r46948 - generate the key!

Author: hawkowl
Date: Tue Mar  8 09:22:50 2016
New Revision: 46948

Modified:
   branches/manhole-hardcodedkey-8229/twisted/conch/manhole_tap.py
   branches/manhole-hardcodedkey-8229/twisted/conch/ssh/keys.py

Log:
generate the key!

Modified: branches/manhole-hardcodedkey-8229/twisted/conch/manhole_tap.py
==============================================================================
--- branches/manhole-hardcodedkey-8229/twisted/conch/manhole_tap.py	(original)
+++ branches/manhole-hardcodedkey-8229/twisted/conch/manhole_tap.py	Tue Mar  8 09:22:50 2016
@@ -12,10 +12,11 @@
 from twisted.internet import protocol
 from twisted.application import service, strports
 from twisted.cred import portal, checkers
-from twisted.python import usage
+from twisted.python import usage, filepath
 
-from twisted.conch.insults import insults
 from twisted.conch import manhole, manhole_ssh, telnet
+from twisted.conch.insults import insults
+from twisted.conch.ssh import keys
 
 class makeTelnetProtocol:
     def __init__(self, portal):
@@ -29,7 +30,7 @@
 class chainedProtocolFactory:
     def __init__(self, namespace):
         self.namespace = namespace
-    
+
     def __call__(self):
         return insults.ServerProtocol(manhole.ColoredManhole, self.namespace)
 
@@ -53,18 +54,23 @@
     optParameters = [
         ["telnetPort", "t", None, "strports description of the address on which to listen for telnet connections"],
         ["sshPort", "s", None, "strports description of the address on which to listen for ssh connections"],
-        ["passwd", "p", "/etc/passwd", "name of a passwd(5)-format username/password file"]]
+        ["passwd", "p", "/etc/passwd", "name of a passwd(5)-format username/password file"],
+        ["sshKeyDir", None, None, "Directory where the autogenerated SSH key is kept."],
+        ["sshKeyName", None, None, "Filename of the autogenerated SSH key."],
+        ["sshKeySize", None, 4096, "Size of the automatically generated SSH key."],
+    ]
 
     def __init__(self):
         usage.Options.__init__(self)
         self['namespace'] = None
-    
+
     def postOptions(self):
         if self['telnetPort'] is None and self['sshPort'] is None:
             raise usage.UsageError("At least one of --telnetPort and --sshPort must be specified")
 
 def makeService(options):
-    """Create a manhole server service.
+    """
+    Create a manhole server service.
 
     @type options: C{dict}
     @param options: A mapping describing the configuration of
@@ -87,7 +93,6 @@
     @rtype: L{twisted.application.service.IService}
     @return: A manhole service.
     """
-
     svc = service.MultiService()
 
     namespace = options['namespace']
@@ -116,8 +121,12 @@
 
         sshPortal = portal.Portal(sshRealm, [checker])
         sshFactory = manhole_ssh.ConchFactory(sshPortal)
-        sshService = strports.service(options['sshPort'],
-                                      sshFactory)
+
+        sshKey = keys._generateSavedRSAKey()
+        sshFactory.publicKeys["ssh-rsa"] = sshKey
+        sshFactory.privateKeys["ssh-rsa"] = sshKey
+
+        sshService = strports.service(options['sshPort'], sshFactory)
         sshService.setServiceParent(svc)
 
     return svc

Modified: branches/manhole-hardcodedkey-8229/twisted/conch/ssh/keys.py
==============================================================================
--- branches/manhole-hardcodedkey-8229/twisted/conch/ssh/keys.py	(original)
+++ branches/manhole-hardcodedkey-8229/twisted/conch/ssh/keys.py	Tue Mar  8 09:22:50 2016
@@ -15,7 +15,7 @@
 
 from cryptography.exceptions import InvalidSignature
 from cryptography.hazmat.backends import default_backend
-from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives import hashes, serialization
 from cryptography.hazmat.primitives.asymmetric import dsa, rsa, padding
 try:
     from cryptography.hazmat.primitives.asymmetric.utils import (
@@ -33,7 +33,7 @@
 
 from twisted.conch.ssh import common, sexpy
 from twisted.conch.ssh.common import int_from_bytes, int_to_bytes
-from twisted.python import randbytes
+from twisted.python import randbytes, filepath
 from twisted.python.compat import iterbytes, long, izip, nativeString, _PY3
 from twisted.python.deprecate import deprecated, getDeprecationWarningString
 from twisted.python.versions import Version
@@ -1229,6 +1229,49 @@
         raise BadKeyError("invalid key object", obj)
 
 
+
+def _generateSavedRSAKey(directory=None, filename="server.pem", keySize=4096):
+    """
+    This function generates a persistent server key
+    """
+    if directory is None:
+        from appdirs import user_data_dir
+        directory = user_data_dir("Twisted", "Conch")
+
+    configDir = filepath.FilePath(directory)
+    configDir.makedirs(ignoreExistingDirectory=True)
+    pemFile = configDir.child(filename)
+
+    # If it doesn't exist, we want to generate a new key and save it
+    if not pemFile.exists():
+        privateKey = rsa.generate_private_key(
+            public_exponent=65537,
+            key_size=keySize,
+            backend=default_backend()
+        )
+
+        pem = privateKey.private_bytes(
+            encoding=serialization.Encoding.PEM,
+            format=serialization.PrivateFormat.TraditionalOpenSSL,
+            encryption_algorithm=serialization.NoEncryption()
+        )
+
+        pemFile.setContent(pem)
+
+    # By this point (save any hilarious race conditions) we should have a
+    # working PEM file. Load it!
+    # (Future archelogical readers: I chose not to short circuit above, because
+    # then there's two exit paths to this code!)
+    with pemFile.open("rb") as key_file:
+        privateKey = serialization.load_pem_private_key(
+            key_file.read(),
+            password=None,
+            backend=default_backend()
+        )
+        return Key(privateKey)
+
+
+
 if _PY3:
     # The objectType function is deprecated and not being ported to Python 3.
     del objectType