x86/bhi：由于 BHI 缓解，避免在 #DB 处理程序中出现警告（CVE-2024-42240）
CVE编号
CVE-2024-42240利用情况
暂无补丁情况
N/A披露时间
2024-08-08漏洞描述
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. ]解决建议
建议您更新当前系统或软件至最新版，完成漏洞的修复。受影响软件情况
| # | 类型 | 厂商 | 产品 | 版本 | 影响面 | ||||
| 1 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 运行在以下环境 | |||||||||
| 系统 | debian_11 | linux | * | Up to (excluding) 5.10.221-1 | |||||
| 运行在以下环境 | |||||||||
| 系统 | linux | linux_kernel | * | From (including) 5.15.163 | Up to (excluding) 6.1.100 | ||||
| 运行在以下环境 | |||||||||
| 系统 | linux | linux_kernel | * | From (including) 6.2 | Up to (excluding) 6.6.41 | ||||
| 运行在以下环境 | |||||||||
| 系统 | linux | linux_kernel | * | From (including) 6.7 | Up to (excluding) 6.9.10 | ||||
- 攻击路径 本地
- 攻击复杂度 低
- 权限要求 低
- 影响范围 未更改
- 用户交互 无
- 可用性 高
- 保密性 无
- 完整性 无
| CWE-ID | 漏洞类型 |
| CWE-835 | 不可达退出条件的循环（无限循环） |
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