* sys/netinet6/esp_input.c: check packet length before fetching   ESP authentication data.
* sys/netinet6/esp_input.c: check packet length before fetching
  ESP authentication data.

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame