CVE-2021-47335

f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances

Severity Score

"-"

*CVSS v-

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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

f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances

As syzbot reported, there is an use-after-free issue during f2fs recovery:

Use-after-free write at 0xffff88823bc16040 (in kfence-#10):
kmem_cache_destroy+0x1f/0x120 mm/slab_common.c:486
f2fs_recover_fsync_data+0x75b0/0x8380 fs/f2fs/recovery.c:869
f2fs_fill_super+0x9393/0xa420 fs/f2fs/super.c:3945
mount_bdev+0x26c/0x3a0 fs/super.c:1367
legacy_get_tree+0xea/0x180 fs/fs_context.c:592
vfs_get_tree+0x86/0x270 fs/super.c:1497
do_new_mount fs/namespace.c:2905 [inline]
path_mount+0x196f/0x2be0 fs/namespace.c:3235
do_mount fs/namespace.c:3248 [inline]
__do_sys_mount fs/namespace.c:3456 [inline]
__se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433
do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae

The root cause is multi f2fs filesystem instances can race on accessing
global fsync_entry_slab pointer, result in use-after-free issue of slab
cache, fixes to init/destroy this slab cache only once during module
init/destroy procedure to avoid this issue.

En el kernel de Linux, se resolvió la siguiente vulnerabilidad: f2fs: solución para evitar ejecuciónes en fsync_entry_slab por instancias de múltiples sistemas de archivos. Como informó syzbot, hay un problema de use after free durante la recuperación de f2fs: escritura de use after free en 0xffff88823bc16040 ( en kfence-#10): kmem_cache_destroy+0x1f/0x120 mm/slab_common.c:486 f2fs_recover_fsync_data+0x75b0/0x8380 fs/f2fs/recovery.c:869 f2fs_fill_super+0x9393/0xa420 fs/f2fs/super.c:3945 _bdev+0x26c /0x3a0 fs/super.c:1367 Legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x86/0x270 fs/super.c:1497 do_new_mount fs/namespace.c:2905 [en línea] path_mount+0x196f/0x2be0 fs /namespace.c:3235 do_mount fs/namespace.c:3248 [en línea] __do_sys_mount fs/namespace.c:3456 [en línea] __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3433 do_syscall_64+0x3f/0xb0 arch/x86/entry /common.c:47 Entry_SYSCALL_64_after_hwframe+0x44/0xae La causa principal es que varias instancias del sistema de archivos f2fs pueden acelerarse al acceder al puntero global fsync_entry_slab, lo que resulta en un problema de use after free del caché de slab, se corrige para iniciar/destruir este caché de slab solo una vez durante procedimiento de inicio/destrucción del módulo para evitar este problema.

*Credits: N/A

CVSS Scores

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Privileges Required

User Interaction

Scope

Confidentiality

Integrity

Availability

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-05-21 CVE Reserved
2024-05-21 CVE Published
2024-05-22 EPSS Updated
2024-11-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (4)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048	2021-07-19
https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409	2021-07-19
https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a	2021-07-19
https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347	2021-05-14

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				< 5.10.51 Search vendor "Linux" for product "Linux Kernel" and version " < 5.10.51"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				< 5.12.18 Search vendor "Linux" for product "Linux Kernel" and version " < 5.12.18"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				< 5.13.3 Search vendor "Linux" for product "Linux Kernel" and version " < 5.13.3"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				< 5.14 Search vendor "Linux" for product "Linux Kernel" and version " < 5.14"		en		Affected