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nvd416baaa9-dc9f-4396-8d5f-8c081fb06d67NVD:CVE-2023-52476
HistoryFeb 29, 2024 - 6:15 a.m.

CVE-2023-52476

2024-02-2906:15:45
416baaa9-dc9f-4396-8d5f-8c081fb06d67
web.nvd.nist.gov
linux
kernel
vulnerability
cve-2023-52476
vsyscall
address filtering
bug fix
oops
page fault
security fix

7.2 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

15.7%

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.

7.2 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

15.7%