CVE-2024-57892 Information

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.

[akpm@linux-foundation.org: coding-style cleanups]

Reference

https://git.kernel.org/stable/c/2e3d203b1adede46bbba049e497765d67865be18 https://git.kernel.org/stable/c/5f3fd772d152229d94602bca243fbb658068a597 https://git.kernel.org/stable/c/ba950a02d8d23811aa1120affd3adedcfac6153d