mbedtls

mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2026-05-05 01:23:39 +02:00

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Gilles Peskine 5ee94d52a6 More variety of CBC decrypt tests

Have tests without padding, with valid PKCS7 padding and with several kinds
of invalid PKCS7 padding.

    #!/usr/bin/env python3
    from Crypto.Cipher import AES

    KEYS = {
        128: bytes.fromhex("ffffffffe00000000000000000000000"),
        192: bytes.fromhex("000000000000000000000000000000000000000000000000"),
        256: bytes.fromhex("0000000000000000000000000000000000000000000000000000000000000000"),
    }
    IV = bytes.fromhex("00000000000000000000000000000000")

    def decrypt_test_vec(cf, bits, mode, padded_hex, padding_length, note=''):
        depends = ['MBEDTLS_AES_C', 'MBEDTLS_CIPHER_MODE_CBC']
        plaintext = bytes.fromhex(padded_hex)
        plaintext_length = len(plaintext)
        if bits != 128:
            depends.append('!MBEDTLS_AES_ONLY_128_BIT_KEY_LENGTH')
        key = KEYS[bits]
        iv = IV
        result = '0'
        if mode == 'NONE':
            padding_description = 'no padding'
            assert padding_length == 0
        else:
            depends.append('MBEDTLS_CIPHER_PADDING_' + mode)
            padding_description = mode
            if padding_length is None:
                result = 'MBEDTLS_ERR_CIPHER_INVALID_PADDING'
                plaintext_length = 0
            else:
                plaintext_length -= padding_length
        cipher = AES.new(key, AES.MODE_CBC, iv=iv)
        ciphertext = cipher.encrypt(plaintext)
        function = 'decrypt_test_vec'
        cf_maybe = ''
        if cf:
            function += '_cf'
            cf_maybe = 'CF '
            depends.append('HAVE_CONSTANT_TIME_AES')
        if note:
            note = f' ({note})'
        print(f'''\
    {cf_maybe}AES-{bits}-CBC Decrypt test vector, {padding_description}{note}
    depends_on:{':'.join(depends)}
    {function}:MBEDTLS_CIPHER_AES_{bits}_CBC:MBEDTLS_PADDING_{mode}:"{key.hex()}":"{iv.hex()}":"{ciphertext.hex()}":"{plaintext[:plaintext_length].hex()}":"":"":{result}:0
    ''')

    def emit_tests(cf):
        # Already existing tests
        decrypt_test_vec(cf, 128, 'NONE', "00000000000000000000000000000000", 0)
        decrypt_test_vec(cf, 192, 'NONE', "fffffffff80000000000000000000000", 0)
        decrypt_test_vec(cf, 256, 'NONE', "ff000000000000000000000000000000", 0)

        # New tests
        decrypt_test_vec(cf, 128, 'PKCS7', "00000000000000000000000000000001", 1, 'good pad 1')
        decrypt_test_vec(cf, 192, 'PKCS7', "fffffffff80000000000000000000001", 1, 'good pad 1')
        decrypt_test_vec(cf, 256, 'PKCS7', "ff000000000000000000000000000001", 1, 'good pad 1')
        decrypt_test_vec(cf, 128, 'PKCS7', "00000000000000000000000000000202", 2, 'good pad 2')
        decrypt_test_vec(cf, 192, 'PKCS7', "fffffffff80000000000000000000202", 2, 'good pad 2')
        decrypt_test_vec(cf, 256, 'PKCS7', "ff000000000000000000000000000202", 2, 'good pad 2')
        decrypt_test_vec(cf, 128, 'PKCS7', "2a0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f", 15, 'good pad 15')
        decrypt_test_vec(cf, 192, 'PKCS7', "2a0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f", 15, 'good pad 15')
        decrypt_test_vec(cf, 256, 'PKCS7', "2a0f0f0f0f0f0f0f0f0f0f0f0f0f0f0f", 15, 'good pad 15')
        decrypt_test_vec(cf, 128, 'PKCS7', "10101010101010101010101010101010", 16, 'good pad 16')
        decrypt_test_vec(cf, 192, 'PKCS7', "10101010101010101010101010101010", 16, 'good pad 16')
        decrypt_test_vec(cf, 256, 'PKCS7', "10101010101010101010101010101010", 16, 'good pad 16')
        decrypt_test_vec(cf, 128, 'PKCS7', "00000000000000000000000000000000", None, 'bad pad 0')
        decrypt_test_vec(cf, 192, 'PKCS7', "fffffffff80000000000000000000000", None, 'bad pad 0')
        decrypt_test_vec(cf, 256, 'PKCS7', "ff000000000000000000000000000000", None, 'bad pad 0')
        decrypt_test_vec(cf, 128, 'PKCS7', "00000000000000000000000000000102", None, 'bad pad 0102')
        decrypt_test_vec(cf, 192, 'PKCS7', "fffffffff80000000000000000000102", None, 'bad pad 0102')
        decrypt_test_vec(cf, 256, 'PKCS7', "ff000000000000000000000000000102", None, 'bad pad 0102')
        decrypt_test_vec(cf, 128, 'PKCS7', "1111111111111111111111111111111111111111111111111111111111111111", None, 'long, bad pad 17')
        decrypt_test_vec(cf, 192, 'PKCS7', "1111111111111111111111111111111111111111111111111111111111111111", None, 'long, bad pad 17')
        decrypt_test_vec(cf, 256, 'PKCS7', "1111111111111111111111111111111111111111111111111111111111111111", None, 'long, bad pad 17')
        decrypt_test_vec(cf, 128, 'PKCS7', "11111111111111111111111111111111", None, 'short, bad pad 17')
        decrypt_test_vec(cf, 192, 'PKCS7', "11111111111111111111111111111111", None, 'short, bad pad 17')
        decrypt_test_vec(cf, 256, 'PKCS7', "11111111111111111111111111111111", None, 'short, bad pad 17')

    emit_tests(False)

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

2025-08-08 15:14:47 +02:00