2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
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
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>
19 # include "internal/tsan_assist.h"
21 # include "internal/numbers.h"
23 /* How many times to read the TSC as a randomness source. */
24 # define TSC_READ_COUNT 4
26 /* Maximum reseed intervals */
27 # define MAX_RESEED_INTERVAL (1 << 24)
28 # define MAX_RESEED_TIME_INTERVAL (1 << 20) /* approx. 12 days */
30 /* Default reseed intervals */
31 # define MASTER_RESEED_INTERVAL (1 << 8)
32 # define SLAVE_RESEED_INTERVAL (1 << 16)
33 # define MASTER_RESEED_TIME_INTERVAL (60*60) /* 1 hour */
34 # define SLAVE_RESEED_TIME_INTERVAL (7*60) /* 7 minutes */
39 * Maximum input size for the DRBG (entropy, nonce, personalization string)
41 * NIST SP800 90Ar1 allows a maximum of (1 << 35) bits i.e., (1 << 32) bytes.
43 * We lower it to 'only' INT32_MAX bytes, which is equivalent to 2 gigabytes.
45 # define DRBG_MAX_LENGTH INT32_MAX
50 * Maximum allocation size for RANDOM_POOL buffers
52 * The max_len value for the buffer provided to the rand_drbg_get_entropy()
53 * callback is currently 2^31 bytes (2 gigabytes), if a derivation function
54 * is used. Since this is much too large to be allocated, the rand_pool_new()
55 * function chooses more modest values as default pool length, bounded
56 * by RAND_POOL_MIN_LENGTH and RAND_POOL_MAX_LENGTH
58 * The choice of the RAND_POOL_FACTOR is large enough such that the
59 * RAND_POOL can store a random input which has a lousy entropy rate of
60 * 8/256 (= 0.03125) bits per byte. This input will be sent through the
61 * derivation function which 'compresses' the low quality input into a
62 * high quality output.
64 * The factor 1.5 below is the pessimistic estimate for the extra amount
65 * of entropy required when no get_nonce() callback is defined.
67 # define RAND_POOL_FACTOR 256
68 # define RAND_POOL_MAX_LENGTH (RAND_POOL_FACTOR * \
69 3 * (RAND_DRBG_STRENGTH / 16))
71 * = (RAND_POOL_FACTOR * \
72 * 1.5 * (RAND_DRBG_STRENGTH / 8))
76 /* DRBG status values */
77 typedef enum drbg_status_e {
85 typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx,
86 const unsigned char *ent,
88 const unsigned char *nonce,
90 const unsigned char *pers,
93 typedef int (*RAND_DRBG_reseed_fn)(RAND_DRBG *ctx,
94 const unsigned char *ent,
96 const unsigned char *adin,
99 typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx,
102 const unsigned char *adin,
105 typedef int (*RAND_DRBG_uninstantiate_fn)(RAND_DRBG *ctx);
112 typedef struct rand_drbg_method_st {
113 RAND_DRBG_instantiate_fn instantiate;
114 RAND_DRBG_reseed_fn reseed;
115 RAND_DRBG_generate_fn generate;
116 RAND_DRBG_uninstantiate_fn uninstantiate;
119 /* 888 bits from SP800-90Ar1 10.1 table 2 */
120 #define HASH_PRNG_MAX_SEEDLEN (888/8)
122 typedef struct rand_drbg_hash_st {
126 unsigned char V[HASH_PRNG_MAX_SEEDLEN];
127 unsigned char C[HASH_PRNG_MAX_SEEDLEN];
128 /* Temporary value storage: should always exceed max digest length */
129 unsigned char vtmp[HASH_PRNG_MAX_SEEDLEN];
132 typedef struct rand_drbg_hmac_st {
136 unsigned char K[EVP_MAX_MD_SIZE];
137 unsigned char V[EVP_MAX_MD_SIZE];
141 * The state of a DRBG AES-CTR.
143 typedef struct rand_drbg_ctr_st {
145 EVP_CIPHER_CTX *ctx_df;
146 const EVP_CIPHER *cipher;
150 /* Temporary block storage used by ctr_df */
151 unsigned char bltmp[16];
153 unsigned char KX[48];
158 * The 'random pool' acts as a dumb container for collecting random
159 * input from various entropy sources. The pool has no knowledge about
160 * whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
161 * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
162 * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
163 * 4) cleanup the random pool again.
165 * The random pool contains no locking mechanism because its scope and
166 * lifetime is intended to be restricted to a single stack frame.
168 struct rand_pool_st {
169 unsigned char *buffer; /* points to the beginning of the random pool */
170 size_t len; /* current number of random bytes contained in the pool */
172 int attached; /* true pool was attached to existing buffer */
174 size_t min_len; /* minimum number of random bytes requested */
175 size_t max_len; /* maximum number of random bytes (allocated buffer size) */
176 size_t entropy; /* current entropy count in bits */
177 size_t entropy_requested; /* requested entropy count in bits */
181 * The state of all types of DRBGs, even though we only have CTR mode
184 struct rand_drbg_st {
187 int secure; /* 1: allocated on the secure heap, 0: otherwise */
188 int type; /* the nid of the underlying algorithm */
190 * Stores the value of the rand_fork_count global as of when we last
191 * reseeded. The DRBG reseeds automatically whenever drbg->fork_count !=
192 * rand_fork_count. Used to provide fork-safety and reseed this DRBG in
196 unsigned short flags; /* various external flags */
199 * The random_data is used by RAND_add()/drbg_add() to attach random
200 * data to the global drbg, such that the rand_drbg_get_entropy() callback
201 * can pull it during instantiation and reseeding. This is necessary to
202 * reconcile the different philosophies of the RAND and the RAND_DRBG
203 * with respect to how randomness is added to the RNG during reseeding
206 struct rand_pool_st *seed_pool;
209 * Auxiliary pool for additional data.
211 struct rand_pool_st *adin_pool;
214 * The following parameters are setup by the per-type "init" function.
216 * The supported types and their init functions are:
217 * (1) CTR_DRBG: drbg_ctr_init().
218 * (2) HMAC_DRBG: drbg_hmac_init().
219 * (3) HASH_DRBG: drbg_hash_init().
221 * The parameters are closely related to the ones described in
222 * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
223 * crucial difference: In the NIST standard, all counts are given
224 * in bits, whereas in OpenSSL entropy counts are given in bits
225 * and buffer lengths are given in bytes.
227 * Since this difference has lead to some confusion in the past,
228 * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
229 * the 'len' suffix has been added to all buffer sizes for
235 size_t min_entropylen, max_entropylen;
236 size_t min_noncelen, max_noncelen;
237 size_t max_perslen, max_adinlen;
240 * Counts the number of generate requests since the last reseed
241 * (Starts at 1). This value is the reseed_counter as defined in
244 unsigned int reseed_gen_counter;
246 * Maximum number of generate requests until a reseed is required.
247 * This value is ignored if it is zero.
249 unsigned int reseed_interval;
250 /* Stores the time when the last reseeding occurred */
253 * Specifies the maximum time interval (in seconds) between reseeds.
254 * This value is ignored if it is zero.
256 time_t reseed_time_interval;
258 * Counts the number of reseeds since instantiation.
259 * This value is ignored if it is zero.
261 * This counter is used only for seed propagation from the <master> DRBG
262 * to its two children, the <public> and <private> DRBG. This feature is
263 * very special and its sole purpose is to ensure that any randomness which
264 * is added by RAND_add() or RAND_seed() will have an immediate effect on
265 * the output of RAND_bytes() resp. RAND_priv_bytes().
267 TSAN_QUALIFIER unsigned int reseed_prop_counter;
268 unsigned int reseed_next_counter;
273 /* Application data, mainly used in the KATs. */
274 CRYPTO_EX_DATA ex_data;
276 /* Implementation specific data */
283 /* Implementation specific methods */
284 RAND_DRBG_METHOD *meth;
286 /* Callback functions. See comments in rand_lib.c */
287 RAND_DRBG_get_entropy_fn get_entropy;
288 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
289 RAND_DRBG_get_nonce_fn get_nonce;
290 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
293 /* The global RAND method, and the global buffer and DRBG instance. */
294 extern RAND_METHOD rand_meth;
297 * A "generation count" of forks. Incremented in the child process after a
298 * fork. Since rand_fork_count is increment-only, and only ever written to in
299 * the child process of the fork, which is guaranteed to be single-threaded, no
300 * locking is needed for normal (read) accesses; the rest of pthread fork
301 * processing is assumed to introduce the necessary memory barriers. Sibling
302 * children of a given parent will produce duplicate values, but this is not
303 * problematic because the reseeding process pulls input from the system CSPRNG
304 * and/or other global sources, so the siblings will end up generating
305 * different output streams.
307 extern int rand_fork_count;
310 int rand_drbg_restart(RAND_DRBG *drbg,
311 const unsigned char *buffer, size_t len, size_t entropy);
312 size_t rand_drbg_seedlen(RAND_DRBG *drbg);
314 int rand_drbg_lock(RAND_DRBG *drbg);
315 int rand_drbg_unlock(RAND_DRBG *drbg);
316 int rand_drbg_enable_locking(RAND_DRBG *drbg);
319 /* initializes the DRBG implementation */
320 int drbg_ctr_init(RAND_DRBG *drbg);
321 int drbg_hash_init(RAND_DRBG *drbg);
322 int drbg_hmac_init(RAND_DRBG *drbg);