arm64/mm：修复无效 pmd 的错误 file_map_count （CVE-2022-48897）

CVE编号

CVE-2022-48897

利用情况

暂无

补丁情况

N/A

披露时间

2024-08-21

漏洞描述

In the Linux kernel, the following vulnerability has been resolved: arm64/mm: fix incorrect file_map_count for invalid pmd The page table check trigger BUG_ON() unexpectedly when split hugepage: ------------[ cut here ]------------ kernel BUG at mm/page_table_check.c:119! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 7 PID: 210 Comm: transhuge-stres Not tainted 6.1.0-rc3+ #748 Hardware name: linux,dummy-virt (DT) pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : page_table_check_set.isra.0+0x398/0x468 lr : page_table_check_set.isra.0+0x1c0/0x468 [...] Call trace: page_table_check_set.isra.0+0x398/0x468 __page_table_check_pte_set+0x160/0x1c0 __split_huge_pmd_locked+0x900/0x1648 __split_huge_pmd+0x28c/0x3b8 unmap_page_range+0x428/0x858 unmap_single_vma+0xf4/0x1c8 zap_page_range+0x2b0/0x410 madvise_vma_behavior+0xc44/0xe78 do_madvise+0x280/0x698 __arm64_sys_madvise+0x90/0xe8 invoke_syscall.constprop.0+0xdc/0x1d8 do_el0_svc+0xf4/0x3f8 el0_svc+0x58/0x120 el0t_64_sync_handler+0xb8/0xc0 el0t_64_sync+0x19c/0x1a0 [...] On arm64, pmd_leaf() will return true even if the pmd is invalid due to pmd_present_invalid() check. So in pmdp_invalidate() the file_map_count will not only decrease once but also increase once. Then in set_pte_at(), the file_map_count increase again, and so trigger BUG_ON() unexpectedly. Add !pmd_present_invalid() check in pmd_user_accessible_page() to fix the problem.

解决建议

建议您更新当前系统或软件至最新版，完成漏洞的修复。

参考链接
https://git.kernel.org/stable/c/21e5eca0ac9046da9918a919bc92b7b5a78d27e7
https://git.kernel.org/stable/c/74c2f81054510d45b813548cb0a1c4ebf87cdd5f

受影响软件情况

#	类型	厂商	产品	版本	影响面
1
	运行在以下环境
	系统	debian_11	linux	*		Up to (excluding) 5.10.223-1
	运行在以下环境
	系统	debian_12	linux	*		Up to (excluding) 6.1.7-1

CVSS3评分 N/A

• 攻击路径 N/A
• 攻击复杂度 N/A
• 权限要求 N/A
• 影响范围 N/A
• 用户交互 N/A
• 可用性 N/A
• 保密性 N/A
• 完整性 N/A

N/A

CWE-ID	漏洞类型

Exp相关链接

- avd.aliyun.com