1 /* crypto/bn/bn_lib.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
60 # undef NDEBUG /* avoid conflicting definitions */
66 #include "internal/cryptlib.h"
69 /* This stuff appears to be completely unused, so is deprecated */
70 #ifndef OPENSSL_NO_DEPRECATED
72 * For a 32 bit machine
81 static int bn_limit_bits = 0;
82 static int bn_limit_num = 8; /* (1<<bn_limit_bits) */
83 static int bn_limit_bits_low = 0;
84 static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
85 static int bn_limit_bits_high = 0;
86 static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
87 static int bn_limit_bits_mont = 0;
88 static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
90 void BN_set_params(int mult, int high, int low, int mont)
93 if (mult > (int)(sizeof(int) * 8) - 1)
94 mult = sizeof(int) * 8 - 1;
96 bn_limit_num = 1 << mult;
99 if (high > (int)(sizeof(int) * 8) - 1)
100 high = sizeof(int) * 8 - 1;
101 bn_limit_bits_high = high;
102 bn_limit_num_high = 1 << high;
105 if (low > (int)(sizeof(int) * 8) - 1)
106 low = sizeof(int) * 8 - 1;
107 bn_limit_bits_low = low;
108 bn_limit_num_low = 1 << low;
111 if (mont > (int)(sizeof(int) * 8) - 1)
112 mont = sizeof(int) * 8 - 1;
113 bn_limit_bits_mont = mont;
114 bn_limit_num_mont = 1 << mont;
118 int BN_get_params(int which)
121 return (bn_limit_bits);
123 return (bn_limit_bits_high);
125 return (bn_limit_bits_low);
127 return (bn_limit_bits_mont);
133 const BIGNUM *BN_value_one(void)
135 static const BN_ULONG data_one = 1L;
136 static const BIGNUM const_one =
137 { (BN_ULONG *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA };
142 int BN_num_bits_word(BN_ULONG l)
144 static const unsigned char bits[256] = {
145 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
146 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
147 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
148 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
149 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
150 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
151 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
152 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
153 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
154 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
155 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
156 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
157 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
158 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
159 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
160 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
163 #if defined(SIXTY_FOUR_BIT_LONG)
164 if (l & 0xffffffff00000000L) {
165 if (l & 0xffff000000000000L) {
166 if (l & 0xff00000000000000L) {
167 return (bits[(int)(l >> 56)] + 56);
169 return (bits[(int)(l >> 48)] + 48);
171 if (l & 0x0000ff0000000000L) {
172 return (bits[(int)(l >> 40)] + 40);
174 return (bits[(int)(l >> 32)] + 32);
178 # ifdef SIXTY_FOUR_BIT
179 if (l & 0xffffffff00000000LL) {
180 if (l & 0xffff000000000000LL) {
181 if (l & 0xff00000000000000LL) {
182 return (bits[(int)(l >> 56)] + 56);
184 return (bits[(int)(l >> 48)] + 48);
186 if (l & 0x0000ff0000000000LL) {
187 return (bits[(int)(l >> 40)] + 40);
189 return (bits[(int)(l >> 32)] + 32);
195 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
196 if (l & 0xffff0000L) {
198 return (bits[(int)(l >> 24L)] + 24);
200 return (bits[(int)(l >> 16L)] + 16);
204 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
206 return (bits[(int)(l >> 8)] + 8);
209 return (bits[(int)(l)]);
214 int BN_num_bits(const BIGNUM *a)
221 return ((i * BN_BITS2) + BN_num_bits_word(a->d[i]));
224 static void bn_free_d(BIGNUM *a)
226 if (BN_get_flags(a,BN_FLG_SECURE))
227 OPENSSL_secure_free(a->d);
233 void BN_clear_free(BIGNUM *a)
241 OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0]));
242 if (!BN_get_flags(a, BN_FLG_STATIC_DATA))
245 i = BN_get_flags(a, BN_FLG_MALLOCED);
246 OPENSSL_cleanse(a, sizeof(*a));
251 void BN_free(BIGNUM *a)
256 if (!BN_get_flags(a, BN_FLG_STATIC_DATA))
258 if (a->flags & BN_FLG_MALLOCED)
261 #ifndef OPENSSL_NO_DEPRECATED
262 a->flags |= BN_FLG_FREE;
268 void BN_init(BIGNUM *a)
270 memset(a, 0, sizeof(*a));
278 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
279 BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
282 ret->flags = BN_FLG_MALLOCED;
291 BIGNUM *BN_secure_new(void)
293 BIGNUM *ret = BN_new();
295 ret->flags |= BN_FLG_SECURE;
299 /* This is used both by bn_expand2() and bn_dup_expand() */
300 /* The caller MUST check that words > b->dmax before calling this */
301 static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
303 BN_ULONG *A, *a = NULL;
309 if (words > (INT_MAX / (4 * BN_BITS2))) {
310 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
313 if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
314 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
317 if (BN_get_flags(b,BN_FLG_SECURE))
318 a = A = OPENSSL_secure_malloc(words * sizeof(*a));
320 a = A = OPENSSL_malloc(words * sizeof(*a));
322 BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
327 * Valgrind complains in BN_consttime_swap because we process the whole
328 * array even if it's not initialised yet. This doesn't matter in that
329 * function - what's important is constant time operation (we're not
330 * actually going to use the data)
332 memset(a, 0, sizeof(*a) * words);
337 /* Check if the previous number needs to be copied */
339 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
341 * The fact that the loop is unrolled
342 * 4-wise is a tribute to Intel. It's
343 * the one that doesn't have enough
344 * registers to accomodate more data.
345 * I'd unroll it 8-wise otherwise:-)
347 * <appro@fy.chalmers.se>
349 BN_ULONG a0, a1, a2, a3;
360 * workaround for ultrix cc: without 'case 0', the optimizer does
361 * the switch table by doing a=top&3; a--; goto jump_table[a];
362 * which fails for top== 0
364 switch (b->top & 3) {
376 memset(A, 0, sizeof(*A) * words);
377 memcpy(A, b->d, sizeof(b->d[0]) * b->top);
384 * This is an internal function that should not be used in applications. It
385 * ensures that 'b' has enough room for a 'words' word number and initialises
386 * any unused part of b->d with leading zeros. It is mostly used by the
387 * various BIGNUM routines. If there is an error, NULL is returned. If not,
391 BIGNUM *bn_expand2(BIGNUM *b, int words)
395 if (words > b->dmax) {
396 BN_ULONG *a = bn_expand_internal(b, words);
400 OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));
411 BIGNUM *BN_dup(const BIGNUM *a)
419 t = BN_get_flags(a, BN_FLG_SECURE) ? BN_secure_new() : BN_new();
422 if (!BN_copy(t, a)) {
430 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
440 if (bn_wexpand(a, b->top) == NULL)
446 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
447 BN_ULONG a0, a1, a2, a3;
457 /* ultrix cc workaround, see comments in bn_expand_internal */
458 switch (b->top & 3) {
468 memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
477 void BN_swap(BIGNUM *a, BIGNUM *b)
479 int flags_old_a, flags_old_b;
481 int tmp_top, tmp_dmax, tmp_neg;
486 flags_old_a = a->flags;
487 flags_old_b = b->flags;
505 (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
507 (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
512 void BN_clear(BIGNUM *a)
516 memset(a->d, 0, sizeof(*a->d) * a->dmax);
521 BN_ULONG BN_get_word(const BIGNUM *a)
525 else if (a->top == 1)
531 int BN_set_word(BIGNUM *a, BN_ULONG w)
534 if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
538 a->top = (w ? 1 : 0);
543 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
555 /* Skip leading zero's. */
556 for ( ; len > 0 && *s == 0; s++, len--)
563 i = ((n - 1) / BN_BYTES) + 1;
564 m = ((n - 1) % (BN_BYTES));
565 if (bn_wexpand(ret, (int)i) == NULL) {
573 l = (l << 8L) | *(s++);
581 * need to call this due to clear byte at top if avoiding having the top
582 * bit set (-ve number)
588 /* ignore negative */
589 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
595 n = i = BN_num_bytes(a);
597 l = a->d[i / BN_BYTES];
598 *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
603 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
606 BN_ULONG t1, t2, *ap, *bp;
616 for (i = a->top - 1; i >= 0; i--) {
620 return ((t1 > t2) ? 1 : -1);
625 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
631 if ((a == NULL) || (b == NULL)) {
643 if (a->neg != b->neg) {
661 for (i = a->top - 1; i >= 0; i--) {
672 int BN_set_bit(BIGNUM *a, int n)
682 if (bn_wexpand(a, i + 1) == NULL)
684 for (k = a->top; k < i + 1; k++)
689 a->d[i] |= (((BN_ULONG)1) << j);
694 int BN_clear_bit(BIGNUM *a, int n)
707 a->d[i] &= (~(((BN_ULONG)1) << j));
712 int BN_is_bit_set(const BIGNUM *a, int n)
723 return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
726 int BN_mask_bits(BIGNUM *a, int n)
742 a->d[w] &= ~(BN_MASK2 << b);
748 void BN_set_negative(BIGNUM *a, int b)
750 if (b && !BN_is_zero(a))
756 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
764 return ((aa > bb) ? 1 : -1);
765 for (i = n - 2; i >= 0; i--) {
769 return ((aa > bb) ? 1 : -1);
775 * Here follows a specialised variants of bn_cmp_words(). It has the
776 * property of performing the operation on arrays of different sizes. The
777 * sizes of those arrays is expressed through cl, which is the common length
778 * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the
779 * two lengths, calculated as len(a)-len(b). All lengths are the number of
783 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
789 for (i = dl; i < 0; i++) {
791 return -1; /* a < b */
795 for (i = dl; i > 0; i--) {
797 return 1; /* a > b */
800 return bn_cmp_words(a, b, cl);
804 * Constant-time conditional swap of a and b.
805 * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
806 * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
807 * and that no more than nwords are used by either a or b.
808 * a and b cannot be the same number
810 void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
815 bn_wcheck_size(a, nwords);
816 bn_wcheck_size(b, nwords);
819 assert((condition & (condition - 1)) == 0);
820 assert(sizeof(BN_ULONG) >= sizeof(int));
822 condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
824 t = (a->top ^ b->top) & condition;
828 #define BN_CONSTTIME_SWAP(ind) \
830 t = (a->d[ind] ^ b->d[ind]) & condition; \
837 for (i = 10; i < nwords; i++)
838 BN_CONSTTIME_SWAP(i);
841 BN_CONSTTIME_SWAP(9); /* Fallthrough */
843 BN_CONSTTIME_SWAP(8); /* Fallthrough */
845 BN_CONSTTIME_SWAP(7); /* Fallthrough */
847 BN_CONSTTIME_SWAP(6); /* Fallthrough */
849 BN_CONSTTIME_SWAP(5); /* Fallthrough */
851 BN_CONSTTIME_SWAP(4); /* Fallthrough */
853 BN_CONSTTIME_SWAP(3); /* Fallthrough */
855 BN_CONSTTIME_SWAP(2); /* Fallthrough */
857 BN_CONSTTIME_SWAP(1); /* Fallthrough */
859 BN_CONSTTIME_SWAP(0);
861 #undef BN_CONSTTIME_SWAP
864 /* Bits of security, see SP800-57 */
866 int BN_security_bits(int L, int N)
886 return bits >= secbits ? secbits : bits;
889 void BN_zero_ex(BIGNUM *a)
895 int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
897 return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
900 int BN_is_zero(const BIGNUM *a)
905 int BN_is_one(const BIGNUM *a)
907 return BN_abs_is_word(a, 1) && !a->neg;
910 int BN_is_word(const BIGNUM *a, const BN_ULONG w)
912 return BN_abs_is_word(a, w) && (!w || !a->neg);
915 int BN_is_odd(const BIGNUM *a)
917 return (a->top > 0) && (a->d[0] & 1);
920 int BN_is_negative(const BIGNUM *a)
922 return (a->neg != 0);
925 int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
928 return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
931 void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int n)
935 dest->dmax = b->dmax;
937 dest->flags = ((dest->flags & BN_FLG_MALLOCED)
938 | (b->flags & ~BN_FLG_MALLOCED)
939 | BN_FLG_STATIC_DATA | n);
942 BN_GENCB *BN_GENCB_new(void)
946 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
947 BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
954 void BN_GENCB_free(BN_GENCB *cb)
961 void BN_set_flags(BIGNUM *b, int n)
966 int BN_get_flags(const BIGNUM *b, int n)
971 /* Populate a BN_GENCB structure with an "old"-style callback */
972 void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
975 BN_GENCB *tmp_gencb = gencb;
977 tmp_gencb->arg = cb_arg;
978 tmp_gencb->cb.cb_1 = callback;
981 /* Populate a BN_GENCB structure with a "new"-style callback */
982 void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
985 BN_GENCB *tmp_gencb = gencb;
987 tmp_gencb->arg = cb_arg;
988 tmp_gencb->cb.cb_2 = callback;
991 void *BN_GENCB_get_arg(BN_GENCB *cb)
996 BIGNUM *bn_wexpand(BIGNUM *a, int words)
998 return (words <= a->dmax) ? a : bn_expand2(a, words);
1001 void bn_correct_top(BIGNUM *a)
1004 int tmp_top = a->top;
1007 for (ftl = &(a->d[tmp_top - 1]); tmp_top > 0; tmp_top--)