CVE-2021-46972
Apache Linux Linux kernel Dentry Leak
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.
INFO
Published Date :
Feb. 27, 2024, 7:04 p.m.
Last Modified :
Jan. 8, 2025, 5:30 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to address the vulnerability.
- Reboot the system after the kernel update.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-46972.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-46972 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-46972
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-46972 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-46972 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jan. 08, 2025
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NIST CWE-401 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.8 up to (excluding) 5.10.35 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.11.19 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12 up to (excluding) 5.12.2 Changed Reference Type https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 No Types Assigned https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 Patch Changed Reference Type https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 No Types Assigned https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 Patch Changed Reference Type https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 No Types Assigned https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 Patch Changed Reference Type https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 No Types Assigned https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 Patch Changed Reference Type https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 No Types Assigned https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 Patch Changed Reference Type https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 No Types Assigned https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 Patch Changed Reference Type https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 No Types Assigned https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 Patch Changed Reference Type https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 No Types Assigned https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 Patch -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 Added Reference https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 Added Reference https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 Added Reference https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 14, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 27, 2024
Action Type Old Value New Value Added 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. Added Reference Linux https://git.kernel.org/stable/c/71d58457a8afc650da5d3292a7f7029317654d95 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/cf3e3330bc5719fa9d658e3e2f596bde89344a94 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/d587cfaef72b1b6f4b2774827123bce91f497cc8 [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/eaab1d45cdb4bb0c846bd23c3d666d5b90af7b41 [No types assigned]