CVE-2024-57892: ocfs2: fix slab-use-after-free due to dangling pointer dqi_priv
Description
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.
[[email protected]: coding-style cleanups]
Classification
CVE ID: CVE-2024-57892
Affected Products
Vendor: Linux
Product: Linux
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.04% (probability of being exploited)
EPSS Percentile: 5.04% (scored less or equal to compared to others)
EPSS Date: 2025-02-13 (when was this score calculated)
References
https://git.kernel.org/stable/c/2e3d203b1adede46bbba049e497765d67865be18https://git.kernel.org/stable/c/ba950a02d8d23811aa1120affd3adedcfac6153d
https://git.kernel.org/stable/c/5f3fd772d152229d94602bca243fbb658068a597