providers/default/kdfs/scrypt.c

   1 /*
   2  * Copyright 2017-2019 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 "internal/evp_int.h"
  18 #include "internal/numbers.h"
  19 #include "internal/provider_algs.h"
  20 #include "internal/provider_ctx.h"
  21 #include "internal/providercommonerr.h"
  22 #include "internal/provider_algs.h"
  23
  24 #ifndef OPENSSL_NO_SCRYPT
  25
  26 static OSSL_OP_kdf_newctx_fn kdf_scrypt_new;
  27 static OSSL_OP_kdf_freectx_fn kdf_scrypt_free;
  28 static OSSL_OP_kdf_reset_fn kdf_scrypt_reset;
  29 static OSSL_OP_kdf_derive_fn kdf_scrypt_derive;
  30 static OSSL_OP_kdf_settable_ctx_params_fn kdf_scrypt_settable_ctx_params;
  31 static OSSL_OP_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     EVP_MD_meth_free(ctx->sha256);
  78     kdf_scrypt_reset(ctx);
  79     OPENSSL_free(ctx);
  80 }
  81
  82 static void kdf_scrypt_reset(void *vctx)
  83 {
  84     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
  85
  86     OPENSSL_free(ctx->salt);
  87     OPENSSL_clear_free(ctx->pass, ctx->pass_len);
  88     kdf_scrypt_init(ctx);
  89 }
  90
  91 static void kdf_scrypt_init(KDF_SCRYPT *ctx)
  92 {
  93     /* Default values are the most conservative recommendation given in the
  94      * original paper of C. Percival. Derivation uses roughly 1 GiB of memory
  95      * for this parameter choice (approx. 128 * r * N * p bytes).
  96      */
  97     ctx->N = 1 << 20;
  98     ctx->r = 8;
  99     ctx->p = 1;
 100     ctx->maxmem_bytes = 1025 * 1024 * 1024;
 101 }
 102
 103 static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
 104                              const OSSL_PARAM *p)
 105 {
 106     OPENSSL_clear_free(*buffer, *buflen);
 107     if (p->data_size == 0) {
 108         if ((*buffer = OPENSSL_malloc(1)) == NULL) {
 109             ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
 110             return 0;
 111         }
 112     } else if (p->data != NULL) {
 113         *buffer = NULL;
 114         if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
 115             return 0;
 116     }
 117     return 1;
 118 }
 119
 120 static int kdf_scrypt_derive(void *vctx, unsigned char *key,
 121                              size_t keylen)
 122 {
 123     KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
 124
 125     if (ctx->pass == NULL) {
 126         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
 127         return 0;
 128     }
 129
 130     if (ctx->salt == NULL) {
 131         ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
 132         return 0;
 133     }
 134
 135     return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
 136                       ctx->salt_len, ctx->N, ctx->r, ctx->p,
 137                       ctx->maxmem_bytes, key, keylen, ctx->sha256);
 138 }
 139
 140 static int is_power_of_two(uint64_t value)
 141 {
 142     return (value != 0) && ((value & (value - 1)) == 0);
 143 }
 144
 145 static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
 146 {
 147     const OSSL_PARAM *p;
 148     KDF_SCRYPT *ctx = vctx;
 149     uint64_t u64_value;
 150
 151     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
 152         if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
 153             return 0;
 154
 155     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
 156         if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
 157             return 0;
 158
 159     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
 160         != NULL) {
 161         if (!OSSL_PARAM_get_uint64(p, &u64_value)
 162             || u64_value <= 1
 163             || !is_power_of_two(u64_value))
 164             return 0;
 165         ctx->N = u64_value;
 166     }
 167
 168     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
 169         != NULL) {
 170         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 171             return 0;
 172         ctx->r = u64_value;
 173     }
 174
 175     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
 176         != NULL) {
 177         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 178             return 0;
 179         ctx->p = u64_value;
 180     }
 181
 182     if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
 183         != NULL) {
 184         if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
 185             return 0;
 186         ctx->maxmem_bytes = u64_value;
 187     }
 188     return 1;
 189 }
 190
 191 static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(void)
 192 {
 193     static const OSSL_PARAM known_settable_ctx_params[] = {
 194         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
 195         OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
 196         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
 197         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
 198         OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
 199         OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM, NULL),
 200         OSSL_PARAM_END
 201     };
 202     return known_settable_ctx_params;
 203 }
 204
 205 static int kdf_scrypt_get_ctx_params(void *vctx, OSSL_PARAM params[])
 206 {
 207     OSSL_PARAM *p;
 208
 209     if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
 210         return OSSL_PARAM_set_size_t(p, SIZE_MAX);
 211     return -2;
 212 }
 213
 214 static const OSSL_PARAM *kdf_scrypt_gettable_ctx_params(void)
 215 {
 216     static const OSSL_PARAM known_gettable_ctx_params[] = {
 217         OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
 218         OSSL_PARAM_END
 219     };
 220     return known_gettable_ctx_params;
 221 }
 222
 223 const OSSL_DISPATCH kdf_scrypt_functions[] = {
 224     { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_scrypt_new },
 225     { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_scrypt_free },
 226     { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_scrypt_reset },
 227     { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_scrypt_derive },
 228     { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
 229       (void(*)(void))kdf_scrypt_settable_ctx_params },
 230     { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_scrypt_set_ctx_params },
 231     { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
 232       (void(*)(void))kdf_scrypt_gettable_ctx_params },
 233     { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_scrypt_get_ctx_params },
 234     { 0, NULL }
 235 };
 236
 237 #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
 238 static void salsa208_word_specification(uint32_t inout[16])
 239 {
 240     int i;
 241     uint32_t x[16];
 242
 243     memcpy(x, inout, sizeof(x));
 244     for (i = 8; i > 0; i -= 2) {
 245         x[4] ^= R(x[0] + x[12], 7);
 246         x[8] ^= R(x[4] + x[0], 9);
 247         x[12] ^= R(x[8] + x[4], 13);
 248         x[0] ^= R(x[12] + x[8], 18);
 249         x[9] ^= R(x[5] + x[1], 7);
 250         x[13] ^= R(x[9] + x[5], 9);
 251         x[1] ^= R(x[13] + x[9], 13);
 252         x[5] ^= R(x[1] + x[13], 18);
 253         x[14] ^= R(x[10] + x[6], 7);
 254         x[2] ^= R(x[14] + x[10], 9);
 255         x[6] ^= R(x[2] + x[14], 13);
 256         x[10] ^= R(x[6] + x[2], 18);
 257         x[3] ^= R(x[15] + x[11], 7);
 258         x[7] ^= R(x[3] + x[15], 9);
 259         x[11] ^= R(x[7] + x[3], 13);
 260         x[15] ^= R(x[11] + x[7], 18);
 261         x[1] ^= R(x[0] + x[3], 7);
 262         x[2] ^= R(x[1] + x[0], 9);
 263         x[3] ^= R(x[2] + x[1], 13);
 264         x[0] ^= R(x[3] + x[2], 18);
 265         x[6] ^= R(x[5] + x[4], 7);
 266         x[7] ^= R(x[6] + x[5], 9);
 267         x[4] ^= R(x[7] + x[6], 13);
 268         x[5] ^= R(x[4] + x[7], 18);
 269         x[11] ^= R(x[10] + x[9], 7);
 270         x[8] ^= R(x[11] + x[10], 9);
 271         x[9] ^= R(x[8] + x[11], 13);
 272         x[10] ^= R(x[9] + x[8], 18);
 273         x[12] ^= R(x[15] + x[14], 7);
 274         x[13] ^= R(x[12] + x[15], 9);
 275         x[14] ^= R(x[13] + x[12], 13);
 276         x[15] ^= R(x[14] + x[13], 18);
 277     }
 278     for (i = 0; i < 16; ++i)
 279         inout[i] += x[i];
 280     OPENSSL_cleanse(x, sizeof(x));
 281 }
 282
 283 static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
 284 {
 285     uint64_t i, j;
 286     uint32_t X[16], *pB;
 287
 288     memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
 289     pB = B;
 290     for (i = 0; i < r * 2; i++) {
 291         for (j = 0; j < 16; j++)
 292             X[j] ^= *pB++;
 293         salsa208_word_specification(X);
 294         memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
 295     }
 296     OPENSSL_cleanse(X, sizeof(X));
 297 }
 298
 299 static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
 300                         uint32_t *X, uint32_t *T, uint32_t *V)
 301 {
 302     unsigned char *pB;
 303     uint32_t *pV;
 304     uint64_t i, k;
 305
 306     /* Convert from little endian input */
 307     for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
 308         *pV = *pB++;
 309         *pV |= *pB++ << 8;
 310         *pV |= *pB++ << 16;
 311         *pV |= (uint32_t)*pB++ << 24;
 312     }
 313
 314     for (i = 1; i < N; i++, pV += 32 * r)
 315         scryptBlockMix(pV, pV - 32 * r, r);
 316
 317     scryptBlockMix(X, V + (N - 1) * 32 * r, r);
 318
 319     for (i = 0; i < N; i++) {
 320         uint32_t j;
 321         j = X[16 * (2 * r - 1)] % N;
 322         pV = V + 32 * r * j;
 323         for (k = 0; k < 32 * r; k++)
 324             T[k] = X[k] ^ *pV++;
 325         scryptBlockMix(X, T, r);
 326     }
 327     /* Convert output to little endian */
 328     for (i = 0, pB = B; i < 32 * r; i++) {
 329         uint32_t xtmp = X[i];
 330         *pB++ = xtmp & 0xff;
 331         *pB++ = (xtmp >> 8) & 0xff;
 332         *pB++ = (xtmp >> 16) & 0xff;
 333         *pB++ = (xtmp >> 24) & 0xff;
 334     }
 335 }
 336
 337 #ifndef SIZE_MAX
 338 # define SIZE_MAX    ((size_t)-1)
 339 #endif
 340
 341 /*
 342  * Maximum power of two that will fit in uint64_t: this should work on
 343  * most (all?) platforms.
 344  */
 345
 346 #define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)
 347
 348 /*
 349  * Maximum value of p * r:
 350  * p <= ((2^32-1) * hLen) / MFLen =>
 351  * p <= ((2^32-1) * 32) / (128 * r) =>
 352  * p * r <= (2^30-1)
 353  */
 354
 355 #define SCRYPT_PR_MAX   ((1 << 30) - 1)
 356
 357 static int scrypt_alg(const char *pass, size_t passlen,
 358                       const unsigned char *salt, size_t saltlen,
 359                       uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
 360                       unsigned char *key, size_t keylen, EVP_MD *sha256)
 361 {
 362     int rv = 0;
 363     unsigned char *B;
 364     uint32_t *X, *V, *T;
 365     uint64_t i, Blen, Vlen;
 366
 367     /* Sanity check parameters */
 368     /* initial check, r,p must be non zero, N >= 2 and a power of 2 */
 369     if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
 370         return 0;
 371     /* Check p * r < SCRYPT_PR_MAX avoiding overflow */
 372     if (p > SCRYPT_PR_MAX / r) {
 373         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 374         return 0;
 375     }
 376
 377     /*
 378      * Need to check N: if 2^(128 * r / 8) overflows limit this is
 379      * automatically satisfied since N <= UINT64_MAX.
 380      */
 381
 382     if (16 * r <= LOG2_UINT64_MAX) {
 383         if (N >= (((uint64_t)1) << (16 * r))) {
 384             EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 385             return 0;
 386         }
 387     }
 388
 389     /* Memory checks: check total allocated buffer size fits in uint64_t */
 390
 391     /*
 392      * B size in section 5 step 1.S
 393      * Note: we know p * 128 * r < UINT64_MAX because we already checked
 394      * p * r < SCRYPT_PR_MAX
 395      */
 396     Blen = p * 128 * r;
 397     /*
 398      * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
 399      * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
 400      */
 401     if (Blen > INT_MAX) {
 402         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 403         return 0;
 404     }
 405
 406     /*
 407      * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
 408      * This is combined size V, X and T (section 4)
 409      */
 410     i = UINT64_MAX / (32 * sizeof(uint32_t));
 411     if (N + 2 > i / r) {
 412         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 413         return 0;
 414     }
 415     Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
 416
 417     /* check total allocated size fits in uint64_t */
 418     if (Blen > UINT64_MAX - Vlen) {
 419         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 420         return 0;
 421     }
 422
 423     /* Check that the maximum memory doesn't exceed a size_t limits */
 424     if (maxmem > SIZE_MAX)
 425         maxmem = SIZE_MAX;
 426
 427     if (Blen + Vlen > maxmem) {
 428         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_MEMORY_LIMIT_EXCEEDED);
 429         return 0;
 430     }
 431
 432     /* If no key return to indicate parameters are OK */
 433     if (key == NULL)
 434         return 1;
 435
 436     B = OPENSSL_malloc((size_t)(Blen + Vlen));
 437     if (B == NULL) {
 438         EVPerr(EVP_F_SCRYPT_ALG, ERR_R_MALLOC_FAILURE);
 439         return 0;
 440     }
 441     X = (uint32_t *)(B + Blen);
 442     T = X + 32 * r;
 443     V = T + 32 * r;
 444     if (PKCS5_PBKDF2_HMAC(pass, passlen, salt, saltlen, 1, sha256,
 445                           (int)Blen, B) == 0)
 446         goto err;
 447
 448     for (i = 0; i < p; i++)
 449         scryptROMix(B + 128 * r * i, r, N, X, T, V);
 450
 451     if (PKCS5_PBKDF2_HMAC(pass, passlen, B, (int)Blen, 1, sha256,
 452                           keylen, key) == 0)
 453         goto err;
 454     rv = 1;
 455  err:
 456     if (rv == 0)
 457         EVPerr(EVP_F_SCRYPT_ALG, EVP_R_PBKDF2_ERROR);
 458
 459     OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
 460     return rv;
 461 }
 462
 463 #endif