diff --git a/receiver/challenges/test_sheesh_standalone.py b/receiver/challenges/test_sheesh_standalone.py new file mode 100644 index 0000000..3512f6d --- /dev/null +++ b/receiver/challenges/test_sheesh_standalone.py @@ -0,0 +1,191 @@ +from .Challenge import Challenge + +import subprocess +import time +import re +import os + +class Sheesh(Challenge): + flag_location = 'flags/sheesh.txt' + history_location = 'history/sheesh.txt' + + _CONTAINER = "sheesh_container" + _SERVICE_CMD = ["docker", "exec", "-i", _CONTAINER, "python3", "/usr/local/bin/chall.py"] + _HEX_RE = re.compile(r'^[0-9a-fA-F]+$') + + def _read_container_flag(self) -> str: + out = subprocess.run(["docker", "exec", self._CONTAINER, "cat", "/flag.txt"], + capture_output=True, text=True) + if out.returncode != 0 or not out.stdout.strip(): + raise FileNotFoundError("Flag not found in container (/flag.txt)") + return out.stdout.strip() + + def _spawn(self): + return subprocess.Popen( + self._SERVICE_CMD, + stdin=subprocess.PIPE, + stdout=subprocess.PIPE, + stderr=subprocess.STDOUT, + text=True, + bufsize=0, + ) + + def _read_until(self, proc, token, timeout=5.0, max_bytes=1_000_000): + start = time.time() + buf = [] + r = proc.stdout.read + while True: + if time.time() - start > timeout: + tail = ''.join(buf)[-500:] + raise TimeoutError(f"Timeout waiting for '{token}'. Got so far:\n{tail}") + ch = r(1) + if ch == "" and proc.poll() is not None: + raise RuntimeError(f"Process ended while waiting for '{token}'. Output:\n{''.join(buf)}") + buf.append(ch) + if len(buf) > max_bytes: + raise RuntimeError("Exceeded max read size") + if token in "".join(buf): + return "".join(buf) + + def _send_line(self, proc, s: str): + proc.stdin.write(s + "\n") + proc.stdin.flush() + + def _expect_hex_field(self, text: str, label: str) -> str: + m = re.search(rf"{re.escape(label)}\s*:\s*([0-9a-fA-F]+)", text) + assert m, f"Missing '{label}' in output. Tail:\n{text[-400:]}" + hx = m.group(1) + assert self._HEX_RE.match(hx), f"{label} is not hex" + return hx + + def distribute(self, flag): + try: + os.makedirs(os.path.dirname(self.flag_location), exist_ok=True) + with open(self.flag_location, 'w') as f: + f.write(flag) + + os.makedirs(os.path.dirname(self.history_location), exist_ok=True) + with open(self.history_location, 'a') as f: + f.write(flag + '\n') + + self.logger.info(f'Flag {flag} written to {self.flag_location}') + return True + except Exception as e: + self.logger.error(f'Could not write flag to {self.flag_location}: {e}') + return False + + def check(self): + try: + with open(self.flag_location, 'r') as f: + host_flag = f.read().strip() + container_flag = self._read_container_flag() + assert host_flag == container_flag, 'Flag mismatch between host and container' + self.logger.info('[ok] flag parity (sheesh)') + + proc = self._spawn() + + def menu(): + self._read_until(proc, "> ", timeout=5.0) + + menu() + + self._send_line(proc, "1") + self._read_until(proc, "pt: ", timeout=3.0) + pt_hex = "414243444546" # "ABCDEF" + self._send_line(proc, pt_hex) + out = self._read_until(proc, "\n\n", timeout=3.0) + ct_hex = self._expect_hex_field(out, "ct") + ct = bytes.fromhex(ct_hex) + assert len(ct) == 16 + len(bytes.fromhex(pt_hex)), "CFB ct length mismatch (IV+PT)" + iv_a = ct[:16] + self.logger.info("[ok] encrypt(1) basic") + + menu() + self._send_line(proc, "1") + self._read_until(proc, "pt: ", timeout=3.0) + pt_hex2 = "00" * 8 + self._send_line(proc, pt_hex2) + out2 = self._read_until(proc, "\n\n", timeout=3.0) + ct2_hex = self._expect_hex_field(out2, "ct") + ct2 = bytes.fromhex(ct2_hex) + assert len(ct2) == 16 + len(bytes.fromhex(pt_hex2)), "Second CFB ct length mismatch" + iv_b = ct2[:16] + assert iv_a != iv_b, "CFB IV appears reused" + self.logger.info("[ok] encrypt(1) IV rotates") + + menu() + self._send_line(proc, "3") + self._read_until(proc, "pt: ", timeout=3.0) + self._send_line(proc, "00" * 15) + out3a = self._read_until(proc, "\n", timeout=3.0) + assert "hmmm" in out3a.lower(), "Option 3 must reject non-16-byte input (15B)" + + menu() + self._send_line(proc, "3") + self._read_until(proc, "pt: ", timeout=3.0) + self._send_line(proc, "00" * 17) + out3b = self._read_until(proc, "\n", timeout=3.0) + assert "hmmm" in out3b.lower(), "Option 3 must reject non-16-byte input (17B)" + + menu() + self._send_line(proc, "3") + self._read_until(proc, "pt: ", timeout=3.0) + self._send_line(proc, "11" * 16) + out3 = self._read_until(proc, "\n\n", timeout=3.0) + ct3_hex = self._expect_hex_field(out3, "ct") + ct3 = bytes.fromhex(ct3_hex) + assert len(ct3) in (16, 32), f"Unexpected CT length for option 3: {len(ct3)} (expected 16 or 32)" + if len(ct3) == 16: + self.logger.info("[ok] get third(3): vuln flavor (16-byte CT)") + else: + self.logger.info("[ok] get third(3): patched flavor (32-byte CT)") + + menu() + self._send_line(proc, "3") + out4 = self._read_until(proc, "\n", timeout=3.0) + assert "sheesh" in out4.lower(), "Second call to option 3 should be rejected with 'sheesh'" + self.logger.info("[ok] get third(3) lockout") + + menu() + self._send_line(proc, "2") + out5 = self._read_until(proc, "\n\n", timeout=3.0) + iv1_hex = self._expect_hex_field(out5, "iv1") + iv2_hex = self._expect_hex_field(out5, "iv2") + ct5_hex = self._expect_hex_field(out5, "ct") + assert len(bytes.fromhex(iv1_hex)) == 16, "iv1 length invalid" + assert len(bytes.fromhex(iv2_hex)) == 16, "iv2 length invalid" + assert len(bytes.fromhex(ct5_hex)) >= 16 and len(bytes.fromhex(ct5_hex)) % 16 == 0, "CBC ct invalid length" + self.logger.info("[ok] profit(2) first call") + + menu() + self._send_line(proc, "2") + out6 = self._read_until(proc, "\n\n", timeout=3.0) + iv1_hex_2 = self._expect_hex_field(out6, "iv1") + iv2_hex_2 = self._expect_hex_field(out6, "iv2") + assert iv1_hex_2 != iv1_hex or iv2_hex_2 != iv2_hex, "IVs did not change between consecutive '2' calls" + self.logger.info("[ok] profit(2) fresh IVs") + + menu() + self._send_line(proc, "4") + try: + proc.wait(timeout=2.0) + except subprocess.TimeoutExpired: + proc.kill() + raise AssertionError("Program did not exit after option 4") + self.logger.info("[ok] service exit on 4") + + proc_alarm = self._spawn() + self._read_until(proc_alarm, "zzz", timeout=190.0) # 180s + slack + try: + proc_alarm.wait(timeout=5.0) + except subprocess.TimeoutExpired: + proc_alarm.kill() + raise AssertionError("Alarm fired but process did not exit") + self.logger.info("[ok] alarm fired ('zzz') and process self-terminated") + + self.logger.info('Check passed for sheesh') + return True + + except Exception as e: + self.logger.error(f'Could not check sheesh: {e}') + return False