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 /* For a 32 bit machine
80 static int bn_limit_bits=0;
81 static int bn_limit_num=8; /* (1<<bn_limit_bits) */
82 static int bn_limit_bits_low=0;
83 static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
84 static int bn_limit_bits_high=0;
85 static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
86 static int bn_limit_bits_mont=0;
87 static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
89 void BN_set_params(int mult, int high, int low, int mont)
93 if (mult > (sizeof(int)*8)-1)
100 if (high > (sizeof(int)*8)-1)
101 high=sizeof(int)*8-1;
102 bn_limit_bits_high=high;
103 bn_limit_num_high=1<<high;
107 if (low > (sizeof(int)*8)-1)
109 bn_limit_bits_low=low;
110 bn_limit_num_low=1<<low;
114 if (mont > (sizeof(int)*8)-1)
115 mont=sizeof(int)*8-1;
116 bn_limit_bits_mont=mont;
117 bn_limit_num_mont=1<<mont;
121 int BN_get_params(int which)
123 if (which == 0) return(bn_limit_bits);
124 else if (which == 1) return(bn_limit_bits_high);
125 else if (which == 2) return(bn_limit_bits_low);
126 else if (which == 3) return(bn_limit_bits_mont);
130 BIGNUM *BN_value_one(void)
132 static BN_ULONG data_one=1L;
133 static BIGNUM const_one={&data_one,1,1,0};
138 char *BN_options(void)
141 static char data[16];
147 sprintf(data,"bn(%d,%d)",(int)sizeof(BN_ULLONG)*8,
148 (int)sizeof(BN_ULONG)*8);
150 sprintf(data,"bn(%d,%d)",(int)sizeof(BN_ULONG)*8,
151 (int)sizeof(BN_ULONG)*8);
157 int BN_num_bits_word(BN_ULONG l)
159 static const char bits[256]={
160 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
161 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
162 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
163 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
164 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
165 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
166 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
167 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
168 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
169 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
170 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
171 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
172 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
173 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
174 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
175 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
178 #if defined(SIXTY_FOUR_BIT_LONG)
179 if (l & 0xffffffff00000000L)
181 if (l & 0xffff000000000000L)
183 if (l & 0xff00000000000000L)
185 return(bits[(int)(l>>56)]+56);
187 else return(bits[(int)(l>>48)]+48);
191 if (l & 0x0000ff0000000000L)
193 return(bits[(int)(l>>40)]+40);
195 else return(bits[(int)(l>>32)]+32);
200 #ifdef SIXTY_FOUR_BIT
201 if (l & 0xffffffff00000000LL)
203 if (l & 0xffff000000000000LL)
205 if (l & 0xff00000000000000LL)
207 return(bits[(int)(l>>56)]+56);
209 else return(bits[(int)(l>>48)]+48);
213 if (l & 0x0000ff0000000000LL)
215 return(bits[(int)(l>>40)]+40);
217 else return(bits[(int)(l>>32)]+32);
224 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
228 return(bits[(int)(l>>24L)]+24);
229 else return(bits[(int)(l>>16L)]+16);
234 #if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
236 return(bits[(int)(l>>8)]+8);
239 return(bits[(int)(l )] );
244 int BN_num_bits(const BIGNUM *a)
251 if (a->top == 0) return(0);
254 i=(a->top-1)*BN_BITS2;
255 return(i+BN_num_bits_word(l));
258 void BN_clear_free(BIGNUM *a)
262 if (a == NULL) return;
265 memset(a->d,0,a->dmax*sizeof(a->d[0]));
266 if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
269 i=BN_get_flags(a,BN_FLG_MALLOCED);
270 memset(a,0,sizeof(BIGNUM));
275 void BN_free(BIGNUM *a)
277 if (a == NULL) return;
278 if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
280 a->flags|=BN_FLG_FREE; /* REMOVE? */
281 if (a->flags & BN_FLG_MALLOCED)
285 void BN_init(BIGNUM *a)
287 memset(a,0,sizeof(BIGNUM));
294 if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
296 BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
299 ret->flags=BN_FLG_MALLOCED;
307 /* This is an internal function that should not be used in applications.
308 * It ensures that 'b' has enough room for a 'words' word number number.
309 * It is mostly used by the various BIGNUM routines. If there is an error,
310 * NULL is returned. If not, 'b' is returned. */
312 BIGNUM *bn_expand2(BIGNUM *b, int words)
322 if (words > (INT_MAX/(4*BN_BITS2)))
324 BNerr(BN_F_BN_EXPAND2,BN_R_TOO_LARGE);
329 if (BN_get_flags(b,BN_FLG_STATIC_DATA))
331 BNerr(BN_F_BN_EXPAND2,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
334 a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1));
337 BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE);
342 /* Check if the previous number needs to be copied */
346 /* This lot is an unrolled loop to copy b->top
347 * BN_ULONGs from B to A
350 * I have nothing against unrolling but it's usually done for
351 * several reasons, namely:
352 * - minimize percentage of decision making code, i.e. branches;
353 * - avoid cache trashing;
354 * - make it possible to schedule loads earlier;
355 * Now let's examine the code below. The cornerstone of C is
356 * "programmer is always right" and that's what we love it for:-)
357 * For this very reason C compilers have to be paranoid when it
358 * comes to data aliasing and assume the worst. Yeah, but what
359 * does it mean in real life? This means that loop body below will
360 * be compiled to sequence of loads immediately followed by stores
361 * as compiler assumes the worst, something in A==B+1 style. As a
362 * result CPU pipeline is going to starve for incoming data. Secondly
363 * if A and B happen to share same cache line such code is going to
364 * cause severe cache trashing. Both factors have severe impact on
365 * performance of modern CPUs and this is the reason why this
366 * particular piece of code is #ifdefed away and replaced by more
367 * "friendly" version found in #else section below. This comment
368 * also applies to BN_copy function.
370 * <appro@fy.chalmers.se>
372 for (i=b->top&(~7); i>0; i-=8)
374 A[0]=B[0]; A[1]=B[1]; A[2]=B[2]; A[3]=B[3];
375 A[4]=B[4]; A[5]=B[5]; A[6]=B[6]; A[7]=B[7];
396 /* I need the 'case 0' entry for utrix cc.
397 * If the optimizer is turned on, it does the
398 * switch table by doing
401 * goto jump_table[a];
402 * If top is 0, this makes us jump to 0xffffffc
403 * which is rather bad :-(.
409 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
412 * The fact that the loop is unrolled
413 * 4-wise is a tribute to Intel. It's
414 * the one that doesn't have enough
415 * registers to accomodate more data.
416 * I'd unroll it 8-wise otherwise:-)
418 * <appro@fy.chalmers.se>
420 BN_ULONG a0,a1,a2,a3;
421 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
422 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
429 case 0: ; /* ultrix cc workaround, see above */
438 /* Now need to zero any data between b->top and b->max */
441 for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
443 A[0]=0; A[1]=0; A[2]=0; A[3]=0;
444 A[4]=0; A[5]=0; A[6]=0; A[7]=0;
446 for (i=(b->dmax - b->top)&7; i>0; i--,A++)
449 memset(A,0,sizeof(BN_ULONG)*(words+1));
450 memcpy(A,b->d,sizeof(b->d[0])*b->top);
455 /* memset(&(p[b->max]),0,((words+1)-b->max)*sizeof(BN_ULONG)); */
456 /* { int i; for (i=b->max; i<words+1; i++) p[i]=i;} */
462 BIGNUM *BN_dup(const BIGNUM *a)
466 if (a == NULL) return NULL;
471 if (r == NULL) return(NULL);
472 return((BIGNUM *)BN_copy(r,a));
475 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
483 if (a == b) return(a);
484 if (bn_wexpand(a,b->top) == NULL) return(NULL);
489 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
491 BN_ULONG a0,a1,a2,a3;
492 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
493 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
500 case 0: ; /* ultrix cc workaround, see comments in bn_expand2 */
503 memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
506 /* memset(&(a->d[b->top]),0,sizeof(a->d[0])*(a->max-b->top));*/
508 if ((a->top == 0) && (a->d != NULL))
514 void BN_clear(BIGNUM *a)
517 memset(a->d,0,a->dmax*sizeof(a->d[0]));
522 BN_ULONG BN_get_word(BIGNUM *a)
528 if (n > sizeof(BN_ULONG))
530 for (i=a->top-1; i>=0; i--)
532 #ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
533 ret<<=BN_BITS4; /* stops the compiler complaining */
543 int BN_set_word(BIGNUM *a, BN_ULONG w)
546 if (bn_expand(a,sizeof(BN_ULONG)*8) == NULL) return(0);
548 n=sizeof(BN_ULONG)/BN_BYTES;
551 a->d[0]=(BN_ULONG)w&BN_MASK2;
552 if (a->d[0] != 0) a->top=1;
555 /* the following is done instead of
556 * w>>=BN_BITS2 so compilers don't complain
557 * on builds where sizeof(long) == BN_TYPES */
558 #ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
564 a->d[i]=(BN_ULONG)w&BN_MASK2;
565 if (a->d[i] != 0) a->top=i+1;
570 /* ignore negative */
571 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
577 if (ret == NULL) ret=BN_new();
578 if (ret == NULL) return(NULL);
586 if (bn_expand(ret,(int)(n+2)*8) == NULL)
588 i=((n-1)/BN_BYTES)+1;
589 m=((n-1)%(BN_BYTES));
601 /* need to call this due to clear byte at top if avoiding
602 * having the top bit set (-ve number) */
607 /* ignore negative */
608 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
617 *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
622 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
625 BN_ULONG t1,t2,*ap,*bp;
631 if (i != 0) return(i);
634 for (i=a->top-1; i>=0; i--)
639 return(t1 > t2?1:-1);
644 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
650 if ((a == NULL) || (b == NULL))
663 if (a->neg != b->neg)
671 else { gt= -1; lt=1; }
673 if (a->top > b->top) return(gt);
674 if (a->top < b->top) return(lt);
675 for (i=a->top-1; i>=0; i--)
679 if (t1 > t2) return(gt);
680 if (t1 < t2) return(lt);
685 int BN_set_bit(BIGNUM *a, int n)
693 if (bn_wexpand(a,i+1) == NULL) return(0);
694 for(k=a->top; k<i+1; k++)
699 a->d[i]|=(((BN_ULONG)1)<<j);
703 int BN_clear_bit(BIGNUM *a, int n)
709 if (a->top <= i) return(0);
711 a->d[i]&=(~(((BN_ULONG)1)<<j));
716 int BN_is_bit_set(const BIGNUM *a, int n)
720 if (n < 0) return(0);
723 if (a->top <= i) return(0);
724 return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
727 int BN_mask_bits(BIGNUM *a, int n)
733 if (w >= a->top) return(0);
739 a->d[w]&= ~(BN_MASK2<<b);
745 int bn_cmp_words(BN_ULONG *a, BN_ULONG *b, int n)
752 if (aa != bb) return((aa > bb)?1:-1);
753 for (i=n-2; i>=0; i--)
757 if (aa != bb) return((aa > bb)?1:-1);