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)
280 if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
281 BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
284 ret->flags = BN_FLG_MALLOCED;
289 BIGNUM *BN_secure_new(void)
291 BIGNUM *ret = BN_new();
293 ret->flags |= BN_FLG_SECURE;
297 /* This is used both by bn_expand2() and bn_dup_expand() */
298 /* The caller MUST check that words > b->dmax before calling this */
299 static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
301 BN_ULONG *A, *a = NULL;
307 if (words > (INT_MAX / (4 * BN_BITS2))) {
308 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
311 if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
312 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
315 if (BN_get_flags(b,BN_FLG_SECURE))
316 a = A = OPENSSL_secure_malloc(words * sizeof(*a));
318 a = A = OPENSSL_malloc(words * sizeof(*a));
320 BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
325 * Valgrind complains in BN_consttime_swap because we process the whole
326 * array even if it's not initialised yet. This doesn't matter in that
327 * function - what's important is constant time operation (we're not
328 * actually going to use the data)
330 memset(a, 0, sizeof(*a) * words);
335 /* Check if the previous number needs to be copied */
337 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
339 * The fact that the loop is unrolled
340 * 4-wise is a tribute to Intel. It's
341 * the one that doesn't have enough
342 * registers to accomodate more data.
343 * I'd unroll it 8-wise otherwise:-)
345 * <appro@fy.chalmers.se>
347 BN_ULONG a0, a1, a2, a3;
358 * workaround for ultrix cc: without 'case 0', the optimizer does
359 * the switch table by doing a=top&3; a--; goto jump_table[a];
360 * which fails for top== 0
362 switch (b->top & 3) {
374 memset(A, 0, sizeof(*A) * words);
375 memcpy(A, b->d, sizeof(b->d[0]) * b->top);
382 * This is an internal function that should not be used in applications. It
383 * ensures that 'b' has enough room for a 'words' word number and initialises
384 * any unused part of b->d with leading zeros. It is mostly used by the
385 * various BIGNUM routines. If there is an error, NULL is returned. If not,
389 BIGNUM *bn_expand2(BIGNUM *b, int words)
393 if (words > b->dmax) {
394 BN_ULONG *a = bn_expand_internal(b, words);
398 OPENSSL_cleanse(b->d, b->dmax * sizeof(b->d[0]));
409 BIGNUM *BN_dup(const BIGNUM *a)
417 t = BN_get_flags(a, BN_FLG_SECURE) ? BN_secure_new() : BN_new();
420 if (!BN_copy(t, a)) {
428 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
438 if (bn_wexpand(a, b->top) == NULL)
444 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
445 BN_ULONG a0, a1, a2, a3;
455 /* ultrix cc workaround, see comments in bn_expand_internal */
456 switch (b->top & 3) {
466 memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
475 void BN_swap(BIGNUM *a, BIGNUM *b)
477 int flags_old_a, flags_old_b;
479 int tmp_top, tmp_dmax, tmp_neg;
484 flags_old_a = a->flags;
485 flags_old_b = b->flags;
503 (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
505 (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
510 void BN_clear(BIGNUM *a)
514 memset(a->d, 0, sizeof(*a->d) * a->dmax);
519 BN_ULONG BN_get_word(const BIGNUM *a)
523 else if (a->top == 1)
529 int BN_set_word(BIGNUM *a, BN_ULONG w)
532 if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
536 a->top = (w ? 1 : 0);
541 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
553 /* Skip leading zero's. */
554 for ( ; len > 0 && *s == 0; s++, len--)
561 i = ((n - 1) / BN_BYTES) + 1;
562 m = ((n - 1) % (BN_BYTES));
563 if (bn_wexpand(ret, (int)i) == NULL) {
571 l = (l << 8L) | *(s++);
579 * need to call this due to clear byte at top if avoiding having the top
580 * bit set (-ve number)
586 /* ignore negative */
587 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
593 n = i = BN_num_bytes(a);
595 l = a->d[i / BN_BYTES];
596 *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
601 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
604 BN_ULONG t1, t2, *ap, *bp;
614 for (i = a->top - 1; i >= 0; i--) {
618 return ((t1 > t2) ? 1 : -1);
623 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
629 if ((a == NULL) || (b == NULL)) {
641 if (a->neg != b->neg) {
659 for (i = a->top - 1; i >= 0; i--) {
670 int BN_set_bit(BIGNUM *a, int n)
680 if (bn_wexpand(a, i + 1) == NULL)
682 for (k = a->top; k < i + 1; k++)
687 a->d[i] |= (((BN_ULONG)1) << j);
692 int BN_clear_bit(BIGNUM *a, int n)
705 a->d[i] &= (~(((BN_ULONG)1) << j));
710 int BN_is_bit_set(const BIGNUM *a, int n)
721 return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
724 int BN_mask_bits(BIGNUM *a, int n)
740 a->d[w] &= ~(BN_MASK2 << b);
746 void BN_set_negative(BIGNUM *a, int b)
748 if (b && !BN_is_zero(a))
754 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
762 return ((aa > bb) ? 1 : -1);
763 for (i = n - 2; i >= 0; i--) {
767 return ((aa > bb) ? 1 : -1);
773 * Here follows a specialised variants of bn_cmp_words(). It has the
774 * property of performing the operation on arrays of different sizes. The
775 * sizes of those arrays is expressed through cl, which is the common length
776 * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the
777 * two lengths, calculated as len(a)-len(b). All lengths are the number of
781 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
787 for (i = dl; i < 0; i++) {
789 return -1; /* a < b */
793 for (i = dl; i > 0; i--) {
795 return 1; /* a > b */
798 return bn_cmp_words(a, b, cl);
802 * Constant-time conditional swap of a and b.
803 * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
804 * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
805 * and that no more than nwords are used by either a or b.
806 * a and b cannot be the same number
808 void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
813 bn_wcheck_size(a, nwords);
814 bn_wcheck_size(b, nwords);
817 assert((condition & (condition - 1)) == 0);
818 assert(sizeof(BN_ULONG) >= sizeof(int));
820 condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
822 t = (a->top ^ b->top) & condition;
826 #define BN_CONSTTIME_SWAP(ind) \
828 t = (a->d[ind] ^ b->d[ind]) & condition; \
835 for (i = 10; i < nwords; i++)
836 BN_CONSTTIME_SWAP(i);
839 BN_CONSTTIME_SWAP(9); /* Fallthrough */
841 BN_CONSTTIME_SWAP(8); /* Fallthrough */
843 BN_CONSTTIME_SWAP(7); /* Fallthrough */
845 BN_CONSTTIME_SWAP(6); /* Fallthrough */
847 BN_CONSTTIME_SWAP(5); /* Fallthrough */
849 BN_CONSTTIME_SWAP(4); /* Fallthrough */
851 BN_CONSTTIME_SWAP(3); /* Fallthrough */
853 BN_CONSTTIME_SWAP(2); /* Fallthrough */
855 BN_CONSTTIME_SWAP(1); /* Fallthrough */
857 BN_CONSTTIME_SWAP(0);
859 #undef BN_CONSTTIME_SWAP
862 /* Bits of security, see SP800-57 */
864 int BN_security_bits(int L, int N)
884 return bits >= secbits ? secbits : bits;
887 void BN_zero_ex(BIGNUM *a)
893 int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
895 return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
898 int BN_is_zero(const BIGNUM *a)
903 int BN_is_one(const BIGNUM *a)
905 return BN_abs_is_word(a, 1) && !a->neg;
908 int BN_is_word(const BIGNUM *a, const BN_ULONG w)
910 return BN_abs_is_word(a, w) && (!w || !a->neg);
913 int BN_is_odd(const BIGNUM *a)
915 return (a->top > 0) && (a->d[0] & 1);
918 int BN_is_negative(const BIGNUM *a)
920 return (a->neg != 0);
923 int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
926 return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
929 void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int flags)
933 dest->dmax = b->dmax;
935 dest->flags = ((dest->flags & BN_FLG_MALLOCED)
936 | (b->flags & ~BN_FLG_MALLOCED)
937 | BN_FLG_STATIC_DATA | flags);
940 BN_GENCB *BN_GENCB_new(void)
944 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
945 BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
952 void BN_GENCB_free(BN_GENCB *cb)
959 void BN_set_flags(BIGNUM *b, int n)
964 int BN_get_flags(const BIGNUM *b, int n)
969 /* Populate a BN_GENCB structure with an "old"-style callback */
970 void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
973 BN_GENCB *tmp_gencb = gencb;
975 tmp_gencb->arg = cb_arg;
976 tmp_gencb->cb.cb_1 = callback;
979 /* Populate a BN_GENCB structure with a "new"-style callback */
980 void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
983 BN_GENCB *tmp_gencb = gencb;
985 tmp_gencb->arg = cb_arg;
986 tmp_gencb->cb.cb_2 = callback;
989 void *BN_GENCB_get_arg(BN_GENCB *cb)
994 BIGNUM *bn_wexpand(BIGNUM *a, int words)
996 return (words <= a->dmax) ? a : bn_expand2(a, words);
999 void bn_correct_top(BIGNUM *a)
1002 int tmp_top = a->top;
1005 for (ftl = &(a->d[tmp_top - 1]); tmp_top > 0; tmp_top--)