Commit ARC changes from Brandon Long <blong@google.com>

- These will need some rework to integrate into the packcage - we do not want to ship two modules

dknewkey.py

@@ -0,0 +1,81 @@
+#!/usr/bin/python
+# This software is provided 'as-is', without any express or implied
+# warranty.  In no event will the author be held liable for any damages
+# arising from the use of this software.
+#
+# Permission is granted to anyone to use this software for any purpose,
+# including commercial applications, and to alter it and redistribute it
+# freely, subject to the following restrictions:
+#
+# 1. The origin of this software must not be misrepresented; you must not
+#    claim that you wrote the original software. If you use this software
+#    in a product, an acknowledgment in the product documentation would be
+#    appreciated but is not required.
+# 2. Altered source versions must be plainly marked as such, and must not be
+#    misrepresented as being the original software.
+# 3. This notice may not be removed or altered from any source distribution.
+#
+# Copyright (c) 2016 Google, Inc.
+# Contact: Brandon Long <blong@google.com>
+
+r"""Generates new domainkeys pairs.
+
+Sample usage:
+
+   dknewkey.py <keyname>
+"""
+
+
+import os
+import subprocess
+import sys
+import tempfile
+
+# how strong are our keys?
+BITS_REQUIRED = 2048
+
+# what openssl binary do we use to do key manipulation?
+OPENSSL_BINARY = '/usr/bin/openssl'
+
+def GenKeys(private_key_file):
+  """ Generates a suitable private key.  Output is unprotected.
+  You should encrypt your keys.
+  """
+  print >> sys.stderr, 'generating ' + private_key_file
+  subprocess.check_call([OPENSSL_BINARY, 'genrsa', '-out', private_key_file,
+                         str(BITS_REQUIRED)])
+
+
+def ExtractDnsPublicKey(private_key_file, dns_file):
+  """ Given a key, extract the bit we should place in DNS.
+  """
+  print >> sys.stderr, 'extracting ' + private_key_file
+  working_file = tempfile.NamedTemporaryFile(delete=False).name
+  subprocess.check_call([OPENSSL_BINARY, 'rsa', '-in', private_key_file,
+                         '-out', working_file, '-pubout', '-outform', 'PEM'])
+  cmd = 'grep -v ^-- %s | tr -d \'\\n\'' % working_file
+  try:
+    output = subprocess.check_output(cmd, shell=True)
+  finally:
+    os.unlink(working_file)
+  dns_fp = open(dns_file, "w+")
+  print >> sys.stderr, 'writing ' + dns_file
+  print >> dns_fp, "k=rsa; p=%s" % output
+  dns_fp.close()
+
+
+def main(argv):
+  if len(argv) != 2:
+    print >> sys.stderr, '%s: <keyname>' % argv[0]
+    sys.exit(1)
+
+  key_name = argv[1]
+  private_key_file = key_name + '.key'
+  dns_file = key_name + '.dns'
+
+  GenKeys(private_key_file)
+  ExtractDnsPublicKey(private_key_file, dns_file)
+
+
+if __name__ == '__main__':
+  main(sys.argv)