pse2john: port script to Python 3 and handle multiple PSE files

run/pse2john.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 
 """pysap - Python library for crafting SAP's network protocols packets"""
 
@@ -19,52 +19,93 @@
 # details.
 
 # Standard imports
-import os
-import sys
+from argparse import ArgumentParser
 from binascii import hexlify
+from os import path
+from sys import stderr, stdout
 
 # Custom imports
-from pysap.SAPPSE import (SAPPSEFile, PKCS12_ALGORITHM_PBE1_SHA_3DES_CBC)
-
-
-def parse_pse(filename):
-    """Parses a PSE file and produces a JtR compatible hash"""
-    with open(filename, "rb") as fp:
-        data = fp.read()
-
-    pse_file = SAPPSEFile(data)
-
-    if pse_file.enc_cont.algorithm_identifier.alg_id == PKCS12_ALGORITHM_PBE1_SHA_3DES_CBC:
-        pbe_algo = 1
-        salt = hexlify(pse_file.enc_cont.algorithm_identifier.parameters.salt.val)
-        salt_size = len(pse_file.enc_cont.algorithm_identifier.parameters.salt.val)
-        iterations = pse_file.enc_cont.algorithm_identifier.parameters.iterations.val
-        iv = ""
-        iv_size = len(iv)
+try:
+    import pysap
+    from pysap.SAPPSE import (SAPPSEFile, PKCS12_ALGORITHM_PBE1_SHA_3DES_CBC)
+except ImportError:
+    stderr.write("pysap is missing, run 'pip install --user pysap' to install it!\n")
+    raise SystemExit(1)
+
+
+def parse_options(argv=None):
+    """Parse command line options."""
+    description = ("This script can be used to parse PSE files and extract "
+                   "encrypted material and data in a format that John the "
+                   "Ripper or other cracking tools can use to look for the "
+                   "decryption PIN.")
+
+    parser = ArgumentParser(
+        usage="%(prog)s <input_file>", description=description,
+        epilog=pysap.epilog)
+    parser.add_argument(
+        "-o", "--output", help="Filename to write the output to [stdout]")
+    parser.add_argument(
+        "input_files", metavar="input_file", nargs="+",
+        help="PSE file to parse")
+    return parser.parse_args(argv)
+
+
+def process_file(filename, output_file=stdout, error_file=stderr):
+    """Process a PSE file and write John the Ripper material if supported."""
+    try:
+        with open(filename, "rb") as fp:
+            data = fp.read()
+
+        pse_file = SAPPSEFile(data)
+
+        if not pse_file.is_encrypted():
+            raise Exception("PSE file is already unencrypted")
+
+        if pse_file.enc_cont.algorithm_identifier.alg_id == \
+                PKCS12_ALGORITHM_PBE1_SHA_3DES_CBC:
+            pbe_algo = 1
+            salt = hexlify(
+                pse_file.enc_cont.algorithm_identifier.parameters.salt.val
+            ).decode("ascii")
+            salt_size = len(
+                pse_file.enc_cont.algorithm_identifier.parameters.salt.val)
+            iterations = pse_file.enc_cont.algorithm_identifier.parameters.iterations.val
+            iv = ""
+            iv_size = len(iv)
+        else:
+            raise Exception("Unsupported encryption algorithm")
+
+        encrypted_pin = hexlify(pse_file.enc_cont.encrypted_pin.val).decode("ascii")
+        encrypted_pin_length = len(pse_file.enc_cont.encrypted_pin.val)
+    except Exception as e:
+        error_file.write("{}: {}\n".format(filename, e))
+        return False
+
+    output_file.write(
+        "{}:$pse${}${}${}${}${}${}${}${}:::::\n".format(
+            path.basename(filename), pbe_algo, iterations, salt_size, salt,
+            iv_size, iv, encrypted_pin_length, encrypted_pin))
+    return True
+
+
+def main(argv=None):
+    options = parse_options(argv)
+
+    if options.output:
+        output_file = open(options.output, "w")
     else:
-        raise Exception("Unsupported encryption algorithm")
+        output_file = stdout
 
-    encrypted_pin = hexlify(pse_file.enc_cont.encrypted_pin.val)
-    encrypted_pin_length = len(pse_file.enc_cont.encrypted_pin.val)
+    try:
+        for input_file in options.input_files:
+            process_file(input_file, output_file)
+    finally:
+        if options.output:
+            output_file.close()
 
-    return "{}:$pse${}${}${}${}${}${}${}${}:::::\n".format(os.path.basename(filename),
-            pbe_algo, iterations, salt_size, salt, iv_size, iv,
-            encrypted_pin_length, encrypted_pin)
+    return 0
 
 
 if __name__ == "__main__":
-    DESCRIPTION = """This script can be used to parse PSE files and extract encrypted material and
-data in a format that John the Ripper or other cracking tools can use to look
-for the decryption PIN.\n"""
-
-
-    USAGE = "Usage: %s <.pse file(s)>\n"
-
-    if len(sys.argv) < 2:
-        sys.stderr.write("%s\n" % DESCRIPTION)
-        sys.stderr.write(USAGE % sys.argv[0])
-        sys.exit(1)
-
-    for i in range(1, len(sys.argv)):
-        line = parse_pse(sys.argv[i])
-        sys.stdout.write(line)
+    raise SystemExit(main())