providers/implementations/kdfs/scrypt.c

   1 /*
   2  * Copyright 2017-2020 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 <stdlib.h>
  11 #include <stdarg.h>
  12 #include <string.h>
  13 #include <openssl/evp.h>
  14 #include <openssl/kdf.h>
  15 #include <openssl/err.h>
  16 #include <openssl/core_names.h>
  17 #include "crypto/evp.h"
  18 #include "internal/numbers.h"
  19 #include "prov/implementations.h"
  20 #include "prov/provider_ctx.h"
  21 #include "prov/providercommonerr.h"
  22 #include "prov/implementations.h"
  23
  24 #ifndef OPENSSL_NO_SCRYPT
  25
  26 static OSSL_FUNC_kdf_newctx_fn kdf_scrypt_new;
  27 static OSSL_FUNC_kdf_freectx_fn kdf_scrypt_free;
  28 static OSSL_FUNC_kdf_reset_fn kdf_scrypt_reset;
  29 static OSSL_FUNC_kdf_derive_fn kdf_scrypt_derive;
  30 static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_scrypt_settable_ctx_params;
  31 static OSSL_FUNC_kdf_set_ctx_params_fn kdf_scrypt_set_ctx_params;
  32
  33 static int scrypt_alg(const char *pass, size_t passlen,
  34                       const unsigned char *salt, size_t saltlen,
  35                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
  36                       unsigned char *key, size_t keylen, EVP_MD *sha256);
  37
  38 typedef struct {
  39     void *provctx;
  40     unsigned char *pass;
  41     size_t pass_len;
  42     unsigned char *salt;
  43     size_t salt_len;
  44     uint64_t N;
  45     uint64_t r, p;
  46     uint64_t maxmem_bytes;
  47     EVP_MD *sha256;
  48 } KDF_SCRYPT;
  49
  50 static void kdf_scrypt_init(KDF_SCRYPT *ctx);
  51
  52 static void *kdf_scrypt_new(void *provctx)
  53 {
  54     KDF_SCRYPT *ctx;
  55
  56     ctx = OPENSSL_zalloc(sizeof(*ctx));
  57     if (ctx == NULL) {
  58         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
  59         return NULL;
  60     }
  61     ctx->provctx = provctx;
  62     ctx->sha256 = EVP_MD_fetch(PROV_LIBRARY_CONTEXT_OF(provctx),
  63                                "sha256", NULL);
  64     if (ctx->sha256 == NULL) {
  65         OPENSSL_free(ctx);
  66         ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA256);
  67         return NULL;
  68     }
  69     kdf_scrypt_init(ctx);
  70     return ctx;
  71 }
  72
  73 static void kdf_scrypt_free(void *vctx)
  74 {
  75     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  76
  77     if (ctx != NULL) {
  78         EVP_MD_free(ctx->sha256);
  79         kdf_scrypt_reset(ctx);
  80         OPENSSL_free(ctx);
  81     }
  82 }
  83
  84 static void kdf_scrypt_reset(void *vctx)
  85 {
  86     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  87
  88     OPENSSL_free(ctx->salt);
  89     OPENSSL_clear_free(ctx->pass, ctx->pass_len);
  90     kdf_scrypt_init(ctx);
  91 }
  92
  93 static void kdf_scrypt_init(KDF_SCRYPT *ctx)
  94 {
  95     /* Default values are the most conservative recommendation given in the
  96      * original paper of C. Percival. Derivation uses roughly 1 GiB of memory
  97      * for this parameter choice (approx. 128 * r * N * p bytes).
  98      */
  99     ctx->N = 1 << 20;
 100     ctx->r = 8;
 101     ctx->p = 1;
 102     ctx->maxmem_bytes = 1025 * 1024 * 1024;
 103 }
 104
 105 static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
 106                              const OSSL_PARAM *p)
 107 {
 108     OPENSSL_clear_free(*buffer, *buflen);
 109     if (p->data_size == 0) {
 110         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
 111             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 112             return 0;
 113         }
 114     } else if (p->data != NULL) {
 115         *buffer = NULL;
 116         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 117             return 0;
 118     }
 119     return 1;
 120 }
 121
 122 static int kdf_scrypt_derive(void *vctx, unsigned char *key,
 123                              size_t keylen)
 124 {
 125     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
 126
 127     if (ctx->pass == NULL) {
 128         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 129         return 0;
 130     }
 131
 132     if (ctx->salt == NULL) {
 133         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 134         return 0;
 135     }
 136
 137     return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
 138                       ctx->salt_len, ctx->N, ctx->r, ctx->p,
 139                       ctx->maxmem_bytes, key, keylen, ctx->sha256);
 140 }
 141
 142 static int is_power_of_two(uint64_t value)
 143 {
 144     return (value != 0) && ((value & (value - 1)) == 0);
 145 }
 146
 147 static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 148 {
 149     const OSSL_PARAM *p;
 150     KDF_SCRYPT *ctx = vctx;
 151     uint64_t u64_value;
 152
 153     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 154         if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
 155             return 0;
 156
 157     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
 158         if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
 159             return 0;
 160
 161     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
 162         != NULL) {
 163         if (!OSSL_PARAM_get_uint64(p, &u64_value)
 164             || u64_value <= 1
 165             || !is_power_of_two(u64_value))
 166             return 0;
 167         ctx->N = u64_value;
 168     }
 169
 170     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
 171         != NULL) {
 172         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 173             return 0;
 174         ctx->r = u64_value;
 175     }
 176
 177     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
 178         != NULL) {
 179         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 180             return 0;
 181         ctx->p = u64_value;
 182     }
 183
 184     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
 185         != NULL) {
 186         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 187             return 0;
 188         ctx->maxmem_bytes = u64_value;
 189     }
 190     return 1;
 191 }
 192
 193 static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(void)
 194 {
 195     static const OSSL_PARAM known_settable_ctx_params[] = {
 196         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 197         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 198         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
 199         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
 200         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
 201         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM, NULL),
 202         OSSL_PARAM_END
 203     };
 204     return known_settable_ctx_params;
 205 }
 206
 207 static int kdf_scrypt_get_ctx_params(void *vctx, OSSL_PARAM params[])
 208 {
 209     OSSL_PARAM *p;
 210
 211     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 212         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 213     return -2;
 214 }
 215
 216 static const OSSL_PARAM *kdf_scrypt_gettable_ctx_params(void)
 217 {
 218     static const OSSL_PARAM known_gettable_ctx_params[] = {
 219         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 220         OSSL_PARAM_END
 221     };
 222     return known_gettable_ctx_params;
 223 }
 224
 225 const OSSL_DISPATCH kdf_scrypt_functions[] = {
 226     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_scrypt_new },
 227     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_scrypt_free },
 228     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_scrypt_reset },
 229     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_scrypt_derive },
 230     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 231       (void(*)(void))kdf_scrypt_settable_ctx_params },
 232     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_scrypt_set_ctx_params },
 233     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 234       (void(*)(void))kdf_scrypt_gettable_ctx_params },
 235     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_scrypt_get_ctx_params },
 236     { 0, NULL }
 237 };
 238
 239 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
 240 static void salsa208_word_specification(uint32_t inout[16])
 241 {
 242     int i;
 243     uint32_t x[16];
 244
 245     memcpy(x, inout, sizeof(x));
 246     for (i = 8; i > 0; i -= 2) {
 247         x[4] ^= R(x[0] + x[12], 7);
 248         x[8] ^= R(x[4] + x[0], 9);
 249         x[12] ^= R(x[8] + x[4], 13);
 250         x[0] ^= R(x[12] + x[8], 18);
 251         x[9] ^= R(x[5] + x[1], 7);
 252         x[13] ^= R(x[9] + x[5], 9);
 253         x[1] ^= R(x[13] + x[9], 13);
 254         x[5] ^= R(x[1] + x[13], 18);
 255         x[14] ^= R(x[10] + x[6], 7);
 256         x[2] ^= R(x[14] + x[10], 9);
 257         x[6] ^= R(x[2] + x[14], 13);
 258         x[10] ^= R(x[6] + x[2], 18);
 259         x[3] ^= R(x[15] + x[11], 7);
 260         x[7] ^= R(x[3] + x[15], 9);
 261         x[11] ^= R(x[7] + x[3], 13);
 262         x[15] ^= R(x[11] + x[7], 18);
 263         x[1] ^= R(x[0] + x[3], 7);
 264         x[2] ^= R(x[1] + x[0], 9);
 265         x[3] ^= R(x[2] + x[1], 13);
 266         x[0] ^= R(x[3] + x[2], 18);
 267         x[6] ^= R(x[5] + x[4], 7);
 268         x[7] ^= R(x[6] + x[5], 9);
 269         x[4] ^= R(x[7] + x[6], 13);
 270         x[5] ^= R(x[4] + x[7], 18);
 271         x[11] ^= R(x[10] + x[9], 7);
 272         x[8] ^= R(x[11] + x[10], 9);
 273         x[9] ^= R(x[8] + x[11], 13);
 274         x[10] ^= R(x[9] + x[8], 18);
 275         x[12] ^= R(x[15] + x[14], 7);
 276         x[13] ^= R(x[12] + x[15], 9);
 277         x[14] ^= R(x[13] + x[12], 13);
 278         x[15] ^= R(x[14] + x[13], 18);
 279     }
 280     for (i = 0; i < 16; ++i)
 281         inout[i] += x[i];
 282     OPENSSL_cleanse(x, sizeof(x));
 283 }
 284
 285 static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
 286 {
 287     uint64_t i, j;
 288     uint32_t X[16], *pB;
 289
 290     memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
 291     pB = B;
 292     for (i = 0; i < r * 2; i++) {
 293         for (j = 0; j < 16; j++)
 294             X[j] ^= *pB++;
 295         salsa208_word_specification(X);
 296         memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
 297     }
 298     OPENSSL_cleanse(X, sizeof(X));
 299 }
 300
 301 static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
 302                         uint32_t *X, uint32_t *T, uint32_t *V)
 303 {
 304     unsigned char *pB;
 305     uint32_t *pV;
 306     uint64_t i, k;
 307
 308     /* Convert from little endian input */
 309     for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
 310         *pV = *pB++;
 311         *pV |= *pB++ << 8;
 312         *pV |= *pB++ << 16;
 313         *pV |= (uint32_t)*pB++ << 24;
 314     }
 315
 316     for (i = 1; i < N; i++, pV += 32 * r)
 317         scryptBlockMix(pV, pV - 32 * r, r);
 318
 319     scryptBlockMix(X, V + (N - 1) * 32 * r, r);
 320
 321     for (i = 0; i < N; i++) {
 322         uint32_t j;
 323         j = X[16 * (2 * r - 1)] % N;
 324         pV = V + 32 * r * j;
 325         for (k = 0; k < 32 * r; k++)
 326             T[k] = X[k] ^ *pV++;
 327         scryptBlockMix(X, T, r);
 328     }
 329     /* Convert output to little endian */
 330     for (i = 0, pB = B; i < 32 * r; i++) {
 331         uint32_t xtmp = X[i];
 332         *pB++ = xtmp & 0xff;
 333         *pB++ = (xtmp >> 8) & 0xff;
 334         *pB++ = (xtmp >> 16) & 0xff;
 335         *pB++ = (xtmp >> 24) & 0xff;
 336     }
 337 }
 338
 339 #ifndef SIZE_MAX
 340 # define SIZE_MAX    ((size_t)-1)
 341 #endif
 342
 343 /*
 344  * Maximum power of two that will fit in uint64_t: this should work on
 345  * most (all?) platforms.
 346  */
 347
 348 #define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)
 349
 350 /*
 351  * Maximum value of p * r:
 352  * p <= ((2^32-1) * hLen) / MFLen =>
 353  * p <= ((2^32-1) * 32) / (128 * r) =>
 354  * p * r <= (2^30-1)
 355  */
 356
 357 #define SCRYPT_PR_MAX   ((1 << 30) - 1)
 358
 359 static int scrypt_alg(const char *pass, size_t passlen,
 360                       const unsigned char *salt, size_t saltlen,
 361                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
 362                       unsigned char *key, size_t keylen, EVP_MD *sha256)
 363 {
 364     int rv = 0;
 365     unsigned char *B;
 366     uint32_t *X, *V, *T;
 367     uint64_t i, Blen, Vlen;
 368
 369     /* Sanity check parameters */
 370     /* initial check, r,p must be non zero, N >= 2 and a power of 2 */
 371     if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
 372         return 0;
 373     /* Check p * r < SCRYPT_PR_MAX avoiding overflow */
 374     if (p > SCRYPT_PR_MAX / r) {
 375         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 376         return 0;
 377     }
 378
 379     /*
 380      * Need to check N: if 2^(128 * r / 8) overflows limit this is
 381      * automatically satisfied since N <= UINT64_MAX.
 382      */
 383
 384     if (16 * r <= LOG2_UINT64_MAX) {
 385         if (N >= (((uint64_t)1) << (16 * r))) {
 386             EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 387             return 0;
 388         }
 389     }
 390
 391     /* Memory checks: check total allocated buffer size fits in uint64_t */
 392
 393     /*
 394      * B size in section 5 step 1.S
 395      * Note: we know p * 128 * r < UINT64_MAX because we already checked
 396      * p * r < SCRYPT_PR_MAX
 397      */
 398     Blen = p * 128 * r;
 399     /*
 400      * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
 401      * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
 402      */
 403     if (Blen > INT_MAX) {
 404         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 405         return 0;
 406     }
 407
 408     /*
 409      * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
 410      * This is combined size V, X and T (section 4)
 411      */
 412     i = UINT64_MAX / (32 * sizeof(uint32_t));
 413     if (N + 2 > i / r) {
 414         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 415         return 0;
 416     }
 417     Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
 418
 419     /* check total allocated size fits in uint64_t */
 420     if (Blen > UINT64_MAX - Vlen) {
 421         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 422         return 0;
 423     }
 424
 425     /* Check that the maximum memory doesn't exceed a size_t limits */
 426     if (maxmem > SIZE_MAX)
 427         maxmem = SIZE_MAX;
 428
 429     if (Blen + Vlen > maxmem) {
 430         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 431         return 0;
 432     }
 433
 434     /* If no key return to indicate parameters are OK */
 435     if (key == NULL)
 436         return 1;
 437
 438     B = OPENSSL_malloc((size_t)(Blen + Vlen));
 439     if (B == NULL) {
 440         EVPerr(EVP_F_SCRYPT_ALG, ERR_R_MALLOC_FAILURE);
 441         return 0;
 442     }
 443     X = (uint32_t *)(B + Blen);
 444     T = X + 32 * r;
 445     V = T + 32 * r;
 446     if (PKCS5_PBKDF2_HMAC(pass, passlen, salt, saltlen, 1, sha256,
 447                           (int)Blen, B) == 0)
 448         goto err;
 449
 450     for (i = 0; i < p; i++)
 451         scryptROMix(B + 128 * r * i, r, N, X, T, V);
 452
 453     if (PKCS5_PBKDF2_HMAC(pass, passlen, B, (int)Blen, 1, sha256,
 454                           keylen, key) == 0)
 455         goto err;
 456     rv = 1;
 457  err:
 458     if (rv == 0)
 459         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_PBKDF2_ERROR);
 460
 461     OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
 462     return rv;
 463 }
 464
 465 #endif