From 61b952b817fdf5f4e4d1caac6b5d2da9a33e3225 Mon Sep 17 00:00:00 2001
From: Phil <phil@secdev.org>
Date: Sat, 20 Oct 2007 12:40:36 +0200
Subject: [PATCH] Made DHCPOptionsField robust to garbage
---
scapy.py | 44 +++++++++++++++++++++++++++++---------------
1 file changed, 29 insertions(+), 15 deletions(-)
diff --git a/scapy.py b/scapy.py
index a7980e69..c93528d0 100755
--- a/scapy.py
+++ b/scapy.py
@@ -6831,15 +6831,18 @@ class DHCPOptionsField(StrField):
def i2repr(self,pkt,x):
s = []
for v in x:
- if type(v) is tuple and len(v) == 2:
+ if type(v) is tuple and len(v) in [2,3]:
if DHCPRevOptions.has_key(v[0]) and isinstance(DHCPRevOptions[v[0]][1],Field):
f = DHCPRevOptions[v[0]][1]
vv = f.i2repr(pkt,v[1])
else:
vv = repr(v[1])
- s.append("%s=%s" % (v[0],vv))
+ r = "%s=%s" % (v[0],vv)
+ if len(v) > 2:
+ r += " (garbage=%r)" % v[2]
+ s.append(r)
else:
- s.append(str(v))
+ s.append(sane(v))
return "[%s]" % (" ".join(s))
def getfield(self, pkt, s):
@@ -6856,7 +6859,10 @@ class DHCPOptionsField(StrField):
opt.append("pad")
x = x[1:]
continue
- if DHCPOptions.has_key(o):
+ if len(x) < 2 or len(x) < ord(x[1])+2:
+ opt.append(x)
+ break
+ elif DHCPOptions.has_key(o):
f = DHCPOptions[o]
if isinstance(f, str):
@@ -6865,11 +6871,16 @@ class DHCPOptionsField(StrField):
x = x[olen+2:]
else:
olen = ord(x[1])
- left, val = f.getfield(pkt,x[2:olen+2])
-# val = f.m2i(pkt,val)
-# if left:
-# print "m2i data left left=%s" % left
- opt.append((f.name, val))
+ try:
+ left, val = f.getfield(pkt,x[2:olen+2])
+ except:
+ opt.append(x)
+ break
+ if left:
+ otuple = (f.name, val, left)
+ else:
+ otuple = (f.name, val)
+ opt.append(otuple)
x = x[olen+2:]
else:
olen = ord(x[1])
@@ -6877,11 +6888,12 @@ class DHCPOptionsField(StrField):
x = x[olen+2:]
return opt
def i2m(self, pkt, x):
- #print "i2m x=%s" % x
+ if type(x) is str:
+ return x
s = ""
for o in x:
- if type(o) is tuple and len(o) == 2:
- name, val = o
+ if type(o) is tuple and len(o) in [2,3]:
+ name, val = o[:2]
if isinstance(name, int):
onum, oval = name, val
@@ -6890,12 +6902,12 @@ class DHCPOptionsField(StrField):
if f is None:
oval = val
else:
-# oval = f.addfield(pkt,"",f.i2m(pkt,f.any2i(pkt,val)))
oval = f.addfield(pkt,"",f.any2i(pkt,val))
-
else:
warning("Unknown field option %s" % name)
continue
+ if len(o) > 2:
+ oval += o[2]
s += chr(onum)
s += chr(len(oval))
@@ -6905,7 +6917,9 @@ class DHCPOptionsField(StrField):
DHCPRevOptions[o][1] == None):
s += chr(DHCPRevOptions[o][0])
elif type(o) is int:
- s += chr(o)
+ s += chr(o)+"\0"
+ elif type(o) is str:
+ s += o
else:
warning("Malformed option %s" % o)
return s
--
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