| /* crypto/modes/wrap128.c */ |
| /* |
| * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL |
| * project. Mode with padding contributed by Petr Spacek |
| * (pspacek@redhat.com). |
| */ |
| /* ==================================================================== |
| * Copyright (c) 2013 The OpenSSL Project. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. All advertising materials mentioning features or use of this |
| * software must display the following acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" |
| * |
| * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to |
| * endorse or promote products derived from this software without |
| * prior written permission. For written permission, please contact |
| * licensing@OpenSSL.org. |
| * |
| * 5. Products derived from this software may not be called "OpenSSL" |
| * nor may "OpenSSL" appear in their names without prior written |
| * permission of the OpenSSL Project. |
| * |
| * 6. Redistributions of any form whatsoever must retain the following |
| * acknowledgment: |
| * "This product includes software developed by the OpenSSL Project |
| * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY |
| * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * ==================================================================== |
| */ |
| |
| /** Beware! |
| * |
| * Following wrapping modes were designed for AES but this implementation |
| * allows you to use them for any 128 bit block cipher. |
| */ |
| |
| #include "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 Plain text as n 64-bit blocks, n >= 2. |
| * @param[in] inlen Length of in. |
| * @param[out] out Cipher text. 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. |
| * 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 Plain text without IV. |
| * Minimal buffer length = (inlen - 8) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Ciphertext text 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 multiply 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 IV check. |
| * First block of plain text have to match supplied IV otherwise an error is |
| * returned. |
| * |
| * @param[in] key Key value. |
| * @param[out] iv Unchecked IV value. Minimal buffer length = 8 bytes. |
| * @param[out] out Plain text without IV. |
| * Minimal buffer length = (inlen - 8) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Ciphertext text 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 multiply 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 != inlen) |
| return ret; |
| |
| if (!iv) |
| iv = default_iv; |
| if (CRYPTO_memcmp(out, iv, 8)) { |
| OPENSSL_cleanse(out, inlen); |
| return 0; |
| } |
| return inlen; |
| } |
| |
| /** 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 Cipher text. Minimal buffer length = (inlen + 15) bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Plain text 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 */ |
| const size_t blocks_padded = (inlen + 8) / 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 Plain text. Minimal buffer length = inlen bytes. |
| * Input and output buffers can overlap if block function |
| * supports that. |
| * @param[in] in Ciphertext text 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 multiply 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: Cipher text length has to be (n+1) 64-bit blocks. */ |
| if ((inlen & 0x7) != 0 || inlen < 16 || inlen >= CRYPTO128_WRAP_MAX) |
| return 0; |
| |
| memmove(out, in, inlen); |
| 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]) |
| */ |
| block(out, out, key); |
| memcpy(aiv, out, 8); |
| /* Remove AIV */ |
| memmove(out, out + 8, 8); |
| padded_len = 8; |
| } else { |
| padded_len = inlen - 8; |
| ret = crypto_128_unwrap_raw(key, aiv, out, out, 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 = (aiv[4] << 24) | (aiv[5] << 16) | (aiv[6] << 8) | 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; |
| } |
