Merge pull request #859 from tlsfuzzer/marvin-workaround

Alternative script for testing Bleichenbacher timing vulnerability

scripts/marvin-ciphertext-generator.py

@@ -0,0 +1,168 @@
+# Author: Hubert Kario, (c) 2021-2023
+# Released under Gnu GPL v2.0, see LICENSE file for details
+"""Bleichenbacher attack test for Marvin workaround."""
+from __future__ import print_function
+import sys
+import getopt
+import os
+from threading import Thread, Event
+
+from tlslite.x509 import X509
+from tlslite.utils.keyfactory import parsePEMKey
+from tlsfuzzer.utils.progress_report import progress_report
+from tlsfuzzer.utils.log import Log
+from tlsfuzzer.utils.rsa import MarvinCiphertextGenerator
+
+
+version = 5
+
+
+def help_msg():
+    """Print usage information."""
+    print("Usage: <script-name> ...]")
+    print(" -o dir         Specifies output directory for timing information")
+    print("                /tmp by default")
+    print(" --repeat rep   How many ciphertexts should be generated for each test")
+    print("                100 by default")
+    print(" --pms-len len  Generate ciphertexts that decrypt to specified")
+    print("                number of bytes, 48 by default.")
+    print(" --srv-key key  File with server private key.")
+    print(" --srv-cert crt File with server certificate.")
+    print(" --pms-tls-version ver Control the TLS version in the decrypted or")
+    print("                synthethic plaintext. If left undefined the script")
+    print("                will make sure not to generate message values that")
+    print("                start with values appropriate for SSLv3, TLS 1.0,")
+    print("                TLS 1.1, and TLS 1.2. If set, it should be a")
+    print("                hex-encoded integer representing two bytes to be")
+    print("                used as the version, e.g. \"0x0303\" for TLS 1.2")
+    print("                Note: using this option will significantly increase")
+    print("                the time to generate ciphertexts.")
+    print(" --probe-reuse num How many times to reuse a probe before generating")
+    print("                a new one. Low values will increase time to generate")
+    print("                probes while large values risk false positives caused")
+    print("                by ciphertext value. Set to 0 to never regenerate.")
+    print("                Default 1")
+    print(" --status-delay num How long to wait between status line updates.")
+    print("                In seconds. Default: 2.0")
+    print(" --help         this message")
+
+
+def main():
+    """Generate test ciphertexts for Marvin workaround."""
+    repetitions = 100
+    outdir = "/tmp"
+    pms_len = 48
+    srv_key = None
+    srv_cert = None
+    pms_tls_version = None
+    probe_reuse = 1
+    status_delay = 2.0
+
+    argv = sys.argv[1:]
+    opts, args = getopt.getopt(argv,
+                               "o:",
+                               ["help",
+                                "repeat=",
+                                "pms-len=",
+                                "srv-key=",
+                                "srv-cert=",
+                                "pms-tls-version=",
+                                "probe-reuse=",
+                                "status-delay="])
+    for opt, arg in opts:
+        if opt == '-o':
+            outdir = arg
+        elif opt == "--repeat":
+            repetitions = int(arg)
+        elif opt == "--pms-len":
+            pms_len = int(arg)
+        elif opt == "--srv-key":
+            with open(arg, "rb") as f:
+                text_key = f.read()
+            if sys.version_info[0] >= 3:
+                text_key = str(text_key, "utf-8")
+            srv_key = parsePEMKey(text_key, private=True)
+        elif opt == "--srv-cert":
+            with open(arg, "rb") as f:
+                text_cert = f.read()
+            if sys.version_info[0] >= 3:
+                text_cert = str(text_cert, "utf-8")
+            srv_cert = X509()
+            srv_cert.parse(text_cert)
+        elif opt == "--pms-tls-version":
+            int_ver = int(arg, 16)
+            pms_tls_version = divmod(int_ver, 256)
+        elif opt == "--probe-reuse":
+            probe_reuse = int(arg)
+        elif opt == "--status-delay":
+            status_delay = float(arg)
+        elif opt == '--help':
+            help_msg()
+            sys.exit(0)
+        else:
+            raise ValueError("Unknown option: {0}".format(opt))
+
+    if not srv_cert or not srv_key:
+        print("You must provide server private key and certificate")
+        sys.exit(1)
+
+    if args:
+        print("Unexpected arguments: {0}".format(args))
+        sys.exit(1)
+
+    print("Test generating ciphertexts...")
+    marvin_gen = MarvinCiphertextGenerator(
+        srv_key, srv_cert.publicKey, pms_len, pms_tls_version)
+    ciphertexts = marvin_gen.generate()
+    print("Test passed.")
+
+    print("Generating ciphertexts...")
+
+    with open(
+        os.path.join(outdir, 'pms_values.bin'),
+        "wb"
+    ) as pms_file:
+        # create a real order of tests to run
+        log = Log(os.path.join(outdir, "log.csv"))
+
+        log.start_log(ciphertexts.keys())
+        for _ in range(repetitions):
+            log.shuffle_new_run()
+        log.write()
+        log.read_log()
+        test_classes = log.get_classes()
+
+        status = [0, len(test_classes) * repetitions, Event()]
+        kwargs = dict()
+        kwargs['delay'] = status_delay
+        progress = Thread(target=progress_report, args=(status,),
+                          kwargs=kwargs)
+        progress.start()
+
+        exp_key_size = (len(srv_cert.publicKey) + 7) // 8
+
+        # generate the PMS values
+        try:
+            for executed, index in enumerate(log.iterate_log()):
+                if probe_reuse and \
+                        executed % (len(test_classes) * probe_reuse) == 0:
+                    ciphertexts = marvin_gen.generate()
+
+                status[0] = executed
+
+                g_name = test_classes[index]
+
+                res = ciphertexts[g_name]
+                assert len(res) == exp_key_size, len(res)
+
+                pms_file.write(res)
+        finally:
+            status[2].set()
+            progress.join()
+            print()
+
+    print("Done")
+
+
+if __name__ == "__main__":
+    main()