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899b9b19a4
boringssl/include/openssl/bn.h
David Benjamin 899b9b19a4 Ensure |BN_div| never gives negative zero in the no_branch code. 
Have |bn_correct_top| fix |bn->neg| if the input is zero so that we
don't have negative zeros lying around.

Thanks to Brian Smith for noticing.

Change-Id: I91bcadebc8e353bb29c81c4367e85853886c8e4e
Reviewed-on: https://boringssl-review.googlesource.com/9074
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2016-08-02 18:53:45 +00:00

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/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
/* ====================================================================
* Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
*
* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* openssl-core@openssl.org.
*
* 5. Products derived from this software may not be called "OpenSSL"
* nor may "OpenSSL" appear in their names without prior written
* permission of the OpenSSL Project.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the OpenSSL Project
* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
*
* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This product includes cryptographic software written by Eric Young
* (eay@cryptsoft.com). This product includes software written by Tim
* Hudson (tjh@cryptsoft.com).
*
*/
/* ====================================================================
* Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
*
* Portions of the attached software ("Contribution") are developed by
* SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
*
* The Contribution is licensed pursuant to the Eric Young open source
* license provided above.
*
* The binary polynomial arithmetic software is originally written by
* Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
* Laboratories. */
#ifndef OPENSSL_HEADER_BN_H
#define OPENSSL_HEADER_BN_H
#include <openssl/base.h>
#include <openssl/thread.h>
#include <inttypes.h> /* for PRIu64 and friends */
#include <stdio.h> /* for FILE* */
#if defined(__cplusplus)
extern "C" {
#endif
/* BN provides support for working with arbitary sized integers. For example,
* although the largest integer supported by the compiler might be 64 bits, BN
* will allow you to work with numbers until you run out of memory. */
/* BN_ULONG is the native word size when working with big integers.
*
* Note: on some platforms, inttypes.h does not define print format macros in
* C++ unless |__STDC_FORMAT_MACROS| defined. As this is a public header, bn.h
* does not define |__STDC_FORMAT_MACROS| itself. C++ source files which use the
* FMT macros must define it externally. */
#if defined(OPENSSL_64_BIT)
#define BN_ULONG uint64_t
#define BN_BITS2 64
#define BN_DEC_FMT1 "%" PRIu64
#define BN_DEC_FMT2 "%019" PRIu64
#define BN_HEX_FMT1 "%" PRIx64
#elif defined(OPENSSL_32_BIT)
#define BN_ULONG uint32_t
#define BN_BITS2 32
#define BN_DEC_FMT1 "%" PRIu32
#define BN_DEC_FMT2 "%09" PRIu32
#define BN_HEX_FMT1 "%" PRIx32
#else
#error "Must define either OPENSSL_32_BIT or OPENSSL_64_BIT"
#endif
/* Allocation and freeing. */
/* BN_new creates a new, allocated BIGNUM and initialises it. */
OPENSSL_EXPORT BIGNUM *BN_new(void);
/* BN_init initialises a stack allocated |BIGNUM|. */
OPENSSL_EXPORT void BN_init(BIGNUM *bn);
/* BN_free frees the data referenced by |bn| and, if |bn| was originally
* allocated on the heap, frees |bn| also. */
OPENSSL_EXPORT void BN_free(BIGNUM *bn);
/* BN_clear_free erases and frees the data referenced by |bn| and, if |bn| was
* originally allocated on the heap, frees |bn| also. */
OPENSSL_EXPORT void BN_clear_free(BIGNUM *bn);
/* BN_dup allocates a new BIGNUM and sets it equal to |src|. It returns the
* allocated BIGNUM on success or NULL otherwise. */
OPENSSL_EXPORT BIGNUM *BN_dup(const BIGNUM *src);
/* BN_copy sets |dest| equal to |src| and returns |dest| or NULL on allocation
* failure. */
OPENSSL_EXPORT BIGNUM *BN_copy(BIGNUM *dest, const BIGNUM *src);
/* BN_clear sets |bn| to zero and erases the old data. */
OPENSSL_EXPORT void BN_clear(BIGNUM *bn);
/* BN_value_one returns a static BIGNUM with value 1. */
OPENSSL_EXPORT const BIGNUM *BN_value_one(void);
/* BN_with_flags initialises a stack allocated |BIGNUM| with pointers to the
* contents of |in| but with |flags| ORed into the flags field.
*
* Note: the two BIGNUMs share state and so |out| should /not/ be passed to
* |BN_free|. */
OPENSSL_EXPORT void BN_with_flags(BIGNUM *out, const BIGNUM *in, int flags);
/* Basic functions. */
/* BN_num_bits returns the minimum number of bits needed to represent the
* absolute value of |bn|. */
OPENSSL_EXPORT unsigned BN_num_bits(const BIGNUM *bn);
/* BN_num_bytes returns the minimum number of bytes needed to represent the
* absolute value of |bn|. */
OPENSSL_EXPORT unsigned BN_num_bytes(const BIGNUM *bn);
/* BN_zero sets |bn| to zero. */
OPENSSL_EXPORT void BN_zero(BIGNUM *bn);
/* BN_one sets |bn| to one. It returns one on success or zero on allocation
* failure. */
OPENSSL_EXPORT int BN_one(BIGNUM *bn);
/* BN_set_word sets |bn| to |value|. It returns one on success or zero on
* allocation failure. */
OPENSSL_EXPORT int BN_set_word(BIGNUM *bn, BN_ULONG value);
/* BN_set_negative sets the sign of |bn|. */
OPENSSL_EXPORT void BN_set_negative(BIGNUM *bn, int sign);
/* BN_is_negative returns one if |bn| is negative and zero otherwise. */
OPENSSL_EXPORT int BN_is_negative(const BIGNUM *bn);
/* BN_get_flags returns |bn->flags| & |flags|. */
OPENSSL_EXPORT int BN_get_flags(const BIGNUM *bn, int flags);
/* BN_set_flags sets |flags| on |bn|. */
OPENSSL_EXPORT void BN_set_flags(BIGNUM *bn, int flags);
/* Conversion functions. */
/* BN_bin2bn sets |*ret| to the value of |len| bytes from |in|, interpreted as
* a big-endian number, and returns |ret|. If |ret| is NULL then a fresh
* |BIGNUM| is allocated and returned. It returns NULL on allocation
* failure. */
OPENSSL_EXPORT BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret);
/* BN_bn2bin serialises the absolute value of |in| to |out| as a big-endian
* integer, which must have |BN_num_bytes| of space available. It returns the
* number of bytes written. */
OPENSSL_EXPORT size_t BN_bn2bin(const BIGNUM *in, uint8_t *out);
/* BN_bn2bin_padded serialises the absolute value of |in| to |out| as a
* big-endian integer. The integer is padded with leading zeros up to size
* |len|. If |len| is smaller than |BN_num_bytes|, the function fails and
* returns 0. Otherwise, it returns 1. */
OPENSSL_EXPORT int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in);
/* BN_bn2cbb_padded behaves like |BN_bn2bin_padded| but writes to a |CBB|. */
OPENSSL_EXPORT int BN_bn2cbb_padded(CBB *out, size_t len, const BIGNUM *in);
/* BN_bn2hex returns an allocated string that contains a NUL-terminated, hex
* representation of |bn|. If |bn| is negative, the first char in the resulting
* string will be '-'. Returns NULL on allocation failure. */
OPENSSL_EXPORT char *BN_bn2hex(const BIGNUM *bn);
/* BN_hex2bn parses the leading hex number from |in|, which may be proceeded by
* a '-' to indicate a negative number and may contain trailing, non-hex data.
* If |outp| is not NULL, it constructs a BIGNUM equal to the hex number and
* stores it in |*outp|. If |*outp| is NULL then it allocates a new BIGNUM and
* updates |*outp|. It returns the number of bytes of |in| processed or zero on
* error. */
OPENSSL_EXPORT int BN_hex2bn(BIGNUM **outp, const char *in);
/* BN_bn2dec returns an allocated string that contains a NUL-terminated,
* decimal representation of |bn|. If |bn| is negative, the first char in the
* resulting string will be '-'. Returns NULL on allocation failure. */
OPENSSL_EXPORT char *BN_bn2dec(const BIGNUM *a);
/* BN_dec2bn parses the leading decimal number from |in|, which may be
* proceeded by a '-' to indicate a negative number and may contain trailing,
* non-decimal data. If |outp| is not NULL, it constructs a BIGNUM equal to the
* decimal number and stores it in |*outp|. If |*outp| is NULL then it
* allocates a new BIGNUM and updates |*outp|. It returns the number of bytes
* of |in| processed or zero on error. */
OPENSSL_EXPORT int BN_dec2bn(BIGNUM **outp, const char *in);
/* BN_asc2bn acts like |BN_dec2bn| or |BN_hex2bn| depending on whether |in|
* begins with "0X" or "0x" (indicating hex) or not (indicating decimal). A
* leading '-' is still permitted and comes before the optional 0X/0x. It
* returns one on success or zero on error. */
OPENSSL_EXPORT int BN_asc2bn(BIGNUM **outp, const char *in);
/* BN_print writes a hex encoding of |a| to |bio|. It returns one on success
* and zero on error. */
OPENSSL_EXPORT int BN_print(BIO *bio, const BIGNUM *a);
/* BN_print_fp acts like |BIO_print|, but wraps |fp| in a |BIO| first. */
OPENSSL_EXPORT int BN_print_fp(FILE *fp, const BIGNUM *a);
/* BN_get_word returns the absolute value of |bn| as a single word. If |bn| is
* too large to be represented as a single word, the maximum possible value
* will be returned. */
OPENSSL_EXPORT BN_ULONG BN_get_word(const BIGNUM *bn);
/* ASN.1 functions. */
/* BN_parse_asn1_unsigned parses a non-negative DER INTEGER from |cbs| writes
* the result to |ret|. It returns one on success and zero on failure. */
OPENSSL_EXPORT int BN_parse_asn1_unsigned(CBS *cbs, BIGNUM *ret);
/* BN_parse_asn1_unsigned_buggy acts like |BN_parse_asn1_unsigned| but tolerates
* some invalid encodings. Do not use this function. */
OPENSSL_EXPORT int BN_parse_asn1_unsigned_buggy(CBS *cbs, BIGNUM *ret);
/* BN_marshal_asn1 marshals |bn| as a non-negative DER INTEGER and appends the
* result to |cbb|. It returns one on success and zero on failure. */
OPENSSL_EXPORT int BN_marshal_asn1(CBB *cbb, const BIGNUM *bn);
/* Internal functions.
*
* These functions are useful for code that is doing low-level manipulations of
* BIGNUM values. However, be sure that no other function in this file does
* what you want before turning to these. */
/* bn_correct_top decrements |bn->top| until |bn->d[top-1]| is non-zero or
* until |top| is zero. If |bn| is zero, |bn->neg| is set to zero. */
OPENSSL_EXPORT void bn_correct_top(BIGNUM *bn);
/* bn_wexpand ensures that |bn| has at least |words| works of space without
* altering its value. It returns one on success or zero on allocation
* failure. */
OPENSSL_EXPORT BIGNUM *bn_wexpand(BIGNUM *bn, size_t words);
/* BIGNUM pools.
*
* Certain BIGNUM operations need to use many temporary variables and
* allocating and freeing them can be quite slow. Thus such opertions typically
* take a |BN_CTX| parameter, which contains a pool of |BIGNUMs|. The |ctx|
* argument to a public function may be NULL, in which case a local |BN_CTX|
* will be created just for the lifetime of that call.
*
* A function must call |BN_CTX_start| first. Then, |BN_CTX_get| may be called
* repeatedly to obtain temporary |BIGNUM|s. All |BN_CTX_get| calls must be made
* before calling any other functions that use the |ctx| as an argument.
*
* Finally, |BN_CTX_end| must be called before returning from the function.
* When |BN_CTX_end| is called, the |BIGNUM| pointers obtained from
* |BN_CTX_get| become invalid. */
/* BN_CTX_new returns a new, empty BN_CTX or NULL on allocation failure. */
OPENSSL_EXPORT BN_CTX *BN_CTX_new(void);
/* BN_CTX_free frees all BIGNUMs contained in |ctx| and then frees |ctx|
* itself. */
OPENSSL_EXPORT void BN_CTX_free(BN_CTX *ctx);
/* BN_CTX_start "pushes" a new entry onto the |ctx| stack and allows future
* calls to |BN_CTX_get|. */
OPENSSL_EXPORT void BN_CTX_start(BN_CTX *ctx);
/* BN_CTX_get returns a new |BIGNUM|, or NULL on allocation failure. Once
* |BN_CTX_get| has returned NULL, all future calls will also return NULL until
* |BN_CTX_end| is called. */
OPENSSL_EXPORT BIGNUM *BN_CTX_get(BN_CTX *ctx);
/* BN_CTX_end invalidates all |BIGNUM|s returned from |BN_CTX_get| since the
* matching |BN_CTX_start| call. */
OPENSSL_EXPORT void BN_CTX_end(BN_CTX *ctx);
/* Simple arithmetic */
/* BN_add sets |r| = |a| + |b|, where |r| may be the same pointer as either |a|
* or |b|. It returns one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_uadd sets |r| = |a| + |b|, where |a| and |b| are non-negative and |r| may
* be the same pointer as either |a| or |b|. It returns one on success and zero
* on allocation failure. */
OPENSSL_EXPORT int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_add_word adds |w| to |a|. It returns one on success and zero otherwise. */
OPENSSL_EXPORT int BN_add_word(BIGNUM *a, BN_ULONG w);
/* BN_sub sets |r| = |a| - |b|, where |r| may be the same pointer as either |a|
* or |b|. It returns one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_usub sets |r| = |a| - |b|, where |a| and |b| are non-negative integers,
* |b| < |a| and |r| may be the same pointer as either |a| or |b|. It returns
* one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b);
/* BN_sub_word subtracts |w| from |a|. It returns one on success and zero on
* allocation failure. */
OPENSSL_EXPORT int BN_sub_word(BIGNUM *a, BN_ULONG w);
/* BN_mul sets |r| = |a| * |b|, where |r| may be the same pointer as |a| or
* |b|. Returns one on success and zero otherwise. */
OPENSSL_EXPORT int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
BN_CTX *ctx);
/* BN_mul_word sets |bn| = |bn| * |w|. It returns one on success or zero on
* allocation failure. */
OPENSSL_EXPORT int BN_mul_word(BIGNUM *bn, BN_ULONG w);
/* BN_sqr sets |r| = |a|^2 (i.e. squares), where |r| may be the same pointer as
* |a|. Returns one on success and zero otherwise. This is more efficient than
* BN_mul(r, a, a, ctx). */
OPENSSL_EXPORT int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx);
/* BN_div divides |numerator| by |divisor| and places the result in |quotient|
* and the remainder in |rem|. Either of |quotient| or |rem| may be NULL, in
* which case the respective value is not returned. The result is rounded
* towards zero; thus if |numerator| is negative, the remainder will be zero or
* negative. It returns one on success or zero on error. */
OPENSSL_EXPORT int BN_div(BIGNUM *quotient, BIGNUM *rem,
const BIGNUM *numerator, const BIGNUM *divisor,
BN_CTX *ctx);
/* BN_div_word sets |numerator| = |numerator|/|divisor| and returns the
* remainder or (BN_ULONG)-1 on error. */
OPENSSL_EXPORT BN_ULONG BN_div_word(BIGNUM *numerator, BN_ULONG divisor);
/* BN_sqrt sets |*out_sqrt| (which may be the same |BIGNUM| as |in|) to the
* square root of |in|, using |ctx|. It returns one on success or zero on
* error. Negative numbers and non-square numbers will result in an error with
* appropriate errors on the error queue. */
OPENSSL_EXPORT int BN_sqrt(BIGNUM *out_sqrt, const BIGNUM *in, BN_CTX *ctx);
/* Comparison functions */
/* BN_cmp returns a value less than, equal to or greater than zero if |a| is
* less than, equal to or greater than |b|, respectively. */
OPENSSL_EXPORT int BN_cmp(const BIGNUM *a, const BIGNUM *b);
/* BN_cmp_word is like |BN_cmp| except it takes its second argument as a
* |BN_ULONG| instead of a |BIGNUM|. */
OPENSSL_EXPORT int BN_cmp_word(const BIGNUM *a, BN_ULONG b);
/* BN_ucmp returns a value less than, equal to or greater than zero if the
* absolute value of |a| is less than, equal to or greater than the absolute
* value of |b|, respectively. */
OPENSSL_EXPORT int BN_ucmp(const BIGNUM *a, const BIGNUM *b);
/* BN_equal_consttime returns one if |a| is equal to |b|, and zero otherwise.
* It takes an amount of time dependent on the sizes of |a| and |b|, but
* independent of the contents (including the signs) of |a| and |b|. */
OPENSSL_EXPORT int BN_equal_consttime(const BIGNUM *a, const BIGNUM *b);
/* BN_abs_is_word returns one if the absolute value of |bn| equals |w| and zero
* otherwise. */
OPENSSL_EXPORT int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w);
/* BN_is_zero returns one if |bn| is zero and zero otherwise. */
OPENSSL_EXPORT int BN_is_zero(const BIGNUM *bn);
/* BN_is_one returns one if |bn| equals one and zero otherwise. */
OPENSSL_EXPORT int BN_is_one(const BIGNUM *bn);
/* BN_is_word returns one if |bn| is exactly |w| and zero otherwise. */
OPENSSL_EXPORT int BN_is_word(const BIGNUM *bn, BN_ULONG w);
/* BN_is_odd returns one if |bn| is odd and zero otherwise. */
OPENSSL_EXPORT int BN_is_odd(const BIGNUM *bn);
/* Bitwise operations. */
/* BN_lshift sets |r| equal to |a| << n. The |a| and |r| arguments may be the
* same |BIGNUM|. It returns one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
/* BN_lshift1 sets |r| equal to |a| << 1, where |r| and |a| may be the same
* pointer. It returns one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_lshift1(BIGNUM *r, const BIGNUM *a);
/* BN_rshift sets |r| equal to |a| >> n, where |r| and |a| may be the same
* pointer. It returns one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_rshift(BIGNUM *r, const BIGNUM *a, int n);
/* BN_rshift1 sets |r| equal to |a| >> 1, where |r| and |a| may be the same
* pointer. It returns one on success and zero on allocation failure. */
OPENSSL_EXPORT int BN_rshift1(BIGNUM *r, const BIGNUM *a);
/* BN_set_bit sets the |n|th, least-significant bit in |a|. For example, if |a|
* is 2 then setting bit zero will make it 3. It returns one on success or zero
* on allocation failure. */
OPENSSL_EXPORT int BN_set_bit(BIGNUM *a, int n);
/* BN_clear_bit clears the |n|th, least-significant bit in |a|. For example, if
* |a| is 3, clearing bit zero will make it two. It returns one on success or
* zero on allocation failure. */
OPENSSL_EXPORT int BN_clear_bit(BIGNUM *a, int n);
/* BN_is_bit_set returns the value of the |n|th, least-significant bit in |a|,
* or zero if the bit doesn't exist. */
OPENSSL_EXPORT int BN_is_bit_set(const BIGNUM *a, int n);
/* BN_mask_bits truncates |a| so that it is only |n| bits long. It returns one
* on success or zero if |n| is greater than the length of |a| already. */
OPENSSL_EXPORT int BN_mask_bits(BIGNUM *a, int n);
/* Modulo arithmetic. */
/* BN_mod_word returns |a| mod |w| or (BN_ULONG)-1 on error. */
OPENSSL_EXPORT BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w);
/* BN_mod is a helper macro that calls |BN_div| and discards the quotient. */
#define BN_mod(rem, numerator, divisor, ctx) \
BN_div(NULL, (rem), (numerator), (divisor), (ctx))
/* BN_nnmod is a non-negative modulo function. It acts like |BN_mod|, but 0 <=
* |rem| < |divisor| is always true. It returns one on success and zero on
* error. */
OPENSSL_EXPORT int BN_nnmod(BIGNUM *rem, const BIGNUM *numerator,
const BIGNUM *divisor, BN_CTX *ctx);
/* BN_mod_add sets |r| = |a| + |b| mod |m|. It returns one on success and zero
* on error. */
OPENSSL_EXPORT int BN_mod_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m, BN_CTX *ctx);
/* BN_mod_add_quick acts like |BN_mod_add| but requires that |a| and |b| be
* non-negative and less than |m|. */
OPENSSL_EXPORT int BN_mod_add_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m);
/* BN_mod_sub sets |r| = |a| - |b| mod |m|. It returns one on success and zero
* on error. */
OPENSSL_EXPORT int BN_mod_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m, BN_CTX *ctx);
/* BN_mod_sub_quick acts like |BN_mod_sub| but requires that |a| and |b| be
* non-negative and less than |m|. */
OPENSSL_EXPORT int BN_mod_sub_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m);
/* BN_mod_mul sets |r| = |a|*|b| mod |m|. It returns one on success and zero
* on error. */
OPENSSL_EXPORT int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
const BIGNUM *m, BN_CTX *ctx);
/* BN_mod_sqr sets |r| = |a|^2 mod |m|. It returns one on success and zero
* on error. */
OPENSSL_EXPORT int BN_mod_sqr(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
BN_CTX *ctx);
/* BN_mod_lshift sets |r| = (|a| << n) mod |m|, where |r| and |a| may be the
* same pointer. It returns one on success and zero on error. */
OPENSSL_EXPORT int BN_mod_lshift(BIGNUM *r, const BIGNUM *a, int n,
const BIGNUM *m, BN_CTX *ctx);
/* BN_mod_lshift_quick acts like |BN_mod_lshift| but requires that |a| be
* non-negative and less than |m|. */
OPENSSL_EXPORT int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n,
const BIGNUM *m);
/* BN_mod_lshift1 sets |r| = (|a| << 1) mod |m|, where |r| and |a| may be the
* same pointer. It returns one on success and zero on error. */
OPENSSL_EXPORT int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m,
BN_CTX *ctx);
/* BN_mod_lshift1_quick acts like |BN_mod_lshift1| but requires that |a| be
* non-negative and less than |m|. */
OPENSSL_EXPORT int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a,
const BIGNUM *m);
/* BN_mod_sqrt returns a |BIGNUM|, r, such that r^2 == a (mod p). |p| must be a
* prime. */
OPENSSL_EXPORT BIGNUM *BN_mod_sqrt(BIGNUM *in, const BIGNUM *a, const BIGNUM *p,
BN_CTX *ctx);
/* Random and prime number generation. */
/* BN_rand sets |rnd| to a random number of length |bits|. If |top| is zero, the
* most-significant bit, if any, will be set. If |top| is one, the two most
* significant bits, if any, will be set.
*
* If |top| is -1 then no extra action will be taken and |BN_num_bits(rnd)| may
* not equal |bits| if the most significant bits randomly ended up as zeros.
*
* If |bottom| is non-zero, the least-significant bit, if any, will be set. The
* function returns one on success or zero otherwise. */
OPENSSL_EXPORT int BN_rand(BIGNUM *rnd, int bits, int top, int bottom);
/* BN_pseudo_rand is an alias for |BN_rand|. */
OPENSSL_EXPORT int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom);
/* BN_rand_range is equivalent to |BN_rand_range_ex| with |min_inclusive| set
* to zero and |max_exclusive| set to |range|. */
OPENSSL_EXPORT int BN_rand_range(BIGNUM *rnd, const BIGNUM *range);
/* BN_rand_range_ex sets |rnd| to a random value in
* [min_inclusive..max_exclusive). It returns one on success and zero
* otherwise. */
OPENSSL_EXPORT int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive,
const BIGNUM *max_exclusive);
/* BN_pseudo_rand_range is an alias for BN_rand_range. */
OPENSSL_EXPORT int BN_pseudo_rand_range(BIGNUM *rnd, const BIGNUM *range);
/* BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike
* BN_rand_range, it also includes the contents of |priv| and |message| in the
* generation so that an RNG failure isn't fatal as long as |priv| remains
* secret. This is intended for use in DSA and ECDSA where an RNG weakness
* leads directly to private key exposure unless this function is used.
* It returns one on success and zero on error. */
OPENSSL_EXPORT int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range,
const BIGNUM *priv,
const uint8_t *message,
size_t message_len, BN_CTX *ctx);
/* BN_GENCB holds a callback function that is used by generation functions that
* can take a very long time to complete. Use |BN_GENCB_set| to initialise a
* |BN_GENCB| structure.
*
* The callback receives the address of that |BN_GENCB| structure as its last
* argument and the user is free to put an arbitary pointer in |arg|. The other
* arguments are set as follows:
* event=BN_GENCB_GENERATED, n=i: after generating the i'th possible prime
* number.
* event=BN_GENCB_PRIME_TEST, n=-1: when finished trial division primality
* checks.
* event=BN_GENCB_PRIME_TEST, n=i: when the i'th primality test has finished.
*
* The callback can return zero to abort the generation progress or one to
* allow it to continue.
*
* When other code needs to call a BN generation function it will often take a
* BN_GENCB argument and may call the function with other argument values. */
#define BN_GENCB_GENERATED 0
#define BN_GENCB_PRIME_TEST 1
struct bn_gencb_st {
void *arg; /* callback-specific data */
int (*callback)(int event, int n, struct bn_gencb_st *);
};
/* BN_GENCB_set configures |callback| to call |f| and sets |callout->arg| to
* |arg|. */
OPENSSL_EXPORT void BN_GENCB_set(BN_GENCB *callback,
int (*f)(int event, int n,
struct bn_gencb_st *),
void *arg);
/* BN_GENCB_call calls |callback|, if not NULL, and returns the return value of
* the callback, or 1 if |callback| is NULL. */
OPENSSL_EXPORT int BN_GENCB_call(BN_GENCB *callback, int event, int n);
/* BN_generate_prime_ex sets |ret| to a prime number of |bits| length. If safe
* is non-zero then the prime will be such that (ret-1)/2 is also a prime.
* (This is needed for Diffie-Hellman groups to ensure that the only subgroups
* are of size 2 and (p-1)/2.).
*
* If |add| is not NULL, the prime will fulfill the condition |ret| % |add| ==
* |rem| in order to suit a given generator. (If |rem| is NULL then |ret| %
* |add| == 1.)
*
* If |cb| is not NULL, it will be called during processing to give an
* indication of progress. See the comments for |BN_GENCB|. It returns one on
* success and zero otherwise. */
OPENSSL_EXPORT int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe,
const BIGNUM *add, const BIGNUM *rem,
BN_GENCB *cb);
/* BN_prime_checks is magic value that can be used as the |checks| argument to
* the primality testing functions in order to automatically select a number of
* Miller-Rabin checks that gives a false positive rate of ~2^{-80}. */
#define BN_prime_checks 0
/* BN_primality_test sets |*is_probably_prime| to one if |candidate| is
* probably a prime number by the Miller-Rabin test or zero if it's certainly
* not.
*
* If |do_trial_division| is non-zero then |candidate| will be tested against a
* list of small primes before Miller-Rabin tests. The probability of this
* function returning a false positive is 2^{2*checks}. If |checks| is
* |BN_prime_checks| then a value that results in approximately 2^{-80} false
* positive probability is used. If |cb| is not NULL then it is called during
* the checking process. See the comment above |BN_GENCB|.
*
* The function returns one on success and zero on error.
*
* (If you are unsure whether you want |do_trial_division|, don't set it.) */
OPENSSL_EXPORT int BN_primality_test(int *is_probably_prime,
const BIGNUM *candidate, int checks,
BN_CTX *ctx, int do_trial_division,
BN_GENCB *cb);
/* BN_is_prime_fasttest_ex returns one if |candidate| is probably a prime
* number by the Miller-Rabin test, zero if it's certainly not and -1 on error.
*
* If |do_trial_division| is non-zero then |candidate| will be tested against a
* list of small primes before Miller-Rabin tests. The probability of this
* function returning one when |candidate| is composite is 2^{2*checks}. If
* |checks| is |BN_prime_checks| then a value that results in approximately
* 2^{-80} false positive probability is used. If |cb| is not NULL then it is
* called during the checking process. See the comment above |BN_GENCB|.
*
* WARNING: deprecated. Use |BN_primality_test|. */
OPENSSL_EXPORT int BN_is_prime_fasttest_ex(const BIGNUM *candidate, int checks,
BN_CTX *ctx, int do_trial_division,
BN_GENCB *cb);
/* BN_is_prime_ex acts the same as |BN_is_prime_fasttest_ex| with
* |do_trial_division| set to zero.
*
* WARNING: deprecated: Use |BN_primality_test|. */
OPENSSL_EXPORT int BN_is_prime_ex(const BIGNUM *candidate, int checks,
BN_CTX *ctx, BN_GENCB *cb);
/* Number theory functions */
/* BN_gcd sets |r| = gcd(|a|, |b|). It returns one on success and zero
* otherwise. */
OPENSSL_EXPORT int BN_gcd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
BN_CTX *ctx);
/* BN_mod_inverse sets |out| equal to |a|^-1, mod |n|. If |out| is NULL, a
* fresh BIGNUM is allocated. It returns the result or NULL on error.
*
* If either of |a| or |n| have |BN_FLG_CONSTTIME| set then the operation is
* performed using an algorithm that avoids some branches but which isn't
* constant-time. This function shouldn't be used for secret values, even
* with |BN_FLG_CONSTTIME|; use |BN_mod_inverse_blinded| instead. Or, if
* |n| is guaranteed to be prime, use
* |BN_mod_exp_mont_consttime(out, a, m_minus_2, m, ctx, m_mont)|, taking
* advantage of Fermat's Little Theorem. */
OPENSSL_EXPORT BIGNUM *BN_mod_inverse(BIGNUM *out, const BIGNUM *a,
const BIGNUM *n, BN_CTX *ctx);
/* BN_mod_inverse_blinded sets |out| equal to |a|^-1, mod |n|, where |n| is the
* Montgomery modulus for |mont|. |a| must be non-negative and must be less
* than |n|. |n| must be greater than 1. |a| is blinded (masked by a random
* value) to protect it against side-channel attacks. |BN_mod_inverse_blinded|
* may or may not ignore the |BN_FLG_CONSTTIME| flag on any/all of its inputs.
* It returns one on success or zero on failure. On failure, if the failure was
* caused by |a| having no inverse mod |n| then |*out_no_inverse| will be set
* to one; otherwise it will be set to zero. */
int BN_mod_inverse_blinded(BIGNUM *out, int *out_no_inverse, const BIGNUM *a,
const BN_MONT_CTX *mont, BN_CTX *ctx);
/* BN_kronecker returns the Kronecker symbol of |a| and |b| (which is -1, 0 or
* 1), or -2 on error. */
OPENSSL_EXPORT int BN_kronecker(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx);
/* Montgomery arithmetic. */
/* BN_MONT_CTX contains the precomputed values needed to work in a specific
* Montgomery domain. */
/* BN_MONT_CTX_new returns a fresh BN_MONT_CTX or NULL on allocation failure. */
OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_new(void);
/* BN_MONT_CTX_free frees memory associated with |mont|. */
OPENSSL_EXPORT void BN_MONT_CTX_free(BN_MONT_CTX *mont);
/* BN_MONT_CTX_copy sets |to| equal to |from|. It returns |to| on success or
* NULL on error. */
OPENSSL_EXPORT BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to,
const BN_MONT_CTX *from);
/* BN_MONT_CTX_set sets up a Montgomery context given the modulus, |mod|. It
* returns one on success and zero on error. */
OPENSSL_EXPORT int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod,
BN_CTX *ctx);
/* BN_MONT_CTX_set_locked takes |lock| and checks whether |*pmont| is NULL. If
* so, it creates a new |BN_MONT_CTX| and sets the modulus for it to |mod|. It
* then stores it as |*pmont|. It returns one on success and zero on error.
*
* If |*pmont| is already non-NULL then it does nothing and returns one. */
int BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, CRYPTO_MUTEX *lock,
const BIGNUM *mod, BN_CTX *bn_ctx);
/* BN_to_montgomery sets |ret| equal to |a| in the Montgomery domain. It
* returns one on success and zero on error. */
OPENSSL_EXPORT int BN_to_montgomery(BIGNUM *ret, const BIGNUM *a,
const BN_MONT_CTX *mont, BN_CTX *ctx);
/* BN_from_montgomery sets |ret| equal to |a| * R^-1, i.e. translates values
* out of the Montgomery domain. It returns one on success or zero on error. */
OPENSSL_EXPORT int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a,
const BN_MONT_CTX *mont, BN_CTX *ctx);
/* BN_mod_mul_montgomery set |r| equal to |a| * |b|, in the Montgomery domain.
* Both |a| and |b| must already be in the Montgomery domain (by
* |BN_to_montgomery|). It returns one on success or zero on error. */
OPENSSL_EXPORT int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a,
const BIGNUM *b,
const BN_MONT_CTX *mont, BN_CTX *ctx);
/* Exponentiation. */
/* BN_exp sets |r| equal to |a|^{|p|}. It does so with a square-and-multiply
* algorithm that leaks side-channel information. It returns one on success or
* zero otherwise. */
OPENSSL_EXPORT int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
BN_CTX *ctx);
/* BN_mod_exp sets |r| equal to |a|^{|p|} mod |m|. It does so with the best
* algorithm for the values provided and can run in constant time if
* |BN_FLG_CONSTTIME| is set for |p|. It returns one on success or zero
* otherwise. */
OPENSSL_EXPORT int BN_mod_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx);
OPENSSL_EXPORT int BN_mod_exp_mont(BIGNUM *r, const BIGNUM *a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx,
const BN_MONT_CTX *mont);
OPENSSL_EXPORT int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a,
const BIGNUM *p, const BIGNUM *m,
BN_CTX *ctx,
const BN_MONT_CTX *mont);
/* Deprecated functions */
/* BN_bn2mpi serialises the value of |in| to |out|, using a format that consists
* of the number's length in bytes represented as a 4-byte big-endian number,
* and the number itself in big-endian format, where the most significant bit
* signals a negative number. (The representation of numbers with the MSB set is
* prefixed with null byte). |out| must have sufficient space available; to
* find the needed amount of space, call the function with |out| set to NULL. */
OPENSSL_EXPORT size_t BN_bn2mpi(const BIGNUM *in, uint8_t *out);
/* BN_mpi2bn parses |len| bytes from |in| and returns the resulting value. The
* bytes at |in| are expected to be in the format emitted by |BN_bn2mpi|.
*
* If |out| is NULL then a fresh |BIGNUM| is allocated and returned, otherwise
* |out| is reused and returned. On error, NULL is returned and the error queue
* is updated. */
OPENSSL_EXPORT BIGNUM *BN_mpi2bn(const uint8_t *in, size_t len, BIGNUM *out);
/* BN_mod_exp_mont_word is like |BN_mod_exp_mont| except that the base |a| is
* given as a |BN_ULONG| instead of a |BIGNUM *|. It returns one on success
* or zero otherwise. */
OPENSSL_EXPORT int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
const BIGNUM *m, BN_CTX *ctx,
const BN_MONT_CTX *mont);
/* BN_mod_exp2_mont calculates (a1^p1) * (a2^p2) mod m. It returns 1 on success
* or zero otherwise. */
OPENSSL_EXPORT int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1,
const BIGNUM *p1, const BIGNUM *a2,
const BIGNUM *p2, const BIGNUM *m,
BN_CTX *ctx, const BN_MONT_CTX *mont);
/* Private functions */
struct bignum_st {
BN_ULONG *d; /* Pointer to an array of 'BN_BITS2' bit chunks in little-endian
order. */
int top; /* Index of last used element in |d|, plus one. */
int dmax; /* Size of |d|, in words. */
int neg; /* one if the number is negative */
int flags; /* bitmask of BN_FLG_* values */
};
struct bn_mont_ctx_st {
BIGNUM RR; /* used to convert to montgomery form */
BIGNUM N; /* The modulus */
BN_ULONG n0[2]; /* least significant words of (R*Ri-1)/N */
};
OPENSSL_EXPORT unsigned BN_num_bits_word(BN_ULONG l);
#define BN_FLG_MALLOCED 0x01
#define BN_FLG_STATIC_DATA 0x02
/* avoid leaking exponent information through timing, BN_mod_exp_mont() will
* call BN_mod_exp_mont_consttime, BN_div() will call BN_div_no_branch,
* BN_mod_inverse() will call BN_mod_inverse_no_branch. */
#define BN_FLG_CONSTTIME 0x04
#if defined(__cplusplus)
} /* extern C */
#endif
#define BN_R_ARG2_LT_ARG3 100
#define BN_R_BAD_RECIPROCAL 101
#define BN_R_BIGNUM_TOO_LONG 102
#define BN_R_BITS_TOO_SMALL 103
#define BN_R_CALLED_WITH_EVEN_MODULUS 104
#define BN_R_DIV_BY_ZERO 105
#define BN_R_EXPAND_ON_STATIC_BIGNUM_DATA 106
#define BN_R_INPUT_NOT_REDUCED 107
#define BN_R_INVALID_RANGE 108
#define BN_R_NEGATIVE_NUMBER 109
#define BN_R_NOT_A_SQUARE 110
#define BN_R_NOT_INITIALIZED 111
#define BN_R_NO_INVERSE 112
#define BN_R_PRIVATE_KEY_TOO_LARGE 113
#define BN_R_P_IS_NOT_PRIME 114
#define BN_R_TOO_MANY_ITERATIONS 115
#define BN_R_TOO_MANY_TEMPORARY_VARIABLES 116
#define BN_R_BAD_ENCODING 117
#define BN_R_ENCODE_ERROR 118
#endif /* OPENSSL_HEADER_BN_H */
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