summaryrefslogtreecommitdiffstats
path: root/contrib/restricted/google/boringssl/include/openssl/rand.h
blob: af47f147f9cae8c8a1b149bd091eee6f14e94662 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
// Copyright 2014 The BoringSSL Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef OPENSSL_HEADER_RAND_H
#define OPENSSL_HEADER_RAND_H

#include <contrib/restricted/google/boringssl/include/openssl/base.h>   // IWYU pragma: export

#if defined(__cplusplus)
extern "C" {
#endif


// Random number generation.


// RAND_bytes writes |len| bytes of random data to |buf| and returns one. In the
// event that sufficient random data can not be obtained, |abort| is called.
OPENSSL_EXPORT int RAND_bytes(uint8_t *buf, size_t len);


// Obscure functions.

#if !defined(OPENSSL_WINDOWS)
// RAND_enable_fork_unsafe_buffering indicates that clones of the address space,
// e.g. via |fork|, will never call into BoringSSL. It may be used to disable
// BoringSSL's more expensive fork-safety measures. However, calling this
// function and then using BoringSSL across |fork| calls will leak secret keys.
// |fd| must be -1.
//
// WARNING: This function affects BoringSSL for the entire address space. Thus
// this function should never be called by library code, only by code with
// global knowledge of the application's use of BoringSSL.
//
// Do not use this function unless a performance issue was measured with the
// default behavior. BoringSSL can efficiently detect forks on most platforms,
// in which case this function is a no-op and is unnecessary. In particular,
// Linux kernel versions 4.14 or later provide |MADV_WIPEONFORK|. Future
// versions of BoringSSL will remove this functionality when older kernels are
// sufficiently rare.
//
// This function has an unusual name because it historically controlled internal
// buffers, but no longer does.
OPENSSL_EXPORT void RAND_enable_fork_unsafe_buffering(int fd);

// RAND_disable_fork_unsafe_buffering restores BoringSSL's default fork-safety
// protections. See also |RAND_enable_fork_unsafe_buffering|.
OPENSSL_EXPORT void RAND_disable_fork_unsafe_buffering(void);
#endif

#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)
// RAND_reset_for_fuzzing resets the fuzzer-only deterministic RNG. This
// function is only defined in the fuzzer-only build configuration.
OPENSSL_EXPORT void RAND_reset_for_fuzzing(void);
#endif

// RAND_get_system_entropy_for_custom_prng writes |len| bytes of random data
// from a system entropy source to |buf|. The maximum length of entropy which
// may be requested is 256 bytes. If more than 256 bytes of data is requested,
// or if sufficient random data can not be obtained, |abort| is called.
// |RAND_bytes| should normally be used instead of this function. This function
// should only be used for seed values or where |malloc| should not be called
// from BoringSSL. This function is not FIPS compliant.
OPENSSL_EXPORT void RAND_get_system_entropy_for_custom_prng(uint8_t *buf,
                                                            size_t len);

// RAND_maybe_reseed might reseed the PRNG if it's getting close to the reseed
// limit. If it does so, it may briefly block other threads that are
// concurrently calling `RAND_bytes`, but only for ~microseconds. Applications
// may wish to periodically call this function to avoid hitting a reseed while
// servicing a `RAND_bytes` call, which could happen from anywhere and take
// milliseconds or more in FIPS configurations. _Most_ applications, however,
// should ignore this and it only makes a difference in FIPS builds.
//
// Returns one if a reseed was performed and zero otherwise.
OPENSSL_EXPORT int RAND_maybe_reseed(void);


// Deprecated functions

// RAND_pseudo_bytes is a wrapper around |RAND_bytes|.
OPENSSL_EXPORT int RAND_pseudo_bytes(uint8_t *buf, size_t len);

// RAND_seed reads a single byte of random data to ensure that any file
// descriptors etc are opened.
OPENSSL_EXPORT void RAND_seed(const void *buf, int num);

// RAND_load_file returns a nonnegative number.
OPENSSL_EXPORT int RAND_load_file(const char *path, long num);

// RAND_file_name returns NULL.
OPENSSL_EXPORT const char *RAND_file_name(char *buf, size_t num);

// RAND_add does nothing.
OPENSSL_EXPORT void RAND_add(const void *buf, int num, double entropy);

// RAND_egd returns 255.
OPENSSL_EXPORT int RAND_egd(const char *);

// RAND_poll returns one.
OPENSSL_EXPORT int RAND_poll(void);

// RAND_status returns one.
OPENSSL_EXPORT int RAND_status(void);

// RAND_cleanup does nothing.
OPENSSL_EXPORT void RAND_cleanup(void);

// rand_meth_st is typedefed to |RAND_METHOD| in base.h. It isn't used; it
// exists only to be the return type of |RAND_SSLeay|. It's
// external so that variables of this type can be initialized.
struct rand_meth_st {
  void (*seed) (const void *buf, int num);
  int (*bytes) (uint8_t *buf, size_t num);
  void (*cleanup) (void);
  void (*add) (const void *buf, int num, double entropy);
  int (*pseudorand) (uint8_t *buf, size_t num);
  int (*status) (void);
};

// RAND_SSLeay returns a pointer to a dummy |RAND_METHOD|.
OPENSSL_EXPORT RAND_METHOD *RAND_SSLeay(void);

// RAND_OpenSSL returns a pointer to a dummy |RAND_METHOD|.
OPENSSL_EXPORT RAND_METHOD *RAND_OpenSSL(void);

// RAND_get_rand_method returns |RAND_SSLeay()|.
OPENSSL_EXPORT const RAND_METHOD *RAND_get_rand_method(void);

// RAND_set_rand_method returns one.
OPENSSL_EXPORT int RAND_set_rand_method(const RAND_METHOD *);


#if defined(__cplusplus)
}  // extern C
#endif

#endif  // OPENSSL_HEADER_RAND_H