CVE-2021-47202

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> thermal: Fix NULL pointer dereferences in of_thermal_ functions<br /> <br /> of_parse_thermal_zones() parses the thermal-zones node and registers a<br /> thermal_zone device for each subnode. However, if a thermal zone is<br /> consuming a thermal sensor and that thermal sensor device hasn&amp;#39;t probed<br /> yet, an attempt to set trip_point_*_temp for that thermal zone device<br /> can cause a NULL pointer dereference. Fix it.<br /> <br /> console:/sys/class/thermal/thermal_zone87 # echo 120000 &gt; trip_point_0_temp<br /> ...<br /> Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020<br /> ...<br /> Call trace:<br /> of_thermal_set_trip_temp+0x40/0xc4<br /> trip_point_temp_store+0xc0/0x1dc<br /> dev_attr_store+0x38/0x88<br /> sysfs_kf_write+0x64/0xc0<br /> kernfs_fop_write_iter+0x108/0x1d0<br /> vfs_write+0x2f4/0x368<br /> ksys_write+0x7c/0xec<br /> __arm64_sys_write+0x20/0x30<br /> el0_svc_common.llvm.7279915941325364641+0xbc/0x1bc<br /> do_el0_svc+0x28/0xa0<br /> el0_svc+0x14/0x24<br /> el0_sync_handler+0x88/0xec<br /> el0_sync+0x1c0/0x200<br /> <br /> While at it, fix the possible NULL pointer dereference in other<br /> functions as well: of_thermal_get_temp(), of_thermal_set_emul_temp(),<br /> of_thermal_get_trend().