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)
561 i = ((n - 1) / BN_BYTES) + 1;
562 m = ((n - 1) % (BN_BYTES));
563 if (bn_wexpand(ret, (int)i) == NULL) {
570 l = (l << 8L) | *(s++);
578 * need to call this due to clear byte at top if avoiding having the top
579 * bit set (-ve number)
585 /* ignore negative */
586 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
592 n = i = BN_num_bytes(a);
594 l = a->d[i / BN_BYTES];
595 *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
600 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
603 BN_ULONG t1, t2, *ap, *bp;
613 for (i = a->top - 1; i >= 0; i--) {
617 return ((t1 > t2) ? 1 : -1);
622 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
628 if ((a == NULL) || (b == NULL)) {
640 if (a->neg != b->neg) {
658 for (i = a->top - 1; i >= 0; i--) {
669 int BN_set_bit(BIGNUM *a, int n)
679 if (bn_wexpand(a, i + 1) == NULL)
681 for (k = a->top; k < i + 1; k++)
686 a->d[i] |= (((BN_ULONG)1) << j);
691 int BN_clear_bit(BIGNUM *a, int n)
704 a->d[i] &= (~(((BN_ULONG)1) << j));
709 int BN_is_bit_set(const BIGNUM *a, int n)
720 return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
723 int BN_mask_bits(BIGNUM *a, int n)
739 a->d[w] &= ~(BN_MASK2 << b);
745 void BN_set_negative(BIGNUM *a, int b)
747 if (b && !BN_is_zero(a))
753 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
761 return ((aa > bb) ? 1 : -1);
762 for (i = n - 2; i >= 0; i--) {
766 return ((aa > bb) ? 1 : -1);
772 * Here follows a specialised variants of bn_cmp_words(). It has the
773 * property of performing the operation on arrays of different sizes. The
774 * sizes of those arrays is expressed through cl, which is the common length
775 * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the
776 * two lengths, calculated as len(a)-len(b). All lengths are the number of
780 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
786 for (i = dl; i < 0; i++) {
788 return -1; /* a < b */
792 for (i = dl; i > 0; i--) {
794 return 1; /* a > b */
797 return bn_cmp_words(a, b, cl);
801 * Constant-time conditional swap of a and b.
802 * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
803 * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
804 * and that no more than nwords are used by either a or b.
805 * a and b cannot be the same number
807 void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
812 bn_wcheck_size(a, nwords);
813 bn_wcheck_size(b, nwords);
816 assert((condition & (condition - 1)) == 0);
817 assert(sizeof(BN_ULONG) >= sizeof(int));
819 condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
821 t = (a->top ^ b->top) & condition;
825 #define BN_CONSTTIME_SWAP(ind) \
827 t = (a->d[ind] ^ b->d[ind]) & condition; \
834 for (i = 10; i < nwords; i++)
835 BN_CONSTTIME_SWAP(i);
838 BN_CONSTTIME_SWAP(9); /* Fallthrough */
840 BN_CONSTTIME_SWAP(8); /* Fallthrough */
842 BN_CONSTTIME_SWAP(7); /* Fallthrough */
844 BN_CONSTTIME_SWAP(6); /* Fallthrough */
846 BN_CONSTTIME_SWAP(5); /* Fallthrough */
848 BN_CONSTTIME_SWAP(4); /* Fallthrough */
850 BN_CONSTTIME_SWAP(3); /* Fallthrough */
852 BN_CONSTTIME_SWAP(2); /* Fallthrough */
854 BN_CONSTTIME_SWAP(1); /* Fallthrough */
856 BN_CONSTTIME_SWAP(0);
858 #undef BN_CONSTTIME_SWAP
861 /* Bits of security, see SP800-57 */
863 int BN_security_bits(int L, int N)
883 return bits >= secbits ? secbits : bits;
886 void BN_zero_ex(BIGNUM *a)
892 int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
894 return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
897 int BN_is_zero(const BIGNUM *a)
902 int BN_is_one(const BIGNUM *a)
904 return BN_abs_is_word(a, 1) && !a->neg;
907 int BN_is_word(const BIGNUM *a, const BN_ULONG w)
909 return BN_abs_is_word(a, w) && (!w || !a->neg);
912 int BN_is_odd(const BIGNUM *a)
914 return (a->top > 0) && (a->d[0] & 1);
917 int BN_is_negative(const BIGNUM *a)
919 return (a->neg != 0);
922 int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
925 return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
928 void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int n)
932 dest->dmax = b->dmax;
934 dest->flags = ((dest->flags & BN_FLG_MALLOCED)
935 | (b->flags & ~BN_FLG_MALLOCED)
936 | BN_FLG_STATIC_DATA | n);
939 BN_GENCB *BN_GENCB_new(void)
943 if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
944 BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
951 void BN_GENCB_free(BN_GENCB *cb)
958 void BN_set_flags(BIGNUM *b, int n)
963 int BN_get_flags(const BIGNUM *b, int n)
968 /* Populate a BN_GENCB structure with an "old"-style callback */
969 void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
972 BN_GENCB *tmp_gencb = gencb;
974 tmp_gencb->arg = cb_arg;
975 tmp_gencb->cb.cb_1 = callback;
978 /* Populate a BN_GENCB structure with a "new"-style callback */
979 void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
982 BN_GENCB *tmp_gencb = gencb;
984 tmp_gencb->arg = cb_arg;
985 tmp_gencb->cb.cb_2 = callback;
988 void *BN_GENCB_get_arg(BN_GENCB *cb)
993 BIGNUM *bn_wexpand(BIGNUM *a, int words)
995 return (words <= a->dmax) ? a : bn_expand2(a, words);
998 void bn_correct_top(BIGNUM *a)
1001 int tmp_top = a->top;
1004 for (ftl = &(a->d[tmp_top - 1]); tmp_top > 0; tmp_top--)