[project @ robey@lag.net-20051204090414-7c8318ab735f6188]

experimental util functions for parsing/getting openssh host config, and unit tests (turned out to be pretty easy)

paramiko/util.py

@@ -22,6 +22,7 @@ Useful functions used by the rest of paramiko.
 
 from __future__ import generators
 
+import fnmatch
 import sys
 import struct
 import traceback
@@ -218,6 +219,88 @@ def load_host_keys(filename):
     f.close()
     return keys
 
+def parse_ssh_config(file_obj):
+    """
+    Parse a config file of the format used by OpenSSH, and return an object
+    that can be used to make queries to L{lookup_ssh_host_config}.  The
+    format is described in OpenSSH's C{ssh_config} man page.  This method is
+    provided primarily as a convenience to posix users (since the OpenSSH
+    format is a de-facto standard on posix) but should work fine on Windows
+    too.
+
+    The return value is currently a list of dictionaries, each containing
+    host-specific configuration, but this is considered an implementation
+    detail and may be subject to change in later versions.
+
+    @param file_obj: a file-like object to read the config file from
+    @type file_obj: file
+    @return: opaque configuration object
+    @rtype: object
+    """
+    ret = []
+    config = { 'host': '*' }
+    ret.append(config)
+
+    for line in file_obj:
+        line = line.rstrip('\n').lstrip()
+        if (line == '') or (line[0] == '#'):
+            continue
+        if '=' in line:
+            key, value = line.split('=', 1)
+            key = key.strip().lower()
+        else:
+            # find first whitespace, and split there
+            i = 0
+            while (i < len(line)) and not line[i].isspace():
+                i += 1
+            if i == len(line):
+                raise Exception('Unparsable line: %r' % line)
+            key = line[:i].lower()
+            value = line[i:].lstrip()
+
+        if key == 'host':
+            # do we have a pre-existing host config to append to?
+            matches = [c for c in ret if c['host'] == value]
+            if len(matches) > 0:
+                config = matches[0]
+            else:
+                config = { 'host': value }
+                ret.append(config)
+        else:
+            config[key] = value
+
+    return ret
+
+def lookup_ssh_host_config(hostname, config):
+    """
+    Return a dict of config options for a given hostname.  The C{config} object
+    must come from L{parse_ssh_config}.
+
+    The host-matching rules of OpenSSH's C{ssh_config} man page are used, which
+    means that all configuration options from matching host specifications are
+    merged, with more specific hostmasks taking precedence.  In other words, if
+    C{"Port"} is set under C{"Host *"} and also C{"Host *.example.com"}, and
+    the lookup is for C{"ssh.example.com"}, then the port entry for
+    C{"Host *.example.com"} will win out.
+
+    The keys in the returned dict are all normalized to lowercase (look for
+    C{"port"}, not C{"Port"}.  No other processing is done to the keys or
+    values.
+
+    @param hostname: the hostname to lookup
+    @type hostname: str
+    @param config: the config object to search
+    @type config: object
+    """
+    matches = [x for x in config if fnmatch.fnmatch(hostname, x['host'])]
+    # sort in order of shortest match (usually '*') to longest
+    matches.sort(key=lambda x: len(x['host']))
+    ret = {}
+    for m in matches:
+        ret.update(m)
+    del ret['host']
+    return ret
+
 def mod_inverse(x, m):
     # it's crazy how small python can make this function.
     u1, u2, u3 = 1, 0, m

test.py

@@ -30,6 +30,7 @@ sys.path.append('tests/')
 
 from test_message import MessageTest
 from test_file import BufferedFileTest
+from test_util import UtilTest
 from test_pkey import KeyTest
 from test_kex import KexTest
 from test_packetizer import PacketizerTest
@@ -87,6 +88,7 @@ if options.use_sftp:
 suite = unittest.TestSuite()
 suite.addTest(unittest.makeSuite(MessageTest))
 suite.addTest(unittest.makeSuite(BufferedFileTest))
+suite.addTest(unittest.makeSuite(UtilTest))
 if options.use_pkey:
     suite.addTest(unittest.makeSuite(KeyTest))
 suite.addTest(unittest.makeSuite(KexTest))

tests/test_util.py

@@ -0,0 +1,80 @@
+#!/usr/bin/python
+
+# Copyright (C) 2003-2005 Robey Pointer <robey@lag.net>
+#
+# 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.
+
+"""
+Some unit tests for utility functions.
+"""
+
+import cStringIO
+import unittest
+from Crypto.Hash import SHA
+import paramiko.util
+
+
+test_config_file = """\
+Host *
+    User robey
+    IdentityFile    =~/.ssh/id_rsa
+
+# comment
+Host *.example.com
+    \tUser bjork
+Port=3333
+Host *
+ \t  \t Crazy something dumb  
+Host spoo.example.com
+Crazy something else
+"""
+
+
+class UtilTest (unittest.TestCase):
+
+    K = 14730343317708716439807310032871972459448364195094179797249681733965528989482751523943515690110179031004049109375612685505881911274101441415545039654102474376472240501616988799699744135291070488314748284283496055223852115360852283821334858541043710301057312858051901453919067023103730011648890038847384890504L
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def test_1_parse_config(self):
+        global test_config_file
+        f = cStringIO.StringIO(test_config_file)
+        config = paramiko.util.parse_ssh_config(f)
+        self.assertEquals(config, [ {'identityfile': '~/.ssh/id_rsa', 'host': '*', 'user': 'robey',
+                                     'crazy': 'something dumb  '},
+                                    {'host': '*.example.com', 'user': 'bjork', 'port': '3333'},
+                                    {'host': 'spoo.example.com', 'crazy': 'something else'}])
+
+    def test_2_host_config(self):
+        global test_config_file
+        f = cStringIO.StringIO(test_config_file)
+        config = paramiko.util.parse_ssh_config(f)
+        c = paramiko.util.lookup_ssh_host_config('irc.danger.com', config)
+        self.assertEquals(c, {'identityfile': '~/.ssh/id_rsa', 'user': 'robey', 'crazy': 'something dumb  '})
+        c = paramiko.util.lookup_ssh_host_config('irc.example.com', config)
+        self.assertEquals(c, {'identityfile': '~/.ssh/id_rsa', 'user': 'bjork', 'crazy': 'something dumb  ', 'port': '3333'})
+        c = paramiko.util.lookup_ssh_host_config('spoo.example.com', config)
+        self.assertEquals(c, {'identityfile': '~/.ssh/id_rsa', 'user': 'bjork', 'crazy': 'something else', 'port': '3333'})
+
+    def test_3_generate_key_bytes(self):
+        x = paramiko.util.generate_key_bytes(SHA, 'ABCDEFGH', 'This is my secret passphrase.', 64)
+        hex = ''.join(['%02x' % ord(c) for c in x])
+        self.assertEquals(hex, '9110e2f6793b69363e58173e9436b13a5a4b339005741d5c680e505f57d871347b4239f14fb5c46e857d5e100424873ba849ac699cea98d729e57b3e84378e8b')