Chris,
Thanks for pointing that out - I had forgotten about that bug report.
The case I'm looking at is where an ICMP echo request goes out with an
ICMP header of 8 bytes + a payload of 32 bytes for a ping. Then I
receive an ICMP destination host unreachable containing the original IP
header and ICMP header but *not* the 32 byte payload from the original
ICMP echo request. My understanding is that this lack of echo request's
payload (per RFC #792 - "Internet Header + 64 bits of Original Data
Datagram") causes the ICMP echo request to no longer be verifiable. I
have both the original and returned packets and the IP total length is
60 bytes in both cases, unlike in the bug report you had made.