add --code-length, to configure the size of the PAKE code (in bytes/words)

src/wormhole/blocking/transcribe.py

@@ -177,9 +177,9 @@ class Initiator(Common):
         self.timeout = 3*MINUTE
         self.side = "initiator"
 
-    def get_code(self):
+    def get_code(self, code_length=2):
         self.channel_id = self._allocate() # allocate channel
-        self.code = codes.make_code(self.channel_id)
+        self.code = codes.make_code(self.channel_id, code_length)
         self.sp = SPAKE2_A(self.code.encode("ascii"),
                            idA=self.appid+":Initiator",
                            idB=self.appid+":Receiver")
@@ -225,8 +225,9 @@ class Receiver(Common):
         channel_ids = r.json()["channel-ids"]
         return channel_ids
 
-    def input_code(self, prompt="Enter wormhole code: "):
-        code = codes.input_code_with_completion(prompt, self.list_channels)
+    def input_code(self, prompt="Enter wormhole code: ", code_length=2):
+        code = codes.input_code_with_completion(prompt, self.list_channels,
+                                                code_length)
         return code
 
     def set_code(self, code):

src/wormhole/codes.py

@@ -3,10 +3,15 @@ import os
 from .wordlist import (byte_to_even_word, byte_to_odd_word,
                        even_words_lowercase, odd_words_lowercase)
 
-def make_code(channel_id):
-    odd_word = byte_to_odd_word[os.urandom(1)]
-    even_word = byte_to_even_word[os.urandom(1)]
-    return "%d-%s-%s" % (channel_id, odd_word.lower(), even_word.lower())
+def make_code(channel_id, code_length):
+    words = []
+    for i in range(code_length):
+        # we start with an "odd word"
+        if i % 2 == 0:
+            words.append(byte_to_odd_word[os.urandom(1)].lower())
+        else:
+            words.append(byte_to_even_word[os.urandom(1)].lower())
+    return str(channel_id) + "-" + "-".join(words)
 
 def extract_channel_id(code):
     channel_id = int(code.split("-")[0])
@@ -16,8 +21,9 @@ import readline
 #import sys
 
 class CodeInputter:
-    def __init__(self, get_channel_ids):
+    def __init__(self, get_channel_ids, code_length):
         self.get_channel_ids = get_channel_ids
+        self.code_length = code_length
         self.last_text = None # memoize for a speedup
         self.last_matches = None
 
@@ -45,7 +51,7 @@ class CodeInputter:
             matches = self.last_matches
             #print(" old matches", len(matches), file=sys.stderr)
         else:
-            if len(pieces) < 2:
+            if len(pieces) <= 1:
                 channel_ids = self.get_channel_ids()
                 matches = [str(channel_id) for channel_id in channel_ids
                            if str(channel_id).startswith(last)]
@@ -63,15 +69,15 @@ class CodeInputter:
         if state >= len(matches):
             return None
         match = matches[state]
-        if len(pieces) < 3:
+        if len(pieces) < 1+self.code_length:
             match += "-"
         #print(" match: '%s'" % match, file=sys.stderr)
         #sys.stderr.flush()
         return match
 
 
-def input_code_with_completion(prompt, get_channel_ids):
-    c = CodeInputter(get_channel_ids)
+def input_code_with_completion(prompt, get_channel_ids, code_length):
+    c = CodeInputter(get_channel_ids, code_length)
     readline.parse_and_bind("tab: complete")
     readline.set_completer(c.wrap_completer)
     readline.set_completer_delims("")
@@ -79,5 +85,5 @@ def input_code_with_completion(prompt, get_channel_ids):
     return code
 
 if __name__ == "__main__":
-    code = input_code_with_completion("Enter wormhole code: ", lambda: [])
+    code = input_code_with_completion("Enter wormhole code: ", lambda: [], 2)
     print("code is:", code)

src/wormhole/scripts/cmd_receive_file.py

@@ -19,7 +19,8 @@ def receive_file(args):
     r = Receiver(APPID, mydata, args.relay_url)
     code = args.code
     if not code:
-        code = r.input_code("Enter receive-file wormhole code: ")
+        code = r.input_code("Enter receive-file wormhole code: ",
+                            args.code_length)
     r.set_code(code)
 
     try:

src/wormhole/scripts/cmd_receive_text.py

@@ -10,7 +10,8 @@ def receive_text(args):
     r = Receiver(APPID, data, args.relay_url)
     code = args.code
     if not code:
-        code = r.input_code("Enter receive-text wormhole code: ")
+        code = r.input_code("Enter receive-text wormhole code: ",
+                            args.code_length)
     r.set_code(code)
     try:
         them_bytes = r.get_data()

src/wormhole/scripts/cmd_send_file.py

@@ -25,7 +25,7 @@ def send_file(args):
         }).encode("utf-8")
 
     i = Initiator(APPID, data, args.relay_url)
-    code = i.get_code()
+    code = i.get_code(args.code_length)
     print("On the other computer, please run: wormhole receive-file")
     print("Wormhole code is '%s'" % code)
     print()

src/wormhole/scripts/cmd_send_text.py

@@ -10,7 +10,7 @@ def send_text(args):
     data = json.dumps({"message": message,
                        }).encode("utf-8")
     i = Initiator(APPID, data, args.relay_url)
-    code = i.get_code()
+    code = i.get_code(args.code_length)
     print("On the other computer, please run: wormhole receive-text")
     print("Wormhole code is: %s" % code)
     print("")

src/wormhole/scripts/runner.py

@@ -18,6 +18,8 @@ g.add_argument("--relay-url", default=public_relay.RENDEZVOUS_RELAY,
                metavar="URL", help="rendezvous relay to use")
 g.add_argument("--transit-helper", default=public_relay.TRANSIT_RELAY,
                metavar="tcp:HOST:PORT", help="transit relay to use")
+g.add_argument("-c", "--code-length", type=int, default=2,
+               metavar="WORDS", help="length of code (in bytes/words)")
 subparsers = parser.add_subparsers(title="subcommands",
                                    dest="subcommand")