xsk: drain continuation descs after overflow in xsk_build_skb()

Overview

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

xsk: drain continuation descs after overflow in xsk_build_skb()

Fix generic xmit path multi-buffer logic when packets are either too big (count of descriptors exceed MAX_SKB_FRAGS) or an invalid descriptor is included in fragmented packet. Introduce xdp_sock::drain_cont and act upon this flag - when it is set, keep on consuming descriptors from AF_XDP Tx ring and put them directly onto Cq. Previously these descriptors were silently lost and could never be reached again.

Affected

• Linux >= cf24f5a5feeaae34c1a34d1e04f8ac697290427a < ecd0d1cde0478c232a867f14ec99cf97aff5eb30
• Linux >= cf24f5a5feeaae34c1a34d1e04f8ac697290427a < ceb00cb87a22c42d20c39336213db2b843ca9e34
• Linux >= cf24f5a5feeaae34c1a34d1e04f8ac697290427a < 5e94d74e4f3baebaa083288f33b4be7ce0a34982
• Linux >= cf24f5a5feeaae34c1a34d1e04f8ac697290427a < bd44a6dcd4248883de90f5dad53ae80066e27096
• Linux 6.6

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.