|
- /* 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;
- }
-
- /* constant_time_select_ulong returns |x| if |v| is 1 and |y| if |v| is 0. Its
- * behavior is undefined if |v| takes any other value. */
- static BN_ULONG constant_time_select_ulong(int v, BN_ULONG x, BN_ULONG y) {
- BN_ULONG mask = v;
- mask--;
-
- return (~mask & x) | (mask & y);
- }
-
- /* constant_time_le_size_t returns 1 if |x| <= |y| and 0 otherwise. |x| and |y|
- * must not have their MSBs set. */
- static int constant_time_le_size_t(size_t x, size_t y) {
- return ((x - y - 1) >> (sizeof(size_t) * 8 - 1)) & 1;
- }
-
- /* read_word_padded returns the |i|'th word of |in|, if it is not out of
- * bounds. Otherwise, it returns 0. It does so without branches on the size of
- * |in|, however it necessarily does not have the same memory access pattern. If
- * the access would be out of bounds, it reads the last word of |in|. |in| must
- * not be zero. */
- static BN_ULONG read_word_padded(const BIGNUM *in, size_t i) {
- /* Read |in->d[i]| if valid. Otherwise, read the last word. */
- BN_ULONG l = in->d[constant_time_select_ulong(
- constant_time_le_size_t(in->dmax, i), in->dmax - 1, i)];
-
- /* Clamp to zero if above |d->top|. */
- return constant_time_select_ulong(constant_time_le_size_t(in->top, i), 0, l);
- }
-
- int BN_bn2bin_padded(uint8_t *out, size_t len, const BIGNUM *in) {
- size_t i;
- BN_ULONG l;
-
- /* Special case for |in| = 0. Just branch as the probability is negligible. */
- if (BN_is_zero(in)) {
- memset(out, 0, len);
- return 1;
- }
-
- /* Check if the integer is too big. This case can exit early in non-constant
- * time. */
- if ((size_t)in->top > (len + (BN_BYTES - 1)) / BN_BYTES) {
- return 0;
- }
- if ((len % BN_BYTES) != 0) {
- l = read_word_padded(in, len / BN_BYTES);
- if (l >> (8 * (len % BN_BYTES)) != 0) {
- return 0;
- }
- }
-
- /* Write the bytes out one by one. Serialization is done without branching on
- * the bits of |in| or on |in->top|, but if the routine would otherwise read
- * out of bounds, the memory access pattern can't be fixed. However, for an
- * RSA key of size a multiple of the word size, the probability of BN_BYTES
- * leading zero octets is low.
- *
- * See Falko Stenzke, "Manger's Attack revisited", ICICS 2010. */
- i = len;
- while (i--) {
- l = read_word_padded(in, i / BN_BYTES);
- *(out++) = (uint8_t)(l >> (8 * (i % BN_BYTES))) & 0xff;
- }
- return 1;
- }
-
- 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' */
- 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++ = '-';
- }
-
- 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;
- }
- }
|