x86/fpu: Ensure XFD state on signal delivery
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.1.159, 6.6.117, 6.12.58, 6.17.8
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Ensure XFD state on signal delivery Sean reported [1] the following splat when running KVM tests: WARNING: CPU: 232 PID: 15391 at xfd_validate_state+0x65/0x70 Call Trace: <TASK> fpu__clear_user_states+0x9c/0x100 arch_do_signal_or_restart+0x142/0x210 exit_to_user_mode_loop+0x55/0x100 do_syscall_64+0x205/0x2c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Chao further identified [2] a reproducible scenario involving signal delivery: a non-AMX task is preempted by an AMX-enabled task which modifies the XFD MSR. When the non-AMX task resumes and reloads XSTATE with init values, a warning is triggered due to a mismatch between fpstate::xfd and the CPU's current XFD state. fpu__clear_user_states() does not currently re-synchronize the XFD state after such preemption. Invoke xfd_update_state() which detects and corrects the mismatch if there is a dynamic feature. This also benefits the sigreturn path, as fpu__restore_sig() may call fpu__clear_user_states() when the sigframe is inaccessible. [ dhansen: minor changelog munging ]
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 672365477ae8afca5a1cca98c1deb733235e4525 · fixed in eefbfb722042fc9210d2e0ac2b063fd1abf51895; From 672365477ae8afca5a1cca98c1deb733235e4525 · fixed in 1811c610653c0cd21cc9add14595b7cffaeca511; From 672365477ae8afca5a1cca98c1deb733235e4525 · fixed in 5b2619b488f1d08b960c43c6468dd0759e8b3035; From 672365477ae8afca5a1cca98c1deb733235e4525 · fixed in 3f735419c4b43cde42e6d408db39137b82474e31; From 672365477ae8afca5a1cca98c1deb733235e4525 · fixed in 388eff894d6bc5f921e9bfff0e4b0ab2684a96e9
- Linux Linux
5.16
- KernelLinux
From 5.16.0 · fixed in 6.1.159; From 6.2.0 · fixed in 6.6.117; From 6.7.0 · fixed in 6.12.58; From 6.13.0 · fixed in 6.17.8