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			964 lines
		
	
	
	
		
			21 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			964 lines
		
	
	
	
		
			21 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
 | |
|  * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
 | |
|  *
 | |
|  * Licensed under the OpenSSL license (the "License").  You may not use
 | |
|  * this file except in compliance with the License.  You can obtain a copy
 | |
|  * in the file LICENSE in the source distribution or at
 | |
|  * https://www.openssl.org/source/license.html
 | |
|  */
 | |
| 
 | |
| #include <assert.h>
 | |
| #include <limits.h>
 | |
| #include "internal/cryptlib.h"
 | |
| #include "bn_lcl.h"
 | |
| #include <openssl/opensslconf.h>
 | |
| #include "internal/constant_time_locl.h"
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| 
 | |
| /* This stuff appears to be completely unused, so is deprecated */
 | |
| #if OPENSSL_API_COMPAT < 0x00908000L
 | |
| /*-
 | |
|  * For a 32 bit machine
 | |
|  * 2 -   4 ==  128
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|  * 3 -   8 ==  256
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|  * 4 -  16 ==  512
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|  * 5 -  32 == 1024
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|  * 6 -  64 == 2048
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|  * 7 - 128 == 4096
 | |
|  * 8 - 256 == 8192
 | |
|  */
 | |
| static int bn_limit_bits = 0;
 | |
| static int bn_limit_num = 8;    /* (1<<bn_limit_bits) */
 | |
| static int bn_limit_bits_low = 0;
 | |
| static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
 | |
| static int bn_limit_bits_high = 0;
 | |
| static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
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| static int bn_limit_bits_mont = 0;
 | |
| static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
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| 
 | |
| void BN_set_params(int mult, int high, int low, int mont)
 | |
| {
 | |
|     if (mult >= 0) {
 | |
|         if (mult > (int)(sizeof(int) * 8) - 1)
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|             mult = sizeof(int) * 8 - 1;
 | |
|         bn_limit_bits = mult;
 | |
|         bn_limit_num = 1 << mult;
 | |
|     }
 | |
|     if (high >= 0) {
 | |
|         if (high > (int)(sizeof(int) * 8) - 1)
 | |
|             high = sizeof(int) * 8 - 1;
 | |
|         bn_limit_bits_high = high;
 | |
|         bn_limit_num_high = 1 << high;
 | |
|     }
 | |
|     if (low >= 0) {
 | |
|         if (low > (int)(sizeof(int) * 8) - 1)
 | |
|             low = sizeof(int) * 8 - 1;
 | |
|         bn_limit_bits_low = low;
 | |
|         bn_limit_num_low = 1 << low;
 | |
|     }
 | |
|     if (mont >= 0) {
 | |
|         if (mont > (int)(sizeof(int) * 8) - 1)
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|             mont = sizeof(int) * 8 - 1;
 | |
|         bn_limit_bits_mont = mont;
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|         bn_limit_num_mont = 1 << mont;
 | |
|     }
 | |
| }
 | |
| 
 | |
| int BN_get_params(int which)
 | |
| {
 | |
|     if (which == 0)
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|         return bn_limit_bits;
 | |
|     else if (which == 1)
 | |
|         return bn_limit_bits_high;
 | |
|     else if (which == 2)
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|         return bn_limit_bits_low;
 | |
|     else if (which == 3)
 | |
|         return bn_limit_bits_mont;
 | |
|     else
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|         return 0;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| const BIGNUM *BN_value_one(void)
 | |
| {
 | |
|     static const BN_ULONG data_one = 1L;
 | |
|     static const BIGNUM const_one =
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|         { (BN_ULONG *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA };
 | |
| 
 | |
|     return &const_one;
 | |
| }
 | |
| 
 | |
| int BN_num_bits_word(BN_ULONG l)
 | |
| {
 | |
|     BN_ULONG x, mask;
 | |
|     int bits = (l != 0);
 | |
| 
 | |
| #if BN_BITS2 > 32
 | |
|     x = l >> 32;
 | |
|     mask = (0 - x) & BN_MASK2;
 | |
|     mask = (0 - (mask >> (BN_BITS2 - 1)));
 | |
|     bits += 32 & mask;
 | |
|     l ^= (x ^ l) & mask;
 | |
| #endif
 | |
| 
 | |
|     x = l >> 16;
 | |
|     mask = (0 - x) & BN_MASK2;
 | |
|     mask = (0 - (mask >> (BN_BITS2 - 1)));
 | |
|     bits += 16 & mask;
 | |
|     l ^= (x ^ l) & mask;
 | |
| 
 | |
|     x = l >> 8;
 | |
|     mask = (0 - x) & BN_MASK2;
 | |
|     mask = (0 - (mask >> (BN_BITS2 - 1)));
 | |
|     bits += 8 & mask;
 | |
|     l ^= (x ^ l) & mask;
 | |
| 
 | |
|     x = l >> 4;
 | |
|     mask = (0 - x) & BN_MASK2;
 | |
|     mask = (0 - (mask >> (BN_BITS2 - 1)));
 | |
|     bits += 4 & mask;
 | |
|     l ^= (x ^ l) & mask;
 | |
| 
 | |
|     x = l >> 2;
 | |
|     mask = (0 - x) & BN_MASK2;
 | |
|     mask = (0 - (mask >> (BN_BITS2 - 1)));
 | |
|     bits += 2 & mask;
 | |
|     l ^= (x ^ l) & mask;
 | |
| 
 | |
|     x = l >> 1;
 | |
|     mask = (0 - x) & BN_MASK2;
 | |
|     mask = (0 - (mask >> (BN_BITS2 - 1)));
 | |
|     bits += 1 & mask;
 | |
| 
 | |
|     return bits;
 | |
| }
 | |
| 
 | |
| int BN_num_bits(const BIGNUM *a)
 | |
| {
 | |
|     int i = a->top - 1;
 | |
|     bn_check_top(a);
 | |
| 
 | |
|     if (BN_is_zero(a))
 | |
|         return 0;
 | |
|     return ((i * BN_BITS2) + BN_num_bits_word(a->d[i]));
 | |
| }
 | |
| 
 | |
| static void bn_free_d(BIGNUM *a)
 | |
| {
 | |
|     if (BN_get_flags(a, BN_FLG_SECURE))
 | |
|         OPENSSL_secure_free(a->d);
 | |
|     else
 | |
|         OPENSSL_free(a->d);
 | |
| }
 | |
| 
 | |
| 
 | |
| void BN_clear_free(BIGNUM *a)
 | |
| {
 | |
|     if (a == NULL)
 | |
|         return;
 | |
|     if (a->d != NULL && !BN_get_flags(a, BN_FLG_STATIC_DATA)) {
 | |
|         OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0]));
 | |
|         bn_free_d(a);
 | |
|     }
 | |
|     if (BN_get_flags(a, BN_FLG_MALLOCED)) {
 | |
|         OPENSSL_cleanse(a, sizeof(*a));
 | |
|         OPENSSL_free(a);
 | |
|     }
 | |
| }
 | |
| 
 | |
| void BN_free(BIGNUM *a)
 | |
| {
 | |
|     if (a == NULL)
 | |
|         return;
 | |
|     if (!BN_get_flags(a, BN_FLG_STATIC_DATA))
 | |
|         bn_free_d(a);
 | |
|     if (a->flags & BN_FLG_MALLOCED)
 | |
|         OPENSSL_free(a);
 | |
| }
 | |
| 
 | |
| void bn_init(BIGNUM *a)
 | |
| {
 | |
|     static BIGNUM nilbn;
 | |
| 
 | |
|     *a = nilbn;
 | |
|     bn_check_top(a);
 | |
| }
 | |
| 
 | |
| BIGNUM *BN_new(void)
 | |
| {
 | |
|     BIGNUM *ret;
 | |
| 
 | |
|     if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
 | |
|         BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
 | |
|         return NULL;
 | |
|     }
 | |
|     ret->flags = BN_FLG_MALLOCED;
 | |
|     bn_check_top(ret);
 | |
|     return ret;
 | |
| }
 | |
| 
 | |
|  BIGNUM *BN_secure_new(void)
 | |
|  {
 | |
|      BIGNUM *ret = BN_new();
 | |
|      if (ret != NULL)
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|          ret->flags |= BN_FLG_SECURE;
 | |
|      return ret;
 | |
|  }
 | |
| 
 | |
| /* This is used by bn_expand2() */
 | |
| /* The caller MUST check that words > b->dmax before calling this */
 | |
| static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
 | |
| {
 | |
|     BN_ULONG *a = NULL;
 | |
| 
 | |
|     if (words > (INT_MAX / (4 * BN_BITS2))) {
 | |
|         BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
 | |
|         return NULL;
 | |
|     }
 | |
|     if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
 | |
|         BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
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|         return NULL;
 | |
|     }
 | |
|     if (BN_get_flags(b, BN_FLG_SECURE))
 | |
|         a = OPENSSL_secure_zalloc(words * sizeof(*a));
 | |
|     else
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|         a = OPENSSL_zalloc(words * sizeof(*a));
 | |
|     if (a == NULL) {
 | |
|         BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
 | |
|         return NULL;
 | |
|     }
 | |
| 
 | |
|     assert(b->top <= words);
 | |
|     if (b->top > 0)
 | |
|         memcpy(a, b->d, sizeof(*a) * b->top);
 | |
| 
 | |
|     return a;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * This is an internal function that should not be used in applications. It
 | |
|  * ensures that 'b' has enough room for a 'words' word number and initialises
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|  * any unused part of b->d with leading zeros. It is mostly used by the
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|  * various BIGNUM routines. If there is an error, NULL is returned. If not,
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|  * 'b' is returned.
 | |
|  */
 | |
| 
 | |
| BIGNUM *bn_expand2(BIGNUM *b, int words)
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| {
 | |
|     if (words > b->dmax) {
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|         BN_ULONG *a = bn_expand_internal(b, words);
 | |
|         if (!a)
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|             return NULL;
 | |
|         if (b->d) {
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|             OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));
 | |
|             bn_free_d(b);
 | |
|         }
 | |
|         b->d = a;
 | |
|         b->dmax = words;
 | |
|     }
 | |
| 
 | |
|     return b;
 | |
| }
 | |
| 
 | |
| BIGNUM *BN_dup(const BIGNUM *a)
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| {
 | |
|     BIGNUM *t;
 | |
| 
 | |
|     if (a == NULL)
 | |
|         return NULL;
 | |
|     bn_check_top(a);
 | |
| 
 | |
|     t = BN_get_flags(a, BN_FLG_SECURE) ? BN_secure_new() : BN_new();
 | |
|     if (t == NULL)
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|         return NULL;
 | |
|     if (!BN_copy(t, a)) {
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|         BN_free(t);
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|         return NULL;
 | |
|     }
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|     bn_check_top(t);
 | |
|     return t;
 | |
| }
 | |
| 
 | |
| BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
 | |
| {
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|     bn_check_top(b);
 | |
| 
 | |
|     if (a == b)
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|         return a;
 | |
|     if (bn_wexpand(a, b->top) == NULL)
 | |
|         return NULL;
 | |
| 
 | |
|     if (b->top > 0)
 | |
|         memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
 | |
| 
 | |
|     a->neg = b->neg;
 | |
|     a->top = b->top;
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|     a->flags |= b->flags & BN_FLG_FIXED_TOP;
 | |
|     bn_check_top(a);
 | |
|     return a;
 | |
| }
 | |
| 
 | |
| #define FLAGS_DATA(flags) ((flags) & (BN_FLG_STATIC_DATA \
 | |
|                                     | BN_FLG_CONSTTIME   \
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|                                     | BN_FLG_SECURE      \
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|                                     | BN_FLG_FIXED_TOP))
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| #define FLAGS_STRUCT(flags) ((flags) & (BN_FLG_MALLOCED))
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| 
 | |
| void BN_swap(BIGNUM *a, BIGNUM *b)
 | |
| {
 | |
|     int flags_old_a, flags_old_b;
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|     BN_ULONG *tmp_d;
 | |
|     int tmp_top, tmp_dmax, tmp_neg;
 | |
| 
 | |
|     bn_check_top(a);
 | |
|     bn_check_top(b);
 | |
| 
 | |
|     flags_old_a = a->flags;
 | |
|     flags_old_b = b->flags;
 | |
| 
 | |
|     tmp_d = a->d;
 | |
|     tmp_top = a->top;
 | |
|     tmp_dmax = a->dmax;
 | |
|     tmp_neg = a->neg;
 | |
| 
 | |
|     a->d = b->d;
 | |
|     a->top = b->top;
 | |
|     a->dmax = b->dmax;
 | |
|     a->neg = b->neg;
 | |
| 
 | |
|     b->d = tmp_d;
 | |
|     b->top = tmp_top;
 | |
|     b->dmax = tmp_dmax;
 | |
|     b->neg = tmp_neg;
 | |
| 
 | |
|     a->flags = FLAGS_STRUCT(flags_old_a) | FLAGS_DATA(flags_old_b);
 | |
|     b->flags = FLAGS_STRUCT(flags_old_b) | FLAGS_DATA(flags_old_a);
 | |
|     bn_check_top(a);
 | |
|     bn_check_top(b);
 | |
| }
 | |
| 
 | |
| void BN_clear(BIGNUM *a)
 | |
| {
 | |
|     bn_check_top(a);
 | |
|     if (a->d != NULL)
 | |
|         OPENSSL_cleanse(a->d, sizeof(*a->d) * a->dmax);
 | |
|     a->neg = 0;
 | |
|     a->top = 0;
 | |
|     a->flags &= ~BN_FLG_FIXED_TOP;
 | |
| }
 | |
| 
 | |
| BN_ULONG BN_get_word(const BIGNUM *a)
 | |
| {
 | |
|     if (a->top > 1)
 | |
|         return BN_MASK2;
 | |
|     else if (a->top == 1)
 | |
|         return a->d[0];
 | |
|     /* a->top == 0 */
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| int BN_set_word(BIGNUM *a, BN_ULONG w)
 | |
| {
 | |
|     bn_check_top(a);
 | |
|     if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
 | |
|         return 0;
 | |
|     a->neg = 0;
 | |
|     a->d[0] = w;
 | |
|     a->top = (w ? 1 : 0);
 | |
|     a->flags &= ~BN_FLG_FIXED_TOP;
 | |
|     bn_check_top(a);
 | |
|     return 1;
 | |
| }
 | |
| 
 | |
| BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
 | |
| {
 | |
|     unsigned int i, m;
 | |
|     unsigned int n;
 | |
|     BN_ULONG l;
 | |
|     BIGNUM *bn = NULL;
 | |
| 
 | |
|     if (ret == NULL)
 | |
|         ret = bn = BN_new();
 | |
|     if (ret == NULL)
 | |
|         return NULL;
 | |
|     bn_check_top(ret);
 | |
|     /* Skip leading zero's. */
 | |
|     for ( ; len > 0 && *s == 0; s++, len--)
 | |
|         continue;
 | |
|     n = len;
 | |
|     if (n == 0) {
 | |
|         ret->top = 0;
 | |
|         return ret;
 | |
|     }
 | |
|     i = ((n - 1) / BN_BYTES) + 1;
 | |
|     m = ((n - 1) % (BN_BYTES));
 | |
|     if (bn_wexpand(ret, (int)i) == NULL) {
 | |
|         BN_free(bn);
 | |
|         return NULL;
 | |
|     }
 | |
|     ret->top = i;
 | |
|     ret->neg = 0;
 | |
|     l = 0;
 | |
|     while (n--) {
 | |
|         l = (l << 8L) | *(s++);
 | |
|         if (m-- == 0) {
 | |
|             ret->d[--i] = l;
 | |
|             l = 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;
 | |
| }
 | |
| 
 | |
| /* ignore negative */
 | |
| static int bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
 | |
| {
 | |
|     int n;
 | |
|     size_t i, lasti, j, atop, mask;
 | |
|     BN_ULONG l;
 | |
| 
 | |
|     /*
 | |
|      * In case |a| is fixed-top, BN_num_bytes can return bogus length,
 | |
|      * but it's assumed that fixed-top inputs ought to be "nominated"
 | |
|      * even for padded output, so it works out...
 | |
|      */
 | |
|     n = BN_num_bytes(a);
 | |
|     if (tolen == -1) {
 | |
|         tolen = n;
 | |
|     } else if (tolen < n) {     /* uncommon/unlike case */
 | |
|         BIGNUM temp = *a;
 | |
| 
 | |
|         bn_correct_top(&temp);
 | |
|         n = BN_num_bytes(&temp);
 | |
|         if (tolen < n)
 | |
|             return -1;
 | |
|     }
 | |
| 
 | |
|     /* Swipe through whole available data and don't give away padded zero. */
 | |
|     atop = a->dmax * BN_BYTES;
 | |
|     if (atop == 0) {
 | |
|         OPENSSL_cleanse(to, tolen);
 | |
|         return tolen;
 | |
|     }
 | |
| 
 | |
|     lasti = atop - 1;
 | |
|     atop = a->top * BN_BYTES;
 | |
|     for (i = 0, j = 0, to += tolen; j < (size_t)tolen; j++) {
 | |
|         l = a->d[i / BN_BYTES];
 | |
|         mask = 0 - ((j - atop) >> (8 * sizeof(i) - 1));
 | |
|         *--to = (unsigned char)(l >> (8 * (i % BN_BYTES)) & mask);
 | |
|         i += (i - lasti) >> (8 * sizeof(i) - 1); /* stay on last limb */
 | |
|     }
 | |
| 
 | |
|     return tolen;
 | |
| }
 | |
| 
 | |
| int BN_bn2binpad(const BIGNUM *a, unsigned char *to, int tolen)
 | |
| {
 | |
|     if (tolen < 0)
 | |
|         return -1;
 | |
|     return bn2binpad(a, to, tolen);
 | |
| }
 | |
| 
 | |
| int BN_bn2bin(const BIGNUM *a, unsigned char *to)
 | |
| {
 | |
|     return bn2binpad(a, to, -1);
 | |
| }
 | |
| 
 | |
| BIGNUM *BN_lebin2bn(const unsigned char *s, int len, BIGNUM *ret)
 | |
| {
 | |
|     unsigned int i, m;
 | |
|     unsigned int n;
 | |
|     BN_ULONG l;
 | |
|     BIGNUM *bn = NULL;
 | |
| 
 | |
|     if (ret == NULL)
 | |
|         ret = bn = BN_new();
 | |
|     if (ret == NULL)
 | |
|         return NULL;
 | |
|     bn_check_top(ret);
 | |
|     s += len;
 | |
|     /* Skip trailing zeroes. */
 | |
|     for ( ; len > 0 && s[-1] == 0; s--, len--)
 | |
|         continue;
 | |
|     n = len;
 | |
|     if (n == 0) {
 | |
|         ret->top = 0;
 | |
|         return ret;
 | |
|     }
 | |
|     i = ((n - 1) / BN_BYTES) + 1;
 | |
|     m = ((n - 1) % (BN_BYTES));
 | |
|     if (bn_wexpand(ret, (int)i) == NULL) {
 | |
|         BN_free(bn);
 | |
|         return NULL;
 | |
|     }
 | |
|     ret->top = i;
 | |
|     ret->neg = 0;
 | |
|     l = 0;
 | |
|     while (n--) {
 | |
|         s--;
 | |
|         l = (l << 8L) | *s;
 | |
|         if (m-- == 0) {
 | |
|             ret->d[--i] = l;
 | |
|             l = 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;
 | |
| }
 | |
| 
 | |
| int BN_bn2lebinpad(const BIGNUM *a, unsigned char *to, int tolen)
 | |
| {
 | |
|     int i;
 | |
|     BN_ULONG l;
 | |
|     bn_check_top(a);
 | |
|     i = BN_num_bytes(a);
 | |
|     if (tolen < i)
 | |
|         return -1;
 | |
|     /* Add trailing zeroes if necessary */
 | |
|     if (tolen > i)
 | |
|         memset(to + i, 0, tolen - i);
 | |
|     to += i;
 | |
|     while (i--) {
 | |
|         l = a->d[i / BN_BYTES];
 | |
|         to--;
 | |
|         *to = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
 | |
|     }
 | |
|     return tolen;
 | |
| }
 | |
| 
 | |
| int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
 | |
| {
 | |
|     int i;
 | |
|     BN_ULONG t1, t2, *ap, *bp;
 | |
| 
 | |
|     bn_check_top(a);
 | |
|     bn_check_top(b);
 | |
| 
 | |
|     i = a->top - b->top;
 | |
|     if (i != 0)
 | |
|         return i;
 | |
|     ap = a->d;
 | |
|     bp = b->d;
 | |
|     for (i = a->top - 1; i >= 0; i--) {
 | |
|         t1 = ap[i];
 | |
|         t2 = bp[i];
 | |
|         if (t1 != t2)
 | |
|             return ((t1 > t2) ? 1 : -1);
 | |
|     }
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| int BN_cmp(const BIGNUM *a, const BIGNUM *b)
 | |
| {
 | |
|     int i;
 | |
|     int gt, lt;
 | |
|     BN_ULONG t1, t2;
 | |
| 
 | |
|     if ((a == NULL) || (b == NULL)) {
 | |
|         if (a != NULL)
 | |
|             return -1;
 | |
|         else if (b != NULL)
 | |
|             return 1;
 | |
|         else
 | |
|             return 0;
 | |
|     }
 | |
| 
 | |
|     bn_check_top(a);
 | |
|     bn_check_top(b);
 | |
| 
 | |
|     if (a->neg != b->neg) {
 | |
|         if (a->neg)
 | |
|             return -1;
 | |
|         else
 | |
|             return 1;
 | |
|     }
 | |
|     if (a->neg == 0) {
 | |
|         gt = 1;
 | |
|         lt = -1;
 | |
|     } else {
 | |
|         gt = -1;
 | |
|         lt = 1;
 | |
|     }
 | |
| 
 | |
|     if (a->top > b->top)
 | |
|         return gt;
 | |
|     if (a->top < b->top)
 | |
|         return lt;
 | |
|     for (i = a->top - 1; i >= 0; i--) {
 | |
|         t1 = a->d[i];
 | |
|         t2 = b->d[i];
 | |
|         if (t1 > t2)
 | |
|             return gt;
 | |
|         if (t1 < t2)
 | |
|             return lt;
 | |
|     }
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| int BN_set_bit(BIGNUM *a, int n)
 | |
| {
 | |
|     int i, j, k;
 | |
| 
 | |
|     if (n < 0)
 | |
|         return 0;
 | |
| 
 | |
|     i = n / BN_BITS2;
 | |
|     j = n % BN_BITS2;
 | |
|     if (a->top <= i) {
 | |
|         if (bn_wexpand(a, i + 1) == NULL)
 | |
|             return 0;
 | |
|         for (k = a->top; k < i + 1; k++)
 | |
|             a->d[k] = 0;
 | |
|         a->top = i + 1;
 | |
|         a->flags &= ~BN_FLG_FIXED_TOP;
 | |
|     }
 | |
| 
 | |
|     a->d[i] |= (((BN_ULONG)1) << j);
 | |
|     bn_check_top(a);
 | |
|     return 1;
 | |
| }
 | |
| 
 | |
| int BN_clear_bit(BIGNUM *a, int n)
 | |
| {
 | |
|     int i, j;
 | |
| 
 | |
|     bn_check_top(a);
 | |
|     if (n < 0)
 | |
|         return 0;
 | |
| 
 | |
|     i = n / BN_BITS2;
 | |
|     j = n % BN_BITS2;
 | |
|     if (a->top <= i)
 | |
|         return 0;
 | |
| 
 | |
|     a->d[i] &= (~(((BN_ULONG)1) << j));
 | |
|     bn_correct_top(a);
 | |
|     return 1;
 | |
| }
 | |
| 
 | |
| int BN_is_bit_set(const BIGNUM *a, int n)
 | |
| {
 | |
|     int i, j;
 | |
| 
 | |
|     bn_check_top(a);
 | |
|     if (n < 0)
 | |
|         return 0;
 | |
|     i = n / BN_BITS2;
 | |
|     j = n % BN_BITS2;
 | |
|     if (a->top <= i)
 | |
|         return 0;
 | |
|     return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
 | |
| }
 | |
| 
 | |
| int BN_mask_bits(BIGNUM *a, int n)
 | |
| {
 | |
|     int b, w;
 | |
| 
 | |
|     bn_check_top(a);
 | |
|     if (n < 0)
 | |
|         return 0;
 | |
| 
 | |
|     w = n / BN_BITS2;
 | |
|     b = n % BN_BITS2;
 | |
|     if (w >= a->top)
 | |
|         return 0;
 | |
|     if (b == 0)
 | |
|         a->top = w;
 | |
|     else {
 | |
|         a->top = w + 1;
 | |
|         a->d[w] &= ~(BN_MASK2 << b);
 | |
|     }
 | |
|     bn_correct_top(a);
 | |
|     return 1;
 | |
| }
 | |
| 
 | |
| void BN_set_negative(BIGNUM *a, int b)
 | |
| {
 | |
|     if (b && !BN_is_zero(a))
 | |
|         a->neg = 1;
 | |
|     else
 | |
|         a->neg = 0;
 | |
| }
 | |
| 
 | |
| int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
 | |
| {
 | |
|     int i;
 | |
|     BN_ULONG aa, bb;
 | |
| 
 | |
|     if (n == 0)
 | |
|         return 0;
 | |
| 
 | |
|     aa = a[n - 1];
 | |
|     bb = b[n - 1];
 | |
|     if (aa != bb)
 | |
|         return ((aa > bb) ? 1 : -1);
 | |
|     for (i = n - 2; i >= 0; i--) {
 | |
|         aa = a[i];
 | |
|         bb = b[i];
 | |
|         if (aa != bb)
 | |
|             return ((aa > bb) ? 1 : -1);
 | |
|     }
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * Here follows a specialised variants of bn_cmp_words().  It has the
 | |
|  * capability of performing the operation on arrays of different sizes. The
 | |
|  * sizes of those arrays is expressed through cl, which is the common length
 | |
|  * ( basically, min(len(a),len(b)) ), and dl, which is the delta between the
 | |
|  * two lengths, calculated as len(a)-len(b). All lengths are the number of
 | |
|  * BN_ULONGs...
 | |
|  */
 | |
| 
 | |
| int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
 | |
| {
 | |
|     int n, i;
 | |
|     n = cl - 1;
 | |
| 
 | |
|     if (dl < 0) {
 | |
|         for (i = dl; i < 0; i++) {
 | |
|             if (b[n - i] != 0)
 | |
|                 return -1;      /* a < b */
 | |
|         }
 | |
|     }
 | |
|     if (dl > 0) {
 | |
|         for (i = dl; i > 0; i--) {
 | |
|             if (a[n + i] != 0)
 | |
|                 return 1;       /* a > b */
 | |
|         }
 | |
|     }
 | |
|     return bn_cmp_words(a, b, cl);
 | |
| }
 | |
| 
 | |
| /*-
 | |
|  * Constant-time conditional swap of a and b.
 | |
|  * a and b are swapped if condition is not 0.
 | |
|  * nwords is the number of words to swap.
 | |
|  * Assumes that at least nwords are allocated in both a and b.
 | |
|  * Assumes that no more than nwords are used by either a or b.
 | |
|  */
 | |
| void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
 | |
| {
 | |
|     BN_ULONG t;
 | |
|     int i;
 | |
| 
 | |
|     if (a == b)
 | |
|         return;
 | |
| 
 | |
|     bn_wcheck_size(a, nwords);
 | |
|     bn_wcheck_size(b, nwords);
 | |
| 
 | |
|     condition = ((~condition & ((condition - 1))) >> (BN_BITS2 - 1)) - 1;
 | |
| 
 | |
|     t = (a->top ^ b->top) & condition;
 | |
|     a->top ^= t;
 | |
|     b->top ^= t;
 | |
| 
 | |
|     t = (a->neg ^ b->neg) & condition;
 | |
|     a->neg ^= t;
 | |
|     b->neg ^= t;
 | |
| 
 | |
|     /*-
 | |
|      * BN_FLG_STATIC_DATA: indicates that data may not be written to. Intention
 | |
|      * is actually to treat it as it's read-only data, and some (if not most)
 | |
|      * of it does reside in read-only segment. In other words observation of
 | |
|      * BN_FLG_STATIC_DATA in BN_consttime_swap should be treated as fatal
 | |
|      * condition. It would either cause SEGV or effectively cause data
 | |
|      * corruption.
 | |
|      *
 | |
|      * BN_FLG_MALLOCED: refers to BN structure itself, and hence must be
 | |
|      * preserved.
 | |
|      *
 | |
|      * BN_FLG_SECURE: must be preserved, because it determines how x->d was
 | |
|      * allocated and hence how to free it.
 | |
|      *
 | |
|      * BN_FLG_CONSTTIME: sufficient to mask and swap
 | |
|      *
 | |
|      * BN_FLG_FIXED_TOP: indicates that we haven't called bn_correct_top() on
 | |
|      * the data, so the d array may be padded with additional 0 values (i.e.
 | |
|      * top could be greater than the minimal value that it could be). We should
 | |
|      * be swapping it
 | |
|      */
 | |
| 
 | |
| #define BN_CONSTTIME_SWAP_FLAGS (BN_FLG_CONSTTIME | BN_FLG_FIXED_TOP)
 | |
| 
 | |
|     t = ((a->flags ^ b->flags) & BN_CONSTTIME_SWAP_FLAGS) & condition;
 | |
|     a->flags ^= t;
 | |
|     b->flags ^= t;
 | |
| 
 | |
|     /* conditionally swap the data */
 | |
|     for (i = 0; i < nwords; i++) {
 | |
|         t = (a->d[i] ^ b->d[i]) & condition;
 | |
|         a->d[i] ^= t;
 | |
|         b->d[i] ^= t;
 | |
|     }
 | |
| }
 | |
| 
 | |
| #undef BN_CONSTTIME_SWAP_FLAGS
 | |
| 
 | |
| /* Bits of security, see SP800-57 */
 | |
| 
 | |
| int BN_security_bits(int L, int N)
 | |
| {
 | |
|     int secbits, bits;
 | |
|     if (L >= 15360)
 | |
|         secbits = 256;
 | |
|     else if (L >= 7680)
 | |
|         secbits = 192;
 | |
|     else if (L >= 3072)
 | |
|         secbits = 128;
 | |
|     else if (L >= 2048)
 | |
|         secbits = 112;
 | |
|     else if (L >= 1024)
 | |
|         secbits = 80;
 | |
|     else
 | |
|         return 0;
 | |
|     if (N == -1)
 | |
|         return secbits;
 | |
|     bits = N / 2;
 | |
|     if (bits < 80)
 | |
|         return 0;
 | |
|     return bits >= secbits ? secbits : bits;
 | |
| }
 | |
| 
 | |
| void BN_zero_ex(BIGNUM *a)
 | |
| {
 | |
|     a->neg = 0;
 | |
|     a->top = 0;
 | |
|     a->flags &= ~BN_FLG_FIXED_TOP;
 | |
| }
 | |
| 
 | |
| int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
 | |
| {
 | |
|     return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
 | |
| }
 | |
| 
 | |
| int BN_is_zero(const BIGNUM *a)
 | |
| {
 | |
|     return a->top == 0;
 | |
| }
 | |
| 
 | |
| int BN_is_one(const BIGNUM *a)
 | |
| {
 | |
|     return BN_abs_is_word(a, 1) && !a->neg;
 | |
| }
 | |
| 
 | |
| int BN_is_word(const BIGNUM *a, const BN_ULONG w)
 | |
| {
 | |
|     return BN_abs_is_word(a, w) && (!w || !a->neg);
 | |
| }
 | |
| 
 | |
| int BN_is_odd(const BIGNUM *a)
 | |
| {
 | |
|     return (a->top > 0) && (a->d[0] & 1);
 | |
| }
 | |
| 
 | |
| int BN_is_negative(const BIGNUM *a)
 | |
| {
 | |
|     return (a->neg != 0);
 | |
| }
 | |
| 
 | |
| int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
 | |
|                      BN_CTX *ctx)
 | |
| {
 | |
|     return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
 | |
| }
 | |
| 
 | |
| void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int flags)
 | |
| {
 | |
|     dest->d = b->d;
 | |
|     dest->top = b->top;
 | |
|     dest->dmax = b->dmax;
 | |
|     dest->neg = b->neg;
 | |
|     dest->flags = ((dest->flags & BN_FLG_MALLOCED)
 | |
|                    | (b->flags & ~BN_FLG_MALLOCED)
 | |
|                    | BN_FLG_STATIC_DATA | flags);
 | |
| }
 | |
| 
 | |
| BN_GENCB *BN_GENCB_new(void)
 | |
| {
 | |
|     BN_GENCB *ret;
 | |
| 
 | |
|     if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
 | |
|         BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
 | |
|         return NULL;
 | |
|     }
 | |
| 
 | |
|     return ret;
 | |
| }
 | |
| 
 | |
| void BN_GENCB_free(BN_GENCB *cb)
 | |
| {
 | |
|     if (cb == NULL)
 | |
|         return;
 | |
|     OPENSSL_free(cb);
 | |
| }
 | |
| 
 | |
| void BN_set_flags(BIGNUM *b, int n)
 | |
| {
 | |
|     b->flags |= n;
 | |
| }
 | |
| 
 | |
| int BN_get_flags(const BIGNUM *b, int n)
 | |
| {
 | |
|     return b->flags & n;
 | |
| }
 | |
| 
 | |
| /* Populate a BN_GENCB structure with an "old"-style callback */
 | |
| void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
 | |
|                       void *cb_arg)
 | |
| {
 | |
|     BN_GENCB *tmp_gencb = gencb;
 | |
|     tmp_gencb->ver = 1;
 | |
|     tmp_gencb->arg = cb_arg;
 | |
|     tmp_gencb->cb.cb_1 = callback;
 | |
| }
 | |
| 
 | |
| /* Populate a BN_GENCB structure with a "new"-style callback */
 | |
| void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
 | |
|                   void *cb_arg)
 | |
| {
 | |
|     BN_GENCB *tmp_gencb = gencb;
 | |
|     tmp_gencb->ver = 2;
 | |
|     tmp_gencb->arg = cb_arg;
 | |
|     tmp_gencb->cb.cb_2 = callback;
 | |
| }
 | |
| 
 | |
| void *BN_GENCB_get_arg(BN_GENCB *cb)
 | |
| {
 | |
|     return cb->arg;
 | |
| }
 | |
| 
 | |
| BIGNUM *bn_wexpand(BIGNUM *a, int words)
 | |
| {
 | |
|     return (words <= a->dmax) ? a : bn_expand2(a, words);
 | |
| }
 | |
| 
 | |
| void bn_correct_top(BIGNUM *a)
 | |
| {
 | |
|     BN_ULONG *ftl;
 | |
|     int tmp_top = a->top;
 | |
| 
 | |
|     if (tmp_top > 0) {
 | |
|         for (ftl = &(a->d[tmp_top]); tmp_top > 0; tmp_top--) {
 | |
|             ftl--;
 | |
|             if (*ftl != 0)
 | |
|                 break;
 | |
|         }
 | |
|         a->top = tmp_top;
 | |
|     }
 | |
|     if (a->top == 0)
 | |
|         a->neg = 0;
 | |
|     a->flags &= ~BN_FLG_FIXED_TOP;
 | |
|     bn_pollute(a);
 | |
| }
 |