watchdog: pretimeout: Fix UAF in watchdog_unregister_governor()
0Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Track
exploitation probability
—
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
watchdog: pretimeout: Fix UAF in watchdog_unregister_governor()
When a watchdog governor is unregistered, it updates existing watchdog
devices that were using this governor by falling back to `default_gov`.
If the governor being unregistered is currently set as `default_gov`,
the `default_gov` is never cleared. This leads to 2 use-after-free
issues:
1. New watchdog devices registered after this point will inherit the
dangling `default_gov`.
2. Existing watchdog devices using the unregistered governor will have
their `wdd->gov` reassigned to the dangling `default_gov`.
Fix the UAF by clearing `default_gov` if it matches the governor being
unregistered.
Affected products
Linux · LinuxReferences
https://git.kernel.org/stable/c/0ca252720f0e38411cfec3431db9bb1aed0a412chttps://git.kernel.org/stable/c/2e47b91b9b4020fcc01def14d6b6556d66074cf4https://git.kernel.org/stable/c/7362ba0f9c96ac3ad6a2ca3995bd9fc9a28a8661https://git.kernel.org/stable/c/7993d626983cc58fbde9607333cfd2d57725c197https://git.kernel.org/stable/c/7d1658b066de30f4b23afc14814d22416a971e6e