Initial SSH server support.

1 files changed, 78 insertions, 0 deletions

diff --git a/okupy/common/ssh.py b/okupy/common/ssh.py
new file mode 100644
index 0000000..bde138b
--- /dev/null
+++ b/okupy/common/ssh.py
@@ -0,0 +1,78 @@
+# vim:fileencoding=utf8:et:ts=4:sts=4:sw=4:ft=python
+
+from django.conf import settings
+
+import paramiko
+
+from io import BytesIO
+
+import asyncore
+import socket
+import threading
+
+
+LISTEN_BACKLOG = 20
+
+
+class SSHServer(paramiko.ServerInterface):
+    def get_allowed_auths(self, username):
+        return 'publickey'
+
+    def check_auth_publickey(self, username, key):
+        return paramiko.AUTH_SUCCESSFUL
+
+    def check_channel_request(self, kind, chanid):
+        if kind == 'session':
+            return paramiko.OPEN_SUCCEEDED
+        return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED
+
+    def check_channel_subsystem_request(self, channel, name):
+        return False
+
+    def check_channel_exec_request(self, channel, command):
+        channel.send('Not yet implemented, sorry.\r\n')
+        channel.shutdown(2)
+        channel.close()
+        return True
+
+    def check_channel_shell_request(self, channel):
+        channel.send('Not yet implemented, sorry.\r\n')
+        channel.shutdown(2)
+        channel.close()
+        return True
+
+    def check_channel_pty_request(self, channel, term, width, height,
+            pixelwidth, pixelheight, modes):
+        return True
+
+
+class SSHDispatcher(asyncore.dispatcher):
+    def __init__(self, server_key):
+        asyncore.dispatcher.__init__(self)
+        self._server_key = server_key
+
+        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+        self.set_reuse_addr()
+        self.bind(settings.SSH_BIND)
+        self.listen(LISTEN_BACKLOG)
+
+    def handle_accepted(self, conn, addr):
+        t = paramiko.Transport(conn)
+        t.add_server_key(self._server_key)
+        # we need a dummy Event to make it non-blocking
+        # but we don't really need to play with it
+        t.start_server(event=threading.Event(), server=SSHServer())
+
+    # python<3.2 compat
+    def handle_accept(self):
+        ret = self.accept()
+        if ret is not None:
+            self.handle_accepted(*ret)
+
+
+def ssh_main():
+    server_key = paramiko.RSAKey(file_obj=BytesIO(settings.SSH_SERVER_KEY))
+
+    disp = SSHDispatcher(server_key)
+    asyncore.loop()
+    raise SystemError('SSH server loop exited')