CVE - CVE-2024-42240

CVE-ID
CVE-2024-42240	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
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. ]
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 URL:https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 MISC:https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 URL:https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 MISC:https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 URL:https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 MISC:https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf URL:https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf MISC:https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 URL:https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84
Assigning CNA
kernel.org
Date Record Created
20240730	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240730)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
This is an record on the CVE List, which provides common identifiers for publicly known cybersecurity vulnerabilities.
Search CVE Using Keywords: You can also search by reference using the CVE Reference Maps.
For More Information: CVE Request Web Form (select "Other" from dropdown)