CVE-2023-52473: thermal: core: Fix NULL pointer dereference in zone registration error path

Description

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

thermal: core: Fix NULL pointer dereference in zone registration error path

If device_register() in thermal_zone_device_register_with_trips()
returns an error, the tz variable is set to NULL and subsequently
dereferenced in kfree(tz->tzp).

Commit adc8749b150c ("thermal/drivers/core: Use put_device() if
device_register() fails") added the tz = NULL assignment in question to
avoid a possible double-free after dropping the reference to the zone
device. However, after commit 4649620d9404 ("thermal: core: Make
thermal_zone_device_unregister() return after freeing the zone"), that
assignment has become redundant, because dropping the reference to the
zone device does not cause the zone object to be freed any more.

Drop it to address the NULL pointer dereference.

Classification

CVE ID: CVE-2023-52473

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 5.08% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/335176dd8ebaca6493807dceea33c478305667fa
https://git.kernel.org/stable/c/02871710b93058eb1249d5847c0b2d1c2c3c98ae
https://git.kernel.org/stable/c/04e6ccfc93c5a1aa1d75a537cf27e418895e20ea

Timeline