feat: implement binary analysis for lab8

Author: nizw0

lab8/solve.py

@@ -1,11 +1,48 @@
 #!/usr/bin/env python3
 
-import angr,sys
+import sys
+
+import angr
+import claripy
+
+PROJECT_PATH = "./chal"
+
+
+def answer(key):
+    sys.stdout.buffer.write(key)
+
+
+def success(state):
+    return b"Correct" in state.posix.dumps(1)
+
+
+def failure(state):
+    return b"Wrong" in state.posix.dumps(1)
+
 
 def main():
-    secret_key = b""
-    sys.stdout.buffer.write(secret_key)
+    project = angr.Project(PROJECT_PATH, auto_load_libs=False)
+
+    input = claripy.BVS("input", 64)  # 8 bytes
+
+    state = project.factory.full_init_state(stdin=input)
+
+    for byte in input.chop(8):
+        # answer should be printable ascii, 0x20 ~ 0x7E
+        state.solver.add(byte >= 0x20)
+        state.solver.add(byte <= 0x7E)
+
+    simgr = project.factory.simgr(state)
+
+    simgr.explore(find=success, avoid=failure)
+
+    if simgr.found:
+        found = simgr.found[0]
+        solution = found.solver.eval(input, cast_to=bytes)
+        answer(solution)
+    else:
+        raise Exception("AnswerNotFoundError")
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()