# $Id$

"""
Generate .dot description of a certificate tree.

Copyright (C) 2009-2010  Internet Systems Consortium ("ISC")

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

Portions copyright (C) 2008  American Registry for Internet Numbers ("ARIN")

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND ARIN DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS.  IN NO EVENT SHALL ARIN BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.
"""

import POW, sys, glob, os

class x509(object):

  ski = None
  aki = None

  show_file    = False
  show_ski     = False
  show_aki     = False
  show_issuer  = True
  show_subject = True

  cn_only      = True

  subjects = {}

  def __init__(self, filename):

    while filename.startswith("./"):
      filename = filename[2:]

    self.filename = filename

    f = open(filename, "rb")
    text = f.read()
    f.close()

    if "-----BEGIN" in text:
      self.pow = POW.pemRead(POW.X509_CERTIFICATE, text)
    else:
      self.pow = POW.derRead(POW.X509_CERTIFICATE, text)

    self.extensions = dict((e[0], e[2]) for e in (self.pow.getExtension(i) for i in xrange(self.pow.countExtensions())))

    if "subjectKeyIdentifier" in self.extensions:
      self.ski = ":".join(["%02X" % ord(i) for i in self.extensions.get("subjectKeyIdentifier")[1:]])

    if "authorityKeyIdentifier" in self.extensions:
      self.aki = ":".join(["%02X" % ord(i) for i in self.extensions.get("authorityKeyIdentifier")[3:]])

    self.subject = self.canonize(self.pow.getSubject())
    self.issuer  = self.canonize(self.pow.getIssuer())

    if self.subject in self.subjects:
      self.subjects[self.subject].append(self)
    else:
      self.subjects[self.subject] = [self]

  def canonize(self, name):

    if self.cn_only and len(name) == 1 and name[0][0] == "CN":
      return name[0][1]
    else:
      return name

  def set_node(self, node):

    self.node = node

  def dot(self):

    label = []

    if self.show_issuer:
      label.append(("Issuer", self.issuer))

    if self.show_subject:
      label.append(("Subject", self.subject))

    if self.show_file:
      label.append(("File", self.filename))

    if self.show_aki:
      label.append(("AKI", self.aki))

    if self.show_ski:
      label.append(("SKI", self.ski))

    print "#", repr(label)

    if len(label) > 1:
      print '%s [shape = record, label = "{%s}"];' % (self.node, "|".join("{%s|%s}" % (x, y) for x, y in label if y is not None))
    else:
      print '%s [label = "%s"];' % (self.node, label[0][1])

    for issuer in self.subjects.get(self.issuer, ()):

      if issuer is self:
        print "# Issuer is self"
        issuer = None

      if issuer is not None and self.aki is not None and self.ski is not None and self.aki == self.ski:
        print "# Self-signed"
        issuer = None

      if issuer is not None and self.aki is not None and issuer.ski is not None and self.aki != issuer.ski:
        print "# AKI does not match issuer SKI"
        issuer = None

      if issuer is not None:
        print "%s -> %s;" % (issuer.node, self.node)

    print

certs = []

for topdir in sys.argv[1:] or ["."]:
  for dirpath, dirnames, filenames in os.walk(topdir):
    certs += [x509(dirpath + "/" + filename) for filename in filenames if filename.endswith(".cer")]

for i, cert in enumerate(certs):
  cert.set_node("cert_%d" % i)

print """\
digraph certificates {

rotate = 90;
#size = "11,8.5";
splines = true;
ratio = fill;

"""

for cert in certs:
  cert.dot()

print "}"