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Rocky Linux: CVE-2024-42240: kernel-rt (RLSA-2024-7001)

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Rocky Linux: CVE-2024-42240: kernel-rt (RLSA-2024-7001)

Severity
4
CVSS
(AV:L/AC:M/Au:N/C:P/I:P/A:P)
Published
08/07/2024
Created
10/03/2024
Added
10/02/2024
Modified
11/13/2024

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. ]

Solution(s)

  • rocky-upgrade-kernel-rt
  • rocky-upgrade-kernel-rt-core
  • rocky-upgrade-kernel-rt-debug
  • rocky-upgrade-kernel-rt-debug-core
  • rocky-upgrade-kernel-rt-debug-debuginfo
  • rocky-upgrade-kernel-rt-debug-devel
  • rocky-upgrade-kernel-rt-debug-kvm
  • rocky-upgrade-kernel-rt-debug-modules
  • rocky-upgrade-kernel-rt-debug-modules-extra
  • rocky-upgrade-kernel-rt-debuginfo
  • rocky-upgrade-kernel-rt-debuginfo-common-x86_64
  • rocky-upgrade-kernel-rt-devel
  • rocky-upgrade-kernel-rt-kvm
  • rocky-upgrade-kernel-rt-modules
  • rocky-upgrade-kernel-rt-modules-extra

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