CVE-2022-49010

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

hwmon: (coretemp) Check for null before removing sysfs attrs

If coretemp_add_core() gets an error then pdata->core_data[indx] is already NULL and has been kfreed. Dont pass that to sysfs_remove_group() as that will crash in sysfs_remove_group().

[Shortened for readability] [91854.020159] sysfs: cannot create duplicate filename /devices/platform/coretemp.0/hwmon/hwmon2/temp20_label [91855.126115] BUG: kernel NULL pointer dereference, address: 0000000000000188 [91855.165103] #PF: supervisor read access in kernel mode [91855.194506] #PF: error_code(0x0000) - not-present page [91855.224445] PGD 0 P4D 0 [91855.238508] Oops: 0000 [#1] PREEMPT SMP PTI … [91855.342716] RIP: 0010:sysfs_remove_group+0xc/0x80 … [91855.796571] Call Trace: [91855.810524] coretemp_cpu_offline+0x12b/0x1dd [coretemp] [91855.841738] ? coretemp_cpu_online+0x180/0x180 [coretemp] [91855.871107] cpuhp_invoke_callback+0x105/0x4b0 [91855.893432] cpuhp_thread_fun+0x8e/0x150 …

Fix this by checking for NULL first.

Weakness

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/070d5ea4a0592a37ad96ce7f7b6b024f90bb009f
• https://git.kernel.org/stable/c/280110db1a7d62ad635b103bafc3ae96e8bef75c
• https://git.kernel.org/stable/c/7692700ac818866d138a8de555130a6e70e6ac16
• https://git.kernel.org/stable/c/89eecabe6a47403237f45aafd7d24f93cb973653
• https://git.kernel.org/stable/c/a89ff5f5cc64b9fe7a992cf56988fd36f56ca82a
• https://git.kernel.org/stable/c/ae6c8b6e5d5628df1c475c0a8fca1465e205c95b
• https://git.kernel.org/stable/c/f06e0cd01eab954bd5f2190c9faa79bb5357e05b
• https://git.kernel.org/stable/c/fb503d077ff7b43913503eaf72995d1239028b99