x86/bugs: Use code segment selector for VERW operand(CVE-2024-50072)

概要

x86/bugs: Use code segment selector for VERW operand

原文の説明

取得元が公開している説明をそのまま載せています (多くは英語)。

In the Linux kernel, the following vulnerability has been resolved:

x86/bugs: Use code segment selector for VERW operand

Robert Gill reported below #GP in 32-bit mode when dosemu software was
executing vm86() system call:

general protection fault: 0000 [#1] PREEMPT SMP
CPU: 4 PID: 4610 Comm: dosemu.bin Not tainted 6.6.21-gentoo-x86 #1
Hardware name: Dell Inc. PowerEdge 1950/0H723K, BIOS 2.7.0 10/30/2010
EIP: restore_all_switch_stack+0xbe/0xcf
EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000000
ESI: 00000000 EDI: 00000000 EBP: 00000000 ESP: ff8affdc
DS: 0000 ES: 0000 FS: 0000 GS: 0033 SS: 0068 EFLAGS: 00010046
CR0: 80050033 CR2: 00c2101c CR3: 04b6d000 CR4: 000406d0
Call Trace:
show_regs+0x70/0x78
die_addr+0x29/0x70
exc_general_protection+0x13c/0x348
exc_bounds+0x98/0x98
handle_exception+0x14d/0x14d
exc_bounds+0x98/0x98
restore_all_switch_stack+0xbe/0xcf
exc_bounds+0x98/0x98
restore_all_switch_stack+0xbe/0xcf

This only happens in 32-bit mode when VERW based mitigations like MDS/RFDS
are enabled. This is because segment registers with an arbitrary user value
can result in #GP when executing VERW. Intel SDM vol. 2C documents the
following behavior for VERW instruction:

#GP(0) - If a memory operand effective address is outside the CS, DS, ES,
FS, or GS segment limit.

CLEAR_CPU_BUFFERS macro executes VERW instruction before returning to user
space. Use %cs selector to reference VERW operand. This ensures VERW will
not #GP…

出典: OSV.dev (Open Source Vulnerabilities) NVD OSV

影響パッケージ

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.10.229"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.171"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.116"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.58"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.11.5"}]}]

ディストリビューション別の修正状況

各ディストリビューションが公開している、この CVE の修正パッケージ

Debian DEBIAN-CVE-2024-50072 linux 修正版: 5.10.234-1
Ubuntu UBUNTU-CVE-2024-50072 linux-hwe-edge

概要

原文の説明

影響パッケージ

ディストリビューション別の修正状況

参照URL