1/*
2 * Copyright 2017-2021 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 <openssl/proverr.h>
18#include "crypto/evp.h"
19#include "internal/numbers.h"
20#include "prov/implementations.h"
21#include "prov/provider_ctx.h"
22#include "prov/providercommon.h"
23#include "prov/implementations.h"
24
25#ifndef OPENSSL_NO_SCRYPT
26
27static OSSL_FUNC_kdf_newctx_fn kdf_scrypt_new;
28static OSSL_FUNC_kdf_freectx_fn kdf_scrypt_free;
29static OSSL_FUNC_kdf_reset_fn kdf_scrypt_reset;
30static OSSL_FUNC_kdf_derive_fn kdf_scrypt_derive;
31static OSSL_FUNC_kdf_settable_ctx_params_fn kdf_scrypt_settable_ctx_params;
32static OSSL_FUNC_kdf_set_ctx_params_fn kdf_scrypt_set_ctx_params;
33static OSSL_FUNC_kdf_gettable_ctx_params_fn kdf_scrypt_gettable_ctx_params;
34static OSSL_FUNC_kdf_get_ctx_params_fn kdf_scrypt_get_ctx_params;
35
36static int scrypt_alg(const char *pass, size_t passlen,
37                      const unsigned char *salt, size_t saltlen,
38                      uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
39                      unsigned char *key, size_t keylen, EVP_MD *sha256,
40                      OSSL_LIB_CTX *libctx, const char *propq);
41
42typedef struct {
43    OSSL_LIB_CTX *libctx;
44    char *propq;
45    unsigned char *pass;
46    size_t pass_len;
47    unsigned char *salt;
48    size_t salt_len;
49    uint64_t N;
50    uint64_t r, p;
51    uint64_t maxmem_bytes;
52    EVP_MD *sha256;
53} KDF_SCRYPT;
54
55static void kdf_scrypt_init(KDF_SCRYPT *ctx);
56
57static void *kdf_scrypt_new(void *provctx)
58{
59    KDF_SCRYPT *ctx;
60
61    if (!ossl_prov_is_running())
62        return NULL;
63
64    ctx = OPENSSL_zalloc(sizeof(*ctx));
65    if (ctx == NULL) {
66        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
67        return NULL;
68    }
69    ctx->libctx = PROV_LIBCTX_OF(provctx);
70    kdf_scrypt_init(ctx);
71    return ctx;
72}
73
74static void kdf_scrypt_free(void *vctx)
75{
76    KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
77
78    if (ctx != NULL) {
79        OPENSSL_free(ctx->propq);
80        EVP_MD_free(ctx->sha256);
81        kdf_scrypt_reset(ctx);
82        OPENSSL_free(ctx);
83    }
84}
85
86static void kdf_scrypt_reset(void *vctx)
87{
88    KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
89
90    OPENSSL_free(ctx->salt);
91    OPENSSL_clear_free(ctx->pass, ctx->pass_len);
92    kdf_scrypt_init(ctx);
93}
94
95static void kdf_scrypt_init(KDF_SCRYPT *ctx)
96{
97    /* Default values are the most conservative recommendation given in the
98     * original paper of C. Percival. Derivation uses roughly 1 GiB of memory
99     * for this parameter choice (approx. 128 * r * N * p bytes).
100     */
101    ctx->N = 1 << 20;
102    ctx->r = 8;
103    ctx->p = 1;
104    ctx->maxmem_bytes = 1025 * 1024 * 1024;
105}
106
107static int scrypt_set_membuf(unsigned char **buffer, size_t *buflen,
108                             const OSSL_PARAM *p)
109{
110    OPENSSL_clear_free(*buffer, *buflen);
111    *buffer = NULL;
112    *buflen = 0;
113
114    if (p->data_size == 0) {
115        if ((*buffer = OPENSSL_malloc(1)) == NULL) {
116            ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
117            return 0;
118        }
119    } else if (p->data != NULL) {
120        if (!OSSL_PARAM_get_octet_string(p, (void **)buffer, 0, buflen))
121            return 0;
122    }
123    return 1;
124}
125
126static int set_digest(KDF_SCRYPT *ctx)
127{
128    EVP_MD_free(ctx->sha256);
129    ctx->sha256 = EVP_MD_fetch(ctx->libctx, "sha256", ctx->propq);
130    if (ctx->sha256 == NULL) {
131        OPENSSL_free(ctx);
132        ERR_raise(ERR_LIB_PROV, PROV_R_UNABLE_TO_LOAD_SHA256);
133        return 0;
134    }
135    return 1;
136}
137
138static int set_property_query(KDF_SCRYPT *ctx, const char *propq)
139{
140    OPENSSL_free(ctx->propq);
141    ctx->propq = NULL;
142    if (propq != NULL) {
143        ctx->propq = OPENSSL_strdup(propq);
144        if (ctx->propq == NULL) {
145            ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
146            return 0;
147        }
148    }
149    return 1;
150}
151
152static int kdf_scrypt_derive(void *vctx, unsigned char *key, size_t keylen,
153                             const OSSL_PARAM params[])
154{
155    KDF_SCRYPT *ctx = (KDF_SCRYPT *)vctx;
156
157    if (!ossl_prov_is_running() || !kdf_scrypt_set_ctx_params(ctx, params))
158        return 0;
159
160    if (ctx->pass == NULL) {
161        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_PASS);
162        return 0;
163    }
164
165    if (ctx->salt == NULL) {
166        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_SALT);
167        return 0;
168    }
169
170    if (ctx->sha256 == NULL && !set_digest(ctx))
171        return 0;
172
173    return scrypt_alg((char *)ctx->pass, ctx->pass_len, ctx->salt,
174                      ctx->salt_len, ctx->N, ctx->r, ctx->p,
175                      ctx->maxmem_bytes, key, keylen, ctx->sha256,
176                      ctx->libctx, ctx->propq);
177}
178
179static int is_power_of_two(uint64_t value)
180{
181    return (value != 0) && ((value & (value - 1)) == 0);
182}
183
184static int kdf_scrypt_set_ctx_params(void *vctx, const OSSL_PARAM params[])
185{
186    const OSSL_PARAM *p;
187    KDF_SCRYPT *ctx = vctx;
188    uint64_t u64_value;
189
190    if (params == NULL)
191        return 1;
192
193    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PASSWORD)) != NULL)
194        if (!scrypt_set_membuf(&ctx->pass, &ctx->pass_len, p))
195            return 0;
196
197    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SALT)) != NULL)
198        if (!scrypt_set_membuf(&ctx->salt, &ctx->salt_len, p))
199            return 0;
200
201    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_N))
202        != NULL) {
203        if (!OSSL_PARAM_get_uint64(p, &u64_value)
204            || u64_value <= 1
205            || !is_power_of_two(u64_value))
206            return 0;
207        ctx->N = u64_value;
208    }
209
210    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_R))
211        != NULL) {
212        if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
213            return 0;
214        ctx->r = u64_value;
215    }
216
217    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_P))
218        != NULL) {
219        if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
220            return 0;
221        ctx->p = u64_value;
222    }
223
224    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_SCRYPT_MAXMEM))
225        != NULL) {
226        if (!OSSL_PARAM_get_uint64(p, &u64_value) || u64_value < 1)
227            return 0;
228        ctx->maxmem_bytes = u64_value;
229    }
230
231    p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_PROPERTIES);
232    if (p != NULL) {
233        if (p->data_type != OSSL_PARAM_UTF8_STRING
234            || !set_property_query(ctx, p->data)
235            || !set_digest(ctx))
236            return 0;
237    }
238    return 1;
239}
240
241static const OSSL_PARAM *kdf_scrypt_settable_ctx_params(ossl_unused void *ctx,
242                                                        ossl_unused void *p_ctx)
243{
244    static const OSSL_PARAM known_settable_ctx_params[] = {
245        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_PASSWORD, NULL, 0),
246        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_SALT, NULL, 0),
247        OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_N, NULL),
248        OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_R, NULL),
249        OSSL_PARAM_uint32(OSSL_KDF_PARAM_SCRYPT_P, NULL),
250        OSSL_PARAM_uint64(OSSL_KDF_PARAM_SCRYPT_MAXMEM, NULL),
251        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
252        OSSL_PARAM_END
253    };
254    return known_settable_ctx_params;
255}
256
257static int kdf_scrypt_get_ctx_params(void *vctx, OSSL_PARAM params[])
258{
259    OSSL_PARAM *p;
260
261    if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
262        return OSSL_PARAM_set_size_t(p, SIZE_MAX);
263    return -2;
264}
265
266static const OSSL_PARAM *kdf_scrypt_gettable_ctx_params(ossl_unused void *ctx,
267                                                        ossl_unused void *p_ctx)
268{
269    static const OSSL_PARAM known_gettable_ctx_params[] = {
270        OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
271        OSSL_PARAM_END
272    };
273    return known_gettable_ctx_params;
274}
275
276const OSSL_DISPATCH ossl_kdf_scrypt_functions[] = {
277    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))kdf_scrypt_new },
278    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))kdf_scrypt_free },
279    { OSSL_FUNC_KDF_RESET, (void(*)(void))kdf_scrypt_reset },
280    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))kdf_scrypt_derive },
281    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
282      (void(*)(void))kdf_scrypt_settable_ctx_params },
283    { OSSL_FUNC_KDF_SET_CTX_PARAMS, (void(*)(void))kdf_scrypt_set_ctx_params },
284    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
285      (void(*)(void))kdf_scrypt_gettable_ctx_params },
286    { OSSL_FUNC_KDF_GET_CTX_PARAMS, (void(*)(void))kdf_scrypt_get_ctx_params },
287    { 0, NULL }
288};
289
290#define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
291static void salsa208_word_specification(uint32_t inout[16])
292{
293    int i;
294    uint32_t x[16];
295
296    memcpy(x, inout, sizeof(x));
297    for (i = 8; i > 0; i -= 2) {
298        x[4] ^= R(x[0] + x[12], 7);
299        x[8] ^= R(x[4] + x[0], 9);
300        x[12] ^= R(x[8] + x[4], 13);
301        x[0] ^= R(x[12] + x[8], 18);
302        x[9] ^= R(x[5] + x[1], 7);
303        x[13] ^= R(x[9] + x[5], 9);
304        x[1] ^= R(x[13] + x[9], 13);
305        x[5] ^= R(x[1] + x[13], 18);
306        x[14] ^= R(x[10] + x[6], 7);
307        x[2] ^= R(x[14] + x[10], 9);
308        x[6] ^= R(x[2] + x[14], 13);
309        x[10] ^= R(x[6] + x[2], 18);
310        x[3] ^= R(x[15] + x[11], 7);
311        x[7] ^= R(x[3] + x[15], 9);
312        x[11] ^= R(x[7] + x[3], 13);
313        x[15] ^= R(x[11] + x[7], 18);
314        x[1] ^= R(x[0] + x[3], 7);
315        x[2] ^= R(x[1] + x[0], 9);
316        x[3] ^= R(x[2] + x[1], 13);
317        x[0] ^= R(x[3] + x[2], 18);
318        x[6] ^= R(x[5] + x[4], 7);
319        x[7] ^= R(x[6] + x[5], 9);
320        x[4] ^= R(x[7] + x[6], 13);
321        x[5] ^= R(x[4] + x[7], 18);
322        x[11] ^= R(x[10] + x[9], 7);
323        x[8] ^= R(x[11] + x[10], 9);
324        x[9] ^= R(x[8] + x[11], 13);
325        x[10] ^= R(x[9] + x[8], 18);
326        x[12] ^= R(x[15] + x[14], 7);
327        x[13] ^= R(x[12] + x[15], 9);
328        x[14] ^= R(x[13] + x[12], 13);
329        x[15] ^= R(x[14] + x[13], 18);
330    }
331    for (i = 0; i < 16; ++i)
332        inout[i] += x[i];
333    OPENSSL_cleanse(x, sizeof(x));
334}
335
336static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
337{
338    uint64_t i, j;
339    uint32_t X[16], *pB;
340
341    memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
342    pB = B;
343    for (i = 0; i < r * 2; i++) {
344        for (j = 0; j < 16; j++)
345            X[j] ^= *pB++;
346        salsa208_word_specification(X);
347        memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
348    }
349    OPENSSL_cleanse(X, sizeof(X));
350}
351
352static void scryptROMix(unsigned char *B, uint64_t r, uint64_t N,
353                        uint32_t *X, uint32_t *T, uint32_t *V)
354{
355    unsigned char *pB;
356    uint32_t *pV;
357    uint64_t i, k;
358
359    /* Convert from little endian input */
360    for (pV = V, i = 0, pB = B; i < 32 * r; i++, pV++) {
361        *pV = *pB++;
362        *pV |= *pB++ << 8;
363        *pV |= *pB++ << 16;
364        *pV |= (uint32_t)*pB++ << 24;
365    }
366
367    for (i = 1; i < N; i++, pV += 32 * r)
368        scryptBlockMix(pV, pV - 32 * r, r);
369
370    scryptBlockMix(X, V + (N - 1) * 32 * r, r);
371
372    for (i = 0; i < N; i++) {
373        uint32_t j;
374        j = X[16 * (2 * r - 1)] % N;
375        pV = V + 32 * r * j;
376        for (k = 0; k < 32 * r; k++)
377            T[k] = X[k] ^ *pV++;
378        scryptBlockMix(X, T, r);
379    }
380    /* Convert output to little endian */
381    for (i = 0, pB = B; i < 32 * r; i++) {
382        uint32_t xtmp = X[i];
383        *pB++ = xtmp & 0xff;
384        *pB++ = (xtmp >> 8) & 0xff;
385        *pB++ = (xtmp >> 16) & 0xff;
386        *pB++ = (xtmp >> 24) & 0xff;
387    }
388}
389
390#ifndef SIZE_MAX
391# define SIZE_MAX    ((size_t)-1)
392#endif
393
394/*
395 * Maximum power of two that will fit in uint64_t: this should work on
396 * most (all?) platforms.
397 */
398
399#define LOG2_UINT64_MAX         (sizeof(uint64_t) * 8 - 1)
400
401/*
402 * Maximum value of p * r:
403 * p <= ((2^32-1) * hLen) / MFLen =>
404 * p <= ((2^32-1) * 32) / (128 * r) =>
405 * p * r <= (2^30-1)
406 */
407
408#define SCRYPT_PR_MAX   ((1 << 30) - 1)
409
410static int scrypt_alg(const char *pass, size_t passlen,
411                      const unsigned char *salt, size_t saltlen,
412                      uint64_t N, uint64_t r, uint64_t p, uint64_t maxmem,
413                      unsigned char *key, size_t keylen, EVP_MD *sha256,
414                      OSSL_LIB_CTX *libctx, const char *propq)
415{
416    int rv = 0;
417    unsigned char *B;
418    uint32_t *X, *V, *T;
419    uint64_t i, Blen, Vlen;
420
421    /* Sanity check parameters */
422    /* initial check, r,p must be non zero, N >= 2 and a power of 2 */
423    if (r == 0 || p == 0 || N < 2 || (N & (N - 1)))
424        return 0;
425    /* Check p * r < SCRYPT_PR_MAX avoiding overflow */
426    if (p > SCRYPT_PR_MAX / r) {
427        ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
428        return 0;
429    }
430
431    /*
432     * Need to check N: if 2^(128 * r / 8) overflows limit this is
433     * automatically satisfied since N <= UINT64_MAX.
434     */
435
436    if (16 * r <= LOG2_UINT64_MAX) {
437        if (N >= (((uint64_t)1) << (16 * r))) {
438            ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
439            return 0;
440        }
441    }
442
443    /* Memory checks: check total allocated buffer size fits in uint64_t */
444
445    /*
446     * B size in section 5 step 1.S
447     * Note: we know p * 128 * r < UINT64_MAX because we already checked
448     * p * r < SCRYPT_PR_MAX
449     */
450    Blen = p * 128 * r;
451    /*
452     * Yet we pass it as integer to PKCS5_PBKDF2_HMAC... [This would
453     * have to be revised when/if PKCS5_PBKDF2_HMAC accepts size_t.]
454     */
455    if (Blen > INT_MAX) {
456        ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
457        return 0;
458    }
459
460    /*
461     * Check 32 * r * (N + 2) * sizeof(uint32_t) fits in uint64_t
462     * This is combined size V, X and T (section 4)
463     */
464    i = UINT64_MAX / (32 * sizeof(uint32_t));
465    if (N + 2 > i / r) {
466        ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
467        return 0;
468    }
469    Vlen = 32 * r * (N + 2) * sizeof(uint32_t);
470
471    /* check total allocated size fits in uint64_t */
472    if (Blen > UINT64_MAX - Vlen) {
473        ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
474        return 0;
475    }
476
477    /* Check that the maximum memory doesn't exceed a size_t limits */
478    if (maxmem > SIZE_MAX)
479        maxmem = SIZE_MAX;
480
481    if (Blen + Vlen > maxmem) {
482        ERR_raise(ERR_LIB_EVP, EVP_R_MEMORY_LIMIT_EXCEEDED);
483        return 0;
484    }
485
486    /* If no key return to indicate parameters are OK */
487    if (key == NULL)
488        return 1;
489
490    B = OPENSSL_malloc((size_t)(Blen + Vlen));
491    if (B == NULL) {
492        ERR_raise(ERR_LIB_EVP, ERR_R_MALLOC_FAILURE);
493        return 0;
494    }
495    X = (uint32_t *)(B + Blen);
496    T = X + 32 * r;
497    V = T + 32 * r;
498    if (ossl_pkcs5_pbkdf2_hmac_ex(pass, passlen, salt, saltlen, 1, sha256,
499                                  (int)Blen, B, libctx, propq) == 0)
500        goto err;
501
502    for (i = 0; i < p; i++)
503        scryptROMix(B + 128 * r * i, r, N, X, T, V);
504
505    if (ossl_pkcs5_pbkdf2_hmac_ex(pass, passlen, B, (int)Blen, 1, sha256,
506                                  keylen, key, libctx, propq) == 0)
507        goto err;
508    rv = 1;
509 err:
510    if (rv == 0)
511        ERR_raise(ERR_LIB_EVP, EVP_R_PBKDF2_ERROR);
512
513    OPENSSL_clear_free(B, (size_t)(Blen + Vlen));
514    return rv;
515}
516
517#endif
518