In the Linux kernel, the following vulnerability has been resolved:
net: atm: reject out-of-range traffic classes in QoS validation
Reject ATM traffic classes above ATM_ANYCLASS in check_tp(). SO_ATMQOS stores the supplied QoS after check_qos() succeeds, so accepting larger values leaves invalid traffic_class values in vcc->qos.
That bad state later reaches pvc_info(), which indexes class_name[] with vcc->qos.{rx,tp}.traffic_class. Values above ATM_ANYCLASS cause an out-of-bounds read when /proc/net/atm/pvc is read.
Tighten the existing QoS validation so invalid traffic_class values are rejected at the point where user supplied QoS is accepted.
References
- https://git.kernel.org/stable/c/15444b57fdc6fc3f3e22a87f791ae5be81e6ecf5
- https://git.kernel.org/stable/c/1a6dda72455b399ce9c1a12695471dc4d5c61add
- https://git.kernel.org/stable/c/2b3e241729e87afed13ac0f666472d5d6ca42e87
- https://git.kernel.org/stable/c/367acd288bc6255e247cb1a1efbf5c6567cab423
- https://git.kernel.org/stable/c/513f820b3f0cf4462e17d84c39ed3948d061a6ea
- https://git.kernel.org/stable/c/806b7b6edc8446e8b94b706807a7090a14d47b5c
- https://git.kernel.org/stable/c/cdf19f380e46192e7084be559638aab1f6ed86a2
- https://git.kernel.org/stable/c/e62adb157c2eaad9ad4867ec6cd9af5b9a51b1c7