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 intervals */
24 # define MAX_RESEED_INTERVAL (1 << 24)
25 # define MAX_RESEED_TIME_INTERVAL (1 << 20) /* approx. 12 days */
27 /* Default reseed intervals */
28 # define MASTER_RESEED_INTERVAL (1 << 8)
29 # define SLAVE_RESEED_INTERVAL (1 << 16)
30 # define MASTER_RESEED_TIME_INTERVAL (60*60) /* 1 hour */
31 # define SLAVE_RESEED_TIME_INTERVAL (7*60) /* 7 minutes */
35 /* Max size of additional input and personalization string. */
36 # define DRBG_MAX_LENGTH 4096
39 * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
41 * The current factor is large enough that the RAND_POOL can store a
42 * random input which has a lousy entropy rate of 0.0625 bits per byte.
43 * This input will be sent through the derivation function which 'compresses'
44 * the low quality input into a high quality output.
46 # define DRBG_MINMAX_FACTOR 128
49 /* DRBG status values */
50 typedef enum drbg_status_e {
58 * The state of a DRBG AES-CTR.
60 typedef struct rand_drbg_ctr_st {
65 /* Temp variables used by derivation function */
68 /* Temporary block storage used by ctr_df */
69 unsigned char bltmp[16];
76 * The state of all types of DRBGs, even though we only have CTR mode
82 int nid; /* the underlying algorithm */
84 unsigned short flags; /* various external flags */
87 * The random pool is used by RAND_add()/drbg_add() to attach random
88 * data to the global drbg, such that the rand_drbg_get_entropy() callback
89 * can pull it during instantiation and reseeding. This is necessary to
90 * reconcile the different philosophies of the RAND and the RAND_DRBG
91 * with respect to how randomness is added to the RNG during reseeding
97 * The following parameters are setup by the per-type "init" function.
99 * Currently the only type is CTR_DRBG, its init function is ctr_init().
101 * The parameters are closely related to the ones described in
102 * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
103 * crucial difference: In the NIST standard, all counts are given
104 * in bits, whereas in OpenSSL entropy counts are given in bits
105 * and buffer lengths are given in bytes.
107 * Since this difference has lead to some confusion in the past,
108 * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
109 * the 'len' suffix has been added to all buffer sizes for
115 size_t min_entropylen, max_entropylen;
116 size_t min_noncelen, max_noncelen;
117 size_t max_perslen, max_adinlen;
119 /* Counts the number of generate requests since the last reseed. */
120 unsigned int generate_counter;
122 * Maximum number of generate requests until a reseed is required.
123 * This value is ignored if it is zero.
125 unsigned int reseed_interval;
126 /* Stores the time when the last reseeding occurred */
129 * Specifies the maximum time interval (in seconds) between reseeds.
130 * This value is ignored if it is zero.
132 time_t reseed_time_interval;
134 * Counts the number of reseeds since instantiation.
135 * This value is ignored if it is zero.
137 * This counter is used only for seed propagation from the <master> DRBG
138 * to its two children, the <public> and <private> DRBG. This feature is
139 * very special and its sole purpose is to ensure that any randomness which
140 * is added by RAND_add() or RAND_seed() will have an immediate effect on
141 * the output of RAND_bytes() resp. RAND_priv_bytes().
143 unsigned int reseed_counter;
148 /* Application data, mainly used in the KATs. */
149 CRYPTO_EX_DATA ex_data;
151 /* Implementation specific structures; was a union, but inline for now */
154 /* Callback functions. See comments in rand_lib.c */
155 RAND_DRBG_get_entropy_fn get_entropy;
156 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
157 RAND_DRBG_get_nonce_fn get_nonce;
158 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
161 /* The global RAND method, and the global buffer and DRBG instance. */
162 extern RAND_METHOD rand_meth;
164 /* How often we've forked (only incremented in child). */
165 extern int rand_fork_count;
167 /* Hardware-based seeding functions. */
168 size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
169 size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
171 /* DRBG entropy callbacks. */
172 size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
173 unsigned char **pout,
174 int entropy, size_t min_len, size_t max_len);
175 void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
176 unsigned char *out, size_t outlen);
179 int rand_drbg_restart(RAND_DRBG *drbg,
180 const unsigned char *buffer, size_t len, size_t entropy);
182 /* DRBG functions implementing AES-CTR */
183 int ctr_init(RAND_DRBG *drbg);
184 int ctr_uninstantiate(RAND_DRBG *drbg);
185 int ctr_instantiate(RAND_DRBG *drbg,
186 const unsigned char *entropy, size_t entropylen,
187 const unsigned char *nonce, size_t noncelen,
188 const unsigned char *pers, size_t perslen);
189 int ctr_reseed(RAND_DRBG *drbg,
190 const unsigned char *entropy, size_t entropylen,
191 const unsigned char *adin, size_t adinlen);
192 int ctr_generate(RAND_DRBG *drbg,
193 unsigned char *out, size_t outlen,
194 const unsigned char *adin, size_t adinlen);