Linux Kernel XDP_SHARED_UMEM Packet Corruption Vulnerability

A vulnerability in the Linux kernel's XDP_SHARED_UMEM mode has been fixed, addressing an issue where packets were corrupted for the second and any subsequent sockets bound to the same user memory. This problem did not affect the first socket. The corruption occurred because the initialization of DMA addresses for the pre-populated xsk buffer pool entries was only completed for the first socket, leaving others uninitialized. The vulnerability has been resolved by ensuring that DMA addresses in the xsk buffer pool are populated for every socket bound to the same user memory.

Impact

Exploitation of this vulnerability led to packet corruption in the XDP_SHARED_UMEM mode, causing issues for sockets beyond the first one bound to the same user memory.