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#!/usr/local/bin/python3
print("ping fragment with MF that overlaps fragment without MF at the end")
# |----|
# |XXXXXXXXX|
# |---------|
import os
from addr import *
from scapy.all import *
pid=os.getpid()
eid=pid & 0xffff
payload=b"ABCDEFGHIJKLMNOP"
dummy=b"0123456701234567"
packet=IP(src=LOCAL_ADDR, dst=REMOTE_ADDR)/ \
ICMP(type='echo-request', id=eid)/payload
frag=[]
fid=pid & 0xffff
frag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=1, id=fid,
frag=2)/bytes(packet)[36:44])
frag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=1, id=fid,
frag=1, flags='MF')/dummy)
frag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=1, id=fid,
flags='MF')/bytes(packet)[20:36])
eth=[]
for f in frag:
eth.append(Ether(src=LOCAL_MAC, dst=REMOTE_MAC)/f)
if os.fork() == 0:
time.sleep(1)
sendp(eth, iface=LOCAL_IF)
os._exit(0)
ans=sniff(iface=LOCAL_IF, timeout=3, filter=
"ip and src "+REMOTE_ADDR+" and dst "+LOCAL_ADDR+" and icmp")
for a in ans:
if a and a.type == ETH_P_IP and \
a.payload.proto == 1 and \
a.payload.frag == 0 and a.payload.flags == 0 and \
icmptypes[a.payload.payload.type] == 'echo-reply':
id=a.payload.payload.id
print("id=%#x" % (id))
if id != eid:
print("WRONG ECHO REPLY ID")
exit(2)
data=a.payload.payload.payload.load
print("payload=%s" % (data))
if data == payload:
exit(0)
print("PAYLOAD!=%s" % (payload))
exit(1)
print("NO ECHO REPLY")
exit(2)
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