| /* 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; |
| } |
| } |