CVE-2022-48931 Information

Description

In the Linux kernel the following vulnerability has been resolved:

configfs: fix a race in configfs_unregister_subsystem()

When configfs_register_subsystem() or configfs_unregister_subsystem() is executing link_group() or unlink_group() it is possible that two processes add or delete list concurrently. Some unfortunate interleavings of them can cause kernel panic.

One of cases is: A –> B –> C –> D A <– B <– C <– D

 delete list_head B        |      delete list_head C

——————————–|———————————– configfs_unregister_subsystem | configfs_unregister_subsystem unlink_group | unlink_group unlink_obj | unlink_obj list_del_init | list_del_init __list_del_entry | __list_del_entry __list_del | __list_del // next == C | next->prev = prev | | next->prev = prev prev->next = next | | // prev == B | prev->next = next

Fix this by adding mutex when calling link_group() or unlink_group() but parent configfs_subsystem is NULL when config_item is root. So I create a mutex configfs_subsystem_mutex.

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Reference

https://git.kernel.org/stable/c/40805099af11f68c5ca7dbcfacf455da8f99f622 https://git.kernel.org/stable/c/d1654de19d42f513b6cfe955cc77e7f427e05a77 https://git.kernel.org/stable/c/a37024f7757c25550accdebf49e497ad6ae239fe https://git.kernel.org/stable/c/b7e2b91fcb5c78c414e33dc8d50642e307ca0c5a https://git.kernel.org/stable/c/a7ab53d3c27dfe83bb594456b9f38a37796ec39b https://git.kernel.org/stable/c/e7a66dd2687758718eddd79b542a95cf3aa488cc https://git.kernel.org/stable/c/3aadfd46858b1f64d4d6a0654b863e21aabff975 https://git.kernel.org/stable/c/84ec758fb2daa236026506868c8796b0500c047d

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

4.7