boringssl/crypto/bn/convert.c

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/* 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 <ctype.h>
#include <stdio.h>
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include "internal.h"
BIGNUM *BN_bin2bn(const uint8_t *in, size_t len, BIGNUM *ret) {
unsigned num_words, m;
BN_ULONG word = 0;
BIGNUM *bn = NULL;
if (ret == NULL) {
ret = bn = BN_new();
}
if (ret == NULL) {
return NULL;
}
if (len == 0) {
ret->top = 0;
return ret;
}
num_words = ((len - 1) / BN_BYTES) + 1;
m = (len - 1) % BN_BYTES;
if (bn_wexpand(ret, num_words) == NULL) {
if (bn) {
BN_free(bn);
}
return NULL;
}
ret->top = 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;
}
}
/* need to call this due to clear byte at top if avoiding having the top bit
* set (-ve number) */
bn_correct_top(ret);
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 const char hextable[] = "0123456789abcdef";
char *BN_bn2hex(const BIGNUM *bn) {
int i, j, v, z = 0;
char *buf;
char *p;
buf = (char *)OPENSSL_malloc(bn->top * BN_BYTES * 2 + 2);
if (buf == NULL) {
OPENSSL_PUT_ERROR(BN, BN_bn2hex, ERR_R_MALLOC_FAILURE);
return NULL;
}
p = buf;
if (bn->neg) {
*(p++) = '-';
}
if (BN_is_zero(bn)) {
*(p++) = '0';
}
for (i = bn->top - 1; i >= 0; i--) {
for (j = BN_BITS2 - 8; j >= 0; j -= 8) {
/* strip leading zeros */
v = ((int)(bn->d[i] >> (long)j)) & 0xff;
if (z || v != 0) {
*(p++) = hextable[v >> 4];
*(p++) = hextable[v & 0x0f];
z = 1;
}
}
}
*p = '\0';
return buf;
}
/* decode_hex decodes |i| bytes of hex data from |in| and updates |bn|. */
static void decode_hex(BIGNUM *bn, const char *in, int i) {
int h, m, j, k, c;
BN_ULONG l=0;
j = i; /* least significant 'hex' */
m = 0;
h = 0;
while (j > 0) {
m = ((BN_BYTES * 2) <= j) ? (BN_BYTES * 2) : j;
l = 0;
for (;;) {
c = in[j - m];
if ((c >= '0') && (c <= '9')) {
k = c - '0';
} else if ((c >= 'a') && (c <= 'f')) {
k = c - 'a' + 10;
} else if ((c >= 'A') && (c <= 'F')) {
k = c - 'A' + 10;
} else {
k = 0; /* paranoia */
}
l = (l << 4) | k;
if (--m <= 0) {
bn->d[h++] = l;
break;
}
}
j -= (BN_BYTES * 2);
}
bn->top = h;
}
/* decode_dec decodes |i| bytes of decimal data from |in| and updates |bn|. */
static void decode_dec(BIGNUM *bn, const char *in, int i) {
int j;
BN_ULONG l = 0;
j = BN_DEC_NUM - (i % BN_DEC_NUM);
if (j == BN_DEC_NUM) {
j = 0;
}
l = 0;
while (*in) {
l *= 10;
l += *in - '0';
in++;
if (++j == BN_DEC_NUM) {
BN_mul_word(bn, BN_DEC_CONV);
BN_add_word(bn, l);
l = 0;
j = 0;
}
}
}
typedef void (*decode_func) (BIGNUM *bn, const char *in, int i);
typedef int (*char_test_func) (int c);
static int bn_x2bn(BIGNUM **outp, const char *in, decode_func decode, char_test_func want_char) {
BIGNUM *ret = NULL;
int neg = 0, i;
int num;
if (in == NULL || *in == 0) {
return 0;
}
if (*in == '-') {
neg = 1;
in++;
}
for (i = 0; want_char((unsigned char)in[i]); i++) {}
num = i + neg;
if (outp == NULL) {
return num;
}
/* in is the start of the hex digits, and it is 'i' long */
if (*outp == NULL) {
ret = BN_new();
if (ret == NULL) {
return 0;
}
} else {
ret = *outp;
BN_zero(ret);
}
ret->neg = neg;
/* i is the number of hex digests; */
if (bn_expand(ret, i * 4) == NULL) {
goto err;
}
decode(ret, in, i);
bn_correct_top(ret);
*outp = ret;
return num;
err:
if (*outp == NULL) {
BN_free(ret);
}
return 0;
}
int BN_hex2bn(BIGNUM **outp, const char *in) {
return bn_x2bn(outp, in, decode_hex, isxdigit);
}
char *BN_bn2dec(const BIGNUM *a) {
int i = 0, num, ok = 0;
char *buf = NULL;
char *p;
BIGNUM *t = NULL;
BN_ULONG *bn_data = NULL, *lp;
/* get an upper bound for the length of the decimal integer
* num <= (BN_num_bits(a) + 1) * log(2)
* <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1 (rounding error)
* <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1
*/
i = BN_num_bits(a) * 3;
num = i / 10 + i / 1000 + 1 + 1;
bn_data =
(BN_ULONG *)OPENSSL_malloc((num / BN_DEC_NUM + 1) * sizeof(BN_ULONG));
buf = (char *)OPENSSL_malloc(num + 3);
if ((buf == NULL) || (bn_data == NULL)) {
OPENSSL_PUT_ERROR(BN, BN_bn2dec, ERR_R_MALLOC_FAILURE);
goto err;
}
t = BN_dup(a);
if (t == NULL) {
goto err;
}
#define BUF_REMAIN (num + 3 - (size_t)(p - buf))
p = buf;
lp = bn_data;
if (BN_is_zero(t)) {
*(p++) = '0';
*(p++) = '\0';
} else {
if (BN_is_negative(t)) {
*p++ = '-';
}
i = 0;
while (!BN_is_zero(t)) {
*lp = BN_div_word(t, BN_DEC_CONV);
lp++;
}
lp--;
/* We now have a series of blocks, BN_DEC_NUM chars
* in length, where the last one needs truncation.
* The blocks need to be reversed in order. */
BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT1, *lp);
while (*p) {
p++;
}
while (lp != bn_data) {
lp--;
BIO_snprintf(p, BUF_REMAIN, BN_DEC_FMT2, *lp);
while (*p) {
p++;
}
}
}
ok = 1;
err:
if (bn_data != NULL) {
OPENSSL_free(bn_data);
}
if (t != NULL) {
BN_free(t);
}
if (!ok && buf) {
OPENSSL_free(buf);
buf = NULL;
}
return buf;
}
int BN_dec2bn(BIGNUM **outp, const char *in) {
return bn_x2bn(outp, in, decode_dec, isdigit);
}
int BN_asc2bn(BIGNUM **outp, const char *in) {
const char *const orig_in = in;
if (*in == '-') {
in++;
}
if (in[0] == '0' && (in[1] == 'X' || in[1] == 'x')) {
if (!BN_hex2bn(outp, in+2)) {
return 0;
}
} else {
if (!BN_dec2bn(outp, in)) {
return 0;
}
}
if (*orig_in == '-') {
(*outp)->neg = 1;
}
return 1;
}
int BN_print(BIO *bp, const BIGNUM *a) {
int i, j, v, z = 0;
int ret = 0;
if (a->neg && BIO_write(bp, "-", 1) != 1) {
goto end;
}
if (BN_is_zero(a) && BIO_write(bp, "0", 1) != 1) {
goto end;
}
for (i = a->top - 1; i >= 0; i--) {
for (j = BN_BITS2 - 4; j >= 0; j -= 4) {
/* strip leading zeros */
v = ((int)(a->d[i] >> (long)j)) & 0x0f;
if (z || v != 0) {
if (BIO_write(bp, &hextable[v], 1) != 1) {
goto end;
}
z = 1;
}
}
}
ret = 1;
end:
return ret;
}
int BN_print_fp(FILE *fp, const BIGNUM *a) {
BIO *b;
int ret;
b = BIO_new(BIO_s_file());
if (b == NULL) {
return 0;
}
BIO_set_fp(b, fp, BIO_NOCLOSE);
ret = BN_print(b, a);
BIO_free(b);
return ret;
}
BN_ULONG BN_get_word(const BIGNUM *bn) {
switch (bn->top) {
case 0:
return 0;
case 1:
return bn->d[0];
default:
return BN_MASK2;
}
}