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 /* How many times to read the TSC as a randomness source. */
29 # define TSC_READ_COUNT 4
31 /* Maximum amount of randomness to hold in RAND_BYTES_BUFFER. */
32 # define MAX_RANDOMNESS_HELD (4 * RANDOMNESS_NEEDED)
34 /* Maximum count allowed in reseeding */
35 # define MAX_RESEED (1 << 24)
37 /* How often we call RAND_poll() in drbg_entropy_from_system */
38 # define RAND_POLL_RETRIES 8
40 /* Max size of entropy, addin, etc. Larger than any reasonable value */
41 # define DRBG_MAX_LENGTH 0x7ffffff0
44 /* DRBG status values */
45 typedef enum drbg_status_e {
54 * A buffer of random bytes to be fed as "entropy" into the DRBG. RAND_add()
55 * adds data to the buffer, and the drbg_entropy_from_system() pulls data from
56 * the buffer. We have a separate data structure because of the way the
57 * API is defined; otherwise we'd run into deadlocks (RAND_bytes ->
58 * RAND_DRBG_generate* -> drbg_entropy_from_system -> RAND_poll -> RAND_add ->
59 * drbg_add*; the functions with an asterisk lock).
61 typedef struct rand_bytes_buffer_st {
70 * The state of a DRBG AES-CTR.
72 typedef struct rand_drbg_ctr_st {
77 /* Temp variables used by derivation function */
80 /* Temporary block storage used by ctr_df */
81 unsigned char bltmp[16];
88 * The state of all types of DRBGs, even though we only have CTR mode
94 int nid; /* the underlying algorithm */
96 unsigned short flags; /* various external flags */
100 * This is a fixed-size buffer, but we malloc to make it a little
101 * harder to find; a classic security/performance trade-off.
104 unsigned char *randomness;
106 /* These parameters are setup by the per-type "init" function. */
109 size_t min_entropy, max_entropy;
110 size_t min_nonce, max_nonce;
111 size_t max_pers, max_adin;
112 unsigned int reseed_counter;
113 unsigned int reseed_interval;
117 /* Application data, mainly used in the KATs. */
118 CRYPTO_EX_DATA ex_data;
120 /* Implementation specific structures; was a union, but inline for now */
123 /* Callback functions. See comments in rand_lib.c */
124 RAND_DRBG_get_entropy_fn get_entropy;
125 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
126 RAND_DRBG_get_nonce_fn get_nonce;
127 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
130 /* The global RAND method, and the global buffer and DRBG instance. */
131 extern RAND_METHOD rand_meth;
132 extern RAND_BYTES_BUFFER rand_bytes;
133 extern RAND_DRBG rand_drbg;
134 extern RAND_DRBG priv_drbg;
136 /* How often we've forked (only incremented in child). */
137 extern int rand_fork_count;
139 /* Hardware-based seeding functions. */
140 void rand_read_tsc(RAND_poll_fn cb, void *arg);
141 int rand_read_cpu(RAND_poll_fn cb, void *arg);
143 /* DRBG entropy callbacks. */
144 void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out);
145 size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
146 unsigned char **pout,
147 int entropy, size_t min_len, size_t max_len);
148 size_t drbg_entropy_from_system(RAND_DRBG *drbg,
149 unsigned char **pout,
150 int entropy, size_t min_len, size_t max_len);
152 /* DRBG functions implementing AES-CTR */
153 int ctr_init(RAND_DRBG *drbg);
154 int ctr_uninstantiate(RAND_DRBG *drbg);
155 int ctr_instantiate(RAND_DRBG *drbg,
156 const unsigned char *ent, size_t entlen,
157 const unsigned char *nonce, size_t noncelen,
158 const unsigned char *pers, size_t perslen);
159 int ctr_reseed(RAND_DRBG *drbg,
160 const unsigned char *ent, size_t entlen,
161 const unsigned char *adin, size_t adinlen);
162 int ctr_generate(RAND_DRBG *drbg,
163 unsigned char *out, size_t outlen,
164 const unsigned char *adin, size_t adinlen);