CVE-2026-23398 icmp: fix NULL pointer dereference in icmp_tag_validation()

In the Linux kernel, the following vulnerability has been resolved: icmp: fix NULL pointer dereference in icmptagvalidation icmptagvalidation unconditionally dereferences the result of rcudereferenceinetprotosproto without checking for NULL. The inetprotos array is sparse -- only about 15 of 256...