ref: e86bd6a50933e99899d63de755d81b9805827a15
dir: /third_party/boringssl/src/crypto/fipsmodule/bn/bytes.c/
/* Copyright (C) 1995-1998 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.] */
#include <openssl/bn.h>
#include <assert.h>
#include <limits.h>
#include "internal.h"
BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret) {
size_t num_words;
unsigned m;
BN_ULONG word = 0;
BIGNUM *bn = NULL;
if (ret == NULL) {
ret = bn = BN_new();
}
if (ret == NULL) {
return NULL;
}
if (len == 0) {
ret->width = 0;
return ret;
}
num_words = ((len - 1) / BN_BYTES) + 1;
m = (len - 1) % BN_BYTES;
if (!bn_wexpand(ret, num_words)) {
if (bn) {
BN_free(bn);
}
return NULL;
}
// |bn_wexpand| must check bounds on |num_words| to write it into
// |ret->dmax|.
assert(num_words <= INT_MAX);
ret->width = (int)num_words;
ret->neg = 0;
while (len--) {
word = (word << 8) | *(in++);
if (m-- == 0) {
ret->d[--num_words] = word;
word = 0;
m = BN_BYTES - 1;
}
}
return ret;
}
BIGNUM *BN_le2bn(const uint8_t *in, size_t len, BIGNUM *ret) {
BIGNUM *bn = NULL;
if (ret == NULL) {
bn = BN_new();
ret = bn;
}
if (ret == NULL) {
return NULL;
}
if (len == 0) {
ret->width = 0;
ret->neg = 0;
return ret;
}
// Reserve enough space in |ret|.
size_t num_words = ((len - 1) / BN_BYTES) + 1;
if (!bn_wexpand(ret, num_words)) {
BN_free(bn);
return NULL;
}
ret->width = num_words;
// Make sure the top bytes will be zeroed.
ret->d[num_words - 1] = 0;
// We only support little-endian platforms, so we can simply memcpy the
// internal representation.
OPENSSL_memcpy(ret->d, in, len);
return ret;
}
size_t BN_bn2bin(const BIGNUM *in, uint8_t *out) {
size_t n, i;
BN_ULONG l;
n = i = BN_num_bytes(in);
while (i--) {
l = in->d[i / BN_BYTES];
*(out++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
}
return n;
}
static int fits_in_bytes(const uint8_t *bytes, size_t num_bytes, size_t len) {
uint8_t mask = 0;
for (size_t i = len; i < num_bytes; i++) {
mask |= bytes[i];
}
return mask == 0;
}
int BN_bn2le_padded(uint8_t *out, size_t len, const BIGNUM *in) {
const uint8_t *bytes = (const uint8_t *)in->d;
size_t num_bytes = in->width * BN_BYTES;
if (len < num_bytes) {
if (!fits_in_bytes(bytes, num_bytes, len)) {
return 0;
}
num_bytes = len;
}
// We only support little-endian platforms, so we can simply memcpy into the
// internal representation.
OPENSSL_memcpy(out, bytes, num_bytes);
// Pad out the rest of the buffer with zeroes.
OPENSSL_memset(out + num_bytes, 0, len - num_bytes);
return 1;
}
int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in) {
const uint8_t *bytes = (const uint8_t *)in->d;
size_t num_bytes = in->width * BN_BYTES;
if (len < num_bytes) {
if (!fits_in_bytes(bytes, num_bytes, len)) {
return 0;
}
num_bytes = len;
}
// We only support little-endian platforms, so we can simply write the buffer
// in reverse.
for (size_t i = 0; i < num_bytes; i++) {
out[len - i - 1] = bytes[i];
}
// Pad out the rest of the buffer with zeroes.
OPENSSL_memset(out, 0, len - num_bytes);
return 1;
}
BN_ULONG BN_get_word(const BIGNUM *bn) {
switch (bn_minimal_width(bn)) {
case 0:
return 0;
case 1:
return bn->d[0];
default:
return BN_MASK2;
}
}
int BN_get_u64(const BIGNUM *bn, uint64_t *out) {
switch (bn_minimal_width(bn)) {
case 0:
*out = 0;
return 1;
case 1:
*out = bn->d[0];
return 1;
#if defined(OPENSSL_32_BIT)
case 2:
*out = (uint64_t) bn->d[0] | (((uint64_t) bn->d[1]) << 32);
return 1;
#endif
default:
return 0;
}
}