CVE-2021-47335

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-47335
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.

5.5 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409 Patch
https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048 Patch
https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347 Patch
https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a Patch
https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409 Patch
https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048 Patch
https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347 Patch
https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
History

12 May 2025, 19:58

Type Values Removed Values Added
CWE CWE-416
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5
First Time Linux linux Kernel
Linux
References () https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409 - () https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409 - Patch
References () https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048 - () https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048 - Patch
References () https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347 - () https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347 - Patch
References () https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a - () https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a - Patch

21 Nov 2024, 06:35

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409 - () https://git.kernel.org/stable/c/79fa5d944c875711253a23b8155b36883c696409 -
References () https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048 - () https://git.kernel.org/stable/c/86786603014e0a22d0d6af8e80ae4b8687927048 -
References () https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347 - () https://git.kernel.org/stable/c/cad83c968c2ebe97905f900326988ed37146c347 -
References () https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a - () https://git.kernel.org/stable/c/e472b276a0d2180808009be38105e12754432e2a -
Summary
  • (es) 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.

21 May 2024, 15:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-05-21 15:15

Updated : 2025-05-12 19:58

NVD link : CVE-2021-47335

Mitre link : CVE-2021-47335

CVE.ORG link : CVE-2021-47335

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-416

Use After Free