include/crypto/rand.h

   1 /*
   2  * Copyright 2016-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   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
   8  */
   9
  10 /*
  11  * Licensed under the Apache License 2.0 (the "License");
  12  * you may not use this file except in compliance with the License.
  13  * You may obtain a copy of the License at
  14  * https://www.openssl.org/source/license.html
  15  * or in the file LICENSE in the source distribution.
  16  */
  17
  18 #ifndef OSSL_CRYPTO_RAND_H
  19 # define OSSL_CRYPTO_RAND_H
  20
  21 # include <openssl/rand.h>
  22 # include "crypto/rand_pool.h"
  23
  24 /*
  25  * Defines related to seed sources
  26  */
  27 #ifndef DEVRANDOM
  28 /*
  29  * set this to a comma-separated list of 'random' device files to try out. By
  30  * default, we will try to read at least one of these files
  31  */
  32 # define DEVRANDOM "/dev/urandom", "/dev/random", "/dev/hwrng", "/dev/srandom"
  33 # if defined(__linux) && !defined(__ANDROID__)
  34 #  ifndef DEVRANDOM_WAIT
  35 #   define DEVRANDOM_WAIT   "/dev/random"
  36 #  endif
  37 /*
  38  * Linux kernels 4.8 and later changes how their random device works and there
  39  * is no reliable way to tell that /dev/urandom has been seeded -- getentropy(2)
  40  * should be used instead.
  41  */
  42 #  ifndef DEVRANDOM_SAFE_KERNEL
  43 #   define DEVRANDOM_SAFE_KERNEL        4, 8
  44 #  endif
  45 /*
  46  * Some operating systems do not permit select(2) on their random devices,
  47  * defining this to zero will force the use of read(2) to extract one byte
  48  * from /dev/random.
  49  */
  50 #  ifndef DEVRANDM_WAIT_USE_SELECT
  51 #   define DEVRANDM_WAIT_USE_SELECT     1
  52 #  endif
  53 /*
  54  * Define the shared memory identifier used to indicate if the operating
  55  * system has properly seeded the DEVRANDOM source.
  56  */
  57 #  ifndef OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID
  58 #   define OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID 114
  59 #  endif
  60
  61 # endif
  62 #endif
  63
  64 #if !defined(OPENSSL_NO_EGD) && !defined(DEVRANDOM_EGD)
  65 /*
  66  * set this to a comma-separated list of 'egd' sockets to try out. These
  67  * sockets will be tried in the order listed in case accessing the device
  68  * files listed in DEVRANDOM did not return enough randomness.
  69  */
  70 # define DEVRANDOM_EGD "/var/run/egd-pool", "/dev/egd-pool", "/etc/egd-pool", "/etc/entropy"
  71 #endif
  72
  73 void rand_cleanup_int(void);
  74
  75 /*
  76  * Initialise the random pool reseeding sources.
  77  *
  78  * Returns 1 on success and 0 on failure.
  79  */
  80 int rand_pool_init(void);
  81
  82 /*
  83  * Finalise the random pool reseeding sources.
  84  */
  85 void rand_pool_cleanup(void);
  86
  87 /*
  88  * Control the random pool use of open file descriptors.
  89  */
  90 void rand_pool_keep_random_devices_open(int keep);
  91
  92 /*
  93  * Configuration
  94  */
  95 void ossl_random_add_conf_module(void);
  96
  97 /*
  98  * Get and cleanup random seed material.
  99  */
 100 size_t ossl_rand_get_entropy(ossl_unused OSSL_CORE_HANDLE *handle,
 101                              unsigned char **pout, int entropy,
 102                              size_t min_len, size_t max_len);
 103 void ossl_rand_cleanup_entropy(ossl_unused OSSL_CORE_HANDLE *handle,
 104                                unsigned char *buf, size_t len);
 105 size_t ossl_rand_get_nonce(ossl_unused OSSL_CORE_HANDLE *handle,
 106                            unsigned char **pout, size_t min_len, size_t max_len,
 107                            const void *salt, size_t salt_len);
 108 void ossl_rand_cleanup_nonce(ossl_unused OSSL_CORE_HANDLE *handle,
 109                              unsigned char *buf, size_t len);
 110
 111 /*
 112  * Get seeding material from the operating system sources.
 113  */
 114 size_t ossl_pool_acquire_entropy(RAND_POOL *pool);
 115 int ossl_pool_add_nonce_data(RAND_POOL *pool);
 116
 117 #endif