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

ipvs: fix the checksum validations

ip vs in icmp v6() is missing checksum validation for ICMPv6 packets from clients. In fact, as for TCP/UDP we should validate the checksum for ICMP packets only when we mangle the packets on MASQ or on reply for tunnel.

Also, Sashiko points out that handle response icmp() being common for IPv4 and IPv6 is missing the pseudo-header calculation while validating ICMPv6 messages from real servers which is a problem if checksum is not validated by the hardware.

Fix the problems by creating ip vs checksum common check() helper and use it for TCP/UDP/ICMP both for IPv4 and IPv6. Rely on the nf checksum() for validating the ICMP messages but use it also for TCP and UDP.

Use correct IP offset for IP VS DBG RL PKT for TCP/UDP/SCTP.

IPVS packets (TCP/UDP/SCTP/ICMP) do not need checksum validation on LOCAL OUT (local clients or local real servers) and on FORWARD (traffic from servers on LAN). Do it only on LOCAL IN, in case nf checksum() is not called on PRE ROUTING.

Also, ip vs checksum complete() can be marked static.