Linux Distros 未修補弱點:CVE-2024-26670

medium Nessus Plugin ID 227890

概要

Linux/Unix 主機上安裝的一個或多個套件存有弱點,供應商表示將不會修補。

說明

Linux/Unix 主機上安裝了一個或多個受到弱點影響的套件,且供應商未提供可用的修補程式。

- 在 Linux 核心中,已解決下列弱點: arm64: entry: fix ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD Currently the ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD workaround isn't quite right, as it is supposed to be applied after the last explicit memory access, but is immediately followed by an LDR. The ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD workaround is used to handle Cortex-A520 erratum 2966298 and Cortex-A510 erratum 3117295, which are described in: * https://developer.arm.com/documentation/SDEN2444153/0600/?lang=en * https://developer.arm.com/documentation/SDEN1873361/1600/?lang=en In both cases the workaround is described as: | If pagetable isolation is disabled, the context switch logic in the | kernel can be updated to execute the following sequence on affected | cores before exiting to EL0, and after all explicit memory accesses: | | 1. A non-shareable TLBI to any context and/or address, including | unused contexts or addresses, such as a `TLBI VALE1 Xzr`. | | 2. A DSB NSH to guarantee completion of the TLBI.
The important part being that the TLBI+DSB must be placed after all explicit memory accesses.
Unfortunately, as-implemented, the TLBI+DSB is immediately followed by an LDR, as we have: | alternative_if ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD | tlbi vale1, xzr | dsb nsh | alternative_else_nop_endif | alternative_if_not ARM64_UNMAP_KERNEL_AT_EL0 | ldr lr, [sp, #S_LR] | add sp, sp, #PT_REGS_SIZE // restore sp | eret | alternative_else_nop_endif | | [ ... KPTI exception return path ... ] This patch fixes this by reworking the logic to place the TLBI+DSB immediately before the ERET, after all explicit memory accesses. The ERET is currently in a separate alternative block, and alternatives cannot be nested. To account for this, the alternative block for ARM64_UNMAP_KERNEL_AT_EL0 is replaced with a single alternative branch to skip the KPTI logic, with the new shape of the logic being: | alternative_insn b .L_skip_tramp_exit_\@, nop, ARM64_UNMAP_KERNEL_AT_EL0 | [ ... KPTI exception return path ... ] | .L_skip_tramp_exit_\@: | | ldr lr, [sp, #S_LR] | add sp, sp, #PT_REGS_SIZE // restore sp | | alternative_if ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD | tlbi vale1, xzr | dsb nsh | alternative_else_nop_endif | eret The new structure means that the workaround is only applied when KPTI is not in use; this is fine as noted in the documented implications of the erratum: | Pagetable isolation between EL0 and higher level ELs prevents the | issue from occurring. ... and as per the workaround description quoted above, the workaround is only necessary If pagetable isolation is disabled.
(CVE-2024-26670)

請注意,Nessus 依賴供應商報告的套件存在。

解決方案

目前尚未有已知的解決方案。

Plugin 詳細資訊

嚴重性: Medium

ID: 227890

檔案名稱: unpatched_CVE_2024_26670.nasl

版本: 1.1

類型: local

代理程式: unix

系列: Misc.

已發布: 2025/3/5

已更新: 2025/3/5

支援的感應器: Nessus Agent, Nessus

風險資訊

VPR

風險因素: Medium

分數: 4.4

CVSS v2

風險因素: Medium

基本分數: 4.6

時間性分數: 3.4

媒介: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS 評分資料來源: CVE-2024-26670

CVSS v3

風險因素: Medium

基本分數: 4.4

時間性分數: 3.9

媒介: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

時間媒介: CVSS:3.0/E:U/RL:O/RC:C

弱點資訊

必要的 KB 項目: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched

可輕鬆利用: No known exploits are available

弱點發布日期: 2024/4/2

參考資訊

CVE: CVE-2024-26670