/* 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 #include #include #include #include "bn_lcl.h" const char *BN_version="Big Number"; /* For a 32 bit machine * 2 - 4 == 128 * 3 - 8 == 256 * 4 - 16 == 512 * 5 - 32 == 1024 * 6 - 64 == 2048 * 7 - 128 == 4096 * 8 - 256 == 8192 */ static int bn_limit_bits=0; static int bn_limit_num=8; /* (1<>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))) free(a->d); } i=BN_get_flags(a,BN_FLG_MALLOCED); memset(a,0,sizeof(BIGNUM)); if (i) free(a); } void BN_free(BIGNUM *a) { if (a == NULL) return; if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA))) free(a->d); a->flags|=BN_FLG_FREE; /* REMOVE? */ if (a->flags & BN_FLG_MALLOCED) free(a); } void BN_init(BIGNUM *a) { memset(a,0,sizeof(BIGNUM)); } BIGNUM *BN_new(void) { BIGNUM *ret; if ((ret=(BIGNUM *)malloc(sizeof(BIGNUM))) == NULL) { return(NULL); } ret->flags=BN_FLG_MALLOCED; ret->top=0; ret->neg=0; ret->dmax=0; ret->d=NULL; return(ret); } /* 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) { bn_check_top(b); if (BN_get_flags(b,BN_FLG_STATIC_DATA)) { return(NULL); } a=A=(BN_ULONG *)malloc(sizeof(BN_ULONG)*(words+1)); if (A == NULL) { 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. * * */ 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:-) * * */ 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 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; itop) == 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); } 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>=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 (ret == NULL) ret=BN_new(); 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); } 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_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)<