1/*
2 * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
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
8 */
9
10#include <string.h>
11#include <stdlib.h>
12#include <openssl/crypto.h>
13#include <openssl/evp.h>
14#include <openssl/core_names.h>
15#include <openssl/params.h>
16#include "crypto/modes.h"
17#include "crypto/siv.h"
18
19#ifndef OPENSSL_NO_SIV
20
21__owur static ossl_inline uint32_t rotl8(uint32_t x)
22{
23 return (x << 8) | (x >> 24);
24}
25
26__owur static ossl_inline uint32_t rotr8(uint32_t x)
27{
28 return (x >> 8) | (x << 24);
29}
30
31__owur static ossl_inline uint64_t byteswap8(uint64_t x)
32{
33 uint32_t high = (uint32_t)(x >> 32);
34 uint32_t low = (uint32_t)x;
35
36 high = (rotl8(high) & 0x00ff00ff) | (rotr8(high) & 0xff00ff00);
37 low = (rotl8(low) & 0x00ff00ff) | (rotr8(low) & 0xff00ff00);
38 return ((uint64_t)low) << 32 | (uint64_t)high;
39}
40
41__owur static ossl_inline uint64_t siv128_getword(SIV_BLOCK const *b, size_t i)
42{
43 const union {
44 long one;
45 char little;
46 } is_endian = { 1 };
47
48 if (is_endian.little)
49 return byteswap8(b->word[i]);
50 return b->word[i];
51}
52
53static ossl_inline void siv128_putword(SIV_BLOCK *b, size_t i, uint64_t x)
54{
55 const union {
56 long one;
57 char little;
58 } is_endian = { 1 };
59
60 if (is_endian.little)
61 b->word[i] = byteswap8(x);
62 else
63 b->word[i] = x;
64}
65
66static ossl_inline void siv128_xorblock(SIV_BLOCK *x,
67 SIV_BLOCK const *y)
68{
69 x->word[0] ^= y->word[0];
70 x->word[1] ^= y->word[1];
71}
72
73/*
74 * Doubles |b|, which is 16 bytes representing an element
75 * of GF(2**128) modulo the irreducible polynomial
76 * x**128 + x**7 + x**2 + x + 1.
77 * Assumes two's-complement arithmetic
78 */
79static ossl_inline void siv128_dbl(SIV_BLOCK *b)
80{
81 uint64_t high = siv128_getword(b, 0);
82 uint64_t low = siv128_getword(b, 1);
83 uint64_t high_carry = high & (((uint64_t)1) << 63);
84 uint64_t low_carry = low & (((uint64_t)1) << 63);
85 int64_t low_mask = -((int64_t)(high_carry >> 63)) & 0x87;
86 uint64_t high_mask = low_carry >> 63;
87
88 high = (high << 1) | high_mask;
89 low = (low << 1) ^ (uint64_t)low_mask;
90 siv128_putword(b, 0, high);
91 siv128_putword(b, 1, low);
92}
93
94__owur static ossl_inline int siv128_do_s2v_p(SIV128_CONTEXT *ctx, SIV_BLOCK *out,
95 unsigned char const* in, size_t len)
96{
97 SIV_BLOCK t;
98 size_t out_len = sizeof(out->byte);
99 EVP_MAC_CTX *mac_ctx;
100 int ret = 0;
101
102 mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init);
103 if (mac_ctx == NULL)
104 return 0;
105
106 if (len >= SIV_LEN) {
107 if (!EVP_MAC_update(mac_ctx, in, len - SIV_LEN))
108 goto err;
109 memcpy(&t, in + (len-SIV_LEN), SIV_LEN);
110 siv128_xorblock(&t, &ctx->d);
111 if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
112 goto err;
113 } else {
114 memset(&t, 0, sizeof(t));
115 memcpy(&t, in, len);
116 t.byte[len] = 0x80;
117 siv128_dbl(&ctx->d);
118 siv128_xorblock(&t, &ctx->d);
119 if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
120 goto err;
121 }
122 if (!EVP_MAC_final(mac_ctx, out->byte, &out_len, sizeof(out->byte))
123 || out_len != SIV_LEN)
124 goto err;
125
126 ret = 1;
127
128err:
129 EVP_MAC_CTX_free(mac_ctx);
130 return ret;
131}
132
133
134__owur static ossl_inline int siv128_do_encrypt(EVP_CIPHER_CTX *ctx, unsigned char *out,
135 unsigned char const *in, size_t len,
136 SIV_BLOCK *icv)
137{
138 int out_len = (int)len;
139
140 if (!EVP_CipherInit_ex(ctx, NULL, NULL, NULL, icv->byte, 1))
141 return 0;
142 return EVP_EncryptUpdate(ctx, out, &out_len, in, out_len);
143}
144
145/*
146 * Create a new SIV128_CONTEXT
147 */
148SIV128_CONTEXT *CRYPTO_siv128_new(const unsigned char *key, int klen, EVP_CIPHER* cbc, EVP_CIPHER* ctr)
149{
150 SIV128_CONTEXT *ctx;
151 int ret;
152
153 if ((ctx = OPENSSL_malloc(sizeof(*ctx))) != NULL) {
154 ret = CRYPTO_siv128_init(ctx, key, klen, cbc, ctr);
155 if (ret)
156 return ctx;
157 OPENSSL_free(ctx);
158 }
159
160 return NULL;
161}
162
163/*
164 * Initialise an existing SIV128_CONTEXT
165 */
166int CRYPTO_siv128_init(SIV128_CONTEXT *ctx, const unsigned char *key, int klen,
167 const EVP_CIPHER* cbc, const EVP_CIPHER* ctr)
168{
169 static const unsigned char zero[SIV_LEN] = { 0 };
170 size_t out_len = SIV_LEN;
171 EVP_MAC_CTX *mac_ctx = NULL;
172 OSSL_PARAM params[3];
173 const char *cbc_name = EVP_CIPHER_name(cbc);
174
175 params[0] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,
176 (char *)cbc_name, 0);
177 params[1] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
178 (void *)key, klen);
179 params[2] = OSSL_PARAM_construct_end();
180
181 memset(&ctx->d, 0, sizeof(ctx->d));
182 ctx->cipher_ctx = NULL;
183 ctx->mac_ctx_init = NULL;
184
185 if (key == NULL || cbc == NULL || ctr == NULL
186 || (ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL
187 /* TODO(3.0) library context */
188 || (ctx->mac =
189 EVP_MAC_fetch(NULL, OSSL_MAC_NAME_CMAC, NULL)) == NULL
190 || (ctx->mac_ctx_init = EVP_MAC_CTX_new(ctx->mac)) == NULL
191 || !EVP_MAC_CTX_set_params(ctx->mac_ctx_init, params)
192 || !EVP_EncryptInit_ex(ctx->cipher_ctx, ctr, NULL, key + klen, NULL)
193 || (mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
194 || !EVP_MAC_update(mac_ctx, zero, sizeof(zero))
195 || !EVP_MAC_final(mac_ctx, ctx->d.byte, &out_len,
196 sizeof(ctx->d.byte))) {
197 EVP_CIPHER_CTX_free(ctx->cipher_ctx);
198 EVP_MAC_CTX_free(ctx->mac_ctx_init);
199 EVP_MAC_CTX_free(mac_ctx);
200 EVP_MAC_free(ctx->mac);
201 return 0;
202 }
203 EVP_MAC_CTX_free(mac_ctx);
204
205 ctx->final_ret = -1;
206 ctx->crypto_ok = 1;
207
208 return 1;
209}
210
211/*
212 * Copy an SIV128_CONTEXT object
213 */
214int CRYPTO_siv128_copy_ctx(SIV128_CONTEXT *dest, SIV128_CONTEXT *src)
215{
216 memcpy(&dest->d, &src->d, sizeof(src->d));
217 if (!EVP_CIPHER_CTX_copy(dest->cipher_ctx, src->cipher_ctx))
218 return 0;
219 EVP_MAC_CTX_free(dest->mac_ctx_init);
220 dest->mac_ctx_init = EVP_MAC_CTX_dup(src->mac_ctx_init);
221 if (dest->mac_ctx_init == NULL)
222 return 0;
223 return 1;
224}
225
226/*
227 * Provide any AAD. This can be called multiple times.
228 * Per RFC5297, the last piece of associated data
229 * is the nonce, but it's not treated special
230 */
231int CRYPTO_siv128_aad(SIV128_CONTEXT *ctx, const unsigned char *aad,
232 size_t len)
233{
234 SIV_BLOCK mac_out;
235 size_t out_len = SIV_LEN;
236 EVP_MAC_CTX *mac_ctx;
237
238 siv128_dbl(&ctx->d);
239
240 if ((mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
241 || !EVP_MAC_update(mac_ctx, aad, len)
242 || !EVP_MAC_final(mac_ctx, mac_out.byte, &out_len,
243 sizeof(mac_out.byte))
244 || out_len != SIV_LEN) {
245 EVP_MAC_CTX_free(mac_ctx);
246 return 0;
247 }
248 EVP_MAC_CTX_free(mac_ctx);
249
250 siv128_xorblock(&ctx->d, &mac_out);
251
252 return 1;
253}
254
255/*
256 * Provide any data to be encrypted. This can be called once.
257 */
258int CRYPTO_siv128_encrypt(SIV128_CONTEXT *ctx,
259 const unsigned char *in, unsigned char *out,
260 size_t len)
261{
262 SIV_BLOCK q;
263
264 /* can only do one crypto operation */
265 if (ctx->crypto_ok == 0)
266 return 0;
267 ctx->crypto_ok--;
268
269 if (!siv128_do_s2v_p(ctx, &q, in, len))
270 return 0;
271
272 memcpy(ctx->tag.byte, &q, SIV_LEN);
273 q.byte[8] &= 0x7f;
274 q.byte[12] &= 0x7f;
275
276 if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q))
277 return 0;
278 ctx->final_ret = 0;
279 return len;
280}
281
282/*
283 * Provide any data to be decrypted. This can be called once.
284 */
285int CRYPTO_siv128_decrypt(SIV128_CONTEXT *ctx,
286 const unsigned char *in, unsigned char *out,
287 size_t len)
288{
289 unsigned char* p;
290 SIV_BLOCK t, q;
291 int i;
292
293 /* can only do one crypto operation */
294 if (ctx->crypto_ok == 0)
295 return 0;
296 ctx->crypto_ok--;
297
298 memcpy(&q, ctx->tag.byte, SIV_LEN);
299 q.byte[8] &= 0x7f;
300 q.byte[12] &= 0x7f;
301
302 if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q)
303 || !siv128_do_s2v_p(ctx, &t, out, len))
304 return 0;
305
306 p = ctx->tag.byte;
307 for (i = 0; i < SIV_LEN; i++)
308 t.byte[i] ^= p[i];
309
310 if ((t.word[0] | t.word[1]) != 0) {
311 OPENSSL_cleanse(out, len);
312 return 0;
313 }
314 ctx->final_ret = 0;
315 return len;
316}
317
318/*
319 * Return the already calculated final result.
320 */
321int CRYPTO_siv128_finish(SIV128_CONTEXT *ctx)
322{
323 return ctx->final_ret;
324}
325
326/*
327 * Set the tag
328 */
329int CRYPTO_siv128_set_tag(SIV128_CONTEXT *ctx, const unsigned char *tag, size_t len)
330{
331 if (len != SIV_LEN)
332 return 0;
333
334 /* Copy the tag from the supplied buffer */
335 memcpy(ctx->tag.byte, tag, len);
336 return 1;
337}
338
339/*
340 * Retrieve the calculated tag
341 */
342int CRYPTO_siv128_get_tag(SIV128_CONTEXT *ctx, unsigned char *tag, size_t len)
343{
344 if (len != SIV_LEN)
345 return 0;
346
347 /* Copy the tag into the supplied buffer */
348 memcpy(tag, ctx->tag.byte, len);
349 return 1;
350}
351
352/*
353 * Release all resources
354 */
355int CRYPTO_siv128_cleanup(SIV128_CONTEXT *ctx)
356{
357 if (ctx != NULL) {
358 EVP_CIPHER_CTX_free(ctx->cipher_ctx);
359 ctx->cipher_ctx = NULL;
360 EVP_MAC_CTX_free(ctx->mac_ctx_init);
361 ctx->mac_ctx_init = NULL;
362 EVP_MAC_free(ctx->mac);
363 ctx->mac = NULL;
364 OPENSSL_cleanse(&ctx->d, sizeof(ctx->d));
365 OPENSSL_cleanse(&ctx->tag, sizeof(ctx->tag));
366 ctx->final_ret = -1;
367 ctx->crypto_ok = 1;
368 }
369 return 1;
370}
371
372int CRYPTO_siv128_speed(SIV128_CONTEXT *ctx, int arg)
373{
374 ctx->crypto_ok = (arg == 1) ? -1 : 1;
375 return 1;
376}
377
378#endif /* OPENSSL_NO_SIV */
379