CVE-2021-47623

2024-07-1612:15:02

Linux

web.nvd.nist.gov

linux kernel

powerpc fixmap

vulnerability

unmap issue

map_kernel_page

cpu

pid

warning

set_pte_at

map_kernel_page

pte

cve

AI Score

6.5

Confidence

Low

EPSS

Percentile

16.0%

JSON

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

powerpc/fixmap: Fix VM debug warning on unmap

Unmapping a fixmap entry is done by calling __set_fixmap()
with FIXMAP_PAGE_CLEAR as flags.

Today, powerpc __set_fixmap() calls map_kernel_page().

map_kernel_page() is not happy when called a second time
for the same page.

WARNING: CPU: 0 PID: 1 at arch/powerpc/mm/pgtable.c:194 set_pte_at+0xc/0x1e8
CPU: 0 PID: 1 Comm: swapper Not tainted 5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty #682
NIP:  c0017cd4 LR: c00187f0 CTR: 00000010
REGS: e1011d50 TRAP: 0700   Not tainted  (5.16.0-rc3-s3k-dev-01993-g350ff07feb7d-dirty)
MSR:  00029032 &lt;EE,ME,IR,DR,RI&gt;  CR: 42000208  XER: 00000000

GPR00: c0165fec e1011e10 c14c0000 c0ee2550 ff800000 c0f3d000 00000000 c001686c
GPR08: 00001000 b00045a9 00000001 c0f58460 c0f50000 00000000 c0007e10 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
GPR24: 00000000 00000000 c0ee2550 00000000 c0f57000 00000ff8 00000000 ff800000
NIP [c0017cd4] set_pte_at+0xc/0x1e8
LR [c00187f0] map_kernel_page+0x9c/0x100
Call Trace:
[e1011e10] [c0736c68] vsnprintf+0x358/0x6c8 (unreliable)
[e1011e30] [c0165fec] __set_fixmap+0x30/0x44
[e1011e40] [c0c13bdc] early_iounmap+0x11c/0x170
[e1011e70] [c0c06cb0] ioremap_legacy_serial_console+0x88/0xc0
[e1011e90] [c0c03634] do_one_initcall+0x80/0x178
[e1011ef0] [c0c0385c] kernel_init_freeable+0xb4/0x250
[e1011f20] [c0007e34] kernel_init+0x24/0x140
[e1011f30] [c0016268] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
7fe3fb78 48019689 80010014 7c630034 83e1000c 5463d97e 7c0803a6 38210010
4e800020 81250000 712a0001 41820008 &lt;0fe00000&gt; 9421ffe0 93e1001c 48000030

Implement unmap_kernel_page() which clears an existing pte.

Affected configurations

Vulners

Node

linuxlinux_kernelRange5.10.0–5.10.101

linuxlinux_kernelRange5.11.0–5.15.24

linuxlinux_kernelRange5.16.0–5.16.10

linuxlinux_kernelRange5.17.0≥

VendorProductVersionCPE
linuxlinux_kernel*cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor	Product	Version	CPE
linux	linux_kernel	*	cpe:2.3:o:linux:linux_kernel::::::::

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "arch/powerpc/include/asm/book3s/32/pgtable.h",
      "arch/powerpc/include/asm/book3s/64/pgtable.h",
      "arch/powerpc/include/asm/fixmap.h",
      "arch/powerpc/include/asm/nohash/32/pgtable.h",
      "arch/powerpc/include/asm/nohash/64/pgtable.h",
      "arch/powerpc/mm/pgtable.c"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "67baac10dd5a",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "43ae0ccc4d27",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "033fd42c18d9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "aec982603aa8",
        "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/powerpc/include/asm/book3s/32/pgtable.h",
      "arch/powerpc/include/asm/book3s/64/pgtable.h",
      "arch/powerpc/include/asm/fixmap.h",
      "arch/powerpc/include/asm/nohash/32/pgtable.h",
      "arch/powerpc/include/asm/nohash/64/pgtable.h",
      "arch/powerpc/mm/pgtable.c"
    ],
    "versions": [
      {
        "version": "5.10.101",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.24",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16.10",
        "lessThanOrEqual": "5.16.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.17",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]