crypto/modes/siv128.c

   1 /*
   2  * Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (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/endian.h"
  17 #include "crypto/modes.h"
  18 #include "crypto/siv.h"
  19
  20 #ifndef OPENSSL_NO_SIV
  21
  22 __owur static ossl_inline uint32_t rotl8(uint32_t x)
  23 {
  24     return (x << 8) | (x >> 24);
  25 }
  26
  27 __owur static ossl_inline uint32_t rotr8(uint32_t x)
  28 {
  29     return (x >> 8) | (x << 24);
  30 }
  31
  32 __owur static ossl_inline uint64_t byteswap8(uint64_t x)
  33 {
  34     uint32_t high = (uint32_t)(x >> 32);
  35     uint32_t low = (uint32_t)x;
  36
  37     high = (rotl8(high) & 0x00ff00ff) | (rotr8(high) & 0xff00ff00);
  38     low = (rotl8(low) & 0x00ff00ff) | (rotr8(low) & 0xff00ff00);
  39     return ((uint64_t)low) << 32 | (uint64_t)high;
  40 }
  41
  42 __owur static ossl_inline uint64_t siv128_getword(SIV_BLOCK const *b, size_t i)
  43 {
  44     DECLARE_IS_ENDIAN;
  45
  46     if (IS_LITTLE_ENDIAN)
  47         return byteswap8(b->word[i]);
  48     return b->word[i];
  49 }
  50
  51 static ossl_inline void siv128_putword(SIV_BLOCK *b, size_t i, uint64_t x)
  52 {
  53     DECLARE_IS_ENDIAN;
  54
  55     if (IS_LITTLE_ENDIAN)
  56         b->word[i] = byteswap8(x);
  57     else
  58         b->word[i] = x;
  59 }
  60
  61 static ossl_inline void siv128_xorblock(SIV_BLOCK *x,
  62                                         SIV_BLOCK const *y)
  63 {
  64     x->word[0] ^= y->word[0];
  65     x->word[1] ^= y->word[1];
  66 }
  67
  68 /*
  69  * Doubles |b|, which is 16 bytes representing an element
  70  * of GF(2**128) modulo the irreducible polynomial
  71  * x**128 + x**7 + x**2 + x + 1.
  72  * Assumes two's-complement arithmetic
  73  */
  74 static ossl_inline void siv128_dbl(SIV_BLOCK *b)
  75 {
  76     uint64_t high = siv128_getword(b, 0);
  77     uint64_t low = siv128_getword(b, 1);
  78     uint64_t high_carry = high & (((uint64_t)1) << 63);
  79     uint64_t low_carry = low & (((uint64_t)1) << 63);
  80     int64_t low_mask = -((int64_t)(high_carry >> 63)) & 0x87;
  81     uint64_t high_mask = low_carry >> 63;
  82
  83     high = (high << 1) | high_mask;
  84     low = (low << 1) ^ (uint64_t)low_mask;
  85     siv128_putword(b, 0, high);
  86     siv128_putword(b, 1, low);
  87 }
  88
  89 __owur static ossl_inline int siv128_do_s2v_p(SIV128_CONTEXT *ctx, SIV_BLOCK *out,
  90                                               unsigned char const* in, size_t len)
  91 {
  92     SIV_BLOCK t;
  93     size_t out_len = sizeof(out->byte);
  94     EVP_MAC_CTX *mac_ctx;
  95     int ret = 0;
  96
  97     mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init);
  98     if (mac_ctx == NULL)
  99         return 0;
 100
 101     if (len >= SIV_LEN) {
 102         if (!EVP_MAC_update(mac_ctx, in, len - SIV_LEN))
 103             goto err;
 104         memcpy(&t, in + (len-SIV_LEN), SIV_LEN);
 105         siv128_xorblock(&t, &ctx->d);
 106         if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
 107             goto err;
 108     } else {
 109         memset(&t, 0, sizeof(t));
 110         memcpy(&t, in, len);
 111         t.byte[len] = 0x80;
 112         siv128_dbl(&ctx->d);
 113         siv128_xorblock(&t, &ctx->d);
 114         if (!EVP_MAC_update(mac_ctx, t.byte, SIV_LEN))
 115             goto err;
 116     }
 117     if (!EVP_MAC_final(mac_ctx, out->byte, &out_len, sizeof(out->byte))
 118         || out_len != SIV_LEN)
 119         goto err;
 120
 121     ret = 1;
 122
 123 err:
 124     EVP_MAC_CTX_free(mac_ctx);
 125     return ret;
 126 }
 127
 128
 129 __owur static ossl_inline int siv128_do_encrypt(EVP_CIPHER_CTX *ctx, unsigned char *out,
 130                                              unsigned char const *in, size_t len,
 131                                              SIV_BLOCK *icv)
 132 {
 133     int out_len = (int)len;
 134
 135     if (!EVP_CipherInit_ex(ctx, NULL, NULL, NULL, icv->byte, 1))
 136         return 0;
 137     return EVP_EncryptUpdate(ctx, out, &out_len, in, out_len);
 138 }
 139
 140 /*
 141  * Create a new SIV128_CONTEXT
 142  */
 143 SIV128_CONTEXT *CRYPTO_siv128_new(const unsigned char *key, int klen,
 144                                   EVP_CIPHER *cbc, EVP_CIPHER *ctr,
 145                                   OSSL_LIB_CTX *libctx, const char *propq)
 146 {
 147     SIV128_CONTEXT *ctx;
 148     int ret;
 149
 150     if ((ctx = OPENSSL_malloc(sizeof(*ctx))) != NULL) {
 151         ret = CRYPTO_siv128_init(ctx, key, klen, cbc, ctr, libctx, propq);
 152         if (ret)
 153             return ctx;
 154         OPENSSL_free(ctx);
 155     }
 156
 157     return NULL;
 158 }
 159
 160 /*
 161  * Initialise an existing SIV128_CONTEXT
 162  */
 163 int CRYPTO_siv128_init(SIV128_CONTEXT *ctx, const unsigned char *key, int klen,
 164                        const EVP_CIPHER *cbc, const EVP_CIPHER *ctr,
 165                        OSSL_LIB_CTX *libctx, const char *propq)
 166 {
 167     static const unsigned char zero[SIV_LEN] = { 0 };
 168     size_t out_len = SIV_LEN;
 169     EVP_MAC_CTX *mac_ctx = NULL;
 170     OSSL_PARAM params[3];
 171     const char *cbc_name;
 172
 173     if (ctx == NULL)
 174         return 0;
 175
 176     memset(&ctx->d, 0, sizeof(ctx->d));
 177     EVP_CIPHER_CTX_free(ctx->cipher_ctx);
 178     EVP_MAC_CTX_free(ctx->mac_ctx_init);
 179     EVP_MAC_free(ctx->mac);
 180     ctx->mac = NULL;
 181     ctx->cipher_ctx = NULL;
 182     ctx->mac_ctx_init = NULL;
 183
 184     if (key == NULL || cbc == NULL || ctr == NULL)
 185         return 0;
 186
 187     cbc_name = EVP_CIPHER_name(cbc);
 188     params[0] = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER,
 189                                                  (char *)cbc_name, 0);
 190     params[1] = OSSL_PARAM_construct_octet_string(OSSL_MAC_PARAM_KEY,
 191                                                   (void *)key, klen);
 192     params[2] = OSSL_PARAM_construct_end();
 193
 194     if ((ctx->cipher_ctx = EVP_CIPHER_CTX_new()) == NULL
 195             || (ctx->mac =
 196                 EVP_MAC_fetch(libctx, OSSL_MAC_NAME_CMAC, propq)) == NULL
 197             || (ctx->mac_ctx_init = EVP_MAC_CTX_new(ctx->mac)) == NULL
 198             || !EVP_MAC_CTX_set_params(ctx->mac_ctx_init, params)
 199             || !EVP_EncryptInit_ex(ctx->cipher_ctx, ctr, NULL, key + klen, NULL)
 200             || (mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
 201             || !EVP_MAC_update(mac_ctx, zero, sizeof(zero))
 202             || !EVP_MAC_final(mac_ctx, ctx->d.byte, &out_len,
 203                               sizeof(ctx->d.byte))) {
 204         EVP_CIPHER_CTX_free(ctx->cipher_ctx);
 205         EVP_MAC_CTX_free(ctx->mac_ctx_init);
 206         EVP_MAC_CTX_free(mac_ctx);
 207         EVP_MAC_free(ctx->mac);
 208         return 0;
 209     }
 210     EVP_MAC_CTX_free(mac_ctx);
 211
 212     ctx->final_ret = -1;
 213     ctx->crypto_ok = 1;
 214
 215     return 1;
 216 }
 217
 218 /*
 219  * Copy an SIV128_CONTEXT object
 220  */
 221 int CRYPTO_siv128_copy_ctx(SIV128_CONTEXT *dest, SIV128_CONTEXT *src)
 222 {
 223     memcpy(&dest->d, &src->d, sizeof(src->d));
 224     if (dest->cipher_ctx == NULL) {
 225         dest->cipher_ctx = EVP_CIPHER_CTX_new();
 226         if (dest->cipher_ctx == NULL)
 227             return 0;
 228     }
 229     if (!EVP_CIPHER_CTX_copy(dest->cipher_ctx, src->cipher_ctx))
 230         return 0;
 231     EVP_MAC_CTX_free(dest->mac_ctx_init);
 232     dest->mac_ctx_init = EVP_MAC_CTX_dup(src->mac_ctx_init);
 233     if (dest->mac_ctx_init == NULL)
 234         return 0;
 235     dest->mac = src->mac;
 236     if (dest->mac != NULL)
 237         EVP_MAC_up_ref(dest->mac);
 238     return 1;
 239 }
 240
 241 /*
 242  * Provide any AAD. This can be called multiple times.
 243  * Per RFC5297, the last piece of associated data
 244  * is the nonce, but it's not treated special
 245  */
 246 int CRYPTO_siv128_aad(SIV128_CONTEXT *ctx, const unsigned char *aad,
 247                       size_t len)
 248 {
 249     SIV_BLOCK mac_out;
 250     size_t out_len = SIV_LEN;
 251     EVP_MAC_CTX *mac_ctx;
 252
 253     siv128_dbl(&ctx->d);
 254
 255     if ((mac_ctx = EVP_MAC_CTX_dup(ctx->mac_ctx_init)) == NULL
 256         || !EVP_MAC_update(mac_ctx, aad, len)
 257         || !EVP_MAC_final(mac_ctx, mac_out.byte, &out_len,
 258                           sizeof(mac_out.byte))
 259         || out_len != SIV_LEN) {
 260         EVP_MAC_CTX_free(mac_ctx);
 261         return 0;
 262     }
 263     EVP_MAC_CTX_free(mac_ctx);
 264
 265     siv128_xorblock(&ctx->d, &mac_out);
 266
 267     return 1;
 268 }
 269
 270 /*
 271  * Provide any data to be encrypted. This can be called once.
 272  */
 273 int CRYPTO_siv128_encrypt(SIV128_CONTEXT *ctx,
 274                           const unsigned char *in, unsigned char *out,
 275                           size_t len)
 276 {
 277     SIV_BLOCK q;
 278
 279     /* can only do one crypto operation */
 280     if (ctx->crypto_ok == 0)
 281         return 0;
 282     ctx->crypto_ok--;
 283
 284     if (!siv128_do_s2v_p(ctx, &q, in, len))
 285         return 0;
 286
 287     memcpy(ctx->tag.byte, &q, SIV_LEN);
 288     q.byte[8] &= 0x7f;
 289     q.byte[12] &= 0x7f;
 290
 291     if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q))
 292         return 0;
 293     ctx->final_ret = 0;
 294     return len;
 295 }
 296
 297 /*
 298  * Provide any data to be decrypted. This can be called once.
 299  */
 300 int CRYPTO_siv128_decrypt(SIV128_CONTEXT *ctx,
 301                           const unsigned char *in, unsigned char *out,
 302                           size_t len)
 303 {
 304     unsigned char* p;
 305     SIV_BLOCK t, q;
 306     int i;
 307
 308     /* can only do one crypto operation */
 309     if (ctx->crypto_ok == 0)
 310         return 0;
 311     ctx->crypto_ok--;
 312
 313     memcpy(&q, ctx->tag.byte, SIV_LEN);
 314     q.byte[8] &= 0x7f;
 315     q.byte[12] &= 0x7f;
 316
 317     if (!siv128_do_encrypt(ctx->cipher_ctx, out, in, len, &q)
 318         || !siv128_do_s2v_p(ctx, &t, out, len))
 319         return 0;
 320
 321     p = ctx->tag.byte;
 322     for (i = 0; i < SIV_LEN; i++)
 323         t.byte[i] ^= p[i];
 324
 325     if ((t.word[0] | t.word[1]) != 0) {
 326         OPENSSL_cleanse(out, len);
 327         return 0;
 328     }
 329     ctx->final_ret = 0;
 330     return len;
 331 }
 332
 333 /*
 334  * Return the already calculated final result.
 335  */
 336 int CRYPTO_siv128_finish(SIV128_CONTEXT *ctx)
 337 {
 338     return ctx->final_ret;
 339 }
 340
 341 /*
 342  * Set the tag
 343  */
 344 int CRYPTO_siv128_set_tag(SIV128_CONTEXT *ctx, const unsigned char *tag, size_t len)
 345 {
 346     if (len != SIV_LEN)
 347         return 0;
 348
 349     /* Copy the tag from the supplied buffer */
 350     memcpy(ctx->tag.byte, tag, len);
 351     return 1;
 352 }
 353
 354 /*
 355  * Retrieve the calculated tag
 356  */
 357 int CRYPTO_siv128_get_tag(SIV128_CONTEXT *ctx, unsigned char *tag, size_t len)
 358 {
 359     if (len != SIV_LEN)
 360         return 0;
 361
 362     /* Copy the tag into the supplied buffer */
 363     memcpy(tag, ctx->tag.byte, len);
 364     return 1;
 365 }
 366
 367 /*
 368  * Release all resources
 369  */
 370 int CRYPTO_siv128_cleanup(SIV128_CONTEXT *ctx)
 371 {
 372     if (ctx != NULL) {
 373         EVP_CIPHER_CTX_free(ctx->cipher_ctx);
 374         ctx->cipher_ctx = NULL;
 375         EVP_MAC_CTX_free(ctx->mac_ctx_init);
 376         ctx->mac_ctx_init = NULL;
 377         EVP_MAC_free(ctx->mac);
 378         ctx->mac = NULL;
 379         OPENSSL_cleanse(&ctx->d, sizeof(ctx->d));
 380         OPENSSL_cleanse(&ctx->tag, sizeof(ctx->tag));
 381         ctx->final_ret = -1;
 382         ctx->crypto_ok = 1;
 383     }
 384     return 1;
 385 }
 386
 387 int CRYPTO_siv128_speed(SIV128_CONTEXT *ctx, int arg)
 388 {
 389     ctx->crypto_ok = (arg == 1) ? -1 : 1;
 390     return 1;
 391 }
 392
 393 #endif                          /* OPENSSL_NO_SIV */