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"
21 * Amount of randomness (in bytes) we want for initial seeding.
22 * This is based on the fact that we use AES-128 as the CRBG, and
23 * that we use the derivation function. If either of those changes,
24 * (see rand_init() in rand_lib.c), change this.
26 # define RANDOMNESS_NEEDED 16
28 /* Maximum amount of randomness to hold in RAND_BYTES_BUFFER. */
29 # define MAX_RANDOMNESS_HELD (4 * RANDOMNESS_NEEDED)
31 /* Maximum count allowed in reseeding */
32 # define MAX_RESEED (1 << 24)
34 /* How often we call RAND_poll() in drbg_entropy_from_system */
35 # define RAND_POLL_RETRIES 8
37 /* Max size of entropy, addin, etc. Larger than any reasonable value */
38 # define DRBG_MAX_LENGTH 0x7ffffff0
41 /* DRBG status values */
42 typedef enum drbg_status_e {
51 * A buffer of random bytes to be fed as "entropy" into the DRBG. RAND_add()
52 * adds data to the buffer, and the drbg_entropy_from_system() pulls data from
53 * the buffer. We have a separate data structure because of the way the
54 * API is defined; otherwise we'd run into deadlocks (RAND_bytes ->
55 * RAND_DRBG_generate* -> drbg_entropy_from_system -> RAND_poll -> RAND_add ->
56 * drbg_add*; the functions with an asterisk lock).
58 typedef struct rand_bytes_buffer_st {
66 * The state of a DRBG AES-CTR.
68 typedef struct rand_drbg_ctr_st {
73 /* Temp variables used by derivation function */
76 /* Temporary block storage used by ctr_df */
77 unsigned char bltmp[16];
84 * The state of all types of DRBGs, even though we only have CTR mode
90 int nid; /* the underlying algorithm */
92 unsigned short flags; /* various external flags */
93 unsigned short filled;
95 * This is a fixed-size buffer, but we malloc to make it a little
96 * harder to find; a classic security/performance trade-off.
99 unsigned char *randomness;
101 /* These parameters are setup by the per-type "init" function. */
104 size_t min_entropy, max_entropy;
105 size_t min_nonce, max_nonce;
106 size_t max_pers, max_adin;
107 unsigned int reseed_counter;
108 unsigned int reseed_interval;
112 /* Application data, mainly used in the KATs. */
113 CRYPTO_EX_DATA ex_data;
115 /* Implementation specific structures; was a union, but inline for now */
118 /* Callback functions. See comments in rand_lib.c */
119 RAND_DRBG_get_entropy_fn get_entropy;
120 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
121 RAND_DRBG_get_nonce_fn get_nonce;
122 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
125 /* The global RAND method, and the global buffer and DRBG instance. */
126 extern RAND_METHOD rand_meth;
127 extern RAND_BYTES_BUFFER rand_bytes;
128 extern RAND_DRBG rand_drbg;
129 extern RAND_DRBG priv_drbg;
131 /* How often we've forked (only incremented in child). */
132 extern int rand_fork_count;
134 /* Hardware-based seeding functions. */
135 void rand_read_tsc(RAND_poll_fn cb, void *arg);
136 int rand_read_cpu(RAND_poll_fn cb, void *arg);
138 /* DRBG entropy callbacks. */
139 void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out);
140 size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
141 unsigned char **pout,
142 int entropy, size_t min_len, size_t max_len);
143 size_t drbg_entropy_from_system(RAND_DRBG *drbg,
144 unsigned char **pout,
145 int entropy, size_t min_len, size_t max_len);
147 /* DRBG functions implementing AES-CTR */
148 int ctr_init(RAND_DRBG *drbg);
149 int ctr_uninstantiate(RAND_DRBG *drbg);
150 int ctr_instantiate(RAND_DRBG *drbg,
151 const unsigned char *ent, size_t entlen,
152 const unsigned char *nonce, size_t noncelen,
153 const unsigned char *pers, size_t perslen);
154 int ctr_reseed(RAND_DRBG *drbg,
155 const unsigned char *ent, size_t entlen,
156 const unsigned char *adin, size_t adinlen);
157 int ctr_generate(RAND_DRBG *drbg,
158 unsigned char *out, size_t outlen,
159 const unsigned char *adin, size_t adinlen);