497 lines
14 KiB
Python
Executable File
497 lines
14 KiB
Python
Executable File
#!/usr/bin/env python
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"""
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Scyther : An automatic verifier for security protocols.
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Copyright (C) 2007 Cas Cremers
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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"""
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"""
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Example script to show how to perform large-scale tests using the
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Scyther Python API (contained in the Scyther subdirectory)
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In this example, multi-protocol attack analysis is performed on a small
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test set.
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Author: Cas Cremers
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"""
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from Scyther import Scyther
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from optparse import OptionParser, SUPPRESS_HELP
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import time
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import os.path
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try:
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from progressbar import *
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PROGRESSBAR = True
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except ImportError:
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from progressbarDummy import *
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PROGRESSBAR = False
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print """
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Missing the progressbar library.
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It can be downloaded from:
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http://code.google.com/p/python-progressbar/
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"""
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FOUND = []
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OPTS = None
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ARGS = None
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#---------------------------------------------------------------------------
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def parseArgs():
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usage = "usage: %s [options] [inputfile]" % sys.argv[0]
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description = "test-mpa.py is a test script to help with multi-protocol analysis."
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parser = OptionParser(usage=usage,description=description)
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# command
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parser.add_option("-t","--typed",dest="types",default=[0],action="store_const",const=[0],
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help="Verify protocols with respect to a typed model (-m 0)")
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parser.add_option("-b","--basic-types",dest="types",default=[1],action="store_const",const=[1],
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help="Verify protocols with respect to basic type flaws only (-m 1)")
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parser.add_option("-u","--untyped",dest="types",default=[2],action="store_const",const=[2],
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help="Verify protocols with respect to an untyped model (-m 2)")
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parser.add_option("-T","--all-types",dest="types",default=[0],action="store_const",const=[0,1,2],
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help="Verify protocols with respect to all matching types")
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parser.add_option("-m","--max-protocols",type="int",dest="maxprotocols",default=3,
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help="Define maximum number of protocols in a multi-protocol attack.")
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parser.add_option("-U","--init-unique",dest="initunique",default=False,action="store_true",
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help="Use Scythers --init-unique switch to filter out initiators talking to themselves.")
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parser.add_option("-E","--extravert",dest="extravert",default=False,action="store_true",
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help="Use Scythers --extravert switch to filter out agents talking to themselves.")
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parser.add_option("","--self-communication",dest="selfcommunication",default=False,action="store_true",
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help="Explore self-communication effects.")
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parser.add_option("-D","--debug",dest="debug",default=False,action="store_true",
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help="Enable debugging features.")
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parser.add_option("-p","--plain",dest="plain",default=False,action="store_true",
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help="Ensure plain output, e.g., no progress bars.")
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return parser.parse_args()
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#---------------------------------------------------------------------------
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class Attack(object):
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def __init__(self,claim,mpalist):
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self.claim = claim
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self.mpalist = mpalist
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def protocol(self):
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return self.claim.protocol
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def mpashort(self):
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s = []
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for fn in self.mpalist:
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ptn = os.path.normpath(fn)
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(head,tail) = os.path.split(ptn)
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s.append(tail)
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return s
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def __str__(self):
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s = "(%s,%s)" % (self.claim.id, self.mpashort())
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return s
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def fullstr(self):
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s = "%s,%s" % (self.claim.id, self.mpalist)
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return s
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def __cmp__(self,other):
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s1 = self.fullstr()
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s2 = other.fullstr()
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if (s1 == s2):
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return 0
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else:
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if s1 < s2:
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return -1
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else:
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return 1
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#---------------------------------------------------------------------------
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def MyScyther(protocollist,filt=None,options=None):
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"""
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Evaluate the composition of the protocols in protocollist.
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If there is a filter, i.e. "ns3,I1" then only this specific claim
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will be evaluated.
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"""
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s = Scyther.Scyther()
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if (options == None) or (options == ""):
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# untyped matching
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s.options = "--match=2"
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else:
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s.options = options.strip() # Some cleanup of string (idiot's normalization)
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for protocol in protocollist:
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s.addFile(protocol)
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s.verifyOne(filt)
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return s
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def getCorrectIsolatedClaims(protocolset,options=None):
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"""
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Given a set of protocols, determine the correct claims when run in
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isolation.
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Returns a tuple, consisting of
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- a list of compiling protocols
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- a list of tuples (protocol,claimid) wich denote correct claims
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"""
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correctclaims = []
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goodprotocols = []
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if not OPTS.plain:
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widgets = ['Scanning for claims that are correct in isolation: ', Percentage(), ' ',
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Bar(marker='#',left='[',right=']')
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]
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pbar = ProgressBar(widgets=widgets, maxval=len(protocolset))
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pbar.start()
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count = 0
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cpcount = 0
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for protocol in protocolset:
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# verify protocol in isolation
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s = MyScyther([protocol],options=options)
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# investigate the results
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goodprotocols.append(protocol)
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allfalse = True
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for claim in s.claims:
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if claim.okay:
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correctclaims.append((protocol,claim.id))
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allfalse = False
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count += 1
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if not allfalse:
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cpcount += 1
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if not OPTS.plain:
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pbar.update(count)
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if not OPTS.plain:
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pbar.finish()
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return (goodprotocols,correctclaims,cpcount)
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def verifyMPAlist(mpalist,claimid,options=None):
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"""
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Verify the existence of an attack in this context
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If an attack is found, we return False, otherwise True. This is
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needed for the iteration later.
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"""
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global OPTS, ARGS
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if OPTS.debug:
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print time.asctime(), mpalist, claimid, options
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s = MyScyther(mpalist,claimid,options)
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claim = s.getClaim(claimid)
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if claim:
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if not claim.okay:
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global FOUND
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# This is an MPA attack!
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if OPTS.debug:
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print "I've found a multi-protocol attack on claim %s in the context %s." % (claimid,str(mpalist))
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FOUND.append(Attack(claim,mpalist))
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return False
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else:
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return True
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def constructMPAlist(protocolset,claimid,mpalist,length,start,callback,options=None):
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"""
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Append a list of parallel protocols, without duplicates,
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such that the added part is lexicographically ordered (from
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index 'start' in the protocol list)
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For each possible list, the function callback is called. If the
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callback returns true, iteration proceeds (returning true in the
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end), otherwise it aborts and returns false.
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"""
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if len(mpalist) < length:
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# list is not long enough yet
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for pn in range(start,len(protocolset)):
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p = protocolset[pn]
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if p not in mpalist:
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if not constructMPAlist(protocolset,claimid,mpalist + [p],length,pn+1,callback,options=options):
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return False
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return True
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else:
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# list is long enough: callback
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return callback(mpalist,claimid,options)
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def findMPA(protocolset,protocol,claimid,maxcount=3,options=None):
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"""
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The protocol claim is assumed to be correct. When does it break?
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"""
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# First we examine 2-protocol attacks, and then increase the
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# number of parallel protocols if we don't find any attacks on the
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# claim.
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count = 2
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if len(protocolset) < maxcount:
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# we cannot have more protocols in parallel than there are
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# protocols.
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maxcount = len(protocolset)
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# the actual incremental search loop
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while count <= maxcount:
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constructMPAlist(protocolset,claimid,[protocol],count,0,verifyMPAlist,options)
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count += 1
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return None
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def findAllMPA(protocolset,maxcount=3,options="",mpaoptions=""):
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"""
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Given a set of protocols, find multi-protocol attacks
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"""
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global FOUND
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FOUND = []
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# Find all correct claims in each protocol
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(protocolset,correct,cpcount) = getCorrectIsolatedClaims(protocolset,options)
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print "Investigating %i correct claims in %i protocols." % (len(correct), cpcount)
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# For all these claims...
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if not OPTS.plain:
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widgets = ['Scanning for MPA attacks: ', Percentage(), ' ',
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Bar(marker='#',left='[',right=']')
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]
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pbar = ProgressBar(widgets=widgets, maxval=len(correct))
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pbar.start()
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count = 0
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# Concatenate options but add space iff needed
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alloptions = (options + " " + mpaoptions).strip()
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for (protocol,claimid) in correct:
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# Try to find multi-protocol attacks
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findMPA(protocolset,protocol,claimid,maxcount,options=alloptions)
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count += 1
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if not OPTS.plain:
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pbar.update(count)
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if not OPTS.plain:
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pbar.finish()
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"""
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The below computation assumes protocol names are unique to files, but if
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they are not, some other errors should have been reported by the Scyther
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backend anyway (conflicting protocol definitions in MPA analysis).
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"""
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mpaprots = []
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res = []
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for att in FOUND:
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pn = att.protocol()
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if pn not in mpaprots:
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mpaprots.append(pn)
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res.append(att)
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print "-" * 70
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print "Summary:"
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print
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print "We scanned %i protocols with options [%s]." % (len(protocolset),options)
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print "We found %i correct claims." % (len(correct))
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print "We then scanned combinations of at most %i protocols with options [%s]." % (maxcount,alloptions)
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print "We found %i MPA attacks." % (len(FOUND))
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print "The attacks involve the claims of %i protocols." % (len(mpaprots))
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print "-" * 70
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print
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return res
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def showDiff(reslist):
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"""
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Show difference between (attacklist,descr) tuples in list
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"""
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for i in range(0,len(reslist)-1):
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(al1,descr1) = reslist[i]
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(al2,descr2) = reslist[i+1]
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print "-" * 70
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print "Comparing the attacks for [%s] with [%s]:" % (descr1,descr2)
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print len(al1), len(al2)
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print repr(al1)
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print repr(al2)
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for a in al2:
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if a not in al1:
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print "New attack: %s" % (a)
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for a in al1:
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if a not in al2:
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print "[Strange] disappeared attack: %s" % (a)
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print "-" * 70
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print
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def scanTypes(l = [],defopts = "",mpaopts = ""):
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global OPTS, ARGS
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reslist = []
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if 0 in OPTS.types:
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# First typed
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print "Scanning without type flaws"
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res = findAllMPA(l,maxcount = OPTS.maxprotocols,options = defopts + " --match=0", mpaoptions = mpaopts)
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reslist.append((res,"no type flaws"))
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if 1 in OPTS.types:
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# Basic type flaws
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print "Scanning for basic type flaws"
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res = findAllMPA(l,maxcount = OPTS.maxprotocols,options = defopts + " --match=1", mpaoptions = mpaopts)
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reslist.append((res,"basic type flaws"))
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if 2 in OPTS.types:
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# All type flaws
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print "Scanning for any type flaws"
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res = findAllMPA(l,maxcount = OPTS.maxprotocols,options = defopts + " --match=2", mpaoptions = mpaopts)
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reslist.append((res,"type flaws"))
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if len(reslist) < 1:
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import sys
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print "Error: we didn't do anything."
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sys.exit()
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return reslist
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def scanSelfComm(l = [],defopts = "",mpaopts = ""):
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global OPTS, ARGS
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reslist = []
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print "Scanning without AA-comm."
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res = findAllMPA(l,maxcount = OPTS.maxprotocols,options = defopts, mpaoptions = mpaopts + " --extravert")
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reslist.append((res,"Allow Alice-Alice"))
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print "Scanning for AA-resp only."
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res = findAllMPA(l,maxcount = OPTS.maxprotocols,options = defopts, mpaoptions = mpaopts + " --init-unique")
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reslist.append((res,"Allow Alice-Alice"))
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print "Scanning for AA-comm."
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res = findAllMPA(l,maxcount = OPTS.maxprotocols,options = defopts, mpaoptions = mpaopts)
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reslist.append((res,"Allow Alice-Alice"))
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return reslist
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def scanSC(l,defopts,mpaopts):
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if (len(OPTS.types) > 1) and (OPTS.selfcommunication):
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import sys
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print "Error: cannot analyze multiple types as well as self-communication at the same time."
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sys.exit()
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if OPTS.selfcommunication:
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reslist = scanSelfComm(l,defopts,mpaopts)
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else:
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reslist = scanTypes(l,defopts,mpaopts)
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if len(reslist) > 1:
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showDiff(reslist)
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def bigTest():
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"""
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Perform the tests as reported in the book.
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"""
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import os
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global OPTS, ARGS
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testpath = "Protocols/MultiProtocolAttacks/"
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fl = os.listdir(testpath)
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nl = []
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for fn in fl:
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if fn.endswith(".spdl"):
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nl.append(fn)
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# Report list
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print "Performing multi-protocol analysis for the following protocols:", nl
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# Prepend again the path
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l = []
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for fn in nl:
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l.append(testpath+fn)
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# Initialize mpa options
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mpaopts = ""
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### Simplified test setup
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#defopts = "--max-runs=3 -T 360"
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### Full test setup
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#defopts = "--max-runs=4 -T 600"
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### Full test setup with --init-unique
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defopts = "--max-runs=4 -T 600"
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if OPTS.extravert:
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mpaopts = (mpaopts + " --extravert").strip()
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if OPTS.initunique:
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mpaopts = (mpaopts + " --init-unique").strip()
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scanSC(l,defopts,mpaopts)
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def simpleTest():
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"""
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Simple test case with a few protocols
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"""
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l = ['nsl3-broken.spdl','ns3.spdl','nsl3.spdl']
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print "Performing multi-protocol analysis for the following protocols:", l
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print
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findAllMPA(l)
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print
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print "Analysis complete."
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def main():
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global OPTS, ARGS
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(OPTS,ARGS) = parseArgs()
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bigTest()
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#simpleTest()
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if __name__ == '__main__':
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main()
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# vim: set ts=4 sw=4 et list lcs=tab\:>-:
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