CVE-2021-47430

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-47430
In the Linux kernel, the following vulnerability has been resolved: x86/entry: Clear X86_FEATURE_SMAP when CONFIG_X86_SMAP=n Commit 3c73b81a9164 ("x86/entry, selftests: Further improve user entry sanity checks") added a warning if AC is set when in the kernel. Commit 662a0221893a3d ("x86/entry: Fix AC assertion") changed the warning to only fire if the CPU supports SMAP. However, the warning can still trigger on a machine that supports SMAP but where it's disabled in the kernel config and when running the syscall_nt selftest, for example: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 49 at irqentry_enter_from_user_mode CPU: 0 PID: 49 Comm: init Tainted: G T 5.15.0-rc4+ #98 e6202628ee053b4f310759978284bd8bb0ce6905 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 RIP: 0010:irqentry_enter_from_user_mode ... Call Trace: ? irqentry_enter ? exc_general_protection ? asm_exc_general_protection ? asm_exc_general_protectio IS_ENABLED(CONFIG_X86_SMAP) could be added to the warning condition, but even this would not be enough in case SMAP is disabled at boot time with the "nosmap" parameter. To be consistent with "nosmap" behaviour, clear X86_FEATURE_SMAP when !CONFIG_X86_SMAP. Found using entry-fuzz + satrandconfig. [ bp: Massage commit message. ]

3.3 /10

CVSS v3 : LOW

V3 Legend

Vector :

Exploitability : 1.8 / Impact : 1.4

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/3958b9c34c2729597e182cc606cc43942fd19f7c Patch
https://git.kernel.org/stable/c/4e9ec1c65da98c293f75d83755dfa5e03075a6d0 Patch
https://git.kernel.org/stable/c/f2447f6587b8ffe42ba04d14ce67d429a1163e5e Patch
https://git.kernel.org/stable/c/3958b9c34c2729597e182cc606cc43942fd19f7c Patch
https://git.kernel.org/stable/c/4e9ec1c65da98c293f75d83755dfa5e03075a6d0 Patch
https://git.kernel.org/stable/c/f2447f6587b8ffe42ba04d14ce67d429a1163e5e 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:5.8:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc7:*:*:*:*:*:*
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

25 Sep 2025, 16:06

Type Values Removed Values Added
First Time Linux linux Kernel
Linux
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 3.3
CWE NVD-CWE-noinfo
CPE cpe:2.3:o:linux:linux_kernel:5.8:rc4:*:*:*:*:*:*
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:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.8:rc5:*:*:*:*:*:*
References () https://git.kernel.org/stable/c/3958b9c34c2729597e182cc606cc43942fd19f7c - () https://git.kernel.org/stable/c/3958b9c34c2729597e182cc606cc43942fd19f7c - Patch
References () https://git.kernel.org/stable/c/4e9ec1c65da98c293f75d83755dfa5e03075a6d0 - () https://git.kernel.org/stable/c/4e9ec1c65da98c293f75d83755dfa5e03075a6d0 - Patch
References () https://git.kernel.org/stable/c/f2447f6587b8ffe42ba04d14ce67d429a1163e5e - () https://git.kernel.org/stable/c/f2447f6587b8ffe42ba04d14ce67d429a1163e5e - Patch

21 Nov 2024, 06:36

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/3958b9c34c2729597e182cc606cc43942fd19f7c - () https://git.kernel.org/stable/c/3958b9c34c2729597e182cc606cc43942fd19f7c -
References () https://git.kernel.org/stable/c/4e9ec1c65da98c293f75d83755dfa5e03075a6d0 - () https://git.kernel.org/stable/c/4e9ec1c65da98c293f75d83755dfa5e03075a6d0 -
References () https://git.kernel.org/stable/c/f2447f6587b8ffe42ba04d14ce67d429a1163e5e - () https://git.kernel.org/stable/c/f2447f6587b8ffe42ba04d14ce67d429a1163e5e -
Summary
  • (es) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: x86/entry: borra X86_FEATURE_SMAP cuando CONFIG_X86_SMAP=n confirmación 3c73b81a9164 ("x86/entry, selftests: mejora aún más las comprobaciones de seguridad de entrada del usuario") agregó una advertencia si AC está configurado en el núcleo. La confirmación 662a0221893a3d ("x86/entry: Reparar aserción de AC") cambió la advertencia para que solo se active si la CPU admite SMAP. Sin embargo, la advertencia aún puede activarse en una máquina que admite SMAP pero donde está deshabilitado en la configuración del kernel y cuando se ejecuta la autoprueba syscall_nt, por ejemplo: ------------[ cortar aquí ]--- --------- ADVERTENCIA: CPU: 0 PID: 49 en irqentry_enter_from_user_mode CPU: 0 PID: 49 Comm: init Tainted: GT 5.15.0-rc4+ #98 e6202628ee053b4f310759978284bd8bb0ce6905 Nombre del hardware: PC estándar QEMU (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 01/04/2014 RIP: 0010:irqentry_enter_from_user_mode... Seguimiento de llamadas:? irqentry_enter? exc_general_protection? asm_exc_general_protection? Se podría agregar asm_exc_general_protectio IS_ENABLED(CONFIG_X86_SMAP) a la condición de advertencia, pero incluso esto no sería suficiente en caso de que SMAP esté deshabilitado en el momento del arranque con el parámetro "nosmap". Para ser coherente con el comportamiento de "nosmap", borre X86_FEATURE_SMAP cuando !CONFIG_X86_SMAP. Encontrado usando Entry-fuzz + satrandconfig. [pb: mensaje de confirmación de masaje. ]

21 May 2024, 15:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-05-21 15:15

Updated : 2025-09-25 16:06

NVD link : CVE-2021-47430

Mitre link : CVE-2021-47430

CVE.ORG link : CVE-2021-47430

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
NVD-CWE-noinfo