| Sažetak |
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: fix slab-use-after-free due to dangling pointer dqi_priv
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] |
