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 (!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);
390 BIGNUM *BN_dup(const BIGNUM *a)
401 if (!BN_copy(t, a)) {
409 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
419 if (bn_wexpand(a, b->top) == NULL)
425 for (i = b->top >> 2; i > 0; i--, A += 4, B += 4) {
426 BN_ULONG a0, a1, a2, a3;
436 /* ultrix cc workaround, see comments in bn_expand_internal */
437 switch (b->top & 3) {
447 memcpy(a->d, b->d, sizeof(b->d[0]) * b->top);
456 void BN_swap(BIGNUM *a, BIGNUM *b)
458 int flags_old_a, flags_old_b;
460 int tmp_top, tmp_dmax, tmp_neg;
465 flags_old_a = a->flags;
466 flags_old_b = b->flags;
484 (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
486 (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
491 void BN_clear(BIGNUM *a)
495 memset(a->d, 0, a->dmax * sizeof(a->d[0]));
500 BN_ULONG BN_get_word(const BIGNUM *a)
504 else if (a->top == 1)
510 int BN_set_word(BIGNUM *a, BN_ULONG w)
513 if (bn_expand(a, (int)sizeof(BN_ULONG) * 8) == NULL)
517 a->top = (w ? 1 : 0);
522 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
540 i = ((n - 1) / BN_BYTES) + 1;
541 m = ((n - 1) % (BN_BYTES));
542 if (bn_wexpand(ret, (int)i) == NULL) {
549 l = (l << 8L) | *(s++);
557 * need to call this due to clear byte at top if avoiding having the top
558 * bit set (-ve number)
564 /* ignore negative */
565 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
571 n = i = BN_num_bytes(a);
573 l = a->d[i / BN_BYTES];
574 *(to++) = (unsigned char)(l >> (8 * (i % BN_BYTES))) & 0xff;
579 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
582 BN_ULONG t1, t2, *ap, *bp;
592 for (i = a->top - 1; i >= 0; i--) {
596 return ((t1 > t2) ? 1 : -1);
601 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
607 if ((a == NULL) || (b == NULL)) {
619 if (a->neg != b->neg) {
637 for (i = a->top - 1; i >= 0; i--) {
648 int BN_set_bit(BIGNUM *a, int n)
658 if (bn_wexpand(a, i + 1) == NULL)
660 for (k = a->top; k < i + 1; k++)
665 a->d[i] |= (((BN_ULONG)1) << j);
670 int BN_clear_bit(BIGNUM *a, int n)
683 a->d[i] &= (~(((BN_ULONG)1) << j));
688 int BN_is_bit_set(const BIGNUM *a, int n)
699 return (int)(((a->d[i]) >> j) & ((BN_ULONG)1));
702 int BN_mask_bits(BIGNUM *a, int n)
718 a->d[w] &= ~(BN_MASK2 << b);
724 void BN_set_negative(BIGNUM *a, int b)
726 if (b && !BN_is_zero(a))
732 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
740 return ((aa > bb) ? 1 : -1);
741 for (i = n - 2; i >= 0; i--) {
745 return ((aa > bb) ? 1 : -1);
751 * Here follows a specialised variants of bn_cmp_words(). It has the
752 * property of performing the operation on arrays of different sizes. The
753 * sizes of those arrays is expressed through cl, which is the common length
754 * ( basicall, min(len(a),len(b)) ), and dl, which is the delta between the
755 * two lengths, calculated as len(a)-len(b). All lengths are the number of
759 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl)
765 for (i = dl; i < 0; i++) {
767 return -1; /* a < b */
771 for (i = dl; i > 0; i--) {
773 return 1; /* a > b */
776 return bn_cmp_words(a, b, cl);
780 * Constant-time conditional swap of a and b.
781 * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
782 * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
783 * and that no more than nwords are used by either a or b.
784 * a and b cannot be the same number
786 void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
791 bn_wcheck_size(a, nwords);
792 bn_wcheck_size(b, nwords);
795 assert((condition & (condition - 1)) == 0);
796 assert(sizeof(BN_ULONG) >= sizeof(int));
798 condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
800 t = (a->top ^ b->top) & condition;
804 #define BN_CONSTTIME_SWAP(ind) \
806 t = (a->d[ind] ^ b->d[ind]) & condition; \
813 for (i = 10; i < nwords; i++)
814 BN_CONSTTIME_SWAP(i);
817 BN_CONSTTIME_SWAP(9); /* Fallthrough */
819 BN_CONSTTIME_SWAP(8); /* Fallthrough */
821 BN_CONSTTIME_SWAP(7); /* Fallthrough */
823 BN_CONSTTIME_SWAP(6); /* Fallthrough */
825 BN_CONSTTIME_SWAP(5); /* Fallthrough */
827 BN_CONSTTIME_SWAP(4); /* Fallthrough */
829 BN_CONSTTIME_SWAP(3); /* Fallthrough */
831 BN_CONSTTIME_SWAP(2); /* Fallthrough */
833 BN_CONSTTIME_SWAP(1); /* Fallthrough */
835 BN_CONSTTIME_SWAP(0);
837 #undef BN_CONSTTIME_SWAP
840 /* Bits of security, see SP800-57 */
842 int BN_security_bits(int L, int N)
862 return bits >= secbits ? secbits : bits;
865 void BN_zero_ex(BIGNUM *a)
871 int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
873 return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
876 int BN_is_zero(const BIGNUM *a)
881 int BN_is_one(const BIGNUM *a)
883 return BN_abs_is_word(a, 1) && !a->neg;
886 int BN_is_word(const BIGNUM *a, const BN_ULONG w)
888 return BN_abs_is_word(a, w) && (!w || !a->neg);
891 int BN_is_odd(const BIGNUM *a)
893 return (a->top > 0) && (a->d[0] & 1);
896 int BN_is_negative(const BIGNUM *a)
898 return (a->neg != 0);
901 int BN_to_montgomery(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
904 return BN_mod_mul_montgomery(r, a, &(mont->RR), mont, ctx);
907 void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int n)
911 dest->dmax = b->dmax;
913 dest->flags = ((dest->flags & BN_FLG_MALLOCED)
914 | (b->flags & ~BN_FLG_MALLOCED)
915 | BN_FLG_STATIC_DATA | n);
918 BN_GENCB *BN_GENCB_new(void)
922 if ((ret = OPENSSL_malloc(sizeof(BN_GENCB))) == NULL) {
923 BNerr(BN_F_BN_GENCB_NEW, ERR_R_MALLOC_FAILURE);
930 void BN_GENCB_free(BN_GENCB *cb)
937 void BN_set_flags(BIGNUM *b, int n)
942 int BN_get_flags(const BIGNUM *b, int n)
947 /* Populate a BN_GENCB structure with an "old"-style callback */
948 void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback) (int, int, void *),
951 BN_GENCB *tmp_gencb = gencb;
953 tmp_gencb->arg = cb_arg;
954 tmp_gencb->cb.cb_1 = callback;
957 /* Populate a BN_GENCB structure with a "new"-style callback */
958 void BN_GENCB_set(BN_GENCB *gencb, int (*callback) (int, int, BN_GENCB *),
961 BN_GENCB *tmp_gencb = gencb;
963 tmp_gencb->arg = cb_arg;
964 tmp_gencb->cb.cb_2 = callback;
967 void *BN_GENCB_get_arg(BN_GENCB *cb)
972 BIGNUM *bn_wexpand(BIGNUM *a, int words)
974 return (words <= a->dmax) ? a : bn_expand2(a, words);
977 void bn_correct_top(BIGNUM *a)
980 int tmp_top = a->top;
983 for (ftl = &(a->d[tmp_top - 1]); tmp_top > 0; tmp_top--)