rdesktop/crypto/bn_lib.c

/* crypto/bn/bn_lib.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#ifndef BN_DEBUG
# undef NDEBUG /* avoid conflicting definitions */
# define NDEBUG
#endif

#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include "bn_lcl.h"

#if 0
BIGNUM *BN_value_one(void)
        {
        static BN_ULONG data_one=1L;
        static BIGNUM const_one={&data_one,1,1,0};

        return(&const_one);
        }
#endif

int BN_num_bits_word(BN_ULONG l)
        {
        static const char bits[256]={
                0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
                5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
                6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
                6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
                7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
                };

#if defined(SIXTY_FOUR_BIT_LONG)
        if (l & 0xffffffff00000000L)
                {
                if (l & 0xffff000000000000L)
                        {
                        if (l & 0xff00000000000000L)
                                {
                                return(bits[(int)(l>>56)]+56);
                                }
                        else    return(bits[(int)(l>>48)]+48);
                        }
                else
                        {
                        if (l & 0x0000ff0000000000L)
                                {
                                return(bits[(int)(l>>40)]+40);
                                }
                        else    return(bits[(int)(l>>32)]+32);
                        }
                }
        else
#else
#ifdef SIXTY_FOUR_BIT
        if (l & 0xffffffff00000000LL)
                {
                if (l & 0xffff000000000000LL)
                        {
                        if (l & 0xff00000000000000LL)
                                {
                                return(bits[(int)(l>>56)]+56);
                                }
                        else    return(bits[(int)(l>>48)]+48);
                        }
                else
                        {
                        if (l & 0x0000ff0000000000LL)
                                {
                                return(bits[(int)(l>>40)]+40);
                                }
                        else    return(bits[(int)(l>>32)]+32);
                        }
                }
        else
#endif
#endif
                {
#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
                if (l & 0xffff0000L)
                        {
                        if (l & 0xff000000L)
                                return(bits[(int)(l>>24L)]+24);
                        else    return(bits[(int)(l>>16L)]+16);
                        }
                else
#endif
                        {
#if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
                        if (l & 0xff00L)
                                return(bits[(int)(l>>8)]+8);
                        else    
#endif
                                return(bits[(int)(l   )]  );
                        }
                }
        }

int BN_num_bits(const BIGNUM *a)
        {
        BN_ULONG l;
        int i;

        bn_check_top(a);

        if (a->top == 0) return(0);
        l=a->d[a->top-1];
        assert(l != 0);
        i=(a->top-1)*BN_BITS2;
        return(i+BN_num_bits_word(l));
        }

void BN_clear_free(BIGNUM *a)
        {
        int i;

        if (a == NULL) return;
        if (a->d != NULL)
                {
                memset(a->d,0,a->dmax*sizeof(a->d[0]));
                if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
                        OPENSSL_free(a->d);
                }
        i=BN_get_flags(a,BN_FLG_MALLOCED);
        memset(a,0,sizeof(BIGNUM));
        if (i)
                OPENSSL_free(a);
        }

void BN_free(BIGNUM *a)
        {
        if (a == NULL) return;
        if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
                OPENSSL_free(a->d);
        a->flags|=BN_FLG_FREE; /* REMOVE? */
        if (a->flags & BN_FLG_MALLOCED)
                OPENSSL_free(a);
        }

void BN_init(BIGNUM *a)
        {
        memset(a,0,sizeof(BIGNUM));
        }

#if 0
BIGNUM *BN_new(void)
        {
        BIGNUM *ret;

        if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
                {
                BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
                return(NULL);
                }
        ret->flags=BN_FLG_MALLOCED;
        ret->top=0;
        ret->neg=0;
        ret->dmax=0;
        ret->d=NULL;
        return(ret);
        }
#endif

/* This is an internal function that should not be used in applications.
 * It ensures that 'b' has enough room for a 'words' word number number.
 * It is mostly used by the various BIGNUM routines. If there is an error,
 * NULL is returned. If not, 'b' is returned. */

BIGNUM *bn_expand2(BIGNUM *b, int words)
        {
        BN_ULONG *A,*a;
        const BN_ULONG *B;
        int i;

        bn_check_top(b);

        if (words > b->dmax)
                {
                if (words > (INT_MAX/(4*BN_BITS2)))
                        {
                        BNerr(BN_F_BN_EXPAND2,BN_R_BIGNUM_TOO_LONG);
                        return NULL;
                        }
                        
                bn_check_top(b);        
                if (BN_get_flags(b,BN_FLG_STATIC_DATA))
                        {
                        BNerr(BN_F_BN_EXPAND2,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
                        return(NULL);
                        }
                a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1));
                if (A == NULL)
                        {
                        BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE);
                        return(NULL);
                        }
#if 1
                B=b->d;
                /* Check if the previous number needs to be copied */
                if (B != NULL)
                        {
#if 0
                        /* This lot is an unrolled loop to copy b->top 
                         * BN_ULONGs from B to A
                         */
/*
 * I have nothing against unrolling but it's usually done for
 * several reasons, namely:
 * - minimize percentage of decision making code, i.e. branches;
 * - avoid cache trashing;
 * - make it possible to schedule loads earlier;
 * Now let's examine the code below. The cornerstone of C is
 * "programmer is always right" and that's what we love it for:-)
 * For this very reason C compilers have to be paranoid when it
 * comes to data aliasing and assume the worst. Yeah, but what
 * does it mean in real life? This means that loop body below will
 * be compiled to sequence of loads immediately followed by stores
 * as compiler assumes the worst, something in A==B+1 style. As a
 * result CPU pipeline is going to starve for incoming data. Secondly
 * if A and B happen to share same cache line such code is going to
 * cause severe cache trashing. Both factors have severe impact on
 * performance of modern CPUs and this is the reason why this
 * particular piece of code is #ifdefed away and replaced by more
 * "friendly" version found in #else section below. This comment
 * also applies to BN_copy function.
 *
 *                                      <appro@fy.chalmers.se>
 */
                        for (i=b->top&(~7); i>0; i-=8)
                                {
                                A[0]=B[0]; A[1]=B[1]; A[2]=B[2]; A[3]=B[3];
                                A[4]=B[4]; A[5]=B[5]; A[6]=B[6]; A[7]=B[7];
                                A+=8;
                                B+=8;
                                }
                        switch (b->top&7)
                                {
                        case 7:
                                A[6]=B[6];
                        case 6:
                                A[5]=B[5];
                        case 5:
                                A[4]=B[4];
                        case 4:
                                A[3]=B[3];
                        case 3:
                                A[2]=B[2];
                        case 2:
                                A[1]=B[1];
                        case 1:
                                A[0]=B[0];
                        case 0:
                                /* I need the 'case 0' entry for utrix cc.
                                 * If the optimizer is turned on, it does the
                                 * switch table by doing
                                 * a=top&7
                                 * a--;
                                 * goto jump_table[a];
                                 * If top is 0, this makes us jump to 0xffffffc 
                                 * which is rather bad :-(.
                                 * eric 23-Apr-1998
                                 */
                                ;
                                }
#else
                        for (i=b->top>>2; i>0; i--,A+=4,B+=4)
                                {
                                /*
                                 * The fact that the loop is unrolled
                                 * 4-wise is a tribute to Intel. It's
                                 * the one that doesn't have enough
                                 * registers to accomodate more data.
                                 * I'd unroll it 8-wise otherwise:-)
                                 *
                                 *              <appro@fy.chalmers.se>
                                 */
                                BN_ULONG a0,a1,a2,a3;
                                a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
                                A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
                                }
                        switch (b->top&3)
                                {
                                case 3: A[2]=B[2];
                                case 2: A[1]=B[1];
                                case 1: A[0]=B[0];
                                case 0: ; /* ultrix cc workaround, see above */
                                }
#endif
                        OPENSSL_free(b->d);
                        }

                b->d=a;
                b->dmax=words;

                /* Now need to zero any data between b->top and b->max */

                A= &(b->d[b->top]);
                for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
                        {
                        A[0]=0; A[1]=0; A[2]=0; A[3]=0;
                        A[4]=0; A[5]=0; A[6]=0; A[7]=0;
                        }
                for (i=(b->dmax - b->top)&7; i>0; i--,A++)
                        A[0]=0;
#else
                        memset(A,0,sizeof(BN_ULONG)*(words+1));
                        memcpy(A,b->d,sizeof(b->d[0])*b->top);
                        b->d=a;
                        b->max=words;
#endif
                
/*              memset(&(p[b->max]),0,((words+1)-b->max)*sizeof(BN_ULONG)); */
/*      { int i; for (i=b->max; i<words+1; i++) p[i]=i;} */

                }
        return(b);
        }

#if 0
BIGNUM *BN_dup(const BIGNUM *a)
        {
        BIGNUM *r;

        if (a == NULL) return NULL;

        bn_check_top(a);

        r=BN_new();
        if (r == NULL) return(NULL);
        return((BIGNUM *)BN_copy(r,a));
        }
#endif

BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
        {
        int i;
        BN_ULONG *A;
        const BN_ULONG *B;

        bn_check_top(b);

        if (a == b) return(a);
        if (bn_wexpand(a,b->top) == NULL) return(NULL);

#if 1
        A=a->d;
        B=b->d;
        for (i=b->top>>2; i>0; i--,A+=4,B+=4)
                {
                BN_ULONG a0,a1,a2,a3;
                a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
                A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
                }
        switch (b->top&3)
                {
                case 3: A[2]=B[2];
                case 2: A[1]=B[1];
                case 1: A[0]=B[0];
                case 0: ; /* ultrix cc workaround, see comments in bn_expand2 */
                }
#else
        memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
#endif

/*      memset(&(a->d[b->top]),0,sizeof(a->d[0])*(a->max-b->top));*/
        a->top=b->top;
        if ((a->top == 0) && (a->d != NULL))
                a->d[0]=0;
        a->neg=b->neg;
        return(a);
        }

#if 0
void BN_clear(BIGNUM *a)
        {
        if (a->d != NULL)
                memset(a->d,0,a->dmax*sizeof(a->d[0]));
        a->top=0;
        a->neg=0;
        }

BN_ULONG BN_get_word(BIGNUM *a)
        {
        int i,n;
        BN_ULONG ret=0;

        n=BN_num_bytes(a);
        if (n > sizeof(BN_ULONG))
                return(BN_MASK2);
        for (i=a->top-1; i>=0; i--)
                {
#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
                ret<<=BN_BITS4; /* stops the compiler complaining */
                ret<<=BN_BITS4;
#else
                ret=0;
#endif
                ret|=a->d[i];
                }
        return(ret);
        }
#endif

int BN_set_word(BIGNUM *a, BN_ULONG w)
        {
        int i,n;
        if (bn_expand(a,sizeof(BN_ULONG)*8) == NULL) return(0);

        n=sizeof(BN_ULONG)/BN_BYTES;
        a->neg=0;
        a->top=0;
        a->d[0]=(BN_ULONG)w&BN_MASK2;
        if (a->d[0] != 0) a->top=1;
        for (i=1; i<n; i++)
                {
                /* the following is done instead of
                 * w>>=BN_BITS2 so compilers don't complain
                 * on builds where sizeof(long) == BN_TYPES */
#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
                w>>=BN_BITS4;
                w>>=BN_BITS4;
#else
                w=0;
#endif
                a->d[i]=(BN_ULONG)w&BN_MASK2;
                if (a->d[i] != 0) a->top=i+1;
                }
        return(1);
        }

/* ignore negative */
BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
        {
        unsigned int i,m;
        unsigned int n;
        BN_ULONG l;

#if 0
        if (ret == NULL) ret=BN_new();
#endif
        if (ret == NULL) return(NULL);
        l=0;
        n=len;
        if (n == 0)
                {
                ret->top=0;
                return(ret);
                }
        if (bn_expand(ret,(int)(n+2)*8) == NULL)
                return(NULL);
        i=((n-1)/BN_BYTES)+1;
        m=((n-1)%(BN_BYTES));
        ret->top=i;
        while (n-- > 0)
                {
                l=(l<<8L)| *(s++);
                if (m-- == 0)
                        {
                        ret->d[--i]=l;
                        l=0;
                        m=BN_BYTES-1;
                        }
                }
        /* need to call this due to clear byte at top if avoiding
         * having the top bit set (-ve number) */
        bn_fix_top(ret);
        return(ret);
        }

/* ignore negative */
int BN_bn2bin(const BIGNUM *a, unsigned char *to)
        {
        int n,i;
        BN_ULONG l;

        n=i=BN_num_bytes(a);
        while (i-- > 0)
                {
                l=a->d[i/BN_BYTES];
                *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
                }
        return(n);
        }

int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
        {
        int i;
        BN_ULONG t1,t2,*ap,*bp;

        bn_check_top(a);
        bn_check_top(b);

        i=a->top-b->top;
        if (i != 0) return(i);
        ap=a->d;
        bp=b->d;
        for (i=a->top-1; i>=0; i--)
                {
                t1= ap[i];
                t2= bp[i];
                if (t1 != t2)
                        return(t1 > t2?1:-1);
                }
        return(0);
        }

#if 0
int BN_cmp(const BIGNUM *a, const BIGNUM *b)
        {
        int i;
        int gt,lt;
        BN_ULONG t1,t2;

        if ((a == NULL) || (b == NULL))
                {
                if (a != NULL)
                        return(-1);
                else if (b != NULL)
                        return(1);
                else
                        return(0);
                }

        bn_check_top(a);
        bn_check_top(b);

        if (a->neg != b->neg)
                {
                if (a->neg)
                        return(-1);
                else    return(1);
                }
        if (a->neg == 0)
                { gt=1; lt= -1; }
        else    { gt= -1; lt=1; }

        if (a->top > b->top) return(gt);
        if (a->top < b->top) return(lt);
        for (i=a->top-1; i>=0; i--)
                {
                t1=a->d[i];
                t2=b->d[i];
                if (t1 > t2) return(gt);
                if (t1 < t2) return(lt);
                }
        return(0);
        }

int BN_set_bit(BIGNUM *a, int n)
        {
        int i,j,k;

        i=n/BN_BITS2;
        j=n%BN_BITS2;
        if (a->top <= i)
                {
                if (bn_wexpand(a,i+1) == NULL) return(0);
                for(k=a->top; k<i+1; k++)
                        a->d[k]=0;
                a->top=i+1;
                }

        a->d[i]|=(((BN_ULONG)1)<<j);
        return(1);
        }

int BN_clear_bit(BIGNUM *a, int n)
        {
        int i,j;

        i=n/BN_BITS2;
        j=n%BN_BITS2;
        if (a->top <= i) return(0);

        a->d[i]&=(~(((BN_ULONG)1)<<j));
        bn_fix_top(a);
        return(1);
        }
#endif

int BN_is_bit_set(const BIGNUM *a, int n)
        {
        int i,j;

        if (n < 0) return(0);
        i=n/BN_BITS2;
        j=n%BN_BITS2;
        if (a->top <= i) return(0);
        return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
        }

#if 0
int BN_mask_bits(BIGNUM *a, int n)
        {
        int b,w;

        w=n/BN_BITS2;
        b=n%BN_BITS2;
        if (w >= a->top) return(0);
        if (b == 0)
                a->top=w;
        else
                {
                a->top=w+1;
                a->d[w]&= ~(BN_MASK2<<b);
                }
        bn_fix_top(a);
        return(1);
        }

int bn_cmp_words(BN_ULONG *a, BN_ULONG *b, int n)
        {
        int i;
        BN_ULONG aa,bb;

        aa=a[n-1];
        bb=b[n-1];
        if (aa != bb) return((aa > bb)?1:-1);
        for (i=n-2; i>=0; i--)
                {
                aa=a[i];
                bb=b[i];
                if (aa != bb) return((aa > bb)?1:-1);
                }
        return(0);
        }
#endif
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 <limits.h>
66	#include <stdio.h>
67	#include "bn_lcl.h"
68
69	#if 0
70	BIGNUM *BN_value_one(void)
71	{
72	static BN_ULONG data_one=1L;
73	static BIGNUM const_one={&data_one,1,1,0};
74
75	return(&const_one);
76	}
77	#endif
78
79	int BN_num_bits_word(BN_ULONG l)
80	{
81	static const char bits[256]={
82	0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
83	5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
84	6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
85	6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
86	7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
87	7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
88	7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
89	7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
90	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
91	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
92	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
93	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
94	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
95	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
96	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
97	8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
98	};
99
100	#if defined(SIXTY_FOUR_BIT_LONG)
101	if (l & 0xffffffff00000000L)
102	{
103	if (l & 0xffff000000000000L)
104	{
105	if (l & 0xff00000000000000L)
106	{
107	return(bits[(int)(l>>56)]+56);
108	}
109	else return(bits[(int)(l>>48)]+48);
110	}
111	else
112	{
113	if (l & 0x0000ff0000000000L)
114	{
115	return(bits[(int)(l>>40)]+40);
116	}
117	else return(bits[(int)(l>>32)]+32);
118	}
119	}
120	else
121	#else
122	#ifdef SIXTY_FOUR_BIT
123	if (l & 0xffffffff00000000LL)
124	{
125	if (l & 0xffff000000000000LL)
126	{
127	if (l & 0xff00000000000000LL)
128	{
129	return(bits[(int)(l>>56)]+56);
130	}
131	else return(bits[(int)(l>>48)]+48);
132	}
133	else
134	{
135	if (l & 0x0000ff0000000000LL)
136	{
137	return(bits[(int)(l>>40)]+40);
138	}
139	else return(bits[(int)(l>>32)]+32);
140	}
141	}
142	else
143	#endif
144	#endif
145	{
146	#if defined(THIRTY_TWO_BIT) \|\| defined(SIXTY_FOUR_BIT) \|\| defined(SIXTY_FOUR_BIT_LONG)
147	if (l & 0xffff0000L)
148	{
149	if (l & 0xff000000L)
150	return(bits[(int)(l>>24L)]+24);
151	else return(bits[(int)(l>>16L)]+16);
152	}
153	else
154	#endif
155	{
156	#if defined(SIXTEEN_BIT) \|\| defined(THIRTY_TWO_BIT) \|\| defined(SIXTY_FOUR_BIT) \|\| defined(SIXTY_FOUR_BIT_LONG)
157	if (l & 0xff00L)
158	return(bits[(int)(l>>8)]+8);
159	else
160	#endif
161	return(bits[(int)(l )] );
162	}
163	}
164	}
165
166	int BN_num_bits(const BIGNUM *a)
167	{
168	BN_ULONG l;
169	int i;
170
171	bn_check_top(a);
172
173	if (a->top == 0) return(0);
174	l=a->d[a->top-1];
175	assert(l != 0);
176	i=(a->top-1)*BN_BITS2;
177	return(i+BN_num_bits_word(l));
178	}
179
180	void BN_clear_free(BIGNUM *a)
181	{
182	int i;
183
184	if (a == NULL) return;
185	if (a->d != NULL)
186	{
187	memset(a->d,0,a->dmax*sizeof(a->d[0]));
188	if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
189	OPENSSL_free(a->d);
190	}
191	i=BN_get_flags(a,BN_FLG_MALLOCED);
192	memset(a,0,sizeof(BIGNUM));
193	if (i)
194	OPENSSL_free(a);
195	}
196
197	void BN_free(BIGNUM *a)
198	{
199	if (a == NULL) return;
200	if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
201	OPENSSL_free(a->d);
202	a->flags\|=BN_FLG_FREE; /* REMOVE? */
203	if (a->flags & BN_FLG_MALLOCED)
204	OPENSSL_free(a);
205	}
206
207	void BN_init(BIGNUM *a)
208	{
209	memset(a,0,sizeof(BIGNUM));
210	}
211
212	#if 0
213	BIGNUM *BN_new(void)
214	{
215	BIGNUM *ret;
216
217	if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
218	{
219	BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
220	return(NULL);
221	}
222	ret->flags=BN_FLG_MALLOCED;
223	ret->top=0;
224	ret->neg=0;
225	ret->dmax=0;
226	ret->d=NULL;
227	return(ret);
228	}
229	#endif
230
231	/* This is an internal function that should not be used in applications.
232	* It ensures that 'b' has enough room for a 'words' word number number.
233	* It is mostly used by the various BIGNUM routines. If there is an error,
234	* NULL is returned. If not, 'b' is returned. */
235
236	BIGNUM bn_expand2(BIGNUM b, int words)
237	{
238	BN_ULONG A,a;
239	const BN_ULONG *B;
240	int i;
241
242	bn_check_top(b);
243
244	if (words > b->dmax)
245	{
246	if (words > (INT_MAX/(4*BN_BITS2)))
247	{
248	BNerr(BN_F_BN_EXPAND2,BN_R_BIGNUM_TOO_LONG);
249	return NULL;
250	}
251
252	bn_check_top(b);
253	if (BN_get_flags(b,BN_FLG_STATIC_DATA))
254	{
255	BNerr(BN_F_BN_EXPAND2,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
256	return(NULL);
257	}
258	a=A=(BN_ULONG )OPENSSL_malloc(sizeof(BN_ULONG)(words+1));
259	if (A == NULL)
260	{
261	BNerr(BN_F_BN_EXPAND2,ERR_R_MALLOC_FAILURE);
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	OPENSSL_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
386	#if 0
387	BIGNUM BN_dup(const BIGNUM a)
388	{
389	BIGNUM *r;
390
391	if (a == NULL) return NULL;
392
393	bn_check_top(a);
394
395	r=BN_new();
396	if (r == NULL) return(NULL);
397	return((BIGNUM *)BN_copy(r,a));
398	}
399	#endif
400
401	BIGNUM BN_copy(BIGNUM a, const BIGNUM *b)
402	{
403	int i;
404	BN_ULONG *A;
405	const BN_ULONG *B;
406
407	bn_check_top(b);
408
409	if (a == b) return(a);
410	if (bn_wexpand(a,b->top) == NULL) return(NULL);
411
412	#if 1
413	A=a->d;
414	B=b->d;
415	for (i=b->top>>2; i>0; i--,A+=4,B+=4)
416	{
417	BN_ULONG a0,a1,a2,a3;
418	a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
419	A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
420	}
421	switch (b->top&3)
422	{
423	case 3: A[2]=B[2];
424	case 2: A[1]=B[1];
425	case 1: A[0]=B[0];
426	case 0: ; /* ultrix cc workaround, see comments in bn_expand2 */
427	}
428	#else
429	memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
430	#endif
431
432	/* memset(&(a->d[b->top]),0,sizeof(a->d[0])(a->max-b->top));/
433	a->top=b->top;
434	if ((a->top == 0) && (a->d != NULL))
435	a->d[0]=0;
436	a->neg=b->neg;
437	return(a);
438	}
439
440	#if 0
441	void BN_clear(BIGNUM *a)
442	{
443	if (a->d != NULL)
444	memset(a->d,0,a->dmax*sizeof(a->d[0]));
445	a->top=0;
446	a->neg=0;
447	}
448
449	BN_ULONG BN_get_word(BIGNUM *a)
450	{
451	int i,n;
452	BN_ULONG ret=0;
453
454	n=BN_num_bytes(a);
455	if (n > sizeof(BN_ULONG))
456	return(BN_MASK2);
457	for (i=a->top-1; i>=0; i--)
458	{
459	#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
460	ret<<=BN_BITS4; /* stops the compiler complaining */
461	ret<<=BN_BITS4;
462	#else
463	ret=0;
464	#endif
465	ret\|=a->d[i];
466	}
467	return(ret);
468	}
469	#endif
470
471	int BN_set_word(BIGNUM *a, BN_ULONG w)
472	{
473	int i,n;
474	if (bn_expand(a,sizeof(BN_ULONG)*8) == NULL) return(0);
475
476	n=sizeof(BN_ULONG)/BN_BYTES;
477	a->neg=0;
478	a->top=0;
479	a->d[0]=(BN_ULONG)w&BN_MASK2;
480	if (a->d[0] != 0) a->top=1;
481	for (i=1; i<n; i++)
482	{
483	/* the following is done instead of
484	* w>>=BN_BITS2 so compilers don't complain
485	* on builds where sizeof(long) == BN_TYPES */
486	#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
487	w>>=BN_BITS4;
488	w>>=BN_BITS4;
489	#else
490	w=0;
491	#endif
492	a->d[i]=(BN_ULONG)w&BN_MASK2;
493	if (a->d[i] != 0) a->top=i+1;
494	}
495	return(1);
496	}
497
498	/* ignore negative */
499	BIGNUM BN_bin2bn(const unsigned char s, int len, BIGNUM *ret)
500	{
501	unsigned int i,m;
502	unsigned int n;
503	BN_ULONG l;
504
505	#if 0
506	if (ret == NULL) ret=BN_new();
507	#endif
508	if (ret == NULL) return(NULL);
509	l=0;
510	n=len;
511	if (n == 0)
512	{
513	ret->top=0;
514	return(ret);
515	}
516	if (bn_expand(ret,(int)(n+2)*8) == NULL)
517	return(NULL);
518	i=((n-1)/BN_BYTES)+1;
519	m=((n-1)%(BN_BYTES));
520	ret->top=i;
521	while (n-- > 0)
522	{
523	l=(l<<8L)\| *(s++);
524	if (m-- == 0)
525	{
526	ret->d[--i]=l;
527	l=0;
528	m=BN_BYTES-1;
529	}
530	}
531	/* need to call this due to clear byte at top if avoiding
532	* having the top bit set (-ve number) */
533	bn_fix_top(ret);
534	return(ret);
535	}
536
537	/* ignore negative */
538	int BN_bn2bin(const BIGNUM a, unsigned char to)
539	{
540	int n,i;
541	BN_ULONG l;
542
543	n=i=BN_num_bytes(a);
544	while (i-- > 0)
545	{
546	l=a->d[i/BN_BYTES];
547	(to++)=(unsigned char)(l>>(8(i%BN_BYTES)))&0xff;
548	}
549	return(n);
550	}
551
552	int BN_ucmp(const BIGNUM a, const BIGNUM b)
553	{
554	int i;
555	BN_ULONG t1,t2,ap,bp;
556
557	bn_check_top(a);
558	bn_check_top(b);
559
560	i=a->top-b->top;
561	if (i != 0) return(i);
562	ap=a->d;
563	bp=b->d;
564	for (i=a->top-1; i>=0; i--)
565	{
566	t1= ap[i];
567	t2= bp[i];
568	if (t1 != t2)
569	return(t1 > t2?1:-1);
570	}
571	return(0);
572	}
573
574	#if 0
575	int BN_cmp(const BIGNUM a, const BIGNUM b)
576	{
577	int i;
578	int gt,lt;
579	BN_ULONG t1,t2;
580
581	if ((a == NULL) \|\| (b == NULL))
582	{
583	if (a != NULL)
584	return(-1);
585	else if (b != NULL)
586	return(1);
587	else
588	return(0);
589	}
590
591	bn_check_top(a);
592	bn_check_top(b);
593
594	if (a->neg != b->neg)
595	{
596	if (a->neg)
597	return(-1);
598	else return(1);
599	}
600	if (a->neg == 0)
601	{ gt=1; lt= -1; }
602	else { gt= -1; lt=1; }
603
604	if (a->top > b->top) return(gt);
605	if (a->top < b->top) return(lt);
606	for (i=a->top-1; i>=0; i--)
607	{
608	t1=a->d[i];
609	t2=b->d[i];
610	if (t1 > t2) return(gt);
611	if (t1 < t2) return(lt);
612	}
613	return(0);
614	}
615
616	int BN_set_bit(BIGNUM *a, int n)
617	{
618	int i,j,k;
619
620	i=n/BN_BITS2;
621	j=n%BN_BITS2;
622	if (a->top <= i)
623	{
624	if (bn_wexpand(a,i+1) == NULL) return(0);
625	for(k=a->top; k<i+1; k++)
626	a->d[k]=0;
627	a->top=i+1;
628	}
629
630	a->d[i]\|=(((BN_ULONG)1)<<j);
631	return(1);
632	}
633
634	int BN_clear_bit(BIGNUM *a, int n)
635	{
636	int i,j;
637
638	i=n/BN_BITS2;
639	j=n%BN_BITS2;
640	if (a->top <= i) return(0);
641
642	a->d[i]&=(~(((BN_ULONG)1)<<j));
643	bn_fix_top(a);
644	return(1);
645	}
646	#endif
647
648	int BN_is_bit_set(const BIGNUM *a, int n)
649	{
650	int i,j;
651
652	if (n < 0) return(0);
653	i=n/BN_BITS2;
654	j=n%BN_BITS2;
655	if (a->top <= i) return(0);
656	return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
657	}
658
659	#if 0
660	int BN_mask_bits(BIGNUM *a, int n)
661	{
662	int b,w;
663
664	w=n/BN_BITS2;
665	b=n%BN_BITS2;
666	if (w >= a->top) return(0);
667	if (b == 0)
668	a->top=w;
669	else
670	{
671	a->top=w+1;
672	a->d[w]&= ~(BN_MASK2<<b);
673	}
674	bn_fix_top(a);
675	return(1);
676	}
677
678	int bn_cmp_words(BN_ULONG a, BN_ULONG b, int n)
679	{
680	int i;
681	BN_ULONG aa,bb;
682
683	aa=a[n-1];
684	bb=b[n-1];
685	if (aa != bb) return((aa > bb)?1:-1);
686	for (i=n-2; i>=0; i--)
687	{
688	aa=a[i];
689	bb=b[i];
690	if (aa != bb) return((aa > bb)?1:-1);
691	}
692	return(0);
693	}
694	#endif