just for now

week06/hard/bob.py

@@ -8,7 +8,31 @@ import random
 from asyncio import StreamReader, StreamWriter
 
 from insecurelib import *
-from pwn_utils.utils import read_line_safe
+
+
+
+async def read_line_safe(reader):
+    """
+    Simple implementation to read a line from an async reader
+    Mimics the original read_line_safe functionality
+    """
+    try:
+        line = await reader.readline()
+        return line.decode().strip()
+    except Exception:
+        return None
+
+
+def log_error(e, client_writer=None):
+    """
+    Basic error logging function
+    """
+    print(f"Error occurred: {e}")
+    if client_writer:
+        try:
+            client_writer.write(f"Error: {str(e)}\n".encode())
+        except Exception:
+            print("Could not send error to client")
 
 log = logging.getLogger(__name__)
 clients = {}  # task -> (reader, writer)
@@ -51,16 +75,16 @@ class AuthenticatedChannel:
     async def do_STS_key_exchange(self):
         # receive p,q and public keypart to other server (over the client) and wait for response
         pgX = await read_line_safe(self.reader)
-
         if pgX is None:
             return
-
         if pgX.count(',') != 2:
             self.writer.write('Invalid amount of arguments (expected 3; p,g,X)\n'.encode())
             await self.writer.drain()
             return
 
         p, g, X = map(int, pgX.split(','))
+        print(p,g,X)
+
 
         # primality and size checks not necessary since fixed values from RFC 3526 are used for STS key exchange
 
@@ -105,8 +129,7 @@ async def do_session_key_DH_exchange(channel: AuthenticatedChannel) -> bytes | N
 
     # send p,q and public keypart
     pgX = f'{p},{g},{X}'
-    await channel.send_encrypted(pgX.encode())
-
+    await channel.send_encrypted(pgX.encode()) # Start debuggin from here bob
     Y = await channel.recv_encrypted()
     log.info(f'received "{Y}" as Y (public key)')
 
@@ -121,6 +144,7 @@ async def do_session_key_DH_exchange(channel: AuthenticatedChannel) -> bytes | N
     # calculate shared key
     key = str(pow(Y, a, mod=p))
     key = KDRV256(key.encode())
+    print("do seession dh is finished")
     return key
 
 
@@ -140,9 +164,9 @@ async def handle_client(client_reader: StreamReader, client_writer: StreamWriter
 
         # do session key DH exchange
         session_key = await do_session_key_DH_exchange(authenticated_channel)
-
+        print("session key obtained")
         message = await authenticated_channel.recv_encrypted()
-
+        print("message received for last: ", message)
         if message is None:
             return
 
@@ -155,7 +179,7 @@ async def handle_client(client_reader: StreamReader, client_writer: StreamWriter
             )
             return
 
-        flag = subprocess.check_output('flag')
+        flag = "flaggy".encode()
         encrypted_flag = encrypt(session_key, flag)
         await authenticated_channel.send_encrypted(encrypted_flag)