1/* Copyright (c) 2014, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15#ifndef OPENSSL_HEADER_RAND_H
16#define OPENSSL_HEADER_RAND_H
17
18#include <openssl/base.h>
19
20#if defined(__cplusplus)
21extern "C" {
22#endif
23
24
25// Random number generation.
26
27
28// RAND_bytes writes |len| bytes of random data to |buf| and returns one.
29OPENSSL_EXPORT int RAND_bytes(uint8_t *buf, size_t len);
30
31// RAND_cleanup frees any resources used by the RNG. This is not safe if other
32// threads might still be calling |RAND_bytes|.
33OPENSSL_EXPORT void RAND_cleanup(void);
34
35
36// Obscure functions.
37
38#if !defined(OPENSSL_WINDOWS)
39// RAND_set_urandom_fd causes the module to use a copy of |fd| for system
40// randomness rather opening /dev/urandom internally. The caller retains
41// ownership of |fd| and is at liberty to close it at any time. This is useful
42// if, due to a sandbox, /dev/urandom isn't available. If used, it must be
43// called before the first call to |RAND_bytes|, and it is mutually exclusive
44// with |RAND_enable_fork_unsafe_buffering|.
45//
46// |RAND_set_urandom_fd| does not buffer any entropy, so it is safe to call
47// |fork| at any time after calling |RAND_set_urandom_fd|.
48OPENSSL_EXPORT void RAND_set_urandom_fd(int fd);
49
50// RAND_enable_fork_unsafe_buffering enables efficient buffered reading of
51// /dev/urandom. It adds an overhead of a few KB of memory per thread. It must
52// be called before the first call to |RAND_bytes| and it is mutually exclusive
53// with calls to |RAND_set_urandom_fd|.
54//
55// If |fd| is non-negative then a copy of |fd| will be used rather than opening
56// /dev/urandom internally. Like |RAND_set_urandom_fd|, the caller retains
57// ownership of |fd|. If |fd| is negative then /dev/urandom will be opened and
58// any error from open(2) crashes the address space.
59//
60// It has an unusual name because the buffer is unsafe across calls to |fork|.
61// Hence, this function should never be called by libraries.
62OPENSSL_EXPORT void RAND_enable_fork_unsafe_buffering(int fd);
63#endif
64
65#if defined(BORINGSSL_UNSAFE_DETERMINISTIC_MODE)
66// RAND_reset_for_fuzzing resets the fuzzer-only deterministic RNG. This
67// function is only defined in the fuzzer-only build configuration.
68OPENSSL_EXPORT void RAND_reset_for_fuzzing(void);
69#endif
70
71
72// Deprecated functions
73
74// RAND_pseudo_bytes is a wrapper around |RAND_bytes|.
75OPENSSL_EXPORT int RAND_pseudo_bytes(uint8_t *buf, size_t len);
76
77// RAND_seed reads a single byte of random data to ensure that any file
78// descriptors etc are opened.
79OPENSSL_EXPORT void RAND_seed(const void *buf, int num);
80
81// RAND_load_file returns a nonnegative number.
82OPENSSL_EXPORT int RAND_load_file(const char *path, long num);
83
84// RAND_file_name returns NULL.
85OPENSSL_EXPORT const char *RAND_file_name(char *buf, size_t num);
86
87// RAND_add does nothing.
88OPENSSL_EXPORT void RAND_add(const void *buf, int num, double entropy);
89
90// RAND_egd returns 255.
91OPENSSL_EXPORT int RAND_egd(const char *);
92
93// RAND_poll returns one.
94OPENSSL_EXPORT int RAND_poll(void);
95
96// RAND_status returns one.
97OPENSSL_EXPORT int RAND_status(void);
98
99// rand_meth_st is typedefed to |RAND_METHOD| in base.h. It isn't used; it
100// exists only to be the return type of |RAND_SSLeay|. It's
101// external so that variables of this type can be initialized.
102struct rand_meth_st {
103 void (*seed) (const void *buf, int num);
104 int (*bytes) (uint8_t *buf, size_t num);
105 void (*cleanup) (void);
106 void (*add) (const void *buf, int num, double entropy);
107 int (*pseudorand) (uint8_t *buf, size_t num);
108 int (*status) (void);
109};
110
111// RAND_SSLeay returns a pointer to a dummy |RAND_METHOD|.
112OPENSSL_EXPORT RAND_METHOD *RAND_SSLeay(void);
113
114// RAND_get_rand_method returns |RAND_SSLeay()|.
115OPENSSL_EXPORT const RAND_METHOD *RAND_get_rand_method(void);
116
117// RAND_set_rand_method does nothing.
118OPENSSL_EXPORT void RAND_set_rand_method(const RAND_METHOD *);
119
120
121#if defined(__cplusplus)
122} // extern C
123#endif
124
125#endif // OPENSSL_HEADER_RAND_H
126