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 */
69 const char BN_version[] = "Big Number" OPENSSL_VERSION_PTEXT;
71 /* This stuff appears to be completely unused, so is deprecated */
72 #ifndef OPENSSL_NO_DEPRECATED
74 * For a 32 bit machine
83 static int bn_limit_bits = 0;
84 static int bn_limit_num = 8; /* (1<<bn_limit_bits) */
85 static int bn_limit_bits_low = 0;
86 static int bn_limit_num_low = 8; /* (1<<bn_limit_bits_low) */
87 static int bn_limit_bits_high = 0;
88 static int bn_limit_num_high = 8; /* (1<<bn_limit_bits_high) */
89 static int bn_limit_bits_mont = 0;
90 static int bn_limit_num_mont = 8; /* (1<<bn_limit_bits_mont) */
92 void BN_set_params(int mult, int high, int low, int mont)
95 if (mult > (int)(sizeof(int) * 8) - 1)
96 mult = sizeof(int) * 8 - 1;
98 bn_limit_num = 1 << mult;
101 if (high > (int)(sizeof(int) * 8) - 1)
102 high = sizeof(int) * 8 - 1;
103 bn_limit_bits_high = high;
104 bn_limit_num_high = 1 << high;
107 if (low > (int)(sizeof(int) * 8) - 1)
108 low = sizeof(int) * 8 - 1;
109 bn_limit_bits_low = low;
110 bn_limit_num_low = 1 << low;
113 if (mont > (int)(sizeof(int) * 8) - 1)
114 mont = sizeof(int) * 8 - 1;
115 bn_limit_bits_mont = mont;
116 bn_limit_num_mont = 1 << mont;
120 int BN_get_params(int which)
123 return (bn_limit_bits);
125 return (bn_limit_bits_high);
127 return (bn_limit_bits_low);
129 return (bn_limit_bits_mont);
135 const BIGNUM *BN_value_one(void)
137 static const BN_ULONG data_one = 1L;
138 static const BIGNUM const_one =
139 { (BN_ULONG *)&data_one, 1, 1, 0, BN_FLG_STATIC_DATA };
144 int BN_num_bits_word(BN_ULONG l)
146 static const unsigned char bits[256] = {
147 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
148 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
149 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
150 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
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 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
154 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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,
161 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
162 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
165 #if defined(SIXTY_FOUR_BIT_LONG)
166 if (l & 0xffffffff00000000L) {
167 if (l & 0xffff000000000000L) {
168 if (l & 0xff00000000000000L) {
169 return (bits[(int)(l >> 56)] + 56);
171 return (bits[(int)(l >> 48)] + 48);
173 if (l & 0x0000ff0000000000L) {
174 return (bits[(int)(l >> 40)] + 40);
176 return (bits[(int)(l >> 32)] + 32);
180 # ifdef SIXTY_FOUR_BIT
181 if (l & 0xffffffff00000000LL) {
182 if (l & 0xffff000000000000LL) {
183 if (l & 0xff00000000000000LL) {
184 return (bits[(int)(l >> 56)] + 56);
186 return (bits[(int)(l >> 48)] + 48);
188 if (l & 0x0000ff0000000000LL) {
189 return (bits[(int)(l >> 40)] + 40);
191 return (bits[(int)(l >> 32)] + 32);
197 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
198 if (l & 0xffff0000L) {
200 return (bits[(int)(l >> 24L)] + 24);
202 return (bits[(int)(l >> 16L)] + 16);
206 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
208 return (bits[(int)(l >> 8)] + 8);
211 return (bits[(int)(l)]);
216 int BN_num_bits(const BIGNUM *a)
223 return ((i * BN_BITS2) + BN_num_bits_word(a->d[i]));
226 void BN_clear_free(BIGNUM *a)
234 OPENSSL_cleanse(a->d, a->dmax * sizeof(a->d[0]));
235 if (!(BN_get_flags(a, BN_FLG_STATIC_DATA)))
238 i = BN_get_flags(a, BN_FLG_MALLOCED);
239 OPENSSL_cleanse(a, sizeof(BIGNUM));
244 void BN_free(BIGNUM *a)
249 if ((a->d != NULL) && !(BN_get_flags(a, BN_FLG_STATIC_DATA)))
251 if (a->flags & BN_FLG_MALLOCED)
254 #ifndef OPENSSL_NO_DEPRECATED
255 a->flags |= BN_FLG_FREE;
261 void BN_init(BIGNUM *a)
263 memset(a, 0, sizeof(BIGNUM));
271 if ((ret = OPENSSL_malloc(sizeof(BIGNUM))) == NULL) {
272 BNerr(BN_F_BN_NEW, ERR_R_MALLOC_FAILURE);
275 ret->flags = BN_FLG_MALLOCED;
284 /* This is used both by bn_expand2() and bn_dup_expand() */
285 /* The caller MUST check that words > b->dmax before calling this */
286 static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
288 BN_ULONG *A, *a = NULL;
294 if (words > (INT_MAX / (4 * BN_BITS2))) {
295 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_BIGNUM_TOO_LONG);
298 if (BN_get_flags(b, BN_FLG_STATIC_DATA)) {
299 BNerr(BN_F_BN_EXPAND_INTERNAL, BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
302 a = A = OPENSSL_malloc(sizeof(BN_ULONG) * words);
304 BNerr(BN_F_BN_EXPAND_INTERNAL, ERR_R_MALLOC_FAILURE);
309 * Valgrind complains in BN_consttime_swap because we process the whole
310 * array even if it's not initialised yet. This doesn't matter in that
311 * function - what's important is constant time operation (we're not
312 * actually going to use the data)
314 memset(a, 0, sizeof(BN_ULONG) * words);
319 /* Check if the previous number needs to be copied */
321 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
323 * The fact that the loop is unrolled
324 * 4-wise is a tribute to Intel. It's
325 * the one that doesn't have enough
326 * registers to accomodate more data.
327 * I'd unroll it 8-wise otherwise:-)
329 * <appro@fy.chalmers.se>
331 BN_ULONG a0, a1, a2, a3;
342 * workaround for ultrix cc: without 'case 0', the optimizer does
343 * the switch table by doing a=top&3; a--; goto jump_table[a];
344 * which fails for top== 0
346 switch (b->top & 3) {
358 memset(A, 0, sizeof(BN_ULONG) * words);
359 memcpy(A, b->d, sizeof(b->d[0]) * b->top);
366 * This is an internal function that should not be used in applications. It
367 * ensures that 'b' has enough room for a 'words' word number and initialises
368 * any unused part of b->d with leading zeros. It is mostly used by the
369 * various BIGNUM routines. If there is an error, NULL is returned. If not,
373 BIGNUM *bn_expand2(BIGNUM *b, int words)
377 if (words > b->dmax) {
378 BN_ULONG *a = bn_expand_internal(b, words);
391 BIGNUM *BN_dup(const BIGNUM *a)
402 if (!BN_copy(t, a)) {
410 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
420 if (bn_wexpand(a, b->top) == NULL)
426 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
427 BN_ULONG a0, a1, a2, a3;
437 /* ultrix cc workaround, see comments in bn_expand_internal */
438 switch (b->top & 3) {
448 memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
457 void BN_swap(BIGNUM *a, BIGNUM *b)
459 int flags_old_a, flags_old_b;
461 int tmp_top, tmp_dmax, tmp_neg;
466 flags_old_a = a->flags;
467 flags_old_b = b->flags;
485 (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
487 (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
492 void BN_clear(BIGNUM *a)
496 memset(a->d, 0, a->dmax * sizeof(a->d[0]));
501 BN_ULONG BN_get_word(const BIGNUM *a)
505 else if (a->top == 1)
511 int BN_set_word(BIGNUM *a, BN_ULONG w)
514 if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
518 a->top = (w ? 1 : 0);
523 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
541 i = ((n - 1) / BN_BYTES) + 1;
542 m = ((n - 1) % (BN_BYTES));
543 if (bn_wexpand(ret, (int)i) == NULL) {
551 l = (l << 8L) | *(s++);
559 * need to call this due to clear byte at top if avoiding having the top
560 * bit set (-ve number)
566 /* ignore negative */
567 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
573 n = i = BN_num_bytes(a);
575 l = a->d[i / BN_BYTES];
576 *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
581 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
584 BN_ULONG t1, t2, *ap, *bp;
594 for (i = a->top - 1; i >= 0; i--) {
598 return ((t1 > t2) ? 1 : -1);
603 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
609 if ((a == NULL) || (b == NULL)) {
621 if (a->neg != b->neg) {
639 for (i = a->top - 1; i >= 0; i--) {
650 int BN_set_bit(BIGNUM *a, int n)
660 if (bn_wexpand(a, i + 1) == NULL)
662 for (k = a->top; k < i + 1; k++)
667 a->d[i] |= (((BN_ULONG)1) << j);
672 int BN_clear_bit(BIGNUM *a, int n)
685 a->d[i] &= (~(((BN_ULONG)1) << j));
690 int BN_is_bit_set(const BIGNUM *a, int n)
701 return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
704 int BN_mask_bits(BIGNUM *a, int n)
720 a->d[w] &= ~(BN_MASK2 << b);
726 void BN_set_negative(BIGNUM *a, int b)
728 if (b && !BN_is_zero(a))
734 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
742 return ((aa > bb) ? 1 : -1);
743 for (i = n - 2; i >= 0; i--) {
747 return ((aa > bb) ? 1 : -1);
753 * Here follows a specialised variants of bn_cmp_words(). It has the
754 * property of performing the operation on arrays of different sizes. The
755 * sizes of those arrays is expressed through cl, which is the common length
756 * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the
757 * two lengths, calculated as len(a)-len(b). All lengths are the number of
761 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
767 for (i = dl; i < 0; i++) {
769 return -1; /* a < b */
773 for (i = dl; i > 0; i--) {
775 return 1; /* a > b */
778 return bn_cmp_words(a, b, cl);
782 * Constant-time conditional swap of a and b.
783 * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
784 * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
785 * and that no more than nwords are used by either a or b.
786 * a and b cannot be the same number
788 void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
793 bn_wcheck_size(a, nwords);
794 bn_wcheck_size(b, nwords);
797 assert((condition & (condition - 1)) == 0);
798 assert(sizeof(BN_ULONG) >= sizeof(int));
800 condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
802 t = (a->top ^ b->top) & condition;
806 #define BN_CONSTTIME_SWAP(ind) \
808 t = (a->d[ind] ^ b->d[ind]) & condition; \
815 for (i = 10; i < nwords; i++)
816 BN_CONSTTIME_SWAP(i);
819 BN_CONSTTIME_SWAP(9); /* Fallthrough */
821 BN_CONSTTIME_SWAP(8); /* Fallthrough */
823 BN_CONSTTIME_SWAP(7); /* Fallthrough */
825 BN_CONSTTIME_SWAP(6); /* Fallthrough */
827 BN_CONSTTIME_SWAP(5); /* Fallthrough */
829 BN_CONSTTIME_SWAP(4); /* Fallthrough */
831 BN_CONSTTIME_SWAP(3); /* Fallthrough */
833 BN_CONSTTIME_SWAP(2); /* Fallthrough */
835 BN_CONSTTIME_SWAP(1); /* Fallthrough */
837 BN_CONSTTIME_SWAP(0);
839 #undef BN_CONSTTIME_SWAP
842 /* Bits of security, see SP800-57 */
844 int BN_security_bits(int L, int N)
864 return bits >= secbits ? secbits : bits;
867 void BN_zero_ex(BIGNUM *a)
873 int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
875 return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
878 int BN_is_zero(const BIGNUM *a)
883 int BN_is_one(const BIGNUM *a)
885 return BN_abs_is_word(a, 1) && !a->neg;
888 int BN_is_word(const BIGNUM *a, const BN_ULONG w)
890 return BN_abs_is_word(a, w) && (!w || !a->neg);
893 int BN_is_odd(const BIGNUM *a)
895 return (a->top > 0) && (a->d[0] & 1);
898 int BN_is_negative(const BIGNUM *a)
900 return (a->neg != 0);
903 int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
906 return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
909 void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int n)
913 dest->dmax = b->dmax;
915 dest->flags = ((dest->flags & BN_FLG_MALLOCED)
916 | (b->flags & ~BN_FLG_MALLOCED)
917 | BN_FLG_STATIC_DATA | n);
920 BN_GENCB *BN_GENCB_new(void)
924 if ((ret = OPENSSL_malloc(sizeof(BN_GENCB))) == NULL) {
925 BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
932 void BN_GENCB_free(BN_GENCB *cb)
939 void BN_set_flags(BIGNUM *b, int n)
944 int BN_get_flags(const BIGNUM *b, int n)
949 /* Populate a BN_GENCB structure with an "old"-style callback */
950 void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
953 BN_GENCB *tmp_gencb = gencb;
955 tmp_gencb->arg = cb_arg;
956 tmp_gencb->cb.cb_1 = callback;
959 /* Populate a BN_GENCB structure with a "new"-style callback */
960 void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
963 BN_GENCB *tmp_gencb = gencb;
965 tmp_gencb->arg = cb_arg;
966 tmp_gencb->cb.cb_2 = callback;
969 void *BN_GENCB_get_arg(BN_GENCB *cb)
974 BIGNUM *bn_wexpand(BIGNUM *a, int words)
976 return (words <= a->dmax) ? a : bn_expand2(a, words);
979 void bn_correct_top(BIGNUM *a)
982 int tmp_top = a->top;
985 for (ftl = &(a->d[tmp_top - 1]); tmp_top > 0; tmp_top--)