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416baaa9-dc9f-4396-8d5f-8c081fb06d67CVE-2021-47556

HistoryMay 24, 2024 - 3:15 p.m.

CVE-2021-47556

2024-05-2415:15:20

CWE-476

416baaa9-dc9f-4396-8d5f-8c081fb06d67

web.nvd.nist.gov

linux

kernel

vulnerability

ethtool

null pointer

dereference

coalesce

driver

callback

netlink

ioctl

nvd

5.5 Medium

CVSS3

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

6.6 Medium

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.0%

JSON

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

ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()

ethtool_set_coalesce() now uses both the .get_coalesce() and
.set_coalesce() callbacks. But the check for their availability is
buggy, so changing the coalesce settings on a device where the driver
provides only one of the callbacks results in a NULL pointer
dereference instead of an -EOPNOTSUPP.

Fix the condition so that the availability of both callbacks is
ensured. This also matches the netlink code.

Note that reproducing this requires some effort - it only affects the
legacy ioctl path, and needs a specific combination of driver options:

have .get_coalesce() and .coalesce_supported but no
.set_coalesce(), or
have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn’t
cause the crash as it first attempts to call ethtool_get_coalesce()
and bails out on error.

Affected configurations

Vulners

NVD

Node

linuxlinux_kernelRange5.15–5.15.6

linuxlinux_kernelRange5.16.0≥

CPENameOperatorVersion
linux:linux_kernellinux linux kernellt5.15.6

CPE	Name	Operator	Version
linux:linux_kernel	linux linux kernel	lt	5.15.6

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ethtool/ioctl.c"
    ],
    "versions": [
      {
        "version": "f3ccfda19319",
        "lessThan": "abfdd9e2f0f9",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "f3ccfda19319",
        "lessThan": "0276af2176c7",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/ethtool/ioctl.c"
    ],
    "versions": [
      {
        "version": "5.15",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.15",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.15.6",
        "lessThanOrEqual": "5.15.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "5.16",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]