CVE-2021-47506

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-47506
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix use-after-free due to delegation race A delegation break could arrive as soon as we've called vfs_setlease. A delegation break runs a callback which immediately (in nfsd4_cb_recall_prepare) adds the delegation to del_recall_lru. If we then exit nfs4_set_delegation without hashing the delegation, it will be freed as soon as the callback is done with it, without ever being removed from del_recall_lru. Symptoms show up later as use-after-free or list corruption warnings, usually in the laundromat thread. I suspect aba2072f4523 "nfsd: grant read delegations to clients holding writes" made this bug easier to hit, but I looked as far back as v3.0 and it looks to me it already had the same problem. So I'm not sure where the bug was introduced; it may have been there from the beginning.

7.8 /10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/04a8d07f3d58308b92630045560799a3faa3ebce Patch
https://git.kernel.org/stable/c/148c816f10fd11df27ca6a9b3238cdd42fa72cd3 Patch
https://git.kernel.org/stable/c/2becaa990b93cbd2928292c0b669d3abb6cf06d4 Patch
https://git.kernel.org/stable/c/33645d3e22720cac1e4548f8fef57bf0649536ee Patch
https://git.kernel.org/stable/c/348714018139c39533c55661a0c7c990671396b4 Patch
https://git.kernel.org/stable/c/548ec0805c399c65ed66c6641be467f717833ab5 Patch
https://git.kernel.org/stable/c/e0759696de6851d7536efddfdd2dfed4c4df1f09 Patch
https://git.kernel.org/stable/c/eeb0711801f5e19ef654371b627682aed3b11373 Patch
https://git.kernel.org/stable/c/04a8d07f3d58308b92630045560799a3faa3ebce Patch
https://git.kernel.org/stable/c/148c816f10fd11df27ca6a9b3238cdd42fa72cd3 Patch
https://git.kernel.org/stable/c/2becaa990b93cbd2928292c0b669d3abb6cf06d4 Patch
https://git.kernel.org/stable/c/33645d3e22720cac1e4548f8fef57bf0649536ee Patch
https://git.kernel.org/stable/c/348714018139c39533c55661a0c7c990671396b4 Patch
https://git.kernel.org/stable/c/548ec0805c399c65ed66c6641be467f717833ab5 Patch
https://git.kernel.org/stable/c/e0759696de6851d7536efddfdd2dfed4c4df1f09 Patch
https://git.kernel.org/stable/c/eeb0711801f5e19ef654371b627682aed3b11373 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:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
History

06 Jan 2025, 20:44

Type Values Removed Values Added
First Time Linux linux Kernel
Linux
CWE CWE-416
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 7.8
CPE cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
References () https://git.kernel.org/stable/c/04a8d07f3d58308b92630045560799a3faa3ebce - () https://git.kernel.org/stable/c/04a8d07f3d58308b92630045560799a3faa3ebce - Patch
References () https://git.kernel.org/stable/c/148c816f10fd11df27ca6a9b3238cdd42fa72cd3 - () https://git.kernel.org/stable/c/148c816f10fd11df27ca6a9b3238cdd42fa72cd3 - Patch
References () https://git.kernel.org/stable/c/2becaa990b93cbd2928292c0b669d3abb6cf06d4 - () https://git.kernel.org/stable/c/2becaa990b93cbd2928292c0b669d3abb6cf06d4 - Patch
References () https://git.kernel.org/stable/c/33645d3e22720cac1e4548f8fef57bf0649536ee - () https://git.kernel.org/stable/c/33645d3e22720cac1e4548f8fef57bf0649536ee - Patch
References () https://git.kernel.org/stable/c/348714018139c39533c55661a0c7c990671396b4 - () https://git.kernel.org/stable/c/348714018139c39533c55661a0c7c990671396b4 - Patch
References () https://git.kernel.org/stable/c/548ec0805c399c65ed66c6641be467f717833ab5 - () https://git.kernel.org/stable/c/548ec0805c399c65ed66c6641be467f717833ab5 - Patch
References () https://git.kernel.org/stable/c/e0759696de6851d7536efddfdd2dfed4c4df1f09 - () https://git.kernel.org/stable/c/e0759696de6851d7536efddfdd2dfed4c4df1f09 - Patch
References () https://git.kernel.org/stable/c/eeb0711801f5e19ef654371b627682aed3b11373 - () https://git.kernel.org/stable/c/eeb0711801f5e19ef654371b627682aed3b11373 - Patch

21 Nov 2024, 06:36

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/04a8d07f3d58308b92630045560799a3faa3ebce - () https://git.kernel.org/stable/c/04a8d07f3d58308b92630045560799a3faa3ebce -
References () https://git.kernel.org/stable/c/148c816f10fd11df27ca6a9b3238cdd42fa72cd3 - () https://git.kernel.org/stable/c/148c816f10fd11df27ca6a9b3238cdd42fa72cd3 -
References () https://git.kernel.org/stable/c/2becaa990b93cbd2928292c0b669d3abb6cf06d4 - () https://git.kernel.org/stable/c/2becaa990b93cbd2928292c0b669d3abb6cf06d4 -
References () https://git.kernel.org/stable/c/33645d3e22720cac1e4548f8fef57bf0649536ee - () https://git.kernel.org/stable/c/33645d3e22720cac1e4548f8fef57bf0649536ee -
References () https://git.kernel.org/stable/c/348714018139c39533c55661a0c7c990671396b4 - () https://git.kernel.org/stable/c/348714018139c39533c55661a0c7c990671396b4 -
References () https://git.kernel.org/stable/c/548ec0805c399c65ed66c6641be467f717833ab5 - () https://git.kernel.org/stable/c/548ec0805c399c65ed66c6641be467f717833ab5 -
References () https://git.kernel.org/stable/c/e0759696de6851d7536efddfdd2dfed4c4df1f09 - () https://git.kernel.org/stable/c/e0759696de6851d7536efddfdd2dfed4c4df1f09 -
References () https://git.kernel.org/stable/c/eeb0711801f5e19ef654371b627682aed3b11373 - () https://git.kernel.org/stable/c/eeb0711801f5e19ef654371b627682aed3b11373 -
Summary
  • (es) En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nfsd: corrige el use-after-free debido a la ejecución de delegación. Una interrupción de la delegación podría llegar tan pronto como hayamos llamado a vfs_setlease. Una interrupción de la delegación ejecuta una devolución de llamada que inmediatamente (en nfsd4_cb_recall_prepare) agrega la delegación a del_recall_lru. Si luego salimos de nfs4_set_delegation sin aplicar hash a la delegación, se liberará tan pronto como finalice la devolución de llamada, sin eliminarse nunca de del_recall_lru. Los síntomas aparecen más tarde como advertencias de use-after-free o de corrupción en la lista, generalmente en el hilo de la lavandería. Sospecho que aba2072f4523 "nfsd: otorgar delegaciones de lectura a clientes que tienen escrituras" hizo que este error fuera más fácil de corregir, pero miré hasta la versión 3.0 y me parece que ya tenía el mismo problema. Entonces no estoy seguro de dónde se introdujo el error; puede que haya estado ahí desde el principio.

24 May 2024, 15:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-05-24 15:15

Updated : 2025-01-06 20:44

NVD link : CVE-2021-47506

Mitre link : CVE-2021-47506

CVE.ORG link : CVE-2021-47506

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-416

Use After Free