CVE-2023-52476: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: perf/x86/lbr: Filter vsyscall addresses We found that a panic can occur when a vsyscall is made while LBR sampling is active. If the vsyscall is interrupted (NMI) for perf sampling, this call sequence can occur (most recent at top): __insn_get_emulate_prefix() insn_get_emulate_prefix() insn_get_prefixes() insn_get_opcode() decode_branch_type() get_branch_type() intel_pmu_lbr_filter() intel_pmu_handle_irq() perf_event_nmi_handler() Within __insn_get_emulate_prefix() at frame 0, a macro is called: peek_nbyte_next(insn_byte_t, insn, i) Within this macro, this dereference occurs: (insn)->next_byte Inspecting registers at this point, the value of the next_byte field is the address of the vsyscall made, for example the location of the vsyscall version of gettimeofday() at 0xffffffffff600000. The access to an address in the vsyscall region will trigger an oops due to an unhandled page fault. To fix the bug, filtering for vsyscalls can be done when determining the branch type. This patch will return a "none" branch if a kernel address if found to lie in the vsyscall region.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 5.15.137
linux	linux_kernel	5.16 — 6.1.59
linux	linux_kernel	6.2 — 6.5.8
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/3863989497652488a50f00e96de4331e5efabc6c https://git.kernel.org/stable/c/e53899771a02f798d436655efbd9d4b46c0f9265 https://git.kernel.org/stable/c/f71edacbd4f99c0e12fe4a4007ab4d687d0688db https://git.kernel.org/stable/c/3863989497652488a50f00e96de4331e5efabc6c https://git.kernel.org/stable/c/403d201d1fd144cb249836dafb222f6375871c6c https://git.kernel.org/stable/c/e53899771a02f798d436655efbd9d4b46c0f9265 https://git.kernel.org/stable/c/f71edacbd4f99c0e12fe4a4007ab4d687d0688db

Frequently Asked Questions

What is CVE-2023-52476? +

In the Linux kernel, the following vulnerability has been resolved: perf/x86/lbr: Filter vsyscall addresses We found that a panic can occur when a vsyscall is made while LBR sampling is active. If the vsyscall is interrupted (NMI) for perf sampling, this call sequence can occur (most recent at top): __insn_get_emulate_prefix() insn_get_emulate_prefix() insn_get_prefixes() insn_get_opcode() decode_branch_type() get_branch_type() intel_pmu_lbr_filter() intel_pmu_handle_irq() perf_event_nmi_handler() Within __insn_get_emulate_prefix() at frame 0, a macro is called: peek_nbyte_next(insn_byte_t, insn, i) Within this macro, this dereference occurs: (insn)->next_byte Inspecting registers at this point, the value of the next_byte field is the address of the vsyscall made, for example the location of the vsyscall version of gettimeofday() at 0xffffffffff600000. The access to an address in the vsyscall region will trigger an oops due to an unhandled page fault. To fix the bug, filtering for vsyscalls can be done when determining the branch type. This patch will return a "none" branch if a kernel address if found to lie in the vsyscall region. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2023-52476? +

CVE-2023-52476 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2023-52476? +

CVE-2023-52476 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-52476? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2023-52476