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LinuxCVE-2022-48897

HistoryAug 21, 2024 - 7:15 a.m.

CVE-2022-48897

2024-08-2107:15:05

Linux

web.nvd.nist.gov

linux kernel

vulnerability

file_map_count

invalid pmd

bug_on

split hugepage

arm64

page table

check

trigger

resolved

cve-2022-48897

CVSS3

5.5

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

AI Score

6.6

Confidence

Low

EPSS

Percentile

9.5%

JSON

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.

Affected configurations

Nvd

Vulners

Node

linuxlinux_kernelRange5.19–6.1.7

linuxlinux_kernelMatch6.2rc1

linuxlinux_kernelMatch6.2rc2

linuxlinux_kernelMatch6.2rc3

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linuxlinux_kernel6.2cpe:2.3:o:linux:linux_kernel:6.2:rc1:*:*:*:*:*:*
linuxlinux_kernel6.2cpe:2.3:o:linux:linux_kernel:6.2:rc2:*:*:*:*:*:*
linuxlinux_kernel6.2cpe:2.3:o:linux:linux_kernel:6.2:rc3:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.2	cpe:2.3:o:linux:linux_kernel:6.2:rc1::::::
linux	linux_kernel	6.2	cpe:2.3:o:linux:linux_kernel:6.2:rc2::::::
linux	linux_kernel	6.2	cpe:2.3:o:linux:linux_kernel:6.2:rc3::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "arch/arm64/include/asm/pgtable.h"
    ],
    "versions": [
      {
        "version": "42b2547137f5",
        "lessThan": "21e5eca0ac90",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "42b2547137f5",
        "lessThan": "74c2f8105451",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "arch/arm64/include/asm/pgtable.h"
    ],
    "versions": [
      {
        "version": "5.19",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.19",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.7",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.2",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]