crypto/rand/rand_lcl.h

   1 /*
   2  * Copyright 1995-2018 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 /* intantiate */
  58 typedef int (*RAND_DRBG_instantiate_fn)(RAND_DRBG *ctx,
  59                                         const unsigned char *ent,
  60                                         size_t entlen,
  61                                         const unsigned char *nonce,
  62                                         size_t noncelen,
  63                                         const unsigned char *pers,
  64                                         size_t perslen);
  65 /* reseed */
  66 typedef int (*RAND_DRBG_reseed_fn)(RAND_DRBG *ctx,
  67                                    const unsigned char *ent,
  68                                    size_t entlen,
  69                                    const unsigned char *adin,
  70                                    size_t adinlen);
  71 /* generat output */
  72 typedef int (*RAND_DRBG_generate_fn)(RAND_DRBG *ctx,
  73                                      unsigned char *out,
  74                                      size_t outlen,
  75                                      const unsigned char *adin,
  76                                      size_t adinlen);
  77 /* uninstantiate */
  78 typedef int (*RAND_DRBG_uninstantiate_fn)(RAND_DRBG *ctx);
  79
  80
  81 /*
  82  * The DRBG methods
  83  */
  84
  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;
  90 } RAND_DRBG_METHOD;
  91
  92
  93 /*
  94  * The state of a DRBG AES-CTR.
  95  */
  96 typedef struct rand_drbg_ctr_st {
  97     AES_KEY ks;
  98     size_t keylen;
  99     unsigned char K[32];
 100     unsigned char V[16];
 101     /* Temp variables used by derivation function */
 102     AES_KEY df_ks;
 103     AES_KEY df_kxks;
 104     /* Temporary block storage used by ctr_df */
 105     unsigned char bltmp[16];
 106     size_t bltmp_pos;
 107     unsigned char KX[48];
 108 } RAND_DRBG_CTR;
 109
 110
 111 /*
 112  * The state of all types of DRBGs, even though we only have CTR mode
 113  * right now.
 114  */
 115 struct rand_drbg_st {
 116     CRYPTO_RWLOCK *lock;
 117     RAND_DRBG *parent;
 118     int nid; /* the underlying algorithm */
 119     int fork_count;
 120     unsigned short flags; /* various external flags */
 121
 122     /*
 123      * The random pool is used by RAND_add()/drbg_add() to attach random
 124      * data to the global drbg, such that the rand_drbg_get_entropy() callback
 125      * can pull it during instantiation and reseeding. This is necessary to
 126      * reconcile the different philosophies of the RAND and the RAND_DRBG
 127      * with respect to how randomness is added to the RNG during reseeding
 128      * (see PR #4328).
 129      */
 130     RAND_POOL *pool;
 131
 132     /*
 133      * The following parameters are setup by the per-type "init" function.
 134      *
 135      * Currently the only type is CTR_DRBG, its init function is drbg_ctr_init().
 136      *
 137      * The parameters are closely related to the ones described in
 138      * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
 139      * crucial difference: In the NIST standard, all counts are given
 140      * in bits, whereas in OpenSSL entropy counts are given in bits
 141      * and buffer lengths are given in bytes.
 142      *
 143      * Since this difference has lead to some confusion in the past,
 144      * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
 145      * the 'len' suffix has been added to all buffer sizes for
 146      * clarification.
 147      */
 148
 149     int strength;
 150     size_t max_request;
 151     size_t min_entropylen, max_entropylen;
 152     size_t min_noncelen, max_noncelen;
 153     size_t max_perslen, max_adinlen;
 154
 155     /* Counts the number of generate requests since the last reseed. */
 156     unsigned int generate_counter;
 157     /*
 158      * Maximum number of generate requests until a reseed is required.
 159      * This value is ignored if it is zero.
 160      */
 161     unsigned int reseed_interval;
 162     /* Stores the time when the last reseeding occurred */
 163     time_t reseed_time;
 164     /*
 165      * Specifies the maximum time interval (in seconds) between reseeds.
 166      * This value is ignored if it is zero.
 167      */
 168     time_t reseed_time_interval;
 169     /*
 170      * Counts the number of reseeds since instantiation.
 171      * This value is ignored if it is zero.
 172      *
 173      * This counter is used only for seed propagation from the <master> DRBG
 174      * to its two children, the <public> and <private> DRBG. This feature is
 175      * very special and its sole purpose is to ensure that any randomness which
 176      * is added by RAND_add() or RAND_seed() will have an immediate effect on
 177      * the output of RAND_bytes() resp. RAND_priv_bytes().
 178      */
 179     unsigned int reseed_counter;
 180
 181     size_t seedlen;
 182     DRBG_STATUS state;
 183
 184     /* Application data, mainly used in the KATs. */
 185     CRYPTO_EX_DATA ex_data;
 186
 187     /* Implementation specific data (currently only one implementation) */
 188     union {
 189         RAND_DRBG_CTR ctr;
 190     } data;
 191
 192     /* Implementation specific methods */
 193     RAND_DRBG_METHOD *meth;
 194
 195     /* Callback functions.  See comments in rand_lib.c */
 196     RAND_DRBG_get_entropy_fn get_entropy;
 197     RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
 198     RAND_DRBG_get_nonce_fn get_nonce;
 199     RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
 200 };
 201
 202 /* The global RAND method, and the global buffer and DRBG instance. */
 203 extern RAND_METHOD rand_meth;
 204
 205 /* How often we've forked (only incremented in child). */
 206 extern int rand_fork_count;
 207
 208 /* Hardware-based seeding functions. */
 209 size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
 210 size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
 211
 212 /* DRBG entropy callbacks. */
 213 size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
 214                              unsigned char **pout,
 215                              int entropy, size_t min_len, size_t max_len);
 216 void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
 217                                unsigned char *out, size_t outlen);
 218 size_t rand_drbg_get_additional_data(unsigned char **pout, size_t max_len);
 219
 220 /* DRBG helpers */
 221 int rand_drbg_restart(RAND_DRBG *drbg,
 222                       const unsigned char *buffer, size_t len, size_t entropy);
 223
 224 /* initializes the AES-CTR DRBG implementation */
 225 int drbg_ctr_init(RAND_DRBG *drbg);
 226
 227 #endif