Red Hat: CVE-2024-27431: kernel: cpumap: Zero-initialise xdp_rxq_info struct before running XDP program (Multiple Advisories)

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

cpumap: Zero-initialise xdp_rxq_info struct before running XDP program

When running an XDP program that is attached to a cpumap entry, we don't
initialise the xdp_rxq_info data structure being used in the xdp_buff
that backs the XDP program invocation. Tobias noticed that this leads to
random values being returned as the xdp_md->rx_queue_index value for XDP
programs running in a cpumap.

This means we're basically returning the contents of the uninitialised
memory, which is bad. Fix this by zero-initialising the rxq data
structure before running the XDP program.