From a57b6ebd98ce759295a8eca1e5c4d223b6d06de5 Mon Sep 17 00:00:00 2001
From: Pierre LALET <pierre.lalet@cea.fr>
Date: Fri, 22 Jan 2016 08:27:54 +0100
Subject: [PATCH] Fix crash when an unpriv user builds an Ether() packet
without dst set
When an Ether() / IP() packet is built with IP.dst set and Ether.dst
not set, Scapy tries to fix Ether.dst by sending an ARP request. This
fails when the user cannot send packets.
Before:
>>> p = str(Ether()/IP(dst="1.2.3.4"))
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/usr/local/lib/python2.7/dist-packages/scapy/packet.py", line 272, in __str__
return self.build()
[...]
File "/usr/local/lib/python2.7/dist-packages/scapy/arch/linux.py", line 414, in __init__
self.ins = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(type))
File "/usr/lib/python2.7/socket.py", line 187, in __init__
_sock = _realsocket(family, type, proto)
error: [Errno 1] Operation not permitted
After:
>>> p = str(Ether()/IP(dst="1.2.3.4"))
WARNING: Mac address to reach destination not found. Using broadcast.
---
scapy/layers/l2.py | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/scapy/layers/l2.py b/scapy/layers/l2.py
index 3d889615..d11bb8da 100644
--- a/scapy/layers/l2.py
+++ b/scapy/layers/l2.py
@@ -7,7 +7,8 @@
Classes and functions for layer 2 protocols.
"""
-import os,struct,time
+import os, struct, time, socket
+
from scapy.base_classes import Net
from scapy.config import conf
from scapy.packet import *
@@ -86,7 +87,10 @@ class DestMACField(MACField):
MACField.__init__(self, name, None)
def i2h(self, pkt, x):
if x is None:
- x = conf.neighbor.resolve(pkt,pkt.payload)
+ try:
+ x = conf.neighbor.resolve(pkt,pkt.payload)
+ except socket.error:
+ pass
if x is None:
x = "ff:ff:ff:ff:ff:ff"
warning("Mac address to reach destination not found. Using broadcast.")
--
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