crypto/modes/siv128.c

   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
  53 static 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
  66 static 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  */
  79 static 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
 128 err:
 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  */
 148 SIV128_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  */
 166 int 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  */
 214 int 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  */
 231 int 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  */
 258 int 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  */
 285 int 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  */
 321 int CRYPTO_siv128_finish(SIV128_CONTEXT *ctx)
 322 {
 323     return ctx->final_ret;
 324 }
 325
 326 /*
 327  * Set the tag
 328  */
 329 int 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  */
 342 int 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  */
 355 int 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
 372 int 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 */