Introduce ECDSA

This just adds tests; hooking this up with paramiko comes in the next
commit.

paramiko/__init__.py

@@ -69,6 +69,7 @@ from ssh_exception import SSHException, PasswordRequiredException, \
 from server import ServerInterface, SubsystemHandler, InteractiveQuery
 from rsakey import RSAKey
 from dsskey import DSSKey
+from ecdsakey import ECDSAKey
 from sftp import SFTPError, BaseSFTP
 from sftp_client import SFTP, SFTPClient
 from sftp_server import SFTPServer

paramiko/ecdsakey.py

@@ -0,0 +1,181 @@
+# Copyright (C) 2003-2007  Robey Pointer <robeypointer@gmail.com>
+#
+# This file is part of paramiko.
+#
+# Paramiko is free software; you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation; either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Paramiko; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+
+"""
+L{ECDSAKey}
+"""
+
+import binascii
+from ecdsa import SigningKey, VerifyingKey, der, curves
+from ecdsa.util import number_to_string, sigencode_string, sigencode_strings, sigdecode_strings
+from Crypto.Hash import SHA256, MD5
+from Crypto.Cipher import DES3
+
+from paramiko.common import *
+from paramiko import util
+from paramiko.message import Message
+from paramiko.ber import BER, BERException
+from paramiko.pkey import PKey
+from paramiko.ssh_exception import SSHException
+
+
+class ECDSAKey (PKey):
+    """
+    Representation of an ECDSA key which can be used to sign and verify SSH2
+    data.
+    """
+
+    def __init__(self, msg=None, data=None, filename=None, password=None, vals=None, file_obj=None):
+        self.verifying_key = None
+        self.signing_key = None
+        if file_obj is not None:
+            self._from_private_key(file_obj, password)
+            return
+        if filename is not None:
+            self._from_private_key_file(filename, password)
+            return
+        if (msg is None) and (data is not None):
+            msg = Message(data)
+        if vals is not None:
+            self.verifying_key, self.signing_key = vals
+        else:
+            if msg is None:
+                raise SSHException('Key object may not be empty')
+            if msg.get_string() != 'ecdsa-sha2-nistp256':
+                raise SSHException('Invalid key')
+            curvename = msg.get_string()
+            if curvename != 'nistp256':
+                raise SSHException("Can't handle curve of type %s" % curvename)
+
+            pointinfo = msg.get_string()
+            if pointinfo[0] != "\x04":
+                raise SSHException('Point compression is being used: %s'%
+                                   binascii.hexlify(pointinfo))
+            self.verifying_key = VerifyingKey.from_string(pointinfo[1:],
+                curve=curves.NIST256p)
+        self.size = 256
+
+    def __str__(self):
+        key = self.verifying_key
+        m = Message()
+        m.add_string('ecdsa-sha2-nistp256')
+        m.add_string('nistp256')
+
+        point_str = "\x04" + key.to_string()
+
+        m.add_string(point_str)
+        return str(m)
+
+    def __hash__(self):
+        h = hash(self.get_name())
+        h = h * 37 + hash(self.verifying_key.pubkey.point.x())
+        h = h * 37 + hash(self.verifying_key.pubkey.point.y())
+        return hash(h)
+
+    def get_name(self):
+        return 'ecdsa-sha2-nistp256'
+
+    def get_bits(self):
+        return self.size
+
+    def can_sign(self):
+        return self.signing_key is not None
+
+    def sign_ssh_data(self, rpool, data):
+        digest = SHA256.new(data).digest()
+        sig = self.signing_key.sign_digest(digest, entropy=rpool.read,
+                                           sigencode=self._sigencode)
+        m = Message()
+        m.add_string('ecdsa-sha2-nistp256')
+        m.add_string(sig)
+        return m
+
+    def verify_ssh_sig(self, data, msg):
+        if msg.get_string() != 'ecdsa-sha2-nistp256':
+            return False
+        sig = msg.get_string()
+
+        # verify the signature by SHA'ing the data and encrypting it
+        # using the public key.
+        hash_obj = SHA256.new(data).digest()
+        return self.verifying_key.verify_digest(sig, hash_obj,
+                                                sigdecode=self._sigdecode)
+
+    def write_private_key_file(self, filename, password=None):
+        key = self.signing_key or self.verifying_key
+        self._write_private_key_file('EC', filename, key.to_der(), password)
+
+    def write_private_key(self, file_obj, password=None):
+        key = self.signing_key or self.verifying_key
+        self._write_private_key('EC', file_obj, key.to_der(), password)
+
+    def generate(bits, progress_func=None):
+        """
+        Generate a new private RSA key.  This factory function can be used to
+        generate a new host key or authentication key.
+
+        @param bits: number of bits the generated key should be.
+        @type bits: int
+        @param progress_func: an optional function to call at key points in
+            key generation (used by C{pyCrypto.PublicKey}).
+        @type progress_func: function
+        @return: new private key
+        @rtype: L{RSAKey}
+        """
+        signing_key = ECDSA.generate()
+        key = ECDSAKey(vals=(signing_key, signing_key.get_verifying_key()))
+        return key
+    generate = staticmethod(generate)
+
+
+    ###  internals...
+
+
+    def _from_private_key_file(self, filename, password):
+        data = self._read_private_key_file('EC', filename, password)
+        self._decode_key(data)
+
+    def _from_private_key(self, file_obj, password):
+        data = self._read_private_key('EC', file_obj, password)
+        self._decode_key(data)
+
+    ALLOWED_PADDINGS = ['\x01', '\x02\x02', '\x03\x03\x03', '\x04\x04\x04\x04',
+                        '\x05\x05\x05\x05\x05', '\x06\x06\x06\x06\x06\x06',
+                        '\x07\x07\x07\x07\x07\x07\x07']
+    def _decode_key(self, data):
+        s, padding = der.remove_sequence(data)
+        if padding:
+            if padding not in self.ALLOWED_PADDINGS:
+                raise ValueError, "weird padding: %s" % (binascii.hexlify(empty))
+            data = data[:-len(padding)]
+        key = SigningKey.from_der(data)
+        self.signing_key = key
+        self.verifying_key = key.get_verifying_key()
+        self.size = 256
+
+    def _sigencode(self, r, s, order):
+        msg = Message()
+        msg.add_mpint(r)
+        msg.add_mpint(s)
+        return str(msg)
+
+    def _sigdecode(self, sig, order):
+        msg = Message(sig)
+        r = msg.get_mpint()
+        s = msg.get_mpint()
+        return (r, s)

requirements.txt

@@ -1,2 +1,3 @@
 pycrypto
 tox
+ecdsa

setup.py

@@ -40,7 +40,9 @@ import sys
 try:
     from setuptools import setup
     kw = {
-        'install_requires': 'pycrypto >= 2.1, != 2.4',
+        'install_requires': ['pycrypto >= 2.1, != 2.4',
+                             'ecdsa',
+                             ],
     }
 except ImportError:
     from distutils.core import setup

tests/test_ecdsa.key

@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIKB6ty3yVyKEnfF/zprx0qwC76MsMlHY4HXCnqho2eKioAoGCCqGSM49
+AwEHoUQDQgAElI9mbdlaS+T9nHxY/59lFnn80EEecZDBHq4gLpccY8Mge5ZTMiMD
+ADRvOqQ5R98Sxst765CAqXmRtz8vwoD96g==
+-----END EC PRIVATE KEY-----

tests/test_ecdsa_password.key

@@ -0,0 +1,8 @@
+-----BEGIN EC PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: AES-128-CBC,EEB56BC745EDB2DE04FC3FE1F8DA387E
+
+wdt7QTCa6ahTJLaEPH7NhHyBcxhzrzf93d4UwQOuAhkM6//jKD4lF9fErHBW0f3B
+ExberCU3UxfEF3xX2thXiLw47JgeOCeQUlqRFx92p36k6YmfNGX6W8CsZ3d+XodF
+Z+pb6m285CiSX+W95NenFMexXFsIpntiCvTifTKJ8os=
+-----END EC PRIVATE KEY-----

tests/test_pkey.py

@@ -23,14 +23,17 @@ Some unit tests for public/private key objects.
 from binascii import hexlify, unhexlify
 import StringIO
 import unittest
-from paramiko import RSAKey, DSSKey, Message, util
+from paramiko import RSAKey, DSSKey, ECDSAKey, Message, util
 from paramiko.common import rng
 
 # from openssh's ssh-keygen
 PUB_RSA = 'ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA049W6geFpmsljTwfvI1UmKWWJPNFI74+vNKTk4dmzkQY2yAMs6FhlvhlI8ysU4oj71ZsRYMecHbBbxdN79+JRFVYTKaLqjwGENeTd+yv4q+V2PvZv3fLnzApI3l7EJCqhWwJUHJ1jAkZzqDx0tyOL4uoZpww3nmE0kb3y21tH4c='
 PUB_DSS = 'ssh-dss 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'
+PUB_ECDSA = 'ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBJSPZm3ZWkvk/Zx8WP+fZRZ5/NBBHnGQwR6uIC6XHGPDIHuWUzIjAwA0bzqkOUffEsbLe+uQgKl5kbc/L8KA/eo='
+
 FINGER_RSA = '1024 60:73:38:44:cb:51:86:65:7f:de:da:a2:2b:5a:57:d5'
 FINGER_DSS = '1024 44:78:f0:b9:a2:3c:c5:18:20:09:ff:75:5b:c1:d2:6c'
+FINGER_ECDSA = '256 25:19:eb:55:e6:a1:47:ff:4f:38:d2:75:6f:a5:d5:60'
 SIGNED_RSA = '20:d7:8a:31:21:cb:f7:92:12:f2:a4:89:37:f5:78:af:e6:16:b6:25:b9:97:3d:a2:cd:5f:ca:20:21:73:4c:ad:34:73:8f:20:77:28:e2:94:15:08:d8:91:40:7a:85:83:bf:18:37:95:dc:54:1a:9b:88:29:6c:73:ca:38:b4:04:f1:56:b9:f2:42:9d:52:1b:29:29:b4:4f:fd:c9:2d:af:47:d2:40:76:30:f3:63:45:0c:d9:1d:43:86:0f:1c:70:e2:93:12:34:f3:ac:c5:0a:2f:14:50:66:59:f1:88:ee:c1:4a:e9:d1:9c:4e:46:f0:0e:47:6f:38:74:f1:44:a8'
 
 RSA_PRIVATE_OUT = """\
@@ -66,6 +69,13 @@ QPSch9pT9XHqn+1rZ4bK+QGA
 -----END DSA PRIVATE KEY-----
 """
 
+ECDSA_PRIVATE_OUT = """\
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIKB6ty3yVyKEnfF/zprx0qwC76MsMlHY4HXCnqho2eKioAoGCCqGSM49
+AwEHoUQDQgAElI9mbdlaS+T9nHxY/59lFnn80EEecZDBHq4gLpccY8Mge5ZTMiMD
+ADRvOqQ5R98Sxst765CAqXmRtz8vwoD96g==
+-----END EC PRIVATE KEY-----
+"""
 
 class KeyTest (unittest.TestCase):
 
@@ -188,3 +198,53 @@ class KeyTest (unittest.TestCase):
         msg = key.sign_ssh_data(rng, 'jerri blank')
         msg.rewind()
         self.assert_(key.verify_ssh_sig('jerri blank', msg))
+
+    def test_10_load_ecdsa(self):
+        key = ECDSAKey.from_private_key_file('tests/test_ecdsa.key')
+        self.assertEquals('ecdsa-sha2-nistp256', key.get_name())
+        exp_ecdsa = FINGER_ECDSA.split()[1].replace(':', '')
+        my_ecdsa = hexlify(key.get_fingerprint())
+        self.assertEquals(exp_ecdsa, my_ecdsa)
+        self.assertEquals(PUB_ECDSA.split()[1], key.get_base64())
+        self.assertEquals(256, key.get_bits())
+
+        s = StringIO.StringIO()
+        key.write_private_key(s)
+        self.assertEquals(ECDSA_PRIVATE_OUT, s.getvalue())
+        s.seek(0)
+        key2 = ECDSAKey.from_private_key(s)
+        self.assertEquals(key, key2)
+
+    def test_11_load_ecdsa_password(self):
+        key = ECDSAKey.from_private_key_file('tests/test_ecdsa_password.key', 'television')
+        self.assertEquals('ecdsa-sha2-nistp256', key.get_name())
+        exp_ecdsa = FINGER_ECDSA.split()[1].replace(':', '')
+        my_ecdsa = hexlify(key.get_fingerprint())
+        self.assertEquals(exp_ecdsa, my_ecdsa)
+        self.assertEquals(PUB_ECDSA.split()[1], key.get_base64())
+        self.assertEquals(256, key.get_bits())
+
+    def test_12_compare_ecdsa(self):
+        # verify that the private & public keys compare equal
+        key = ECDSAKey.from_private_key_file('tests/test_ecdsa.key')
+        self.assertEquals(key, key)
+        pub = ECDSAKey(data=str(key))
+        self.assert_(key.can_sign())
+        self.assert_(not pub.can_sign())
+        self.assertEquals(key, pub)
+
+    def test_13_sign_ecdsa(self):
+        # verify that the rsa private key can sign and verify
+        key = ECDSAKey.from_private_key_file('tests/test_ecdsa.key')
+        msg = key.sign_ssh_data(rng, 'ice weasels')
+        self.assert_(type(msg) is Message)
+        msg.rewind()
+        self.assertEquals('ecdsa-sha2-nistp256', msg.get_string())
+        # ECDSA signatures, like DSS signatures, tend to be different
+        # each time, so we can't compare against a "known correct"
+        # signature.
+        # Even the length of the signature can change.
+
+        msg.rewind()
+        pub = ECDSAKey(data=str(key))
+        self.assert_(pub.verify_ssh_sig('ice weasels', msg))