| /* |
| * Copyright 2013-2018 The OpenSSL Project Authors. All Rights Reserved. |
| * |
| * Licensed under the OpenSSL license (the "License"). You may not use |
| * this file except in compliance with the License. You can obtain a copy |
| * in the file LICENSE in the source distribution or at |
| * https://www.openssl.org/source/license.html |
| */ |
| |
| /** Beware! |
| * |
| * Following wrapping modes were designed for AES but this implementation |
| * allows you to use them for any 128 bit block cipher. |
| */ |
| |
| #include "internal/cryptlib.h" |
| #include <openssl/modes.h> |
| |
| /** RFC 3394 section 2.2.3.1 Default Initial Value */ |
| static const unsigned char default_iv[] = { |
| 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, |
| }; |
| |
| /** RFC 5649 section 3 Alternative Initial Value 32-bit constant */ |
| static const unsigned char default_aiv[] = { |
| 0xA6, 0x59, 0x59, 0xA6 |
| }; |
| |
| /** Input size limit: lower than maximum of standards but far larger than |
| * anything that will be used in practice. |
| */ |
| #define CRYPTO128_WRAP_MAX (1UL << 31) |
| |
| /** Wrapping according to RFC 3394 section 2.2.1. |
| * |
| * @param[in] key Key value. |
| * @param[in] iv IV value. Length = 8 bytes. NULL = use default_iv. |
| * @param[in] in Plaintext as n 64-bit blocks, n >= 2. |
| * @param[in] inlen Length of in. |
| * @param[out] out Ciphertext. Minimal buffer length = (inlen + 8) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] block Block processing function. |
| * @return 0 if inlen does not consist of n 64-bit blocks, n >= 2. |
| * or if inlen > CRYPTO128_WRAP_MAX. |
| * Output length if wrapping succeeded. |
| */ |
| size_t CRYPTO_128_wrap(void *key, const unsigned char *iv, |
| unsigned char *out, |
| const unsigned char *in, size_t inlen, |
| block128_f block) |
| { |
| unsigned char *A, B[16], *R; |
| size_t i, j, t; |
| if ((inlen & 0x7) || (inlen < 16) || (inlen > CRYPTO128_WRAP_MAX)) |
| return 0; |
| A = B; |
| t = 1; |
| memmove(out + 8, in, inlen); |
| if (!iv) |
| iv = default_iv; |
| |
| memcpy(A, iv, 8); |
| |
| for (j = 0; j < 6; j++) { |
| R = out + 8; |
| for (i = 0; i < inlen; i += 8, t++, R += 8) { |
| memcpy(B + 8, R, 8); |
| block(B, B, key); |
| A[7] ^= (unsigned char)(t & 0xff); |
| if (t > 0xff) { |
| A[6] ^= (unsigned char)((t >> 8) & 0xff); |
| A[5] ^= (unsigned char)((t >> 16) & 0xff); |
| A[4] ^= (unsigned char)((t >> 24) & 0xff); |
| } |
| memcpy(R, B + 8, 8); |
| } |
| } |
| memcpy(out, A, 8); |
| return inlen + 8; |
| } |
| |
| /** Unwrapping according to RFC 3394 section 2.2.2 steps 1-2. |
| * The IV check (step 3) is responsibility of the caller. |
| * |
| * @param[in] key Key value. |
| * @param[out] iv Unchecked IV value. Minimal buffer length = 8 bytes. |
| * @param[out] out Plaintext without IV. |
| * Minimal buffer length = (inlen - 8) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Ciphertext as n 64-bit blocks. |
| * @param[in] inlen Length of in. |
| * @param[in] block Block processing function. |
| * @return 0 if inlen is out of range [24, CRYPTO128_WRAP_MAX] |
| * or if inlen is not a multiple of 8. |
| * Output length otherwise. |
| */ |
| static size_t crypto_128_unwrap_raw(void *key, unsigned char *iv, |
| unsigned char *out, |
| const unsigned char *in, size_t inlen, |
| block128_f block) |
| { |
| unsigned char *A, B[16], *R; |
| size_t i, j, t; |
| inlen -= 8; |
| if ((inlen & 0x7) || (inlen < 16) || (inlen > CRYPTO128_WRAP_MAX)) |
| return 0; |
| A = B; |
| t = 6 * (inlen >> 3); |
| memcpy(A, in, 8); |
| memmove(out, in + 8, inlen); |
| for (j = 0; j < 6; j++) { |
| R = out + inlen - 8; |
| for (i = 0; i < inlen; i += 8, t--, R -= 8) { |
| A[7] ^= (unsigned char)(t & 0xff); |
| if (t > 0xff) { |
| A[6] ^= (unsigned char)((t >> 8) & 0xff); |
| A[5] ^= (unsigned char)((t >> 16) & 0xff); |
| A[4] ^= (unsigned char)((t >> 24) & 0xff); |
| } |
| memcpy(B + 8, R, 8); |
| block(B, B, key); |
| memcpy(R, B + 8, 8); |
| } |
| } |
| memcpy(iv, A, 8); |
| return inlen; |
| } |
| |
| /** Unwrapping according to RFC 3394 section 2.2.2, including the IV check. |
| * The first block of plaintext has to match the supplied IV, otherwise an |
| * error is returned. |
| * |
| * @param[in] key Key value. |
| * @param[out] iv IV value to match against. Length = 8 bytes. |
| * NULL = use default_iv. |
| * @param[out] out Plaintext without IV. |
| * Minimal buffer length = (inlen - 8) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Ciphertext as n 64-bit blocks. |
| * @param[in] inlen Length of in. |
| * @param[in] block Block processing function. |
| * @return 0 if inlen is out of range [24, CRYPTO128_WRAP_MAX] |
| * or if inlen is not a multiple of 8 |
| * or if IV doesn't match expected value. |
| * Output length otherwise. |
| */ |
| size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv, |
| unsigned char *out, const unsigned char *in, |
| size_t inlen, block128_f block) |
| { |
| size_t ret; |
| unsigned char got_iv[8]; |
| |
| ret = crypto_128_unwrap_raw(key, got_iv, out, in, inlen, block); |
| if (ret == 0) |
| return 0; |
| |
| if (!iv) |
| iv = default_iv; |
| if (CRYPTO_memcmp(got_iv, iv, 8)) { |
| OPENSSL_cleanse(out, ret); |
| return 0; |
| } |
| return ret; |
| } |
| |
| /** Wrapping according to RFC 5649 section 4.1. |
| * |
| * @param[in] key Key value. |
| * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv. |
| * @param[out] out Ciphertext. Minimal buffer length = (inlen + 15) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Plaintext as n 64-bit blocks, n >= 2. |
| * @param[in] inlen Length of in. |
| * @param[in] block Block processing function. |
| * @return 0 if inlen is out of range [1, CRYPTO128_WRAP_MAX]. |
| * Output length if wrapping succeeded. |
| */ |
| size_t CRYPTO_128_wrap_pad(void *key, const unsigned char *icv, |
| unsigned char *out, |
| const unsigned char *in, size_t inlen, |
| block128_f block) |
| { |
| /* n: number of 64-bit blocks in the padded key data |
| * |
| * If length of plain text is not a multiple of 8, pad the plain text octet |
| * string on the right with octets of zeros, where final length is the |
| * smallest multiple of 8 that is greater than length of plain text. |
| * If length of plain text is a multiple of 8, then there is no padding. */ |
| const size_t blocks_padded = (inlen + 7) / 8; /* CEILING(m/8) */ |
| const size_t padded_len = blocks_padded * 8; |
| const size_t padding_len = padded_len - inlen; |
| /* RFC 5649 section 3: Alternative Initial Value */ |
| unsigned char aiv[8]; |
| int ret; |
| |
| /* Section 1: use 32-bit fixed field for plaintext octet length */ |
| if (inlen == 0 || inlen >= CRYPTO128_WRAP_MAX) |
| return 0; |
| |
| /* Section 3: Alternative Initial Value */ |
| if (!icv) |
| memcpy(aiv, default_aiv, 4); |
| else |
| memcpy(aiv, icv, 4); /* Standard doesn't mention this. */ |
| |
| aiv[4] = (inlen >> 24) & 0xFF; |
| aiv[5] = (inlen >> 16) & 0xFF; |
| aiv[6] = (inlen >> 8) & 0xFF; |
| aiv[7] = inlen & 0xFF; |
| |
| if (padded_len == 8) { |
| /* |
| * Section 4.1 - special case in step 2: If the padded plaintext |
| * contains exactly eight octets, then prepend the AIV and encrypt |
| * the resulting 128-bit block using AES in ECB mode. |
| */ |
| memmove(out + 8, in, inlen); |
| memcpy(out, aiv, 8); |
| memset(out + 8 + inlen, 0, padding_len); |
| block(out, out, key); |
| ret = 16; /* AIV + padded input */ |
| } else { |
| memmove(out, in, inlen); |
| memset(out + inlen, 0, padding_len); /* Section 4.1 step 1 */ |
| ret = CRYPTO_128_wrap(key, aiv, out, out, padded_len, block); |
| } |
| |
| return ret; |
| } |
| |
| /** Unwrapping according to RFC 5649 section 4.2. |
| * |
| * @param[in] key Key value. |
| * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv. |
| * @param[out] out Plaintext. Minimal buffer length = (inlen - 8) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Ciphertext as n 64-bit blocks. |
| * @param[in] inlen Length of in. |
| * @param[in] block Block processing function. |
| * @return 0 if inlen is out of range [16, CRYPTO128_WRAP_MAX], |
| * or if inlen is not a multiple of 8 |
| * or if IV and message length indicator doesn't match. |
| * Output length if unwrapping succeeded and IV matches. |
| */ |
| size_t CRYPTO_128_unwrap_pad(void *key, const unsigned char *icv, |
| unsigned char *out, |
| const unsigned char *in, size_t inlen, |
| block128_f block) |
| { |
| /* n: number of 64-bit blocks in the padded key data */ |
| size_t n = inlen / 8 - 1; |
| size_t padded_len; |
| size_t padding_len; |
| size_t ptext_len; |
| /* RFC 5649 section 3: Alternative Initial Value */ |
| unsigned char aiv[8]; |
| static unsigned char zeros[8] = { 0x0 }; |
| size_t ret; |
| |
| /* Section 4.2: Ciphertext length has to be (n+1) 64-bit blocks. */ |
| if ((inlen & 0x7) != 0 || inlen < 16 || inlen >= CRYPTO128_WRAP_MAX) |
| return 0; |
| |
| if (inlen == 16) { |
| /* |
| * Section 4.2 - special case in step 1: When n=1, the ciphertext |
| * contains exactly two 64-bit blocks and they are decrypted as a |
| * single AES block using AES in ECB mode: AIV | P[1] = DEC(K, C[0] | |
| * C[1]) |
| */ |
| unsigned char buff[16]; |
| |
| block(in, buff, key); |
| memcpy(aiv, buff, 8); |
| /* Remove AIV */ |
| memcpy(out, buff + 8, 8); |
| padded_len = 8; |
| OPENSSL_cleanse(buff, inlen); |
| } else { |
| padded_len = inlen - 8; |
| ret = crypto_128_unwrap_raw(key, aiv, out, in, inlen, block); |
| if (padded_len != ret) { |
| OPENSSL_cleanse(out, inlen); |
| return 0; |
| } |
| } |
| |
| /* |
| * Section 3: AIV checks: Check that MSB(32,A) = A65959A6. Optionally a |
| * user-supplied value can be used (even if standard doesn't mention |
| * this). |
| */ |
| if ((!icv && CRYPTO_memcmp(aiv, default_aiv, 4)) |
| || (icv && CRYPTO_memcmp(aiv, icv, 4))) { |
| OPENSSL_cleanse(out, inlen); |
| return 0; |
| } |
| |
| /* |
| * Check that 8*(n-1) < LSB(32,AIV) <= 8*n. If so, let ptext_len = |
| * LSB(32,AIV). |
| */ |
| |
| ptext_len = ((unsigned int)aiv[4] << 24) |
| | ((unsigned int)aiv[5] << 16) |
| | ((unsigned int)aiv[6] << 8) |
| | (unsigned int)aiv[7]; |
| if (8 * (n - 1) >= ptext_len || ptext_len > 8 * n) { |
| OPENSSL_cleanse(out, inlen); |
| return 0; |
| } |
| |
| /* |
| * Check that the rightmost padding_len octets of the output data are |
| * zero. |
| */ |
| padding_len = padded_len - ptext_len; |
| if (CRYPTO_memcmp(out + ptext_len, zeros, padding_len) != 0) { |
| OPENSSL_cleanse(out, inlen); |
| return 0; |
| } |
| |
| /* Section 4.2 step 3: Remove padding */ |
| return ptext_len; |
| } |
