1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
#!/usr/local/bin/python3
print("drop too long fragment queue, reassemble less fragments")
# |----|
# |----|
# |----|
# ... ...
# |----|
import os
from addr import *
from scapy.all import *
pid=os.getpid()
eid=pid & 0xffff
payload=b"ABCDEFGHIJKLMNOP" * 70
frag=[]
fid=pid & 0xffff
# send packets with 65 and 64 fragments
for max in (64, 63):
eid = ~eid & 0xffff
packet=IP(src=LOCAL_ADDR, dst=REMOTE_ADDR)/ \
ICMP(type='echo-request', id=eid)/payload
fid = ~fid & 0xffff
for i in range(max):
frag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=1, id=fid,
frag=i, flags='MF')/bytes(packet)[20+i*8:20+(i+1)*8])
frag.append(IP(src=LOCAL_ADDR, dst=REMOTE_ADDR, proto=1, id=fid,
frag=max)/bytes(packet)[20+max*8:])
eth=[]
for f in frag:
eth.append(Ether(src=LOCAL_MAC, dst=REMOTE_MAC)/f)
child = os.fork()
if child == 0:
time.sleep(1)
for e in eth:
sendp(e, iface=LOCAL_IF)
time.sleep(0.001)
os._exit(0)
ans=sniff(iface=LOCAL_IF, timeout=6, filter=
"ip and src "+REMOTE_ADDR+" and dst "+LOCAL_ADDR+" and icmp")
os.kill(child, 15)
os.wait()
reply=False
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 & 0xffff:
print("ECHO REPLY FROM 65 FRAGMENTS")
exit(1)
if id != eid:
print("WRONG ECHO REPLY ID")
exit(2)
data=a.payload.payload.payload.load
print("payload=%s" % (data))
if data != payload:
print("PAYLOAD!=%s" % (payload))
exit(2)
reply=True
if not reply:
print("NO ECHO REPLY FROM 64 FRAGMENTS")
exit(1)
exit(0)
|
