CVE-2024-26885

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix DEVMAP_HASH overflow check on 32-bit arches The devmap code allocates a number hash buckets equal to the next power of two of the max_entries value provided when creating the map. When rounding up to the next power of two, the 32-bit variable storing the number of buckets can overflow, and the code checks for overflow by checking if the truncated 32-bit value is equal to 0. However, on 32-bit arches the rounding up itself can overflow mid-way through, because it ends up doing a left-shift of 32 bits on an unsigned long value. If the size of an unsigned long is four bytes, this is undefined behaviour, so there is no guarantee that we'll end up with a nice and tidy 0-value at the end. Syzbot managed to turn this into a crash on arm32 by creating a DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it. Fix this by moving the overflow check to before the rounding up operation.
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:*:*:*:*:*:*:*:*

History

08 Nov 2024, 16:15

Type Values Removed Values Added
References
  • () https://git.kernel.org/stable/c/1f5e352b9088211fa5eb4e1639cd365f4f7d2f65 -

17 Oct 2024, 14:15

Type Values Removed Values Added
References
  • {'url': 'https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html', 'source': '416baaa9-dc9f-4396-8d5f-8c081fb06d67'}
  • () https://git.kernel.org/stable/c/4b81a9f92b3676cb74b907a7a209b3d15bd9a7f9 -

25 Jun 2024, 22:15

Type Values Removed Values Added
References
  • () https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html -

29 Apr 2024, 20:02

Type Values Removed Values Added
First Time Linux
Linux linux Kernel
References () https://git.kernel.org/stable/c/22079b3a423382335f47d9ed32114e6c9fe88d7c - () https://git.kernel.org/stable/c/22079b3a423382335f47d9ed32114e6c9fe88d7c - Patch
References () https://git.kernel.org/stable/c/225da02acdc97af01b6bc6ce1a3e5362bf01d3fb - () https://git.kernel.org/stable/c/225da02acdc97af01b6bc6ce1a3e5362bf01d3fb - Patch
References () https://git.kernel.org/stable/c/250051acc21f9d4c5c595e4fcb55986ea08c4691 - () https://git.kernel.org/stable/c/250051acc21f9d4c5c595e4fcb55986ea08c4691 - Patch
References () https://git.kernel.org/stable/c/281d464a34f540de166cee74b723e97ac2515ec3 - () https://git.kernel.org/stable/c/281d464a34f540de166cee74b723e97ac2515ec3 - Patch
References () https://git.kernel.org/stable/c/c826502bed93970f2fd488918a7b8d5f1d30e2e3 - () https://git.kernel.org/stable/c/c826502bed93970f2fd488918a7b8d5f1d30e2e3 - Patch
References () https://git.kernel.org/stable/c/e89386f62ce9a9ab9a94835a9890883c23d9d52c - () https://git.kernel.org/stable/c/e89386f62ce9a9ab9a94835a9890883c23d9d52c - Patch
References () https://git.kernel.org/stable/c/edf7990baa48de5097daa9ac02e06cb4c798a737 - () https://git.kernel.org/stable/c/edf7990baa48de5097daa9ac02e06cb4c798a737 - Patch
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 7.8
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
CWE CWE-119
Summary
  • (es) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: bpf: corrige la verificación de desbordamiento de DEVMAP_HASH en arcos de 32 bits. El código devmap asigna un número de depósitos de hash igual a la siguiente potencia de dos del valor max_entries proporcionado al crear el mapa. Al redondear a la siguiente potencia de dos, la variable de 32 bits que almacena el número de depósitos puede desbordarse, y el código verifica el desbordamiento comprobando si el valor truncado de 32 bits es igual a 0. Sin embargo, en arcos de 32 bits el redondeo hacia arriba puede desbordarse a mitad de camino, porque termina haciendo un desplazamiento hacia la izquierda de 32 bits en un valor largo sin signo. Si el tamaño de un largo sin firmar es de cuatro bytes, este es un comportamiento indefinido, por lo que no hay garantía de que terminemos con un valor 0 agradable y ordenado al final. Syzbot logró convertir esto en un bloqueo en arm32 creando un DEVMAP_HASH con max_entries > 0x80000000 y luego intentando actualizarlo. Solucione este problema moviendo la verificación de desbordamiento antes de la operación de redondeo.

17 Apr 2024, 11:15

Type Values Removed Values Added
New CVE

Information

Published : 2024-04-17 11:15

Updated : 2024-11-08 16:15


NVD link : CVE-2024-26885

Mitre link : CVE-2024-26885

CVE.ORG link : CVE-2024-26885


JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-119

Improper Restriction of Operations within the Bounds of a Memory Buffer