Merge pull request #501 from MinKuanIsHere/lab8

[LAB8] 313552009

Author: YingMuo

lab8/solve.py

@@ -1,11 +1,64 @@
 #!/usr/bin/env python3
 
-import angr,sys
+import angr
+import claripy
+import logging
+logging.getLogger('angr').setLevel(logging.ERROR)
+import sys
+import os
 
 def main():
-    secret_key = b""
-    sys.stdout.buffer.write(secret_key)
-
+    # Check if ./chal exists
+    if not os.path.isfile('./chal'):
+        print("Error: './chal' binary not found. Run 'make' to compile it.", file=sys.stderr)
+        sys.exit(1)
+    
+    # Load the binary
+    try:
+        proj = angr.Project('./chal', auto_load_libs=False)
+    except Exception as e:
+        print(f"Error loading binary: {e}", file=sys.stderr)
+        sys.exit(1)
+    
+    # Create symbolic input (8 bytes)
+    input_chars = [claripy.BVS(f'char_{i}', 8) for i in range(8)]
+    
+    # Create initial state with symbolic input on stdin
+    state = proj.factory.entry_state(stdin=claripy.Concat(*input_chars))
+    
+    # Constrain input to printable ASCII (32-126)
+    for c in input_chars:
+        state.solver.add(c >= 32)
+        state.solver.add(c <= 126)
+    
+    # Create simulation manager
+    simgr = proj.factory.simulation_manager(state)
+    
+    # Explore to find the path that prints the flag
+    def is_successful(state):
+        stdout_content = state.posix.dumps(1)  # Check stdout
+        return b"Correct!" in stdout_content
+    
+    def is_failed(state):
+        stdout_content = state.posix.dumps(1)
+        return b"Wrong key!" in stdout_content
+    
+    simgr.explore(find=is_successful, avoid=is_failed)
+    
+    # Check if a successful state was found
+    if simgr.found:
+        found_state = simgr.found[0]
+        # Extract concrete values for the input
+        secret_key = b""
+        for c in input_chars:
+            val = found_state.solver.eval(c)
+            secret_key += bytes([val])
+        
+        # Output the secret key to stdout
+        sys.stdout.buffer.write(secret_key)
+    else:
+        print("No solution found!", file=sys.stderr)
+        sys.exit(1)
 
 if __name__ == '__main__':
-    main()
+    main()