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 */
71 const char BN_version[]="Big Number" OPENSSL_VERSION_PTEXT;
73 /* This stuff appears to be completely unused, so is deprecated */
74 #ifndef OPENSSL_NO_DEPRECATED
76 * For a 32 bit machine
85 static int bn_limit_bits=0;
86 static int bn_limit_num=8; /* (1<<bn_limit_bits) */
87 static int bn_limit_bits_low=0;
88 static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
89 static int bn_limit_bits_high=0;
90 static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
91 static int bn_limit_bits_mont=0;
92 static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
94 void BN_set_params(int mult, int high, int low, int mont)
98 if (mult > (int)(sizeof(int)*8)-1)
101 bn_limit_num=1<<mult;
105 if (high > (int)(sizeof(int)*8)-1)
106 high=sizeof(int)*8-1;
107 bn_limit_bits_high=high;
108 bn_limit_num_high=1<<high;
112 if (low > (int)(sizeof(int)*8)-1)
114 bn_limit_bits_low=low;
115 bn_limit_num_low=1<<low;
119 if (mont > (int)(sizeof(int)*8)-1)
120 mont=sizeof(int)*8-1;
121 bn_limit_bits_mont=mont;
122 bn_limit_num_mont=1<<mont;
126 int BN_get_params(int which)
128 if (which == 0) return(bn_limit_bits);
129 else if (which == 1) return(bn_limit_bits_high);
130 else if (which == 2) return(bn_limit_bits_low);
131 else if (which == 3) return(bn_limit_bits_mont);
136 const BIGNUM *BN_value_one(void)
138 static const BN_ULONG data_one=1L;
139 static const BIGNUM const_one={(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)
168 if (l & 0xffff000000000000L)
170 if (l & 0xff00000000000000L)
172 return(bits[(int)(l>>56)]+56);
174 else return(bits[(int)(l>>48)]+48);
178 if (l & 0x0000ff0000000000L)
180 return(bits[(int)(l>>40)]+40);
182 else return(bits[(int)(l>>32)]+32);
187 #ifdef SIXTY_FOUR_BIT
188 if (l & 0xffffffff00000000LL)
190 if (l & 0xffff000000000000LL)
192 if (l & 0xff00000000000000LL)
194 return(bits[(int)(l>>56)]+56);
196 else return(bits[(int)(l>>48)]+48);
200 if (l & 0x0000ff0000000000LL)
202 return(bits[(int)(l>>40)]+40);
204 else return(bits[(int)(l>>32)]+32);
211 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
215 return(bits[(int)(l>>24L)]+24);
216 else return(bits[(int)(l>>16L)]+16);
221 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
223 return(bits[(int)(l>>8)]+8);
226 return(bits[(int)(l )] );
231 int BN_num_bits(const BIGNUM *a)
236 if (BN_is_zero(a)) return 0;
237 return ((i*BN_BITS2) + BN_num_bits_word(a->d[i]));
240 void BN_clear_free(BIGNUM *a)
244 if (a == NULL) return;
248 OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
249 if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
252 i=BN_get_flags(a,BN_FLG_MALLOCED);
253 OPENSSL_cleanse(a,sizeof(BIGNUM));
258 void BN_free(BIGNUM *a)
260 if (a == NULL) return;
262 if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
264 if (a->flags & BN_FLG_MALLOCED)
268 #ifndef OPENSSL_NO_DEPRECATED
269 a->flags|=BN_FLG_FREE;
275 void BN_init(BIGNUM *a)
277 memset(a,0,sizeof(BIGNUM));
285 if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
287 BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
290 ret->flags=BN_FLG_MALLOCED;
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)))
311 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
314 if (BN_get_flags(b,BN_FLG_STATIC_DATA))
316 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
319 a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*words);
322 BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
326 /* Valgrind complains in BN_consttime_swap because we process the whole
327 * array even if it's not initialised yet. This doesn't matter in that
328 * function - what's important is constant time operation (we're not
329 * actually going to use the data)
331 memset(a, 0, sizeof(BN_ULONG)*words);
336 /* Check if the previous number needs to be copied */
339 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
342 * The fact that the loop is unrolled
343 * 4-wise is a tribute to Intel. It's
344 * the one that doesn't have enough
345 * registers to accomodate more data.
346 * I'd unroll it 8-wise otherwise:-)
348 * <appro@fy.chalmers.se>
350 BN_ULONG a0,a1,a2,a3;
351 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
352 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
355 * workaround for ultrix cc: without 'case 0', the optimizer does
356 * the switch table by doing a=top&3; a--; goto jump_table[a];
357 * which fails for top== 0
370 memset(A,0,sizeof(BN_ULONG)*words);
371 memcpy(A,b->d,sizeof(b->d[0])*b->top);
377 /* This is an internal function that should not be used in applications.
378 * It ensures that 'b' has enough room for a 'words' word number
379 * and initialises any unused part of b->d with leading zeros.
380 * It is mostly used by the various BIGNUM routines. If there is an error,
381 * NULL is returned. If not, 'b' is returned. */
383 BIGNUM *bn_expand2(BIGNUM *b, int words)
389 BN_ULONG *a = bn_expand_internal(b, words);
391 if(b->d) OPENSSL_free(b->d);
396 /* None of this should be necessary because of what b->top means! */
398 /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
399 if (b->top < b->dmax)
402 BN_ULONG *A = &(b->d[b->top]);
403 for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
405 A[0]=0; A[1]=0; A[2]=0; A[3]=0;
406 A[4]=0; A[5]=0; A[6]=0; A[7]=0;
408 for (i=(b->dmax - b->top)&7; i>0; i--,A++)
410 assert(A == &(b->d[b->dmax]));
417 BIGNUM *BN_dup(const BIGNUM *a)
421 if (a == NULL) return NULL;
425 if (t == NULL) return NULL;
435 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
443 if (a == b) return(a);
444 if (bn_wexpand(a,b->top) == NULL) return(NULL);
449 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
451 BN_ULONG a0,a1,a2,a3;
452 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
453 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
455 /* ultrix cc workaround, see comments in bn_expand_internal */
464 memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
473 void BN_swap(BIGNUM *a, BIGNUM *b)
475 int flags_old_a, flags_old_b;
477 int tmp_top, tmp_dmax, tmp_neg;
482 flags_old_a = a->flags;
483 flags_old_b = b->flags;
500 a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
501 b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
506 void BN_clear(BIGNUM *a)
510 memset(a->d,0,a->dmax*sizeof(a->d[0]));
515 BN_ULONG BN_get_word(const BIGNUM *a)
519 else if (a->top == 1)
525 int BN_set_word(BIGNUM *a, BN_ULONG w)
528 if (bn_expand(a,(int)sizeof(BN_ULONG)*8) == NULL) return(0);
531 a->top = (w ? 1 : 0);
536 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
545 if (ret == NULL) return(NULL);
554 i=((n-1)/BN_BYTES)+1;
555 m=((n-1)%(BN_BYTES));
556 if (bn_wexpand(ret, (int)i) == NULL)
573 /* need to call this due to clear byte at top if avoiding
574 * having the top bit set (-ve number) */
579 /* ignore negative */
580 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
590 *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
595 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
598 BN_ULONG t1,t2,*ap,*bp;
604 if (i != 0) return(i);
607 for (i=a->top-1; i>=0; i--)
612 return((t1 > t2) ? 1 : -1);
617 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
623 if ((a == NULL) || (b == NULL))
636 if (a->neg != b->neg)
644 else { gt= -1; lt=1; }
646 if (a->top > b->top) return(gt);
647 if (a->top < b->top) return(lt);
648 for (i=a->top-1; i>=0; i--)
652 if (t1 > t2) return(gt);
653 if (t1 < t2) return(lt);
658 int BN_set_bit(BIGNUM *a, int n)
669 if (bn_wexpand(a,i+1) == NULL) return(0);
670 for(k=a->top; k<i+1; k++)
675 a->d[i]|=(((BN_ULONG)1)<<j);
680 int BN_clear_bit(BIGNUM *a, int n)
689 if (a->top <= i) return(0);
691 a->d[i]&=(~(((BN_ULONG)1)<<j));
696 int BN_is_bit_set(const BIGNUM *a, int n)
704 if (a->top <= i) return 0;
705 return (int)(((a->d[i])>>j)&((BN_ULONG)1));
708 int BN_mask_bits(BIGNUM *a, int n)
717 if (w >= a->top) return 0;
723 a->d[w]&= ~(BN_MASK2<<b);
729 void BN_set_negative(BIGNUM *a, int b)
731 if (b && !BN_is_zero(a))
737 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
744 if (aa != bb) return((aa > bb)?1:-1);
745 for (i=n-2; i>=0; i--)
749 if (aa != bb) return((aa > bb)?1:-1);
754 /* Here follows a specialised variants of bn_cmp_words(). It has the
755 property of performing the operation on arrays of different sizes.
756 The sizes of those arrays is expressed through cl, which is the
757 common length ( basicall, min(len(a),len(b)) ), and dl, which is the
758 delta between the two lengths, calculated as len(a)-len(b).
759 All lengths are the number of BN_ULONGs... */
761 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
772 return -1; /* a < b */
780 return 1; /* a > b */
783 return bn_cmp_words(a,b,cl);
787 * Constant-time conditional swap of a and b.
788 * a and b are swapped if condition is not 0. The code assumes that at most one bit of condition is set.
789 * nwords is the number of words to swap. The code assumes that at least nwords are allocated in both a and b,
790 * and that no more than nwords are used by either a or b.
791 * a and b cannot be the same number
793 void BN_consttime_swap(BN_ULONG condition, BIGNUM *a, BIGNUM *b, int nwords)
798 bn_wcheck_size(a, nwords);
799 bn_wcheck_size(b, nwords);
802 assert((condition & (condition - 1)) == 0);
803 assert(sizeof(BN_ULONG) >= sizeof(int));
805 condition = ((condition - 1) >> (BN_BITS2 - 1)) - 1;
807 t = (a->top^b->top) & condition;
811 #define BN_CONSTTIME_SWAP(ind) \
813 t = (a->d[ind] ^ b->d[ind]) & condition; \
821 for (i = 10; i < nwords; i++)
822 BN_CONSTTIME_SWAP(i);
824 case 10: BN_CONSTTIME_SWAP(9); /* Fallthrough */
825 case 9: BN_CONSTTIME_SWAP(8); /* Fallthrough */
826 case 8: BN_CONSTTIME_SWAP(7); /* Fallthrough */
827 case 7: BN_CONSTTIME_SWAP(6); /* Fallthrough */
828 case 6: BN_CONSTTIME_SWAP(5); /* Fallthrough */
829 case 5: BN_CONSTTIME_SWAP(4); /* Fallthrough */
830 case 4: BN_CONSTTIME_SWAP(3); /* Fallthrough */
831 case 3: BN_CONSTTIME_SWAP(2); /* Fallthrough */
832 case 2: BN_CONSTTIME_SWAP(1); /* Fallthrough */
833 case 1: BN_CONSTTIME_SWAP(0);
835 #undef BN_CONSTTIME_SWAP
838 /* Bits of security, see SP800-57 */
840 int BN_security_bits(int L, int N)
860 return bits >= secbits ? secbits : bits;
864 void BN_zero_ex(BIGNUM *a)
870 int BN_abs_is_word(const BIGNUM *a, const BN_ULONG w)
872 return ((a->top == 1) && (a->d[0] == w)) || ((w == 0) && (a->top == 0));
875 int BN_is_zero(const BIGNUM *a)
880 int BN_is_one(const BIGNUM *a)
882 return BN_abs_is_word(a, 1) && !a->neg;
885 int BN_is_word(const BIGNUM *a, const BN_ULONG w)
887 return BN_abs_is_word(a, w) && (!w || !a->neg);
890 int BN_is_odd(const BIGNUM *a)
892 return (a->top > 0) && (a->d[0] & 1);
895 int BN_is_negative(const BIGNUM *a)
897 return (a->neg != 0);
900 int BN_to_montgomery(BIGNUM *r,const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx)
902 return BN_mod_mul_montgomery(r,a,&(mont->RR),mont,ctx);
905 void BN_with_flags(BIGNUM *dest, const BIGNUM *b, int n)
911 dest->flags=((dest->flags & BN_FLG_MALLOCED)
912 | (b->flags & ~BN_FLG_MALLOCED)
917 BN_GENCB *BN_GENCB_new(void)
921 if ((ret=(BN_GENCB *)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)
932 if (cb == NULL) return;
936 void BN_set_flags(BIGNUM *b, int n)
941 int BN_get_flags(const BIGNUM *b, int n)
946 /* Populate a BN_GENCB structure with an "old"-style callback */
947 void BN_GENCB_set_old(BN_GENCB *gencb, void (*callback)(int, int, void *), void *cb_arg)
949 BN_GENCB *tmp_gencb = gencb;
951 tmp_gencb->arg = cb_arg;
952 tmp_gencb->cb.cb_1 = callback;
955 /* Populate a BN_GENCB structure with a "new"-style callback */
956 void BN_GENCB_set(BN_GENCB *gencb, int (*callback)(int, int, BN_GENCB *), void *cb_arg)
958 BN_GENCB *tmp_gencb = gencb;
960 tmp_gencb->arg = cb_arg;
961 tmp_gencb->cb.cb_2 = callback;
964 void *BN_GENCB_get_arg(BN_GENCB *cb)
970 BIGNUM *bn_wexpand(BIGNUM *a, int words)
972 return (words <= a->dmax)?a:bn_expand2(a,words);
975 void bn_correct_top(BIGNUM *a)
978 int tmp_top = a->top;
982 for (ftl= &(a->d[tmp_top-1]); tmp_top > 0; tmp_top--)