CVE-2021-47384 hwmon: (w83793) Fix NULL pointer dereference by removing unnecessary structure field

2024-05-2115:03:44

Linux

github.com

linux kernel

hwmon

w83793

null pointer dereference

structure field

AI Score

6.8

Confidence

Low

EPSS

Percentile

15.5%

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

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

hwmon: (w83793) Fix NULL pointer dereference by removing unnecessary structure field

If driver read tmp value sufficient for
(tmp & 0x08) && (!(tmp & 0x80)) && ((tmp & 0x7) == ((tmp >> 4) & 0x7))
from device then Null pointer dereference occurs.
(It is possible if tmp = 0b0xyz1xyz, where same literals mean same numbers)
Also lm75[] does not serve a purpose anymore after switching to
devm_i2c_new_dummy_device() in w83791d_detect_subclients().

The patch fixes possible NULL pointer dereference by removing lm75[].

Found by Linux Driver Verification project (linuxtesting.org).

[groeck: Dropped unnecessary continuation lines, fixed multi-line alignments]

CNA Affected

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "6cb01fe630ea",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "7c4fd5de39f2",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "746011193f44",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "dd4d747ef05a",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/hwmon/w83793.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "unaffected",
        "version": "5.4.151",
        "versionType": "custom",
        "lessThanOrEqual": "5.4.*"
      },
      {
        "status": "unaffected",
        "version": "5.10.71",
        "versionType": "custom",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.14.10",
        "versionType": "custom",
        "lessThanOrEqual": "5.14.*"
      },
      {
        "status": "unaffected",
        "version": "5.15",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/hwmon/w83793.c"
    ],
    "defaultStatus": "affected"
  }
]