7.8

CVE-2022-50095

posix-cpu-timers: Cleanup CPU timers before freeing them during exec

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

posix-cpu-timers: Cleanup CPU timers before freeing them during exec

Commit 55e8c8eb2c7b ("posix-cpu-timers: Store a reference to a pid not a
task") started looking up tasks by PID when deleting a CPU timer.

When a non-leader thread calls execve, it will switch PIDs with the leader
process. Then, as it calls exit_itimers, posix_cpu_timer_del cannot find
the task because the timer still points out to the old PID.

That means that armed timers won't be disarmed, that is, they won't be
removed from the timerqueue_list. exit_itimers will still release their
memory, and when that list is later processed, it leads to a
use-after-free.

Clean up the timers from the de-threaded task before freeing them. This
prevents a reported use-after-free.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.7 < 5.10.137
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.61
Linux ≫ Linux Kernel Version >= 5.16 < 5.18.18
Linux ≫ Linux Kernel Version >= 5.19 < 5.19.2
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.21% 0.115
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-416 Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

https://git.kernel.org/stable/c/541840859ace9c2ccebc32fa9e376c7bd3def490
Patch
https://git.kernel.org/stable/c/9e255ed238fc67058df87b0388ad6d4b2ef3a2bd
Patch
https://git.kernel.org/stable/c/e8cb6e8fd9890780f1bfcf5592889e1b879e779c
Patch
https://git.kernel.org/stable/c/b2fc1723eb65abb83e00d5f011de670296af0b28
Patch
https://git.kernel.org/stable/c/e362359ace6f87c201531872486ff295df306d13
Patch