ssh server

server.py

@@ -3,5 +3,138 @@
 # 
 
 
+import base64
+from binascii import hexlify
+import os
+import socket
+import sys
+import threading
+import traceback
+
+import paramiko
+from paramiko.py3compat import b, u, decodebytes
+
+
+paramiko.util.log_to_file('demo_server.log')
+
+host_key = paramiko.RSAKey(filename='test_rsa.key')
+
+
+class Server(paramiko.ServerInterface):
+    # 'data' is the output of base64.encodestring(str(key))
+    # (using the "user_rsa_key" files)
+    data = (b'AAAAB3NzaC1yc2EAAAABIwAAAIEAyO4it3fHlmGZWJaGrfeHOVY7RWO3P9M7hp'
+            b'fAu7jJ2d7eothvfeuoRFtJwhUmZDluRdFyhFY/hFAh76PJKGAusIqIQKlkJxMC'
+            b'KDqIexkgHAfID/6mqvmnSJf0b5W8v5h2pI/stOSwTQ+pxVhwJ9ctYDhRSlF0iT'
+            b'UWT10hcuO4Ks8=')
+    good_pub_key = paramiko.RSAKey(data=decodebytes(data))
+
+    def __init__(self):
+        self.event = threading.Event()
+
+    def check_channel_request(self, kind, chanid):
+        if kind == 'session':
+            return paramiko.OPEN_SUCCEEDED
+        return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED
+
+    def check_auth_password(self, username, password):
+        print(username, password)
+        if (username == 'robey') and (password == 'foo'):
+            return paramiko.AUTH_SUCCESSFUL
+        return paramiko.AUTH_FAILED
+
+    def check_auth_publickey(self, username, key):
+        print('Auth attempt with key: ' + u(hexlify(key.get_fingerprint())))
+        if (username == 'robey') and (key == self.good_pub_key):
+            return paramiko.AUTH_SUCCESSFUL
+        return paramiko.AUTH_FAILED
+
+    def get_allowed_auths(self, username):
+        return 'password,publickey'
+
+    def check_channel_shell_request(self, channel):
+        self.event.set()
+        return True
+
+    def check_channel_pty_request(self, channel, term, width, height, pixelwidth,
+                                      pixelheight, modes):
+        return True
+
+
+def handle_ssh_request(client, addr):
+    print('Got a connection!')
+
+    try:
+        t = paramiko.Transport(client, gss_kex=False)
+        t.set_gss_host(socket.getfqdn(""))
+        try:
+            t.load_server_moduli()
+        except:
+            print('(Failed to load moduli -- gex will be unsupported.)')
+            raise
+        t.add_server_key(host_key)
+        server = Server()
+        try:
+            t.start_server(server=server)
+        except paramiko.SSHException:
+            print('*** SSH negotiation failed.')
+            return
+
+        while True:
+            # wait for auth
+            chan = t.accept(20)
+            if chan is None:
+                print('*** No channel.')
+                return
+            print('Authenticated!')
+
+            server.event.wait(10)
+            if not server.event.is_set():
+                print('*** Client never asked for a shell.')
+                return
+
+            chan.send('\r\n\r\nWelcome to my dorky little BBS!\r\n\r\n')
+            chan.send('We are on fire all the time!  Hooray!  Candy corn for everyone!\r\n')
+            chan.send('Happy birthday to Robot Dave!\r\n\r\n')
+            chan.send('Username: ')
+            f = chan.makefile('rU')
+            username = f.readline().strip('\r\n')
+            chan.send('\r\nI don\'t like you, ' + username + '.\r\n')
+            chan.close()
+
+    except Exception as e:
+        print('*** Caught exception: ' + str(e.__class__) + ': ' + str(e))
+        traceback.print_exc()
+        try:
+            t.close()
+        except:
+            pass
+        sys.exit(1)
+
+
+def run_server():
+    try:
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+        sock.bind(('', 2200))
+    except Exception as e:
+        print('*** Bind failed: ' + str(e))
+        traceback.print_exc()
+        sys.exit(1)
+
+    try:
+        sock.listen(100)
+        print('Listening for connection ...')
+        client, addr = sock.accept()
+
+        t = threading.Thread(target=handle_ssh_request, args=(client, addr))
+        t.start()
+
+    except Exception as e:
+        print('*** Listen/accept failed: ' + str(e))
+        traceback.print_exc()
+        sys.exit(1)
+
+
 if __name__ == '__main__':
-    pass
+    run_server()