5.5
MEDIUM
CVE-2024-42240
Linux x86 BHI Mitigation Warnings
Description

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. ]

INFO

Published Date :

Aug. 7, 2024, 4:15 p.m.

Last Modified :

Aug. 8, 2024, 2:53 p.m.

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Remotely Exploitable :

No

Impact Score :

3.6

Exploitability Score :

1.8
Affected Products

The following products are affected by CVE-2024-42240 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
: Total Affected Vendor : 1 | Products : 1
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2024-42240.

URL 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

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2024-42240 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2024-42240 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Aug. 08, 2024

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 No Types Assigned https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 Patch
    Changed Reference Type https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 No Types Assigned https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 Patch
    Changed Reference Type https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 No Types Assigned https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 Patch
    Changed Reference Type https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf No Types Assigned https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf Patch
    Changed Reference Type https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 No Types Assigned https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 Patch
    Added CWE NIST CWE-835
    Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.15.163 up to (excluding) 6.1.100 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.41 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.9.10
  • CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Aug. 07, 2024

    Action Type Old Value New Value
    Added Description 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. ]
    Added Reference kernel.org https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 [No types assigned]
    Added Reference kernel.org https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 [No types assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2024-42240 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2024-42240 weaknesses.

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: