Skip to content

In the Linux kernel, the following vulnerability has been...

Moderate severity Unreviewed Published Feb 28, 2024 to the GitHub Advisory Database • Updated Dec 31, 2024

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

In the Linux kernel, the following vulnerability has been resolved:

f2fs: compress: fix race condition of overwrite vs truncate

pos_fsstress testcase complains a panic as belew:

------------[ cut here ]------------
kernel BUG at fs/f2fs/compress.c:1082!
invalid opcode: 0000 [#1] SMP PTI
CPU: 4 PID: 2753477 Comm: kworker/u16:2 Tainted: G OE 5.12.0-rc1-custom #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
Workqueue: writeback wb_workfn (flush-252:16)
RIP: 0010:prepare_compress_overwrite+0x4c0/0x760 [f2fs]
Call Trace:
f2fs_prepare_compress_overwrite+0x5f/0x80 [f2fs]
f2fs_write_cache_pages+0x468/0x8a0 [f2fs]
f2fs_write_data_pages+0x2a4/0x2f0 [f2fs]
do_writepages+0x38/0xc0
__writeback_single_inode+0x44/0x2a0
writeback_sb_inodes+0x223/0x4d0
__writeback_inodes_wb+0x56/0xf0
wb_writeback+0x1dd/0x290
wb_workfn+0x309/0x500
process_one_work+0x220/0x3c0
worker_thread+0x53/0x420
kthread+0x12f/0x150
ret_from_fork+0x22/0x30

The root cause is truncate() may race with overwrite as below,
so that one reference count left in page can not guarantee the
page attaching in mapping tree all the time, after truncation,
later find_lock_page() may return NULL pointer.

  • prepare_compress_overwrite
  • f2fs_pagecache_get_page
  • unlock_page
    - f2fs_setattr
    - truncate_setsize
    - truncate_inode_page
    - delete_from_page_cache
  • find_lock_page

Fix this by avoiding referencing updated page.

References

Published by the National Vulnerability Database Feb 28, 2024
Published to the GitHub Advisory Database Feb 28, 2024
Last updated Dec 31, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.042%
(5th percentile)

Weaknesses

CVE ID

CVE-2021-46982

GHSA ID

GHSA-phj2-fhf8-vr32

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

Learn more about GitHub language support

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.