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 "internal/modes_int.h"
  17 #include "internal/siv_int.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,
 177                                                  strlen(cbc_name) + 1);
 178     params[1] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 179                                                   (void *)key, klen);
 180     params[2] = OSSL_PARAM_construct_end();
 181
 182     memset(&ctx->d, 0, sizeof(ctx->d));
 183     ctx->cipher_ctx = NULL;
 184     ctx->mac_ctx_init = NULL;
 185
 186     if (key == NULL || cbc == NULL || ctr == NULL
 187             || (ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL
 188             /* TODO(3.0) library context */
 189             || (ctx->mac =
 190                 EVP_MAC_fetch(NULL, OSSL_MAC_NAME_CMAC, NULL)) == NULL
 191             || (ctx->mac_ctx_init = EVP_MAC_CTX_new(ctx->mac)) == NULL
 192             || !EVP_MAC_CTX_set_params(ctx->mac_ctx_init, params)
 193             || !EVP_EncryptInit_ex(ctx->cipher_ctx, ctr, NULL, key + klen, NULL)
 194             || (mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
 195             || !EVP_MAC_update(mac_ctx, zero, sizeof(zero))
 196             || !EVP_MAC_final(mac_ctx, ctx->d.byte, &out_len,
 197                               sizeof(ctx->d.byte))) {
 198         EVP_CIPHER_CTX_free(ctx->cipher_ctx);
 199         EVP_MAC_CTX_free(ctx->mac_ctx_init);
 200         EVP_MAC_CTX_free(mac_ctx);
 201         EVP_MAC_free(ctx->mac);
 202         return 0;
 203     }
 204     EVP_MAC_CTX_free(mac_ctx);
 205
 206     ctx->final_ret = -1;
 207     ctx->crypto_ok = 1;
 208
 209     return 1;
 210 }
 211
 212 /*
 213  * Copy an SIV128_CONTEXT object
 214  */
 215 int CRYPTO_siv128_copy_ctx(SIV128_CONTEXT *dest, SIV128_CONTEXT *src)
 216 {
 217     memcpy(&dest->d, &src->d, sizeof(src->d));
 218     if (!EVP_CIPHER_CTX_copy(dest->cipher_ctx, src->cipher_ctx))
 219         return 0;
 220     EVP_MAC_CTX_free(dest->mac_ctx_init);
 221     dest->mac_ctx_init = EVP_MAC_CTX_dup(src->mac_ctx_init);
 222     if (dest->mac_ctx_init == NULL)
 223         return 0;
 224     return 1;
 225 }
 226
 227 /*
 228  * Provide any AAD. This can be called multiple times.
 229  * Per RFC5297, the last piece of associated data
 230  * is the nonce, but it's not treated special
 231  */
 232 int CRYPTO_siv128_aad(SIV128_CONTEXT *ctx, const unsigned char *aad,
 233                       size_t len)
 234 {
 235     SIV_BLOCK mac_out;
 236     size_t out_len = SIV_LEN;
 237     EVP_MAC_CTX *mac_ctx;
 238
 239     siv128_dbl(&ctx->d);
 240
 241     if ((mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
 242         || !EVP_MAC_update(mac_ctx, aad, len)
 243         || !EVP_MAC_final(mac_ctx, mac_out.byte, &out_len,
 244                           sizeof(mac_out.byte))
 245         || out_len != SIV_LEN) {
 246         EVP_MAC_CTX_free(mac_ctx);
 247         return 0;
 248     }
 249     EVP_MAC_CTX_free(mac_ctx);
 250
 251     siv128_xorblock(&ctx->d, &mac_out);
 252
 253     return 1;
 254 }
 255
 256 /*
 257  * Provide any data to be encrypted. This can be called once.
 258  */
 259 int CRYPTO_siv128_encrypt(SIV128_CONTEXT *ctx,
 260                           const unsigned char *in, unsigned char *out,
 261                           size_t len)
 262 {
 263     SIV_BLOCK q;
 264
 265     /* can only do one crypto operation */
 266     if (ctx->crypto_ok == 0)
 267         return 0;
 268     ctx->crypto_ok--;
 269
 270     if (!siv128_do_s2v_p(ctx, &q, in, len))
 271         return 0;
 272
 273     memcpy(ctx->tag.byte, &q, SIV_LEN);
 274     q.byte[8] &= 0x7f;
 275     q.byte[12] &= 0x7f;
 276
 277     if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q))
 278         return 0;
 279     ctx->final_ret = 0;
 280     return len;
 281 }
 282
 283 /*
 284  * Provide any data to be decrypted. This can be called once.
 285  */
 286 int CRYPTO_siv128_decrypt(SIV128_CONTEXT *ctx,
 287                           const unsigned char *in, unsigned char *out,
 288                           size_t len)
 289 {
 290     unsigned char* p;
 291     SIV_BLOCK t, q;
 292     int i;
 293
 294     /* can only do one crypto operation */
 295     if (ctx->crypto_ok == 0)
 296         return 0;
 297     ctx->crypto_ok--;
 298
 299     memcpy(&q, ctx->tag.byte, SIV_LEN);
 300     q.byte[8] &= 0x7f;
 301     q.byte[12] &= 0x7f;
 302
 303     if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q)
 304         || !siv128_do_s2v_p(ctx, &t, out, len))
 305         return 0;
 306
 307     p = ctx->tag.byte;
 308     for (i = 0; i < SIV_LEN; i++)
 309         t.byte[i] ^= p[i];
 310
 311     if ((t.word[0] | t.word[1]) != 0) {
 312         OPENSSL_cleanse(out, len);
 313         return 0;
 314     }
 315     ctx->final_ret = 0;
 316     return len;
 317 }
 318
 319 /*
 320  * Return the already calculated final result.
 321  */
 322 int CRYPTO_siv128_finish(SIV128_CONTEXT *ctx)
 323 {
 324     return ctx->final_ret;
 325 }
 326
 327 /*
 328  * Set the tag
 329  */
 330 int CRYPTO_siv128_set_tag(SIV128_CONTEXT *ctx, const unsigned char *tag, size_t len)
 331 {
 332     if (len != SIV_LEN)
 333         return 0;
 334
 335     /* Copy the tag from the supplied buffer */
 336     memcpy(ctx->tag.byte, tag, len);
 337     return 1;
 338 }
 339
 340 /*
 341  * Retrieve the calculated tag
 342  */
 343 int CRYPTO_siv128_get_tag(SIV128_CONTEXT *ctx, unsigned char *tag, size_t len)
 344 {
 345     if (len != SIV_LEN)
 346         return 0;
 347
 348     /* Copy the tag into the supplied buffer */
 349     memcpy(tag, ctx->tag.byte, len);
 350     return 1;
 351 }
 352
 353 /*
 354  * Release all resources
 355  */
 356 int CRYPTO_siv128_cleanup(SIV128_CONTEXT *ctx)
 357 {
 358     if (ctx != NULL) {
 359         EVP_CIPHER_CTX_free(ctx->cipher_ctx);
 360         ctx->cipher_ctx = NULL;
 361         EVP_MAC_CTX_free(ctx->mac_ctx_init);
 362         ctx->mac_ctx_init = NULL;
 363         EVP_MAC_free(ctx->mac);
 364         ctx->mac = NULL;
 365         OPENSSL_cleanse(&ctx->d, sizeof(ctx->d));
 366         OPENSSL_cleanse(&ctx->tag, sizeof(ctx->tag));
 367         ctx->final_ret = -1;
 368         ctx->crypto_ok = 1;
 369     }
 370     return 1;
 371 }
 372
 373 int CRYPTO_siv128_speed(SIV128_CONTEXT *ctx, int arg)
 374 {
 375     ctx->crypto_ok = (arg == 1) ? -1 : 1;
 376     return 1;
 377 }
 378
 379 #endif                          /* OPENSSL_NO_SIV */