Root/package/ead/src/tinysrp/bn_lib.c

1/* crypto/bn/bn_lib.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
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.
8 *
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).
15 *
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.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
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)"
40 *
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
51 * SUCH DAMAGE.
52 *
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.]
57 */
58
59#ifndef BN_DEBUG
60# undef NDEBUG /* avoid conflicting definitions */
61# define NDEBUG
62#endif
63
64#include <assert.h>
65#include <stdio.h>
66#include <stdlib.h>
67#include <string.h>
68#include "bn_lcl.h"
69
70const char *BN_version="Big Number";
71
72/* For a 32 bit machine
73 * 2 - 4 == 128
74 * 3 - 8 == 256
75 * 4 - 16 == 512
76 * 5 - 32 == 1024
77 * 6 - 64 == 2048
78 * 7 - 128 == 4096
79 * 8 - 256 == 8192
80 */
81static int bn_limit_bits=0;
82static int bn_limit_num=8; /* (1<<bn_limit_bits) */
83static int bn_limit_bits_low=0;
84static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
85static int bn_limit_bits_high=0;
86static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
87static int bn_limit_bits_mont=0;
88static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
89
90int BN_num_bits_word(BN_ULONG l)
91    {
92    static const char bits[256]={
93        0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
94        5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
95        6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
96        6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
97        7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
98        7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
99        7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
100        7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
101        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
102        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
103        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
104        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
105        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
106        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
107        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
108        8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
109        };
110
111#if defined(SIXTY_FOUR_BIT_LONG)
112    if (l & 0xffffffff00000000L)
113        {
114        if (l & 0xffff000000000000L)
115            {
116            if (l & 0xff00000000000000L)
117                {
118                return(bits[(int)(l>>56)]+56);
119                }
120            else return(bits[(int)(l>>48)]+48);
121            }
122        else
123            {
124            if (l & 0x0000ff0000000000L)
125                {
126                return(bits[(int)(l>>40)]+40);
127                }
128            else return(bits[(int)(l>>32)]+32);
129            }
130        }
131    else
132#else
133#ifdef SIXTY_FOUR_BIT
134    if (l & 0xffffffff00000000LL)
135        {
136        if (l & 0xffff000000000000LL)
137            {
138            if (l & 0xff00000000000000LL)
139                {
140                return(bits[(int)(l>>56)]+56);
141                }
142            else return(bits[(int)(l>>48)]+48);
143            }
144        else
145            {
146            if (l & 0x0000ff0000000000LL)
147                {
148                return(bits[(int)(l>>40)]+40);
149                }
150            else return(bits[(int)(l>>32)]+32);
151            }
152        }
153    else
154#endif
155#endif
156        {
157#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
158        if (l & 0xffff0000L)
159            {
160            if (l & 0xff000000L)
161                return(bits[(int)(l>>24L)]+24);
162            else return(bits[(int)(l>>16L)]+16);
163            }
164        else
165#endif
166            {
167#if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
168            if (l & 0xff00L)
169                return(bits[(int)(l>>8)]+8);
170            else
171#endif
172                return(bits[(int)(l )] );
173            }
174        }
175    }
176
177int BN_num_bits(const BIGNUM *a)
178    {
179    BN_ULONG l;
180    int i;
181
182    bn_check_top(a);
183
184    if (a->top == 0) return(0);
185    l=a->d[a->top-1];
186    assert(l != 0);
187    i=(a->top-1)*BN_BITS2;
188    return(i+BN_num_bits_word(l));
189    }
190
191void BN_clear_free(BIGNUM *a)
192    {
193    int i;
194
195    if (a == NULL) return;
196    if (a->d != NULL)
197        {
198        memset(a->d,0,a->dmax*sizeof(a->d[0]));
199        if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
200            free(a->d);
201        }
202    i=BN_get_flags(a,BN_FLG_MALLOCED);
203    memset(a,0,sizeof(BIGNUM));
204    if (i)
205        free(a);
206    }
207
208void BN_free(BIGNUM *a)
209    {
210    if (a == NULL) return;
211    if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
212        free(a->d);
213    a->flags|=BN_FLG_FREE; /* REMOVE? */
214    if (a->flags & BN_FLG_MALLOCED)
215        free(a);
216    }
217
218void BN_init(BIGNUM *a)
219    {
220    memset(a,0,sizeof(BIGNUM));
221    }
222
223BIGNUM *BN_new(void)
224    {
225    BIGNUM *ret;
226
227    if ((ret=(BIGNUM *)malloc(sizeof(BIGNUM))) == NULL)
228        {
229        return(NULL);
230        }
231    ret->flags=BN_FLG_MALLOCED;
232    ret->top=0;
233    ret->neg=0;
234    ret->dmax=0;
235    ret->d=NULL;
236    return(ret);
237    }
238
239/* This is an internal function that should not be used in applications.
240 * It ensures that 'b' has enough room for a 'words' word number number.
241 * It is mostly used by the various BIGNUM routines. If there is an error,
242 * NULL is returned. If not, 'b' is returned. */
243
244BIGNUM *bn_expand2(BIGNUM *b, int words)
245    {
246    BN_ULONG *A,*a;
247    const BN_ULONG *B;
248    int i;
249
250    bn_check_top(b);
251
252    if (words > b->dmax)
253        {
254        bn_check_top(b);
255        if (BN_get_flags(b,BN_FLG_STATIC_DATA))
256            {
257            return(NULL);
258            }
259        a=A=(BN_ULONG *)malloc(sizeof(BN_ULONG)*(words+1));
260        if (A == NULL)
261            {
262            return(NULL);
263            }
264#if 1
265        B=b->d;
266        /* Check if the previous number needs to be copied */
267        if (B != NULL)
268            {
269#if 0
270            /* This lot is an unrolled loop to copy b->top
271             * BN_ULONGs from B to A
272             */
273/*
274 * I have nothing against unrolling but it's usually done for
275 * several reasons, namely:
276 * - minimize percentage of decision making code, i.e. branches;
277 * - avoid cache trashing;
278 * - make it possible to schedule loads earlier;
279 * Now let's examine the code below. The cornerstone of C is
280 * "programmer is always right" and that's what we love it for:-)
281 * For this very reason C compilers have to be paranoid when it
282 * comes to data aliasing and assume the worst. Yeah, but what
283 * does it mean in real life? This means that loop body below will
284 * be compiled to sequence of loads immediately followed by stores
285 * as compiler assumes the worst, something in A==B+1 style. As a
286 * result CPU pipeline is going to starve for incoming data. Secondly
287 * if A and B happen to share same cache line such code is going to
288 * cause severe cache trashing. Both factors have severe impact on
289 * performance of modern CPUs and this is the reason why this
290 * particular piece of code is #ifdefed away and replaced by more
291 * "friendly" version found in #else section below. This comment
292 * also applies to BN_copy function.
293 *
294 * <appro@fy.chalmers.se>
295 */
296            for (i=b->top&(~7); i>0; i-=8)
297                {
298                A[0]=B[0]; A[1]=B[1]; A[2]=B[2]; A[3]=B[3];
299                A[4]=B[4]; A[5]=B[5]; A[6]=B[6]; A[7]=B[7];
300                A+=8;
301                B+=8;
302                }
303            switch (b->top&7)
304                {
305            case 7:
306                A[6]=B[6];
307            case 6:
308                A[5]=B[5];
309            case 5:
310                A[4]=B[4];
311            case 4:
312                A[3]=B[3];
313            case 3:
314                A[2]=B[2];
315            case 2:
316                A[1]=B[1];
317            case 1:
318                A[0]=B[0];
319            case 0:
320                /* I need the 'case 0' entry for utrix cc.
321                 * If the optimizer is turned on, it does the
322                 * switch table by doing
323                 * a=top&7
324                 * a--;
325                 * goto jump_table[a];
326                 * If top is 0, this makes us jump to 0xffffffc
327                 * which is rather bad :-(.
328                 * eric 23-Apr-1998
329                 */
330                ;
331                }
332#else
333            for (i=b->top>>2; i>0; i--,A+=4,B+=4)
334                {
335                /*
336                 * The fact that the loop is unrolled
337                 * 4-wise is a tribute to Intel. It's
338                 * the one that doesn't have enough
339                 * registers to accomodate more data.
340                 * I'd unroll it 8-wise otherwise:-)
341                 *
342                 * <appro@fy.chalmers.se>
343                 */
344                BN_ULONG a0,a1,a2,a3;
345                a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
346                A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
347                }
348            switch (b->top&3)
349                {
350                case 3: A[2]=B[2];
351                case 2: A[1]=B[1];
352                case 1: A[0]=B[0];
353                case 0: ; /* ultrix cc workaround, see above */
354                }
355#endif
356            free(b->d);
357            }
358
359        b->d=a;
360        b->dmax=words;
361
362        /* Now need to zero any data between b->top and b->max */
363
364        A= &(b->d[b->top]);
365        for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
366            {
367            A[0]=0; A[1]=0; A[2]=0; A[3]=0;
368            A[4]=0; A[5]=0; A[6]=0; A[7]=0;
369            }
370        for (i=(b->dmax - b->top)&7; i>0; i--,A++)
371            A[0]=0;
372#else
373            memset(A,0,sizeof(BN_ULONG)*(words+1));
374            memcpy(A,b->d,sizeof(b->d[0])*b->top);
375            b->d=a;
376            b->max=words;
377#endif
378
379/* memset(&(p[b->max]),0,((words+1)-b->max)*sizeof(BN_ULONG)); */
380/* { int i; for (i=b->max; i<words+1; i++) p[i]=i;} */
381
382        }
383    return(b);
384    }
385
386BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
387    {
388    int i;
389    BN_ULONG *A;
390    const BN_ULONG *B;
391
392    bn_check_top(b);
393
394    if (a == b) return(a);
395    if (bn_wexpand(a,b->top) == NULL) return(NULL);
396
397#if 1
398    A=a->d;
399    B=b->d;
400    for (i=b->top>>2; i>0; i--,A+=4,B+=4)
401        {
402        BN_ULONG a0,a1,a2,a3;
403        a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
404        A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
405        }
406    switch (b->top&3)
407        {
408        case 3: A[2]=B[2];
409        case 2: A[1]=B[1];
410        case 1: A[0]=B[0];
411        case 0: ; /* ultrix cc workaround, see comments in bn_expand2 */
412        }
413#else
414    memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
415#endif
416
417/* memset(&(a->d[b->top]),0,sizeof(a->d[0])*(a->max-b->top));*/
418    a->top=b->top;
419    if ((a->top == 0) && (a->d != NULL))
420        a->d[0]=0;
421    a->neg=b->neg;
422    return(a);
423    }
424
425int BN_set_word(BIGNUM *a, BN_ULONG w)
426    {
427    int i,n;
428    if (bn_expand(a,sizeof(BN_ULONG)*8) == NULL) return(0);
429
430    n=sizeof(BN_ULONG)/BN_BYTES;
431    a->neg=0;
432    a->top=0;
433    a->d[0]=(BN_ULONG)w&BN_MASK2;
434    if (a->d[0] != 0) a->top=1;
435    for (i=1; i<n; i++)
436        {
437        /* the following is done instead of
438         * w>>=BN_BITS2 so compilers don't complain
439         * on builds where sizeof(long) == BN_TYPES */
440#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
441        w>>=BN_BITS4;
442        w>>=BN_BITS4;
443#else
444        w=0;
445#endif
446        a->d[i]=(BN_ULONG)w&BN_MASK2;
447        if (a->d[i] != 0) a->top=i+1;
448        }
449    return(1);
450    }
451
452/* ignore negative */
453BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
454    {
455    unsigned int i,m;
456    unsigned int n;
457    BN_ULONG l;
458
459    if (ret == NULL) ret=BN_new();
460    if (ret == NULL) return(NULL);
461    l=0;
462    n=len;
463    if (n == 0)
464        {
465        ret->top=0;
466        return(ret);
467        }
468    if (bn_expand(ret,(int)(n+2)*8) == NULL)
469        return(NULL);
470    i=((n-1)/BN_BYTES)+1;
471    m=((n-1)%(BN_BYTES));
472    ret->top=i;
473    while (n-- > 0)
474        {
475        l=(l<<8L)| *(s++);
476        if (m-- == 0)
477            {
478            ret->d[--i]=l;
479            l=0;
480            m=BN_BYTES-1;
481            }
482        }
483    /* need to call this due to clear byte at top if avoiding
484     * having the top bit set (-ve number) */
485    bn_fix_top(ret);
486    return(ret);
487    }
488
489/* ignore negative */
490int BN_bn2bin(const BIGNUM *a, unsigned char *to)
491    {
492    int n,i;
493    BN_ULONG l;
494
495    n=i=BN_num_bytes(a);
496    while (i-- > 0)
497        {
498        l=a->d[i/BN_BYTES];
499        *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
500        }
501    return(n);
502    }
503
504int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
505    {
506    int i;
507    BN_ULONG t1,t2,*ap,*bp;
508
509    bn_check_top(a);
510    bn_check_top(b);
511
512    i=a->top-b->top;
513    if (i != 0) return(i);
514    ap=a->d;
515    bp=b->d;
516    for (i=a->top-1; i>=0; i--)
517        {
518        t1= ap[i];
519        t2= bp[i];
520        if (t1 != t2)
521            return(t1 > t2?1:-1);
522        }
523    return(0);
524    }
525
526int BN_cmp(const BIGNUM *a, const BIGNUM *b)
527    {
528    int i;
529    int gt,lt;
530    BN_ULONG t1,t2;
531
532    if ((a == NULL) || (b == NULL))
533        {
534        if (a != NULL)
535            return(-1);
536        else if (b != NULL)
537            return(1);
538        else
539            return(0);
540        }
541
542    bn_check_top(a);
543    bn_check_top(b);
544
545    if (a->neg != b->neg)
546        {
547        if (a->neg)
548            return(-1);
549        else return(1);
550        }
551    if (a->neg == 0)
552        { gt=1; lt= -1; }
553    else { gt= -1; lt=1; }
554
555    if (a->top > b->top) return(gt);
556    if (a->top < b->top) return(lt);
557    for (i=a->top-1; i>=0; i--)
558        {
559        t1=a->d[i];
560        t2=b->d[i];
561        if (t1 > t2) return(gt);
562        if (t1 < t2) return(lt);
563        }
564    return(0);
565    }
566
567int BN_is_bit_set(const BIGNUM *a, int n)
568    {
569    int i,j;
570
571    if (n < 0) return(0);
572    i=n/BN_BITS2;
573    j=n%BN_BITS2;
574    if (a->top <= i) return(0);
575    return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
576    }
577

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