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
Configurations
Configuration 1 (hide)
|
History
08 Aug 2024, 14:53
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-835 | |
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| First Time |
Linux
Linux linux Kernel |
|
| Summary |
|
|
| References | () https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513 - Patch | |
| References | () https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364 - Patch | |
| References | () https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0 - Patch | |
| References | () https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf - Patch | |
| References | () https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84 - Patch |
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')