CVE-2021-47324 watchdog: Fix possible use-after-free in wdt_startup()

2024-05-2114:35:37

Linux

github.com

linux kernel

vulnerability

use-after-free

wdt_startup

fix

del_timer_sync

AI Score

6.8

Confidence

Low

EPSS

Percentile

13.0%

SSVC

Exploitation

none

Automatable

Technical Impact

total

JSON

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

watchdog: Fix possible use-after-free in wdt_startup()

This module’s remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver’s remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

ADP Affected

[
  {
    "cpes": [
      "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*"
    ],
    "vendor": "linux",
    "product": "linux_kernel",
    "versions": [
      {
        "status": "affected",
        "version": "0 1da177e4c3f4",
        "lessThan": "63a3dc24bd05",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "862f2b5a7c38",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
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        "versionType": "git"
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      {
        "status": "affected",
        "version": "1da177e4c3f4",
        "lessThan": "dc9403097be5",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "146cc288fb80",
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      },
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        "status": "affected",
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      },
      {
        "status": "affected",
        "version": "1da177e4c3f4",
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        "status": "affected",
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      },
      {
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      }
    ],
    "defaultStatus": "affected"
  }
]