cc2c7aa91c
Callers that lack hardware random may obtain a speed improvement by calling |RAND_enable_fork_unsafe_buffering|, which enables a thread-local buffer around reads from /dev/urandom. Change-Id: I46e675d1679b20434dd520c58ece0f888f38a241 Reviewed-on: https://boringssl-review.googlesource.com/5792 Reviewed-by: Adam Langley <agl@google.com>
113 lines
4.0 KiB
C
113 lines
4.0 KiB
C
/* Copyright (c) 2014, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#ifndef OPENSSL_HEADER_RAND_H
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#define OPENSSL_HEADER_RAND_H
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#include <openssl/base.h>
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/* Random number generation. */
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/* RAND_bytes writes |len| bytes of random data to |buf| and returns one. */
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OPENSSL_EXPORT int RAND_bytes(uint8_t *buf, size_t len);
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/* RAND_cleanup frees any resources used by the RNG. This is not safe if other
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* threads might still be calling |RAND_bytes|. */
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OPENSSL_EXPORT void RAND_cleanup(void);
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/* Obscure functions. */
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#if !defined(OPENSSL_WINDOWS)
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/* RAND_set_urandom_fd causes the module to use a copy of |fd| for system
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* randomness rather opening /dev/urandom internally. The caller retains
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* ownership of |fd| and is at liberty to close it at any time. This is useful
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* if, due to a sandbox, /dev/urandom isn't available. If used, it must be
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* called before the first call to |RAND_bytes|, and it is mutually exclusive
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* with |RAND_enable_fork_unsafe_buffering|.
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*
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* |RAND_set_urandom_fd| does not buffer any entropy, so it is safe to call
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* |fork| at any time after calling |RAND_set_urandom_fd|. */
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OPENSSL_EXPORT void RAND_set_urandom_fd(int fd);
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/* RAND_enable_fork_unsafe_buffering enables efficient buffered reading of
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* /dev/urandom. It adds an overhead of a few KB of memory per thread. It must
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* be called before the first call to |RAND_bytes| and it is mutually exclusive
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* with calls to |RAND_set_urandom_fd|.
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*
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* If |fd| is non-negative then a copy of |fd| will be used rather than opening
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* /dev/urandom internally. Like |RAND_set_urandom_fd|, the caller retains
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* ownership of |fd|. If |fd| is negative then /dev/urandom will be opened and
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* any error from open(2) crashes the address space.
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*
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* It has an unusual name because the buffer is unsafe across calls to |fork|.
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* Hence, this function should never be called by libraries. */
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OPENSSL_EXPORT void RAND_enable_fork_unsafe_buffering(int fd);
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#endif
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/* Deprecated functions */
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/* RAND_pseudo_bytes is a wrapper around |RAND_bytes|. */
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OPENSSL_EXPORT int RAND_pseudo_bytes(uint8_t *buf, size_t len);
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/* RAND_seed does nothing. */
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OPENSSL_EXPORT void RAND_seed(const void *buf, int num);
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/* RAND_load_file returns a nonnegative number. */
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OPENSSL_EXPORT int RAND_load_file(const char *path, long num);
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/* RAND_add does nothing. */
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OPENSSL_EXPORT void RAND_add(const void *buf, int num, double entropy);
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/* RAND_egd returns 255. */
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OPENSSL_EXPORT int RAND_egd(const char *);
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/* RAND_poll returns one. */
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OPENSSL_EXPORT int RAND_poll(void);
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/* RAND_status returns one. */
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OPENSSL_EXPORT int RAND_status(void);
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/* rand_meth_st is typedefed to |RAND_METHOD| in base.h. It isn't used; it
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* exists only to be the return type of |RAND_SSLeay|. It's
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* external so that variables of this type can be initialized. */
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struct rand_meth_st {
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void (*seed) (const void *buf, int num);
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int (*bytes) (uint8_t *buf, size_t num);
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void (*cleanup) (void);
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void (*add) (const void *buf, int num, double entropy);
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int (*pseudorand) (uint8_t *buf, size_t num);
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int (*status) (void);
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};
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/* RAND_SSLeay returns a pointer to a dummy |RAND_METHOD|. */
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OPENSSL_EXPORT RAND_METHOD *RAND_SSLeay(void);
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/* RAND_set_rand_method does nothing. */
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OPENSSL_EXPORT void RAND_set_rand_method(const RAND_METHOD *);
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#if defined(__cplusplus)
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} /* extern C */
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#endif
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#endif /* OPENSSL_HEADER_RAND_H */
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