2 * Copyright 2013-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
12 * Following wrapping modes were designed for AES but this implementation
13 * allows you to use them for any 128 bit block cipher.
16 #include "internal/cryptlib.h"
17 #include <openssl/modes.h>
19 /** RFC 3394 section 2.2.3.1 Default Initial Value */
20 static const unsigned char default_iv[] = {
21 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6, 0xA6,
24 /** RFC 5649 section 3 Alternative Initial Value 32-bit constant */
25 static const unsigned char default_aiv[] = {
26 0xA6, 0x59, 0x59, 0xA6
29 /** Input size limit: lower than maximum of standards but far larger than
30 * anything that will be used in practice.
32 #define CRYPTO128_WRAP_MAX (1UL << 31)
34 /** Wrapping according to RFC 3394 section 2.2.1.
36 * @param[in] key Key value.
37 * @param[in] iv IV value. Length = 8 bytes. NULL = use default_iv.
38 * @param[in] in Plaintext as n 64-bit blocks, n >= 2.
39 * @param[in] inlen Length of in.
40 * @param[out] out Ciphertext. Minimal buffer length = (inlen + 8) bytes.
41 * Input and output buffers can overlap if block function
43 * @param[in] block Block processing function.
44 * @return 0 if inlen does not consist of n 64-bit blocks, n >= 2.
45 * or if inlen > CRYPTO128_WRAP_MAX.
46 * Output length if wrapping succeeded.
48 size_t CRYPTO_128_wrap(void *key, const unsigned char *iv,
50 const unsigned char *in, size_t inlen,
53 unsigned char *A, B[16], *R;
55 if ((inlen & 0x7) || (inlen < 16) || (inlen > CRYPTO128_WRAP_MAX))
59 memmove(out + 8, in, inlen);
65 for (j = 0; j < 6; j++) {
67 for (i = 0; i < inlen; i += 8, t++, R += 8) {
70 A[7] ^= (unsigned char)(t & 0xff);
72 A[6] ^= (unsigned char)((t >> 8) & 0xff);
73 A[5] ^= (unsigned char)((t >> 16) & 0xff);
74 A[4] ^= (unsigned char)((t >> 24) & 0xff);
83 /** Unwrapping according to RFC 3394 section 2.2.2 steps 1-2.
84 * The IV check (step 3) is responsibility of the caller.
86 * @param[in] key Key value.
87 * @param[out] iv Unchecked IV value. Minimal buffer length = 8 bytes.
88 * @param[out] out Plaintext without IV.
89 * Minimal buffer length = (inlen - 8) bytes.
90 * Input and output buffers can overlap if block function
92 * @param[in] in Ciphertext as n 64-bit blocks.
93 * @param[in] inlen Length of in.
94 * @param[in] block Block processing function.
95 * @return 0 if inlen is out of range [24, CRYPTO128_WRAP_MAX]
96 * or if inlen is not a multiple of 8.
97 * Output length otherwise.
99 static size_t crypto_128_unwrap_raw(void *key, unsigned char *iv,
101 const unsigned char *in, size_t inlen,
104 unsigned char *A, B[16], *R;
107 if ((inlen & 0x7) || (inlen < 16) || (inlen > CRYPTO128_WRAP_MAX))
110 t = 6 * (inlen >> 3);
112 memmove(out, in + 8, inlen);
113 for (j = 0; j < 6; j++) {
115 for (i = 0; i < inlen; i += 8, t--, R -= 8) {
116 A[7] ^= (unsigned char)(t & 0xff);
118 A[6] ^= (unsigned char)((t >> 8) & 0xff);
119 A[5] ^= (unsigned char)((t >> 16) & 0xff);
120 A[4] ^= (unsigned char)((t >> 24) & 0xff);
131 /** Unwrapping according to RFC 3394 section 2.2.2, including the IV check.
132 * The first block of plaintext has to match the supplied IV, otherwise an
135 * @param[in] key Key value.
136 * @param[out] iv IV value to match against. Length = 8 bytes.
137 * NULL = use default_iv.
138 * @param[out] out Plaintext without IV.
139 * Minimal buffer length = (inlen - 8) bytes.
140 * Input and output buffers can overlap if block function
142 * @param[in] in Ciphertext as n 64-bit blocks.
143 * @param[in] inlen Length of in.
144 * @param[in] block Block processing function.
145 * @return 0 if inlen is out of range [24, CRYPTO128_WRAP_MAX]
146 * or if inlen is not a multiple of 8
147 * or if IV doesn't match expected value.
148 * Output length otherwise.
150 size_t CRYPTO_128_unwrap(void *key, const unsigned char *iv,
151 unsigned char *out, const unsigned char *in,
152 size_t inlen, block128_f block)
155 unsigned char got_iv[8];
157 ret = crypto_128_unwrap_raw(key, got_iv, out, in, inlen, block);
163 if (CRYPTO_memcmp(got_iv, iv, 8)) {
164 OPENSSL_cleanse(out, ret);
170 /** Wrapping according to RFC 5649 section 4.1.
172 * @param[in] key Key value.
173 * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv.
174 * @param[out] out Ciphertext. Minimal buffer length = (inlen + 15) bytes.
175 * Input and output buffers can overlap if block function
177 * @param[in] in Plaintext as n 64-bit blocks, n >= 2.
178 * @param[in] inlen Length of in.
179 * @param[in] block Block processing function.
180 * @return 0 if inlen is out of range [1, CRYPTO128_WRAP_MAX].
181 * Output length if wrapping succeeded.
183 size_t CRYPTO_128_wrap_pad(void *key, const unsigned char *icv,
185 const unsigned char *in, size_t inlen,
188 /* n: number of 64-bit blocks in the padded key data
190 * If length of plain text is not a multiple of 8, pad the plain text octet
191 * string on the right with octets of zeros, where final length is the
192 * smallest multiple of 8 that is greater than length of plain text.
193 * If length of plain text is a multiple of 8, then there is no padding. */
194 const size_t blocks_padded = (inlen + 7) / 8; /* CEILING(m/8) */
195 const size_t padded_len = blocks_padded * 8;
196 const size_t padding_len = padded_len - inlen;
197 /* RFC 5649 section 3: Alternative Initial Value */
198 unsigned char aiv[8];
201 /* Section 1: use 32-bit fixed field for plaintext octet length */
202 if (inlen == 0 || inlen >= CRYPTO128_WRAP_MAX)
205 /* Section 3: Alternative Initial Value */
207 memcpy(aiv, default_aiv, 4);
209 memcpy(aiv, icv, 4); /* Standard doesn't mention this. */
211 aiv[4] = (inlen >> 24) & 0xFF;
212 aiv[5] = (inlen >> 16) & 0xFF;
213 aiv[6] = (inlen >> 8) & 0xFF;
214 aiv[7] = inlen & 0xFF;
216 if (padded_len == 8) {
218 * Section 4.1 - special case in step 2: If the padded plaintext
219 * contains exactly eight octets, then prepend the AIV and encrypt
220 * the resulting 128-bit block using AES in ECB mode.
222 memmove(out + 8, in, inlen);
224 memset(out + 8 + inlen, 0, padding_len);
225 block(out, out, key);
226 ret = 16; /* AIV + padded input */
228 memmove(out, in, inlen);
229 memset(out + inlen, 0, padding_len); /* Section 4.1 step 1 */
230 ret = CRYPTO_128_wrap(key, aiv, out, out, padded_len, block);
236 /** Unwrapping according to RFC 5649 section 4.2.
238 * @param[in] key Key value.
239 * @param[in] icv (Non-standard) IV, 4 bytes. NULL = use default_aiv.
240 * @param[out] out Plaintext. Minimal buffer length = inlen bytes.
241 * Input and output buffers can overlap if block function
243 * @param[in] in Ciphertext as n 64-bit blocks.
244 * @param[in] inlen Length of in.
245 * @param[in] block Block processing function.
246 * @return 0 if inlen is out of range [16, CRYPTO128_WRAP_MAX],
247 * or if inlen is not a multiple of 8
248 * or if IV and message length indicator doesn't match.
249 * Output length if unwrapping succeeded and IV matches.
251 size_t CRYPTO_128_unwrap_pad(void *key, const unsigned char *icv,
253 const unsigned char *in, size_t inlen,
256 /* n: number of 64-bit blocks in the padded key data */
257 size_t n = inlen / 8 - 1;
261 /* RFC 5649 section 3: Alternative Initial Value */
262 unsigned char aiv[8];
263 static unsigned char zeros[8] = { 0x0 };
266 /* Section 4.2: Ciphertext length has to be (n+1) 64-bit blocks. */
267 if ((inlen & 0x7) != 0 || inlen < 16 || inlen >= CRYPTO128_WRAP_MAX)
270 memmove(out, in, inlen);
273 * Section 4.2 - special case in step 1: When n=1, the ciphertext
274 * contains exactly two 64-bit blocks and they are decrypted as a
275 * single AES block using AES in ECB mode: AIV | P[1] = DEC(K, C[0] |
278 block(out, out, key);
281 memmove(out, out + 8, 8);
284 padded_len = inlen - 8;
285 ret = crypto_128_unwrap_raw(key, aiv, out, out, inlen, block);
286 if (padded_len != ret) {
287 OPENSSL_cleanse(out, inlen);
293 * Section 3: AIV checks: Check that MSB(32,A) = A65959A6. Optionally a
294 * user-supplied value can be used (even if standard doesn't mention
297 if ((!icv && CRYPTO_memcmp(aiv, default_aiv, 4))
298 || (icv && CRYPTO_memcmp(aiv, icv, 4))) {
299 OPENSSL_cleanse(out, inlen);
304 * Check that 8*(n-1) < LSB(32,AIV) <= 8*n. If so, let ptext_len =
308 ptext_len = ((unsigned int)aiv[4] << 24)
309 | ((unsigned int)aiv[5] << 16)
310 | ((unsigned int)aiv[6] << 8)
311 | (unsigned int)aiv[7];
312 if (8 * (n - 1) >= ptext_len || ptext_len > 8 * n) {
313 OPENSSL_cleanse(out, inlen);
318 * Check that the rightmost padding_len octets of the output data are
321 padding_len = padded_len - ptext_len;
322 if (CRYPTO_memcmp(out + ptext_len, zeros, padding_len) != 0) {
323 OPENSSL_cleanse(out, inlen);
327 /* Section 4.2 step 3: Remove padding */