112 lines
3.2 KiB
Python
112 lines
3.2 KiB
Python
#!/usr/bin/env python3
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"""PBKDF2 helper utilities for hashing and verifying passwords."""
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from __future__ import annotations
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import argparse
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import base64
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import binascii
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import hashlib
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import hmac
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import os
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import sys
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from typing import Sequence
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DEFAULT_SALT_BYTES = 16
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DEFAULT_ITERATIONS = int(os.environ.get("PBKDF2_ITERATIONS", "200000"))
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def hash_password(
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password: str,
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*,
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iterations: int | None = None,
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salt_bytes: int = DEFAULT_SALT_BYTES,
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) -> tuple[str, str]:
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"""Return a base64 encoded salt and hash for ``password``."""
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iterations = iterations or DEFAULT_ITERATIONS
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salt = os.urandom(salt_bytes)
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derived = hashlib.pbkdf2_hmac(
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"sha256",
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password.encode("utf-8"),
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salt,
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iterations,
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)
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return (
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base64.b64encode(salt).decode("utf-8"),
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base64.b64encode(derived).decode("utf-8"),
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)
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def verify_password(
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password: str,
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salt_b64: str,
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hash_b64: str,
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*,
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iterations: int | None = None,
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) -> bool:
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"""Validate ``password`` against the provided base64 salt + hash pair."""
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iterations = iterations or DEFAULT_ITERATIONS
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try:
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salt = base64.b64decode(salt_b64, validate=True)
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stored_hash = base64.b64decode(hash_b64, validate=True)
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except (binascii.Error, ValueError):
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return False
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derived = hashlib.pbkdf2_hmac(
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"sha256",
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password.encode("utf-8"),
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salt,
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iterations,
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)
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return hmac.compare_digest(derived, stored_hash)
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def _build_parser() -> argparse.ArgumentParser:
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parser = argparse.ArgumentParser(
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description="Erstellt sichere PBKDF2-Hashes oder verifiziert bestehende Werte."
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)
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subparsers = parser.add_subparsers(dest="command")
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hash_parser = subparsers.add_parser(
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"hash", help="Erstellt ein Salt und einen Hash für ein Passwort."
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)
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hash_parser.add_argument("password", help="Klartext-Passwort zum Hashen.")
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verify_parser = subparsers.add_parser("verify", help="Überprüft ein Passwort.")
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verify_parser.add_argument("password", help="Klartext-Passwort zur Überprüfung.")
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verify_parser.add_argument("salt", help="Base64-kodiertes Salt.")
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verify_parser.add_argument("hash", help="Base64-kodierter Hash.")
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return parser
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def _normalize_args(argv: Sequence[str] | None) -> list[str]:
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"""Erlaube ``python3 salt.py <passwort>`` als Abkürzung für ``hash``."""
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if not argv:
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return []
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if argv[0] in {"hash", "verify"} or argv[0].startswith("-"):
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return list(argv)
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return ["hash", *argv]
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def main(argv: Sequence[str] | None = None) -> int:
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parser = _build_parser()
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arg_list = list(argv) if argv is not None else sys.argv[1:]
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args = parser.parse_args(_normalize_args(arg_list))
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if args.command == "verify":
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if verify_password(args.password, args.salt, args.hash):
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print("✓ Passwort korrekt")
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return 0
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print("✗ Passwort falsch")
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return 1
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if args.command != "hash":
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parser.error('Bitte einen Hash generieren oder "verify" verwenden.')
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salt, hash_value = hash_password(args.password)
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print(f"Salt: {salt}")
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print(f"Hash: {hash_value}")
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return 0
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if __name__ == "__main__":
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raise SystemExit(main())
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