2 * Copyright 1995-2018 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 <openssl/rand_drbg.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 typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx,
59 const unsigned char *ent,
61 const unsigned char *nonce,
63 const unsigned char *pers,
66 typedef int (*RAND_DRBG_reseed_fn)(RAND_DRBG *ctx,
67 const unsigned char *ent,
69 const unsigned char *adin,
72 typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx,
75 const unsigned char *adin,
78 typedef int (*RAND_DRBG_uninstantiate_fn)(RAND_DRBG *ctx);
85 typedef struct rand_drbg_method_st {
86 RAND_DRBG_instantiate_fn instantiate;
87 RAND_DRBG_reseed_fn reseed;
88 RAND_DRBG_generate_fn generate;
89 RAND_DRBG_uninstantiate_fn uninstantiate;
92 /* 888 bits from SP800-90Ar1 10.1 table 2 */
93 #define HASH_PRNG_MAX_SEEDLEN (888/8)
95 typedef struct rand_drbg_hash_st {
99 unsigned char V[HASH_PRNG_MAX_SEEDLEN];
100 unsigned char C[HASH_PRNG_MAX_SEEDLEN];
101 /* Temporary value storage: should always exceed max digest length */
102 unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN];
105 typedef struct rand_drbg_hmac_st {
109 unsigned char K[EVP_MAX_MD_SIZE];
110 unsigned char V[EVP_MAX_MD_SIZE];
114 * The state of a DRBG AES-CTR.
116 typedef struct rand_drbg_ctr_st {
118 EVP_CIPHER_CTX *ctx_df;
119 const EVP_CIPHER *cipher;
123 /* Temporary block storage used by ctr_df */
124 unsigned char bltmp[16];
126 unsigned char KX[48];
131 * The 'random pool' acts as a dumb container for collecting random
132 * input from various entropy sources. The pool has no knowledge about
133 * whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
134 * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
135 * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
136 * 4) cleanup the random pool again.
138 * The random pool contains no locking mechanism because its scope and
139 * lifetime is intended to be restricted to a single stack frame.
141 struct rand_pool_st {
142 unsigned char *buffer; /* points to the beginning of the random pool */
143 size_t len; /* current number of random bytes contained in the pool */
145 size_t min_len; /* minimum number of random bytes requested */
146 size_t max_len; /* maximum number of random bytes (allocated buffer size) */
147 size_t entropy; /* current entropy count in bits */
148 size_t requested_entropy; /* requested entropy count in bits */
152 * The state of all types of DRBGs, even though we only have CTR mode
155 struct rand_drbg_st {
158 int secure; /* 1: allocated on the secure heap, 0: otherwise */
159 int type; /* the nid of the underlying algorithm */
161 * Stores the value of the rand_fork_count global as of when we last
162 * reseeded. The DRBG reseeds automatically whenever drbg->fork_count !=
163 * rand_fork_count. Used to provide fork-safety and reseed this DRBG in
167 unsigned short flags; /* various external flags */
170 * The random pool is used by RAND_add()/drbg_add() to attach random
171 * data to the global drbg, such that the rand_drbg_get_entropy() callback
172 * can pull it during instantiation and reseeding. This is necessary to
173 * reconcile the different philosophies of the RAND and the RAND_DRBG
174 * with respect to how randomness is added to the RNG during reseeding
177 struct rand_pool_st *pool;
180 * The following parameters are setup by the per-type "init" function.
182 * The supported types and their init functions are:
183 * (1) CTR_DRBG: drbg_ctr_init().
184 * (2) HMAC_DRBG: drbg_hmac_init().
185 * (3) HASH_DRBG: drbg_hash_init().
187 * The parameters are closely related to the ones described in
188 * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
189 * crucial difference: In the NIST standard, all counts are given
190 * in bits, whereas in OpenSSL entropy counts are given in bits
191 * and buffer lengths are given in bytes.
193 * Since this difference has lead to some confusion in the past,
194 * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
195 * the 'len' suffix has been added to all buffer sizes for
201 size_t min_entropylen, max_entropylen;
202 size_t min_noncelen, max_noncelen;
203 size_t max_perslen, max_adinlen;
206 * Counts the number of generate requests since the last reseed
207 * (Starts at 1). This value is the reseed_counter as defined in
210 unsigned int reseed_gen_counter;
212 * Maximum number of generate requests until a reseed is required.
213 * This value is ignored if it is zero.
215 unsigned int reseed_interval;
216 /* Stores the time when the last reseeding occurred */
219 * Specifies the maximum time interval (in seconds) between reseeds.
220 * This value is ignored if it is zero.
222 time_t reseed_time_interval;
224 * Counts the number of reseeds since instantiation.
225 * This value is ignored if it is zero.
227 * This counter is used only for seed propagation from the <master> DRBG
228 * to its two children, the <public> and <private> DRBG. This feature is
229 * very special and its sole purpose is to ensure that any randomness which
230 * is added by RAND_add() or RAND_seed() will have an immediate effect on
231 * the output of RAND_bytes() resp. RAND_priv_bytes().
233 unsigned int reseed_prop_counter;
238 /* Application data, mainly used in the KATs. */
239 CRYPTO_EX_DATA ex_data;
241 /* Implementation specific data */
248 /* Implementation specific methods */
249 RAND_DRBG_METHOD *meth;
251 /* Callback functions. See comments in rand_lib.c */
252 RAND_DRBG_get_entropy_fn get_entropy;
253 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
254 RAND_DRBG_get_nonce_fn get_nonce;
255 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
258 /* The global RAND method, and the global buffer and DRBG instance. */
259 extern RAND_METHOD rand_meth;
262 * A "generation count" of forks. Incremented in the child process after a
263 * fork. Since rand_fork_count is increment-only, and only ever written to in
264 * the child process of the fork, which is guaranteed to be single-threaded, no
265 * locking is needed for normal (read) accesses; the rest of pthread fork
266 * processing is assumed to introduce the necessary memory barriers. Sibling
267 * children of a given parent will produce duplicate values, but this is not
268 * problematic because the reseeding process pulls input from the system CSPRNG
269 * and/or other global sources, so the siblings will end up generating
270 * different output streams.
272 extern int rand_fork_count;
275 int rand_drbg_restart(RAND_DRBG *drbg,
276 const unsigned char *buffer, size_t len, size_t entropy);
279 int rand_drbg_lock(RAND_DRBG *drbg);
280 int rand_drbg_unlock(RAND_DRBG *drbg);
281 int rand_drbg_enable_locking(RAND_DRBG *drbg);
284 /* initializes the DRBG implementation */
285 int drbg_ctr_init(RAND_DRBG *drbg);
286 int drbg_hash_init(RAND_DRBG *drbg);
287 int drbg_hmac_init(RAND_DRBG *drbg);