CVE-2024-57892

/// Technical 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]

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References