1 /*
2  * Copyright 2011-2021 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 <assert.h>
11 #include <stdlib.h>
12 #include <string.h>
13 #include <openssl/sha.h>
14 #include <openssl/crypto.h>
15 #include <openssl/err.h>
16 #include <openssl/rand.h>
17 #include <openssl/core_dispatch.h>
18 #include <openssl/proverr.h>
19 #include "internal/thread_once.h"
20 #include "prov/providercommon.h"
21 #include "prov/provider_ctx.h"
22 #include "prov/provider_util.h"
23 #include "prov/implementations.h"
24 #include "drbg_local.h"
25 
26 static OSSL_FUNC_rand_newctx_fn drbg_hash_new_wrapper;
27 static OSSL_FUNC_rand_freectx_fn drbg_hash_free;
28 static OSSL_FUNC_rand_instantiate_fn drbg_hash_instantiate_wrapper;
29 static OSSL_FUNC_rand_uninstantiate_fn drbg_hash_uninstantiate_wrapper;
30 static OSSL_FUNC_rand_generate_fn drbg_hash_generate_wrapper;
31 static OSSL_FUNC_rand_reseed_fn drbg_hash_reseed_wrapper;
32 static OSSL_FUNC_rand_settable_ctx_params_fn drbg_hash_settable_ctx_params;
33 static OSSL_FUNC_rand_set_ctx_params_fn drbg_hash_set_ctx_params;
34 static OSSL_FUNC_rand_gettable_ctx_params_fn drbg_hash_gettable_ctx_params;
35 static OSSL_FUNC_rand_get_ctx_params_fn drbg_hash_get_ctx_params;
36 static OSSL_FUNC_rand_verify_zeroization_fn drbg_hash_verify_zeroization;
37 
38 /* 888 bits from SP800-90Ar1 10.1 table 2 */
39 #define HASH_PRNG_MAX_SEEDLEN    (888/8)
40 
41 /* 440 bits from SP800-90Ar1 10.1 table 2 */
42 #define HASH_PRNG_SMALL_SEEDLEN   (440/8)
43 
44 /* Determine what seedlen to use based on the block length */
45 #define MAX_BLOCKLEN_USING_SMALL_SEEDLEN (256/8)
46 #define INBYTE_IGNORE ((unsigned char)0xFF)
47 
48 typedef struct rand_drbg_hash_st {
49     PROV_DIGEST digest;
50     EVP_MD_CTX *ctx;
51     size_t blocklen;
52     unsigned char V[HASH_PRNG_MAX_SEEDLEN];
53     unsigned char C[HASH_PRNG_MAX_SEEDLEN];
54     /* Temporary value storage: should always exceed max digest length */
55     unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN];
56 } PROV_DRBG_HASH;
57 
58 /*
59  * SP800-90Ar1 10.3.1 Derivation function using a Hash Function (Hash_df).
60  * The input string used is composed of:
61  *    inbyte - An optional leading byte (ignore if equal to INBYTE_IGNORE)
62  *    in - input string 1 (A Non NULL value).
63  *    in2 - optional input string (Can be NULL).
64  *    in3 - optional input string (Can be NULL).
65  *    These are concatenated as part of the DigestUpdate process.
66  */
hash_df(PROV_DRBG * drbg,unsigned char * out,const unsigned char inbyte,const unsigned char * in,size_t inlen,const unsigned char * in2,size_t in2len,const unsigned char * in3,size_t in3len)67 static int hash_df(PROV_DRBG *drbg, unsigned char *out,
68                    const unsigned char inbyte,
69                    const unsigned char *in, size_t inlen,
70                    const unsigned char *in2, size_t in2len,
71                    const unsigned char *in3, size_t in3len)
72 {
73     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
74     EVP_MD_CTX *ctx = hash->ctx;
75     unsigned char *vtmp = hash->vtmp;
76     /* tmp = counter || num_bits_returned || [inbyte] */
77     unsigned char tmp[1 + 4 + 1];
78     int tmp_sz = 0;
79     size_t outlen = drbg->seedlen;
80     size_t num_bits_returned = outlen * 8;
81     /*
82      * No need to check outlen size here, as the standard only ever needs
83      * seedlen bytes which is always less than the maximum permitted.
84      */
85 
86     /* (Step 3) counter = 1 (tmp[0] is the 8 bit counter) */
87     tmp[tmp_sz++] = 1;
88     /* tmp[1..4] is the fixed 32 bit no_of_bits_to_return */
89     tmp[tmp_sz++] = (unsigned char)((num_bits_returned >> 24) & 0xff);
90     tmp[tmp_sz++] = (unsigned char)((num_bits_returned >> 16) & 0xff);
91     tmp[tmp_sz++] = (unsigned char)((num_bits_returned >> 8) & 0xff);
92     tmp[tmp_sz++] = (unsigned char)(num_bits_returned & 0xff);
93     /* Tack the additional input byte onto the end of tmp if it exists */
94     if (inbyte != INBYTE_IGNORE)
95         tmp[tmp_sz++] = inbyte;
96 
97     /* (Step 4) */
98     for (;;) {
99         /*
100          * (Step 4.1) out = out || Hash(tmp || in || [in2] || [in3])
101          *            (where tmp = counter || num_bits_returned || [inbyte])
102          */
103         if (!(EVP_DigestInit_ex(ctx, ossl_prov_digest_md(&hash->digest), NULL)
104                 && EVP_DigestUpdate(ctx, tmp, tmp_sz)
105                 && EVP_DigestUpdate(ctx, in, inlen)
106                 && (in2 == NULL || EVP_DigestUpdate(ctx, in2, in2len))
107                 && (in3 == NULL || EVP_DigestUpdate(ctx, in3, in3len))))
108             return 0;
109 
110         if (outlen < hash->blocklen) {
111             if (!EVP_DigestFinal(ctx, vtmp, NULL))
112                 return 0;
113             memcpy(out, vtmp, outlen);
114             OPENSSL_cleanse(vtmp, hash->blocklen);
115             break;
116         } else if(!EVP_DigestFinal(ctx, out, NULL)) {
117             return 0;
118         }
119 
120         outlen -= hash->blocklen;
121         if (outlen == 0)
122             break;
123         /* (Step 4.2) counter++ */
124         tmp[0]++;
125         out += hash->blocklen;
126     }
127     return 1;
128 }
129 
130 /* Helper function that just passes 2 input parameters to hash_df() */
hash_df1(PROV_DRBG * drbg,unsigned char * out,const unsigned char in_byte,const unsigned char * in1,size_t in1len)131 static int hash_df1(PROV_DRBG *drbg, unsigned char *out,
132                     const unsigned char in_byte,
133                     const unsigned char *in1, size_t in1len)
134 {
135     return hash_df(drbg, out, in_byte, in1, in1len, NULL, 0, NULL, 0);
136 }
137 
138 /*
139  * Add 2 byte buffers together. The first elements in each buffer are the top
140  * most bytes. The result is stored in the dst buffer.
141  * The final carry is ignored i.e: dst =  (dst + in) mod (2^seedlen_bits).
142  * where dst size is drbg->seedlen, and inlen <= drbg->seedlen.
143  */
add_bytes(PROV_DRBG * drbg,unsigned char * dst,unsigned char * in,size_t inlen)144 static int add_bytes(PROV_DRBG *drbg, unsigned char *dst,
145                      unsigned char *in, size_t inlen)
146 {
147     size_t i;
148     int result;
149     const unsigned char *add;
150     unsigned char carry = 0, *d;
151 
152     assert(drbg->seedlen >= 1 && inlen >= 1 && inlen <= drbg->seedlen);
153 
154     d = &dst[drbg->seedlen - 1];
155     add = &in[inlen - 1];
156 
157     for (i = inlen; i > 0; i--, d--, add--) {
158         result = *d + *add + carry;
159         carry = (unsigned char)(result >> 8);
160         *d = (unsigned char)(result & 0xff);
161     }
162 
163     if (carry != 0) {
164         /* Add the carry to the top of the dst if inlen is not the same size */
165         for (i = drbg->seedlen - inlen; i > 0; --i, d--) {
166             *d += 1;     /* Carry can only be 1 */
167             if (*d != 0) /* exit if carry doesnt propagate to the next byte */
168                 break;
169         }
170     }
171     return 1;
172 }
173 
174 /* V = (V + Hash(inbyte || V  || [additional_input]) mod (2^seedlen) */
add_hash_to_v(PROV_DRBG * drbg,unsigned char inbyte,const unsigned char * adin,size_t adinlen)175 static int add_hash_to_v(PROV_DRBG *drbg, unsigned char inbyte,
176                          const unsigned char *adin, size_t adinlen)
177 {
178     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
179     EVP_MD_CTX *ctx = hash->ctx;
180 
181     return EVP_DigestInit_ex(ctx, ossl_prov_digest_md(&hash->digest), NULL)
182            && EVP_DigestUpdate(ctx, &inbyte, 1)
183            && EVP_DigestUpdate(ctx, hash->V, drbg->seedlen)
184            && (adin == NULL || EVP_DigestUpdate(ctx, adin, adinlen))
185            && EVP_DigestFinal(ctx, hash->vtmp, NULL)
186            && add_bytes(drbg, hash->V, hash->vtmp, hash->blocklen);
187 }
188 
189 /*
190  * The Hashgen() as listed in SP800-90Ar1 10.1.1.4 Hash_DRBG_Generate_Process.
191  *
192  * drbg contains the current value of V.
193  * outlen is the requested number of bytes.
194  * out is a buffer to return the generated bits.
195  *
196  * The algorithm to generate the bits is:
197  *     data = V
198  *     w = NULL
199  *     for (i = 1 to m) {
200  *        W = W || Hash(data)
201  *        data = (data + 1) mod (2^seedlen)
202  *     }
203  *     out = Leftmost(W, outlen)
204  *
205  * Returns zero if an error occurs otherwise it returns 1.
206  */
hash_gen(PROV_DRBG * drbg,unsigned char * out,size_t outlen)207 static int hash_gen(PROV_DRBG *drbg, unsigned char *out, size_t outlen)
208 {
209     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
210     unsigned char one = 1;
211 
212     if (outlen == 0)
213         return 1;
214     memcpy(hash->vtmp, hash->V, drbg->seedlen);
215     for(;;) {
216         if (!EVP_DigestInit_ex(hash->ctx, ossl_prov_digest_md(&hash->digest),
217                                NULL)
218                 || !EVP_DigestUpdate(hash->ctx, hash->vtmp, drbg->seedlen))
219             return 0;
220 
221         if (outlen < hash->blocklen) {
222             if (!EVP_DigestFinal(hash->ctx, hash->vtmp, NULL))
223                 return 0;
224             memcpy(out, hash->vtmp, outlen);
225             return 1;
226         } else {
227             if (!EVP_DigestFinal(hash->ctx, out, NULL))
228                 return 0;
229             outlen -= hash->blocklen;
230             if (outlen == 0)
231                 break;
232             out += hash->blocklen;
233         }
234         add_bytes(drbg, hash->vtmp, &one, 1);
235     }
236     return 1;
237 }
238 
239 /*
240  * SP800-90Ar1 10.1.1.2 Hash_DRBG_Instantiate_Process:
241  *
242  * ent is entropy input obtained from a randomness source of length ent_len.
243  * nonce is a string of bytes of length nonce_len.
244  * pstr is a personalization string received from an application. May be NULL.
245  *
246  * Returns zero if an error occurs otherwise it returns 1.
247  */
drbg_hash_instantiate(PROV_DRBG * drbg,const unsigned char * ent,size_t ent_len,const unsigned char * nonce,size_t nonce_len,const unsigned char * pstr,size_t pstr_len)248 static int drbg_hash_instantiate(PROV_DRBG *drbg,
249                                  const unsigned char *ent, size_t ent_len,
250                                  const unsigned char *nonce, size_t nonce_len,
251                                  const unsigned char *pstr, size_t pstr_len)
252 {
253     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
254 
255     EVP_MD_CTX_free(hash->ctx);
256     hash->ctx = EVP_MD_CTX_new();
257 
258     /* (Step 1-3) V = Hash_df(entropy||nonce||pers, seedlen) */
259     return hash->ctx != NULL
260            && hash_df(drbg, hash->V, INBYTE_IGNORE,
261                       ent, ent_len, nonce, nonce_len, pstr, pstr_len)
262            /* (Step 4) C = Hash_df(0x00||V, seedlen) */
263            && hash_df1(drbg, hash->C, 0x00, hash->V, drbg->seedlen);
264 }
265 
drbg_hash_instantiate_wrapper(void * vdrbg,unsigned int strength,int prediction_resistance,const unsigned char * pstr,size_t pstr_len,const OSSL_PARAM params[])266 static int drbg_hash_instantiate_wrapper(void *vdrbg, unsigned int strength,
267                                          int prediction_resistance,
268                                          const unsigned char *pstr,
269                                          size_t pstr_len,
270                                          const OSSL_PARAM params[])
271 {
272     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
273 
274     if (!ossl_prov_is_running() || !drbg_hash_set_ctx_params(drbg, params))
275         return 0;
276     return ossl_prov_drbg_instantiate(drbg, strength, prediction_resistance,
277                                       pstr, pstr_len);
278 }
279 
280 /*
281  * SP800-90Ar1 10.1.1.3 Hash_DRBG_Reseed_Process:
282  *
283  * ent is entropy input bytes obtained from a randomness source.
284  * addin is additional input received from an application. May be NULL.
285  *
286  * Returns zero if an error occurs otherwise it returns 1.
287  */
drbg_hash_reseed(PROV_DRBG * drbg,const unsigned char * ent,size_t ent_len,const unsigned char * adin,size_t adin_len)288 static int drbg_hash_reseed(PROV_DRBG *drbg,
289                             const unsigned char *ent, size_t ent_len,
290                             const unsigned char *adin, size_t adin_len)
291 {
292     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
293 
294     /* (Step 1-2) V = Hash_df(0x01 || V || entropy_input || additional_input) */
295     /* V about to be updated so use C as output instead */
296     if (!hash_df(drbg, hash->C, 0x01, hash->V, drbg->seedlen, ent, ent_len,
297                  adin, adin_len))
298         return 0;
299     memcpy(hash->V, hash->C, drbg->seedlen);
300     /* (Step 4) C = Hash_df(0x00||V, seedlen) */
301     return hash_df1(drbg, hash->C, 0x00, hash->V, drbg->seedlen);
302 }
303 
drbg_hash_reseed_wrapper(void * vdrbg,int prediction_resistance,const unsigned char * ent,size_t ent_len,const unsigned char * adin,size_t adin_len)304 static int drbg_hash_reseed_wrapper(void *vdrbg, int prediction_resistance,
305                                     const unsigned char *ent, size_t ent_len,
306                                     const unsigned char *adin, size_t adin_len)
307 {
308     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
309 
310     return ossl_prov_drbg_reseed(drbg, prediction_resistance, ent, ent_len,
311                                  adin, adin_len);
312 }
313 
314 /*
315  * SP800-90Ar1 10.1.1.4 Hash_DRBG_Generate_Process:
316  *
317  * Generates pseudo random bytes using the drbg.
318  * out is a buffer to fill with outlen bytes of pseudo random data.
319  * addin is additional input received from an application. May be NULL.
320  *
321  * Returns zero if an error occurs otherwise it returns 1.
322  */
drbg_hash_generate(PROV_DRBG * drbg,unsigned char * out,size_t outlen,const unsigned char * adin,size_t adin_len)323 static int drbg_hash_generate(PROV_DRBG *drbg,
324                               unsigned char *out, size_t outlen,
325                               const unsigned char *adin, size_t adin_len)
326 {
327     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
328     unsigned char counter[4];
329     int reseed_counter = drbg->generate_counter;
330 
331     counter[0] = (unsigned char)((reseed_counter >> 24) & 0xff);
332     counter[1] = (unsigned char)((reseed_counter >> 16) & 0xff);
333     counter[2] = (unsigned char)((reseed_counter >> 8) & 0xff);
334     counter[3] = (unsigned char)(reseed_counter & 0xff);
335 
336     return hash->ctx != NULL
337            && (adin == NULL
338            /* (Step 2) if adin != NULL then V = V + Hash(0x02||V||adin) */
339                || adin_len == 0
340                || add_hash_to_v(drbg, 0x02, adin, adin_len))
341            /* (Step 3) Hashgen(outlen, V) */
342            && hash_gen(drbg, out, outlen)
343            /* (Step 4/5) H = V = (V + Hash(0x03||V) mod (2^seedlen_bits) */
344            && add_hash_to_v(drbg, 0x03, NULL, 0)
345            /* (Step 5) V = (V + H + C + reseed_counter) mod (2^seedlen_bits) */
346            /* V = (V + C) mod (2^seedlen_bits) */
347            && add_bytes(drbg, hash->V, hash->C, drbg->seedlen)
348            /* V = (V + reseed_counter) mod (2^seedlen_bits) */
349            && add_bytes(drbg, hash->V, counter, 4);
350 }
351 
drbg_hash_generate_wrapper(void * vdrbg,unsigned char * out,size_t outlen,unsigned int strength,int prediction_resistance,const unsigned char * adin,size_t adin_len)352 static int drbg_hash_generate_wrapper
353     (void *vdrbg, unsigned char *out, size_t outlen, unsigned int strength,
354      int prediction_resistance, const unsigned char *adin, size_t adin_len)
355 {
356     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
357 
358     return ossl_prov_drbg_generate(drbg, out, outlen, strength,
359                                    prediction_resistance, adin, adin_len);
360 }
361 
drbg_hash_uninstantiate(PROV_DRBG * drbg)362 static int drbg_hash_uninstantiate(PROV_DRBG *drbg)
363 {
364     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
365 
366     OPENSSL_cleanse(hash->V, sizeof(hash->V));
367     OPENSSL_cleanse(hash->C, sizeof(hash->C));
368     OPENSSL_cleanse(hash->vtmp, sizeof(hash->vtmp));
369     return ossl_prov_drbg_uninstantiate(drbg);
370 }
371 
drbg_hash_uninstantiate_wrapper(void * vdrbg)372 static int drbg_hash_uninstantiate_wrapper(void *vdrbg)
373 {
374     return drbg_hash_uninstantiate((PROV_DRBG *)vdrbg);
375 }
376 
drbg_hash_verify_zeroization(void * vdrbg)377 static int drbg_hash_verify_zeroization(void *vdrbg)
378 {
379     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
380     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
381 
382     PROV_DRBG_VERYIFY_ZEROIZATION(hash->V);
383     PROV_DRBG_VERYIFY_ZEROIZATION(hash->C);
384     PROV_DRBG_VERYIFY_ZEROIZATION(hash->vtmp);
385     return 1;
386 }
387 
drbg_hash_new(PROV_DRBG * ctx)388 static int drbg_hash_new(PROV_DRBG *ctx)
389 {
390     PROV_DRBG_HASH *hash;
391 
392     hash = OPENSSL_secure_zalloc(sizeof(*hash));
393     if (hash == NULL) {
394         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
395         return 0;
396     }
397 
398     ctx->data = hash;
399     ctx->seedlen = HASH_PRNG_MAX_SEEDLEN;
400     ctx->max_entropylen = DRBG_MAX_LENGTH;
401     ctx->max_noncelen = DRBG_MAX_LENGTH;
402     ctx->max_perslen = DRBG_MAX_LENGTH;
403     ctx->max_adinlen = DRBG_MAX_LENGTH;
404 
405     /* Maximum number of bits per request = 2^19  = 2^16 bytes */
406     ctx->max_request = 1 << 16;
407     return 1;
408 }
409 
drbg_hash_new_wrapper(void * provctx,void * parent,const OSSL_DISPATCH * parent_dispatch)410 static void *drbg_hash_new_wrapper(void *provctx, void *parent,
411                                    const OSSL_DISPATCH *parent_dispatch)
412 {
413     return ossl_rand_drbg_new(provctx, parent, parent_dispatch, &drbg_hash_new,
414                               &drbg_hash_instantiate, &drbg_hash_uninstantiate,
415                               &drbg_hash_reseed, &drbg_hash_generate);
416 }
417 
drbg_hash_free(void * vdrbg)418 static void drbg_hash_free(void *vdrbg)
419 {
420     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
421     PROV_DRBG_HASH *hash;
422 
423     if (drbg != NULL && (hash = (PROV_DRBG_HASH *)drbg->data) != NULL) {
424         EVP_MD_CTX_free(hash->ctx);
425         ossl_prov_digest_reset(&hash->digest);
426         OPENSSL_secure_clear_free(hash, sizeof(*hash));
427     }
428     ossl_rand_drbg_free(drbg);
429 }
430 
drbg_hash_get_ctx_params(void * vdrbg,OSSL_PARAM params[])431 static int drbg_hash_get_ctx_params(void *vdrbg, OSSL_PARAM params[])
432 {
433     PROV_DRBG *drbg = (PROV_DRBG *)vdrbg;
434     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)drbg->data;
435     const EVP_MD *md;
436     OSSL_PARAM *p;
437 
438     p = OSSL_PARAM_locate(params, OSSL_DRBG_PARAM_DIGEST);
439     if (p != NULL) {
440         md = ossl_prov_digest_md(&hash->digest);
441         if (md == NULL || !OSSL_PARAM_set_utf8_string(p, EVP_MD_get0_name(md)))
442             return 0;
443     }
444 
445     return ossl_drbg_get_ctx_params(drbg, params);
446 }
447 
drbg_hash_gettable_ctx_params(ossl_unused void * vctx,ossl_unused void * p_ctx)448 static const OSSL_PARAM *drbg_hash_gettable_ctx_params(ossl_unused void *vctx,
449                                                        ossl_unused void *p_ctx)
450 {
451     static const OSSL_PARAM known_gettable_ctx_params[] = {
452         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0),
453         OSSL_PARAM_DRBG_GETTABLE_CTX_COMMON,
454         OSSL_PARAM_END
455     };
456     return known_gettable_ctx_params;
457 }
458 
drbg_hash_set_ctx_params(void * vctx,const OSSL_PARAM params[])459 static int drbg_hash_set_ctx_params(void *vctx, const OSSL_PARAM params[])
460 {
461     PROV_DRBG *ctx = (PROV_DRBG *)vctx;
462     PROV_DRBG_HASH *hash = (PROV_DRBG_HASH *)ctx->data;
463     OSSL_LIB_CTX *libctx = PROV_LIBCTX_OF(ctx->provctx);
464     const EVP_MD *md;
465 
466     if (!ossl_prov_digest_load_from_params(&hash->digest, params, libctx))
467         return 0;
468 
469     md = ossl_prov_digest_md(&hash->digest);
470     if (md != NULL) {
471         if ((EVP_MD_get_flags(md) & EVP_MD_FLAG_XOF) != 0) {
472             ERR_raise(ERR_LIB_PROV, PROV_R_XOF_DIGESTS_NOT_ALLOWED);
473             return 0;
474         }
475 
476         /* These are taken from SP 800-90 10.1 Table 2 */
477         hash->blocklen = EVP_MD_get_size(md);
478         /* See SP800-57 Part1 Rev4 5.6.1 Table 3 */
479         ctx->strength = 64 * (hash->blocklen >> 3);
480         if (ctx->strength > 256)
481             ctx->strength = 256;
482         if (hash->blocklen > MAX_BLOCKLEN_USING_SMALL_SEEDLEN)
483             ctx->seedlen = HASH_PRNG_MAX_SEEDLEN;
484         else
485             ctx->seedlen = HASH_PRNG_SMALL_SEEDLEN;
486 
487         ctx->min_entropylen = ctx->strength / 8;
488         ctx->min_noncelen = ctx->min_entropylen / 2;
489     }
490 
491     return ossl_drbg_set_ctx_params(ctx, params);
492 }
493 
drbg_hash_settable_ctx_params(ossl_unused void * vctx,ossl_unused void * p_ctx)494 static const OSSL_PARAM *drbg_hash_settable_ctx_params(ossl_unused void *vctx,
495                                                        ossl_unused void *p_ctx)
496 {
497     static const OSSL_PARAM known_settable_ctx_params[] = {
498         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_PROPERTIES, NULL, 0),
499         OSSL_PARAM_utf8_string(OSSL_DRBG_PARAM_DIGEST, NULL, 0),
500         OSSL_PARAM_DRBG_SETTABLE_CTX_COMMON,
501         OSSL_PARAM_END
502     };
503     return known_settable_ctx_params;
504 }
505 
506 const OSSL_DISPATCH ossl_drbg_hash_functions[] = {
507     { OSSL_FUNC_RAND_NEWCTX, (void(*)(void))drbg_hash_new_wrapper },
508     { OSSL_FUNC_RAND_FREECTX, (void(*)(void))drbg_hash_free },
509     { OSSL_FUNC_RAND_INSTANTIATE,
510       (void(*)(void))drbg_hash_instantiate_wrapper },
511     { OSSL_FUNC_RAND_UNINSTANTIATE,
512       (void(*)(void))drbg_hash_uninstantiate_wrapper },
513     { OSSL_FUNC_RAND_GENERATE, (void(*)(void))drbg_hash_generate_wrapper },
514     { OSSL_FUNC_RAND_RESEED, (void(*)(void))drbg_hash_reseed_wrapper },
515     { OSSL_FUNC_RAND_ENABLE_LOCKING, (void(*)(void))ossl_drbg_enable_locking },
516     { OSSL_FUNC_RAND_LOCK, (void(*)(void))ossl_drbg_lock },
517     { OSSL_FUNC_RAND_UNLOCK, (void(*)(void))ossl_drbg_unlock },
518     { OSSL_FUNC_RAND_SETTABLE_CTX_PARAMS,
519       (void(*)(void))drbg_hash_settable_ctx_params },
520     { OSSL_FUNC_RAND_SET_CTX_PARAMS, (void(*)(void))drbg_hash_set_ctx_params },
521     { OSSL_FUNC_RAND_GETTABLE_CTX_PARAMS,
522       (void(*)(void))drbg_hash_gettable_ctx_params },
523     { OSSL_FUNC_RAND_GET_CTX_PARAMS, (void(*)(void))drbg_hash_get_ctx_params },
524     { OSSL_FUNC_RAND_VERIFY_ZEROIZATION,
525       (void(*)(void))drbg_hash_verify_zeroization },
526     { OSSL_FUNC_RAND_GET_SEED, (void(*)(void))ossl_drbg_get_seed },
527     { OSSL_FUNC_RAND_CLEAR_SEED, (void(*)(void))ossl_drbg_clear_seed },
528     { 0, NULL }
529 };
530