Description (CNA)
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. ]
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected bd53ec80f21839cfd4d852a6088279d602d67e5b before db56615e96c439e13783d7715330e824b4fd4b84; affected 07dbb10f153f483e8249acebdffedf922e2ec2e1 before a765679defe1dc1b8fa01928a6ad6361e72a1364; affected eb36b0dce2138581bc6b5e39d0273cb4c96ded81 before dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf; affected 7390db8aea0d64e9deb28b8e1ce716f5020c7ee5 before 08518d48e5b744620524f0acd7c26c19bda7f513; affected 7390db8aea0d64e9deb28b8e1ce716f5020c7ee5 before ac8b270b61d48fcc61f052097777e3b5e11591e0; affected 8f51637712e4da5be410a1666f8aee0d86eef898; affected 5.15.154 before 5.15.163; affected 6.1.85 before 6.1.100; affected 6.6.26 before 6.6.41; affected 6.8.5 before 6.9 |
| Linux / Linux | affected 6.9; unaffected 0 before 6.9; unaffected 5.15.163 through 5.15.*; unaffected 6.1.100 through 6.1.*; unaffected 6.6.41 through 6.6.*; unaffected 6.9.10 through 6.9.*; unaffected 6.10 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84
- https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364
- https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf
- https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513
- https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0
ADP enrichment
No English description supplied.
No references supplied.
No English description supplied.