working version, for release

Makefile

@@ -5,7 +5,6 @@ build:
 	bash -c '. config.env && \
 	mkdir -p scripts && \
 	cp src/ssh-backdoor scripts/ssh-backdoor && \
-	cp src/ssh-backdoor-connect-local scripts/ssh-backdoor-connect-local && \
 	cp src/ssh-backdoor-connect scripts/ssh-backdoor-connect && \
 	sed \
 	  -e "s/{{BACKDOORHOST}}/$${BACKDOORHOST}/g" \
@@ -15,19 +14,26 @@ build:
 	  -e "s/{{BACKDOORHOST}}/$${BACKDOORHOST}/g" \
 	  -e "s/{{BACKDOORPORT}}/$${BACKDOORPORT}/g" \
 	  -e "s,{{BACKDOORURL}},$${BACKDOORURL},g" \
-	  -e "s,{{BACKDOORURLPATH}},$${BACKDOORURLPATH},g" \
 		src/ssh-backdoor-open > scripts/ssh-backdoor-open && \
 	chmod +x scripts/* && \
 	true'
 
 install: build
 	bash -c '. config.env && \
-  cp -av scripts/ssh-backdoor-open "$${BACKDOORURLPATH}" && \
+  if [[ -n "$${BACKDOORURLPATH}" ]]; then cp -av scripts/ssh-backdoor-open "$${BACKDOORURLPATH}"; fi && \
+  if [[ -n "$${CLIENTURLPATH}" ]]; then cp -av scripts/ssh-backdoor-open "$${BACKDOORURLPATH}"; fi && \
 	mkdir -p ${PREFIX} && \
 	cp -av scripts/ssh-backdoor ${PREFIX}/ssh-backdoor && \
-	cp -av scripts/ssh-backdoor-connect-local ${PREFIX}/ssh-backdoor-connect-local && \
 	cp -av scripts/ssh-backdoor-connect ${PREFIX}/ssh-backdoor-connect && \
 	true'
 
 clean:
 	rm -rf scripts
+
+uninstall:
+	bash -c '\
+	rm -fv ${PREFIX}/ssh-backdoor && \
+	rm -fv ${PREFIX}/ssh-backdoor-connect && \
+	if [[ -f "$${BACKDOORURLPATH}" ]]; then rm -fv $${BACKDOORURLPATH}; fi && \
+	true
+	'

README.md

@@ -0,0 +1,33 @@
+# What?
+
+This is a backdoor for servers in NAT networks.
+
+One server on the public internet acts as a backdoor server, where other
+computers connect, creating reverse tunnels to their ports 22.
+
+The program manages random ports that are then available at the server localhost.
+
+# install
+
+configure  config.env  and run `make install`
+
+- ssh-backdoor will go to ~/bin/ssh-backdoor
+- Servers behind NAT should access the ssh-backdoor-open script over a http(s) server
+- Clients that want to connect to the backdoored servers should be able to access
+  ssh-backdoor-connect script
+- use the 'ad-hoc-www-server' if no proper http server available
+
+# running
+
+- NATted servers must copy their `id_rsa.pub` to backdoor server's `authorized_keys`
+- Clients should do the same, for ease of access
+- Have NATted servers run  `ssh-backdoor-open` at boot (in cron or otherwise)
+- Use the ssh-backdoor command directly, or ssh-backdoor-connect from client machines
+  to connect
+
+
+# utils
+
+- `ssh-list` lists all processes with ssh and backdoor
+- `ssh-kill-all` kills all ssh connections (except the current parent), and all python processes
+

ad-hoc-www-server

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+cd $( dirname $( readlink -f $0 ) )
+set -e
+. config.env
+
+cd "$ADHOCSERVERROOT"
+python3 -m http.server $ADHOCSERVERPORT

config.env.example

@@ -0,0 +1,13 @@
+# Host name of the SSH server (and user name)
+BACKDOORHOST=admin@my.server.org
+# Port of the SSH server
+BACKDOORPORT=22
+# Where to download the ssh-backdoor-open and ssh-backdoor-connect script (may be left empty)
+BACKDOORURL=https://my.server.org/pub/ssh-backdoor-open
+CLIENTURL=https://my.server.org/pub/ssh-backdoor-connect
+# Location of the dowloadable script at the server (may be empty)
+BACKDOORURLPATH=/home/admin/www/pub/ssh-backdoor-open
+CLIENTURLPATH=/home/admin/www/pub/ssh-backdoor-connect
+# Ad-hoc web server port (if used)
+ADHOCSERVERPORT=8080
+ADHOCSERVERROOT=/home/admin/www/pub/

src/ssh-backdoor

@@ -6,6 +6,7 @@ import psutil
 import random
 import sqlite3
 import time, os, sys
+import subprocess
 
 def setup_options():
     ''' Setup the command line options '''
@@ -20,44 +21,6 @@ def setup_options():
         type = str,
         help = "Sqlite file for database: %(default)s"
     )
-    # TODO --connect (replace ssh-local-connect)
-    parser.add_argument(
-        "--clear",
-        action = 'store_true',
-        dest = 'clear',
-        default = False,
-        help = "Clear the database of everything, first"
-    )
-    parser.add_argument(
-        "--kill",
-        action = 'store',
-        dest = 'kill',
-        default = None,
-        type = str,
-        help="Kill processes of given ID"
-    )
-    parser.add_argument(
-        "--list","-l",
-        action = 'store_true',
-        dest = 'list',
-        default = False,
-        help = "List ports"
-    )
-    parser.add_argument(
-        "--list-names",
-        action = 'store_true',
-        dest = 'list_names',
-        default = False,
-        help = "List alive host names only"
-    )
-    parser.add_argument(
-        "--query",
-        action = 'store',
-        dest = 'query',
-        default = None,
-        type = str,
-        help="Query port for an id"
-    )
     parser.add_argument(
         "--quiet", "-q",
         action = 'store_true',
@@ -65,22 +28,78 @@ def setup_options():
         default = False,
         help = "Quiet operation: %(default)s"
     )
-    parser.add_argument(
+
-        "--wait", "-w",
+    subparsers = parser.add_subparsers(
-        action = 'store_true',
+      help = "Help for subcommand",
-        dest = 'wait',
+      dest = 'command'
-        default = False,
-        help = "Enter infinite loop"
     )
-    parser.add_argument(
+    parser_clear = subparsers.add_parser(
+      'clear',
+      help = "Clear the database of everything"
+    )
+
+    parser_connect = subparsers.add_parser(
+      'connect',
+      help = "Connect to a backdoor"
+    )
+    parser_connect.add_argument(
+      dest = "id",
+      help = "Backdoor ID to connect to"
+    )
+
+    parser_kill = subparsers.add_parser(
+      'kill',
+      help = "Kill a backdoor"
+    )
+    parser_kill.add_argument(
+      dest = "id",
+      help = "Backdoor ID to kill"
+    )
+
+    parser_list = subparsers.add_parser(
+        "list",
+        help = "List ports"
+    )
+
+    parser_list_names = subparsers.add_parser(
+        "list-names",
+        help = "List alive host names only"
+    )
+
+    parser_query = subparsers.add_parser(
+        "query",
+        help="Query port for an id"
+    )
+    parser_query.add_argument(
+      dest = "id",
+      help = "Backdoor ID to query"
+    )
+
+    parser_open = subparsers.add_parser(
+        "open",
+        help = "Open a new port. Returns the port number"
+    )
+    parser_open.add_argument(
         action = 'store',
         dest = 'id',
-        default = None ,
         type = str,
-        nargs = '?',
+        help="Id name for backdoor"
-        help="Id name for port"
+    )
+
+    parser_wait = subparsers.add_parser(
+        "keep",
+        help = "Keep updating alive status (for 1 hour)"
+    )
+    parser_wait.add_argument(
+        action = 'store',
+        dest = 'id',
+        type = str,
+        help="Id name for backdoor"
     )
     options=parser.parse_args()
+    if options.command == None:
+        parser.print_help(sys.stderr)
+        sys.exit(1)
     return options
 
 
@@ -254,52 +273,83 @@ class DataBase:
             if len(result) == 0:
                 return port
 
+    def connect_backdoor(self, id):
+        self.db = self.conn.cursor()
+        self.db.execute("SELECT port,pid FROM ports WHERE id = ?", (id,))
+        result = self.db.fetchall()
+        if len(result) == 0:
+            eprint("No such ID")
+            return
+        port = result[0][0]
+        pid = result[0][1]
+        if not self.is_running(pid):
+            eprint("Backdoor not open")
+            return
+
+        user = id.split("@")[0]
+        os.execlp(
+            "ssh",
+            "ssh",
+            "-o", "UserKnownHostsFile=/dev/null",
+            "-o", "StrictHostKeyChecking=no",
+            "-tt", "-XYC",
+            "-p", str(port),
+            "%s@localhost"%( user, )
+        )
+
+
 if __name__ == "__main__":
     opts=setup_options()
     db = DataBase(opts.DB)
     start_time = time.time()
 
-    if opts.clear:
+    if opts.command == "clear":
         db.clear()
 
-    if opts.list_names:
+    if opts.command == "list-names":
         for row in db.list():
-            if row[5]:
+            if row[-1]:
               print(row[0])
         sys.exit(0)
 
-    if opts.list:
+    if opts.command == "list":
         print(tabulate(
             db.list(),
             headers = ['Id','Port','Host','Age','PID','Die','Alive']
         ))
 
-    if opts.query != None:
+    if opts.command == "query":
-        port = db.get_port(opts.query)
+        port = db.get_port(opts.id)
         if port == None:
             sys.exit(1)
         print(port)
         sys.exit(0)
 
-    if opts.kill:
+    if opts.command == "kill":
-        db.set_to_die(opts.kill)
+        db.set_to_die(opts.id)
         sys.exit(0)
 
-    if opts.id != None:
+    if opts.command == "connect":
+        db.connect_backdoor(opts.id)
+
+    if opts.command == "open":
         print(db.update(opts.id))
-        if opts.wait:
+
-            ewrite(
+    if opts.command == "keep":
-                "    Connected\r"
+        print(db.update(opts.id))
-            )
+        ewrite(
-            while True:
+            "    Connected\r"
-                if time.time() - start_time > 3600:
+        )
-                    sys.exit(0)
+        while True:
-                db.check_die()
+            # Run 1 hour, then exit to reconnect
-                db.update(opts.id)
+            if time.time() - start_time > 3600:
-                for i in range(10):
+                sys.exit(0)
-                    time.sleep(10 * random.random())
+            db.check_die()
-                    ewrite(
+            db.update(opts.id)
-                        "    " +
+            for i in range(10):
-                        time.strftime("%c") +
+                time.sleep(10 * random.random())
-                        "\r"
+                ewrite(
-                    )
+                    "    " +
+                    time.strftime("%c") +
+                    "\r"
+                )

src/ssh-backdoor-connect

@@ -15,8 +15,8 @@ BACKDOORHOST={{BACKDOORHOST}}
 BACKDOORPORT={{BACKDOORPORT}}
 _list() {
     echo 'usage: [-auto] user@host'
-    _ssh bin/ssh-backdoor -l
+    _ssh bin/ssh-backdoor list
-    ids=( $( _ssh bin/ssh-backdoor --list-names ) )
+    ids=( $( _ssh bin/ssh-backdoor list-names ) )
     if [[ ${#ids[@]} -eq 0 ]]; then
       exit
     fi
@@ -33,6 +33,8 @@ _ssh() {
     -o UserKnownHostsFile=/dev/null \
     -o StrictHostKeyChecking=no \
     -o ConnectTimeout=10 \
+    -o ServerAliveInterval=15 \
+    -o ServerAliveCountMax=3 \
     -p ${BACKDOORPORT} ${BACKDOORHOST} \
      "$@"
     #~ -o "ExitOnForwardFailure yes" \
@@ -48,17 +50,15 @@ for (( i=1; i<=$#; i++ )); do
   host="${!i}"
 done
 
-port=$( _ssh bin/ssh-backdoor --query "$host" )
+port=$( _ssh bin/ssh-backdoor query "$host" )
 [[ $? -ne 0 ]] && {
     echo No such id
     _list
 }
-login=(${host//@/ })
 while :; do
   _ssh \
   -tt \
-    ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no \
+    bin/ssh-backdoor connect "$host"
-    -tt -XYC -p $port ${login[0]}@localhost
   [[ $? -eq 0 ]] && exit
   [[ "$auto_reconnect" -ne 1 ]] && { exit $?; }
   echo Auto-reconnect

src/ssh-backdoor-connect-local

@@ -1,21 +0,0 @@
-#!/bin/bash
-
-_list() {
-    echo usage: user@host
-    ssh-backdoor -l
-    exit
-}
-
-[[ -z "$1" ]] && _list
-
-port=$( ssh-backdoor --query "$1" )
-[[ $? -ne 0 ]] && {
-    echo No such id
-    _list
-}
-login=(${1//@/ })
-set -x
-exec ssh \
-  -o UserKnownHostsFile=/dev/null \
-  -o StrictHostKeyChecking=no \
-  -tt -XYC -p $port ${login[0]}@localhost

src/ssh-backdoor-open

@@ -31,13 +31,13 @@ USER=$( id -u -n )
 echo use of ssh-add is encouraged
 ( sleep 3; printf "%d\r" $SECONDS ) &
 while true; do
-    port=$( _ssh bin/ssh-backdoor $USER@$HOSTNAME )
+    port=$( _ssh bin/ssh-backdoor open $USER@$HOSTNAME )
     [[ -z "$port" ]] && { sleep 2; continue; }
     echo "$port port assigned"
     #~ _ssh pkill -a -f $USER@$HOSTNAME
     _ssh \
        -R $port:localhost:22 \
-       bin/ssh-backdoor -w $USER@$HOSTNAME || {
+       bin/ssh-backdoor keep $USER@$HOSTNAME || {
       true
          # failed
       #_ssh bin/ssh-kill $USER@$HOSTNAME $port || true

src/ssh-list

@@ -1,4 +0,0 @@
-#!/bin/bash
-
-ps axuw | grep -e [s]sh -e [p]ython3
-

utils/ssh-list

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+ps axuw | grep -e [s]sh -e [b]ackdoor
+