cpumap: Zero-initialise xdp_rxq_info struct before running XDP program

Vulnerability Description

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.

References

• https://git.kernel.org/stable/c/5f4e51abfbe6eb444fa91906a5cd083044278297
• https://git.kernel.org/stable/c/f0363af9619c77730764f10360e36c6445c12f7b
• https://git.kernel.org/stable/c/3420b3ff1ff489c177ea1cb7bd9fbbc4e9a0be95
• https://git.kernel.org/stable/c/f562e4c4aab00986dde3093c4be919c3f2b85a4a
• https://git.kernel.org/stable/c/eaa7cb836659ced2d9f814ac32aa3ec193803ed6
• https://git.kernel.org/stable/c/2487007aa3b9fafbd2cb14068f49791ce1d7ede5