crypto/rand/rand_lcl.h

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   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
   8  */
   9
  10 #ifndef HEADER_RAND_LCL_H
  11 # define HEADER_RAND_LCL_H
  12
  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"
  19
  20 /* How many times to read the TSC as a randomness source. */
  21 # define TSC_READ_COUNT                 4
  22
  23 /* Maximum reseed intervals */
  24 # define MAX_RESEED_INTERVAL                     (1 << 24)
  25 # define MAX_RESEED_TIME_INTERVAL                (1 << 20) /* approx. 12 days */
  26
  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 */
  32
  33
  34
  35 /* Max size of additional input and personalization string. */
  36 # define DRBG_MAX_LENGTH                4096
  37
  38 /*
  39  * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
  40  *
  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.
  45  */
  46 # define DRBG_MINMAX_FACTOR              128
  47
  48
  49 /* DRBG status values */
  50 typedef enum drbg_status_e {
  51     DRBG_UNINITIALISED,
  52     DRBG_READY,
  53     DRBG_ERROR
  54 } DRBG_STATUS;
  55
  56
  57 /*
  58  * The state of a DRBG AES-CTR.
  59  */
  60 typedef struct rand_drbg_ctr_st {
  61     AES_KEY ks;
  62     size_t keylen;
  63     unsigned char K[32];
  64     unsigned char V[16];
  65     /* Temp variables used by derivation function */
  66     AES_KEY df_ks;
  67     AES_KEY df_kxks;
  68     /* Temporary block storage used by ctr_df */
  69     unsigned char bltmp[16];
  70     size_t bltmp_pos;
  71     unsigned char KX[48];
  72 } RAND_DRBG_CTR;
  73
  74
  75 /*
  76  * The state of all types of DRBGs, even though we only have CTR mode
  77  * right now.
  78  */
  79 struct rand_drbg_st {
  80     CRYPTO_RWLOCK *lock;
  81     RAND_DRBG *parent;
  82     int nid; /* the underlying algorithm */
  83     int fork_count;
  84     unsigned short flags; /* various external flags */
  85
  86     /*
  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
  92      * (see PR #4328).
  93      */
  94     RAND_POOL *pool;
  95
  96     /*
  97      * The following parameters are setup by the per-type "init" function.
  98      *
  99      * Currently the only type is CTR_DRBG, its init function is ctr_init().
 100      *
 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.
 106      *
 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
 110      * clarification.
 111      */
 112
 113     int strength;
 114     size_t max_request;
 115     size_t min_entropylen, max_entropylen;
 116     size_t min_noncelen, max_noncelen;
 117     size_t max_perslen, max_adinlen;
 118
 119     /* Counts the number of generate requests since the last reseed. */
 120     unsigned int generate_counter;
 121     /*
 122      * Maximum number of generate requests until a reseed is required.
 123      * This value is ignored if it is zero.
 124      */
 125     unsigned int reseed_interval;
 126     /* Stores the time when the last reseeding occurred */
 127     time_t reseed_time;
 128     /*
 129      * Specifies the maximum time interval (in seconds) between reseeds.
 130      * This value is ignored if it is zero.
 131      */
 132     time_t reseed_time_interval;
 133     /*
 134      * Counts the number of reseeds since instantiation.
 135      * This value is ignored if it is zero.
 136      *
 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().
 142      */
 143     unsigned int reseed_counter;
 144
 145     size_t seedlen;
 146     DRBG_STATUS state;
 147
 148     /* Application data, mainly used in the KATs. */
 149     CRYPTO_EX_DATA ex_data;
 150
 151     /* Implementation specific structures; was a union, but inline for now */
 152     RAND_DRBG_CTR ctr;
 153
 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;
 159 };
 160
 161 /* The global RAND method, and the global buffer and DRBG instance. */
 162 extern RAND_METHOD rand_meth;
 163
 164 /* How often we've forked (only incremented in child). */
 165 extern int rand_fork_count;
 166
 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);
 170
 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);
 177
 178 /* DRBG helpers */
 179 int rand_drbg_restart(RAND_DRBG *drbg,
 180                       const unsigned char *buffer, size_t len, size_t entropy);
 181
 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);
 195
 196 #endif