CVE-2024-42240

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2024-42240
In the Linux kernel, the following vulnerability has been resolved: x86/bhi: Avoid warning in #DB handler due to BHI mitigation When BHI mitigation is enabled, if SYSENTER is invoked with the TF flag set then entry_SYSENTER_compat() uses CLEAR_BRANCH_HISTORY and calls the clear_bhb_loop() before the TF flag is cleared. This causes the #DB handler (exc_debug_kernel()) to issue a warning because single-step is used outside the entry_SYSENTER_compat() function. To address this issue, entry_SYSENTER_compat() should use CLEAR_BRANCH_HISTORY after making sure the TF flag is cleared. The problem can be reproduced with the following sequence: $ cat sysenter_step.c int main() { asm("pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter"); } $ gcc -o sysenter_step sysenter_step.c $ ./sysenter_step Segmentation fault (core dumped) The program is expected to crash, and the #DB handler will issue a warning. Kernel log: WARNING: CPU: 27 PID: 7000 at arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160 ... RIP: 0010:exc_debug_kernel+0xd2/0x160 ... Call Trace: <#DB> ? show_regs+0x68/0x80 ? __warn+0x8c/0x140 ? exc_debug_kernel+0xd2/0x160 ? report_bug+0x175/0x1a0 ? handle_bug+0x44/0x90 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? exc_debug_kernel+0xd2/0x160 exc_debug+0x43/0x50 asm_exc_debug+0x1e/0x40 RIP: 0010:clear_bhb_loop+0x0/0xb0 ... </#DB> <TASK> ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d </TASK> [ bp: Massage commit message. ]

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/08518d48e5b744620524f0acd7c26c19bda7f513 Patch
https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 Patch
https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 Patch
https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf Patch
https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 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

08 Aug 2024, 14:53

Type Values Removed Values Added
CWE CWE-835
First Time Linux linux Kernel
Linux
CPE cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Summary
  • (es) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: x86/bhi: evitar advertencia en el controlador #DB debido a la mitigación de BHI Cuando la mitigación de BHI está habilitada, si se invoca SYSENTER con el indicador TF configurado, entonces Entry_SYSENTER_compat() usa CLEAR_BRANCH_HISTORY y llama al clear_bhb_loop() antes de que se borre la bandera TF. Esto hace que el controlador #DB (exc_debug_kernel()) emita una advertencia porque se utiliza un solo paso fuera de la función Entry_SYSENTER_compat(). Para solucionar este problema, Entry_SYSENTER_compat() debe usar CLEAR_BRANCH_HISTORY después de asegurarse de que el indicador TF esté borrado. El problema se puede reproducir con la siguiente secuencia: $ cat sysenter_step.c int main() { asm("pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter"); } $ gcc -o sysenter_step sysenter_step.c $ ./sysenter_step Fallo de segmentación (núcleo volcado) Se espera que el programa falle y el controlador #DB emitirá una advertencia. Registro del kernel: ADVERTENCIA: CPU: 27 PID: 7000 en arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160... RIP: 0010:exc_debug_kernel+0xd2/0x160... Seguimiento de llamadas: &lt;#DB&gt; ? show_regs+0x68/0x80? __advertir+0x8c/0x140 ? exc_debug_kernel+0xd2/0x160? report_bug+0x175/0x1a0? handle_bug+0x44/0x90? exc_invalid_op+0x1c/0x70? asm_exc_invalid_op+0x1f/0x30? exc_debug_kernel+0xd2/0x160 exc_debug+0x43/0x50 asm_exc_debug+0x1e/0x40 RIP: 0010:clear_bhb_loop+0x0/0xb0 ... ? Entry_SYSENTER_compat_after_hwframe+0x6e/0x8d [bp: mensaje de commit de masaje. ]
References () https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 - () https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 - Patch
References () https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 - () https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 - Patch
References () https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 - () https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 - Patch
References () https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf - () https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf - Patch
References () https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 - () https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 - Patch
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 5.5

07 Aug 2024, 16:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-08-07 16:15

Updated : 2024-08-08 14:53

NVD link : CVE-2024-42240

Mitre link : CVE-2024-42240

CVE.ORG link : CVE-2024-42240

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-835

Loop with Unreachable Exit Condition ('Infinite Loop')