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LinuxCVE-2024-26885

HistoryApr 17, 2024 - 11:15 a.m.

CVE-2024-26885

2024-04-1711:15:10

CWE-119

Linux

web.nvd.nist.gov

linux kernel

bpf

vulnerability

devmap_hash

overflow check

32-bit arches

arm32

nvd

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

AI Score

6.8

Confidence

Low

EPSS

Percentile

5.1%

JSON

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

bpf: Fix DEVMAP_HASH overflow check on 32-bit arches

The devmap code allocates a number hash buckets equal to the next power
of two of the max_entries value provided when creating the map. When
rounding up to the next power of two, the 32-bit variable storing the
number of buckets can overflow, and the code checks for overflow by
checking if the truncated 32-bit value is equal to 0. However, on 32-bit
arches the rounding up itself can overflow mid-way through, because it
ends up doing a left-shift of 32 bits on an unsigned long value. If the
size of an unsigned long is four bytes, this is undefined behaviour, so
there is no guarantee that we’ll end up with a nice and tidy 0-value at
the end.

Syzbot managed to turn this into a crash on arm32 by creating a
DEVMAP_HASH with max_entries > 0x80000000 and then trying to update it.
Fix this by moving the overflow check to before the rounding up
operation.

Affected configurations

Nvd

Vulners

Node

linuxlinux_kernelRange5.4–5.10.214

linuxlinux_kernelRange5.11–5.15.153

linuxlinux_kernelRange5.16–6.1.83

linuxlinux_kernelRange6.2–6.6.23

linuxlinux_kernelRange6.7–6.7.11

linuxlinux_kernelRange6.8–6.8.2

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": [
      "kernel/bpf/devmap.c"
    ],
    "versions": [
      {
        "version": "6f9d451ab1a3",
        "lessThan": "225da02acdc9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6f9d451ab1a3",
        "lessThan": "c826502bed93",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6f9d451ab1a3",
        "lessThan": "edf7990baa48",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6f9d451ab1a3",
        "lessThan": "250051acc21f",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6f9d451ab1a3",
        "lessThan": "22079b3a4233",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6f9d451ab1a3",
        "lessThan": "e89386f62ce9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "6f9d451ab1a3",
        "lessThan": "281d464a34f5",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "kernel/bpf/devmap.c"
    ],
    "versions": [
      {
        "version": "5.4",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.4",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.10.214",
        "lessThanOrEqual": "5.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.153",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.1.83",
        "lessThanOrEqual": "6.1.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.6.23",
        "lessThanOrEqual": "6.6.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.7.11",
        "lessThanOrEqual": "6.7.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.8.2",
        "lessThanOrEqual": "6.8.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.9",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]