Revert "xsk: Support redirect to any socket bound to the same umem"

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: Revert "xsk: Support redirect to any socket bound to the same umem" This reverts commit 2863d665ea41282379f108e4da6c8a2366ba66db. This patch introduced a potential kernel crash when multiple napi instances redirect to the same AF_XDP socket. By removing the queue_index check, it is possible for multiple napi instances to access the Rx ring at the same time, which will result in a corrupted ring state which can lead to a crash when flushing the rings in __xsk_flush(). This can happen when the linked list of sockets to flush gets corrupted by concurrent accesses. A quick and small fix is not possible, so let us revert this for now.

References

• https://git.kernel.org/stable/c/19cb40b1064566ea09538289bfcf5bc7ecb9b6f5
• https://git.kernel.org/stable/c/7fcf26b315bbb728036da0862de6b335da83dff2