Merge cc3c311 into a9b7650

touchdown/ssh/__init__.py

@@ -15,6 +15,9 @@
 from .client import Client, private_key_from_string
 from .connection import Connection, Instance
 
+from . import terminal  # noqa
+
+
 __all__ = [
     "Client",
     "Connection",

touchdown/ssh/agent.py

@@ -0,0 +1,126 @@
+import struct
+import os
+import SocketServer
+import shutil
+import tempfile
+import threading
+import time
+
+import paramiko
+from paramiko.message import Message
+from paramiko.common import asbytes
+from paramiko.py3compat import byte_chr
+
+
+SSH_AGENT_FAILURE = 5
+SSH_AGENT_SUCCESS = 6
+SSH2_AGENT_IDENTITIES_ANSWER = 12
+SSH2_AGENT_SIGN_RESPONSE = 14
+
+
+class ConnectionError(Exception):
+    pass
+
+
+class AgentRequestHandler(SocketServer.BaseRequestHandler):
+
+    def _read(self, wanted):
+        result = ''
+        while len(result) < wanted:
+            buf = self.request.recv(wanted - len(result))
+            if not buf:
+                raise ConnectionError()
+            result += buf
+        return result
+
+    def read_message(self):
+        size = struct.unpack('>I', self._read(4))[0]
+        msg = Message(self._read(size))
+        return ord(msg.get_byte()), msg
+
+    def send_message(self, msg):
+        msg = asbytes(msg)
+        self.request.sendall(struct.pack('>I', len(msg)) + msg)
+
+    def handler_11(self, msg):
+        # SSH2_AGENTC_REQUEST_IDENTITIES = 11
+        m = Message()
+        m.add_byte(byte_chr(SSH2_AGENT_IDENTITIES_ANSWER))
+        m.add_int(len(self.server.identities))
+        for pkey, comment in self.server.identities.values():
+            m.add_string(pkey.asbytes())
+            m.add_string(comment)
+        return m
+
+    def handler_13(self, msg):
+        # SSH2_AGENTC_SIGN_REQUEST = 13
+        pkey, comment = self.server.identities.get(msg.get_binary(), (None, None))
+        data = msg.get_binary()
+        msg.get_int()
+        m = Message()
+        if not pkey:
+            m.add_byte(chr(SSH_AGENT_FAILURE))
+            return m
+        m.add_byte(chr(SSH2_AGENT_SIGN_RESPONSE))
+        m.add_string(pkey.sign_ssh_data(data).asbytes())
+        return m
+
+    def handle(self):
+        while True:
+            try:
+                mtype, msg = self.read_message()
+            except ConnectionError:
+                return
+
+            handler = getattr(self, "handler_{}".format(mtype))
+            if not handler:
+                print "{!r} not a supported message type".format(mtype)
+                continue
+
+            self.send_message(handler(msg))
+
+
+class AgentServer(SocketServer.UnixStreamServer):
+
+    def __init__(self, socket_file):
+        SocketServer.UnixStreamServer.__init__(self, socket_file, AgentRequestHandler)
+        self.identities = {}
+
+    def add(self, pkey, comment):
+        self.identities[pkey.asbytes()] = (pkey, comment)
+
+    def serve_while_pid(self, pid):
+        t = threading.Thread(target=self.serve_forever)
+        t.daemon = True
+        t.start()
+
+        while os.waitpid(pid, 0)[0] != pid:
+            pass
+
+        self.shutdown()
+        self.server_close()
+
+
+def main():
+    pid = os.getpid()
+    socket_dir = tempfile.mkdtemp(prefix='ssh-')
+    socket_file = os.path.join(socket_dir, 'agent.{}'.format(pid))
+
+    child_pid = os.fork()
+    if child_pid:
+        a = AgentServer(socket_file)
+        a.add(
+            paramiko.RSAKey.from_private_key_file('/home/john/test.pem'),
+            'test.pem',
+        )
+        a.serve_while_pid(child_pid)
+        shutil.rmtree(socket_dir)
+        return
+
+    while not os.path.exists(socket_file):
+        time.sleep(0.5)
+
+    os.execvpe("/usr/bin/ssh", ["ssh", "ubuntu@127.0.0.1"], {"SSH_AUTH_SOCK": socket_file})
+
+
+main()

touchdown/ssh/terminal.py

@@ -0,0 +1,23 @@
+# Copyright 2015 Isotoma Limited
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from touchdown.ssh import connection
+
+
+class ConnectionPlan(connection.ConnectionPlan):
+
+    name = "ssh"
+
+    def start(self):
+        pass