2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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
10 #ifndef HEADER_RAND_LCL_H
11 # define HEADER_RAND_LCL_H
13 # include <openssl/aes.h>
14 # include <openssl/evp.h>
15 # include <openssl/sha.h>
16 # include <openssl/hmac.h>
17 # include <openssl/ec.h>
18 # include "internal/rand.h"
20 /* How many times to read the TSC as a randomness source. */
21 # define TSC_READ_COUNT 4
23 /* Maximum reseed interval */
24 # define MAX_RESEED_INTERVAL (1 << 24)
26 /* Default reseed intervals */
27 # define MASTER_RESEED_INTERVAL (1 << 8)
28 # define SLAVE_RESEED_INTERVAL (1 << 16)
30 /* Max size of additional input and personalization string. */
31 # define DRBG_MAX_LENGTH 4096
34 * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
36 * The current factor is large enough that the RAND_POOL can store a
37 * random input which has a lousy entropy rate of 0.0625 bits per byte.
38 * This input will be sent through the derivation function which 'compresses'
39 * the low quality input into a high quality output.
41 # define DRBG_MINMAX_FACTOR 128
44 /* DRBG status values */
45 typedef enum drbg_status_e {
53 * The state of a DRBG AES-CTR.
55 typedef struct rand_drbg_ctr_st {
60 /* Temp variables used by derivation function */
63 /* Temporary block storage used by ctr_df */
64 unsigned char bltmp[16];
71 * The state of all types of DRBGs, even though we only have CTR mode
77 int nid; /* the underlying algorithm */
79 unsigned short flags; /* various external flags */
82 * The random pool is used by RAND_add()/drbg_add() to attach random
83 * data to the global drbg, such that the rand_drbg_get_entropy() callback
84 * can pull it during instantiation and reseeding. This is necessary to
85 * reconcile the different philosophies of the RAND and the RAND_DRBG
86 * with respect to how randomness is added to the RNG during reseeding
92 * The following parameters are setup by the per-type "init" function.
94 * Currently the only type is CTR_DRBG, its init function is ctr_init().
96 * The parameters are closely related to the ones described in
97 * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
98 * crucial difference: In the NIST standard, all counts are given
99 * in bits, whereas in OpenSSL entropy counts are given in bits
100 * and buffer lengths are given in bytes.
102 * Since this difference has lead to some confusion in the past,
103 * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
104 * the 'len' suffix has been added to all buffer sizes for
110 size_t min_entropylen, max_entropylen;
111 size_t min_noncelen, max_noncelen;
112 size_t max_perslen, max_adinlen;
114 /* Counts the number of generate requests since the last reseed. */
115 unsigned int generate_counter;
117 * Maximum number of generate requests until a reseed is required.
118 * This value is ignored if it is zero.
120 unsigned int reseed_interval;
122 * Counts the number of reseeds since instantiation.
123 * This value is ignored if it is zero.
125 * This counter is used only for seed propagation from the <master> DRBG
126 * to its two children, the <public> and <private> DRBG. This feature is
127 * very special and its sole purpose is to ensure that any randomness which
128 * is added by RAND_add() or RAND_seed() will have an immediate effect on
129 * the output of RAND_bytes() resp. RAND_priv_bytes().
131 unsigned int reseed_counter;
136 /* Application data, mainly used in the KATs. */
137 CRYPTO_EX_DATA ex_data;
139 /* Implementation specific structures; was a union, but inline for now */
142 /* Callback functions. See comments in rand_lib.c */
143 RAND_DRBG_get_entropy_fn get_entropy;
144 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
145 RAND_DRBG_get_nonce_fn get_nonce;
146 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
149 /* The global RAND method, and the global buffer and DRBG instance. */
150 extern RAND_METHOD rand_meth;
152 /* How often we've forked (only incremented in child). */
153 extern int rand_fork_count;
155 /* Hardware-based seeding functions. */
156 size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
157 size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
159 /* DRBG entropy callbacks. */
160 size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
161 unsigned char **pout,
162 int entropy, size_t min_len, size_t max_len);
163 void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
164 unsigned char *out, size_t outlen);
167 int rand_drbg_restart(RAND_DRBG *drbg,
168 const unsigned char *buffer, size_t len, size_t entropy);
170 /* DRBG functions implementing AES-CTR */
171 int ctr_init(RAND_DRBG *drbg);
172 int ctr_uninstantiate(RAND_DRBG *drbg);
173 int ctr_instantiate(RAND_DRBG *drbg,
174 const unsigned char *entropy, size_t entropylen,
175 const unsigned char *nonce, size_t noncelen,
176 const unsigned char *pers, size_t perslen);
177 int ctr_reseed(RAND_DRBG *drbg,
178 const unsigned char *entropy, size_t entropylen,
179 const unsigned char *adin, size_t adinlen);
180 int ctr_generate(RAND_DRBG *drbg,
181 unsigned char *out, size_t outlen,
182 const unsigned char *adin, size_t adinlen);