Skip to content

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

Moderate severity Unreviewed Published Feb 27, 2024 to the GitHub Advisory Database • Updated Jan 8, 2025

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

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

ovl: fix leaked dentry

Since commit 6815f479ca90 ("ovl: use only uppermetacopy state in
ovl_lookup()"), overlayfs doesn't put temporary dentry when there is a
metacopy error, which leads to dentry leaks when shutting down the related
superblock:

overlayfs: refusing to follow metacopy origin for (/file0)
...
BUG: Dentry (ptrval){i=3f33,n=file3} still in use (1) [unmount of overlay overlay]
...
WARNING: CPU: 1 PID: 432 at umount_check.cold+0x107/0x14d
CPU: 1 PID: 432 Comm: unmount-overlay Not tainted 5.12.0-rc5 #1
...
RIP: 0010:umount_check.cold+0x107/0x14d
...
Call Trace:
d_walk+0x28c/0x950
? dentry_lru_isolate+0x2b0/0x2b0
? __kasan_slab_free+0x12/0x20
do_one_tree+0x33/0x60
shrink_dcache_for_umount+0x78/0x1d0
generic_shutdown_super+0x70/0x440
kill_anon_super+0x3e/0x70
deactivate_locked_super+0xc4/0x160
deactivate_super+0xfa/0x140
cleanup_mnt+0x22e/0x370
__cleanup_mnt+0x1a/0x30
task_work_run+0x139/0x210
do_exit+0xb0c/0x2820
? __kasan_check_read+0x1d/0x30
? find_held_lock+0x35/0x160
? lock_release+0x1b6/0x660
? mm_update_next_owner+0xa20/0xa20
? reacquire_held_locks+0x3f0/0x3f0
? __sanitizer_cov_trace_const_cmp4+0x22/0x30
do_group_exit+0x135/0x380
__do_sys_exit_group.isra.0+0x20/0x20
__x64_sys_exit_group+0x3c/0x50
do_syscall_64+0x45/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xae
...
VFS: Busy inodes after unmount of overlay. Self-destruct in 5 seconds. Have a nice day...

This fix has been tested with a syzkaller reproducer.

References

Published by the National Vulnerability Database Feb 27, 2024
Published to the GitHub Advisory Database Feb 27, 2024
Last updated Jan 8, 2025

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
Low
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:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.042%
(5th percentile)

Weaknesses

CVE ID

CVE-2021-46972

GHSA ID

GHSA-5fx7-qfg5-mpmc

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.