c6f93a479 (diff) | |
ocfs2: fix slab-use-after-free due to dangling pointer dqi_priv
[ Upstream commit 5f3fd772d152229d94602bca243fbb658068a597 ]
When mounting ocfs2 and then remounting it as read-only, a
slab-use-after-free occurs after the user uses a syscall to
quota_getnextquota. Specifically, sb_dqinfo(sb, type)->dqi_priv is the
dangling pointer.
During the remounting process, the pointer dqi_priv is freed but is never
set as null leaving it to be accessed. Additionally, the read-only option
for remounting sets the DQUOT_SUSPENDED flag instead of setting the
DQUOT_USAGE_ENABLED flags. Moreover, later in the process of getting the
next quota, the function ocfs2_get_next_id is called and only checks the
quota usage flags and not the quota suspended flags.
To fix this, I set dqi_priv to null when it is freed after remounting with
read-only and put a check for DQUOT_SUSPENDED in ocfs2_get_next_id.
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20241218023924.22821-2-dennis.lamerice@gmail.com
Fixes: 8f9e8f5fcc05 ("ocfs2: Fix Q_GETNEXTQUOTA for filesystem without quotas")
Signed-off-by: Dennis Lam <dennis.lamerice@gmail.com>
Reported-by: syzbot+d173bf8a5a7faeede34c@syzkaller.appspotmail.com
Tested-by: syzbot+d173bf8a5a7faeede34c@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6731d26f.050a0220.1fb99c.014b.GAE@google.com/T/
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/ocfs2/quota_global.c | 2 | ||||
| -rw-r--r-- | fs/ocfs2/quota_local.c | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c index dc9f76ab7e13..0dffd6a44d39 100644 --- a/fs/ocfs2/quota_global.c +++ b/fs/ocfs2/quota_global.c @@ -881,7 +881,7 @@ static int ocfs2_get_next_id(struct super_block *sb, struct kqid *qid) int status = 0; trace_ocfs2_get_next_id(from_kqid(&init_user_ns, *qid), type); - if (!sb_has_quota_loaded(sb, type)) { + if (!sb_has_quota_active(sb, type)) { status = -ESRCH; goto out; } diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c index 257f13cdd14c..4b4fa58cd32f 100644 --- a/fs/ocfs2/quota_local.c +++ b/fs/ocfs2/quota_local.c @@ -864,6 +864,7 @@ out: brelse(oinfo->dqi_libh); brelse(oinfo->dqi_lqi_bh); kfree(oinfo); + info->dqi_priv = NULL; return status; } |