Vulnerability CVE-2021-47202

Vulnerability CVE-2021-47202

Published: 2024-04-10

Description:

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

thermal: Fix NULL pointer dereferences in of_thermal_ functions

of_parse_thermal_zones() parses the thermal-zones node and registers a
thermal_zone device for each subnode. However, if a thermal zone is
consuming a thermal sensor and that thermal sensor device hasn't probed
yet, an attempt to set trip_point_*_temp for that thermal zone device
can cause a NULL pointer dereference. Fix it.

console:/sys/class/thermal/thermal_zone87 # echo 120000 > trip_point_0_temp
...
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
...
Call trace:
of_thermal_set_trip_temp+0x40/0xc4
trip_point_temp_store+0xc0/0x1dc
dev_attr_store+0x38/0x88
sysfs_kf_write+0x64/0xc0
kernfs_fop_write_iter+0x108/0x1d0
vfs_write+0x2f4/0x368
ksys_write+0x7c/0xec
__arm64_sys_write+0x20/0x30
el0_svc_common.llvm.7279915941325364641+0xbc/0x1bc
do_el0_svc+0x28/0xa0
el0_svc+0x14/0x24
el0_sync_handler+0x88/0xec
el0_sync+0x1c0/0x200

While at it, fix the possible NULL pointer dereference in other
functions as well: of_thermal_get_temp(), of_thermal_set_emul_temp(),
of_thermal_get_trend().

References:

https://git.kernel.org/stable/c/828f4c31684da94ecf0b44a2cbd35bbede04f0bd

https://git.kernel.org/stable/c/6a315471cb6a07f651e1d3adc8962730f4fcccac

https://git.kernel.org/stable/c/0750f769b95841b34a9fe8c418dd792ff526bf86

https://git.kernel.org/stable/c/ef2590a5305e0b8e9342f84c2214aa478ee7f28e

https://git.kernel.org/stable/c/96cfe05051fd8543cdedd6807ec59a0e6c409195

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