diff options
author | Arne Schwabe <arne@rfc2549.org> | 2012-04-16 19:21:14 +0200 |
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committer | Arne Schwabe <arne@rfc2549.org> | 2012-04-16 19:21:14 +0200 |
commit | 3e4d8f433239c40311037616b1b8833a06651ae0 (patch) | |
tree | 98ab7fce0d011d34677b0beb762d389cb5c39199 /openssl/crypto/bn/bn_mont.c |
Initial import
Diffstat (limited to 'openssl/crypto/bn/bn_mont.c')
-rw-r--r-- | openssl/crypto/bn/bn_mont.c | 567 |
1 files changed, 567 insertions, 0 deletions
diff --git a/openssl/crypto/bn/bn_mont.c b/openssl/crypto/bn/bn_mont.c new file mode 100644 index 00000000..1a866880 --- /dev/null +++ b/openssl/crypto/bn/bn_mont.c @@ -0,0 +1,567 @@ +/* crypto/bn/bn_mont.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.] + */ +/* ==================================================================== + * Copyright (c) 1998-2006 The OpenSSL Project. All rights reserved. + * + * 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 above 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 acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * openssl-core@openssl.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.openssl.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED 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 OpenSSL PROJECT OR + * ITS 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. + * ==================================================================== + * + * This product includes cryptographic software written by Eric Young + * (eay@cryptsoft.com). This product includes software written by Tim + * Hudson (tjh@cryptsoft.com). + * + */ + +/* + * Details about Montgomery multiplication algorithms can be found at + * http://security.ece.orst.edu/publications.html, e.g. + * http://security.ece.orst.edu/koc/papers/j37acmon.pdf and + * sections 3.8 and 4.2 in http://security.ece.orst.edu/koc/papers/r01rsasw.pdf + */ + +#include <stdio.h> +#include "cryptlib.h" +#include "bn_lcl.h" + +#define MONT_WORD /* use the faster word-based algorithm */ + +#ifdef MONT_WORD +static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont); +#endif + +int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, + BN_MONT_CTX *mont, BN_CTX *ctx) + { + BIGNUM *tmp; + int ret=0; +#if defined(OPENSSL_BN_ASM_MONT) && defined(MONT_WORD) + int num = mont->N.top; + + if (num>1 && a->top==num && b->top==num) + { + if (bn_wexpand(r,num) == NULL) return(0); + if (bn_mul_mont(r->d,a->d,b->d,mont->N.d,mont->n0,num)) + { + r->neg = a->neg^b->neg; + r->top = num; + bn_correct_top(r); + return(1); + } + } +#endif + + BN_CTX_start(ctx); + tmp = BN_CTX_get(ctx); + if (tmp == NULL) goto err; + + bn_check_top(tmp); + if (a == b) + { + if (!BN_sqr(tmp,a,ctx)) goto err; + } + else + { + if (!BN_mul(tmp,a,b,ctx)) goto err; + } + /* reduce from aRR to aR */ +#ifdef MONT_WORD + if (!BN_from_montgomery_word(r,tmp,mont)) goto err; +#else + if (!BN_from_montgomery(r,tmp,mont,ctx)) goto err; +#endif + bn_check_top(r); + ret=1; +err: + BN_CTX_end(ctx); + return(ret); + } + +#ifdef MONT_WORD +static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) + { + BIGNUM *n; + BN_ULONG *ap,*np,*rp,n0,v,*nrp; + int al,nl,max,i,x,ri; + + n= &(mont->N); + /* mont->ri is the size of mont->N in bits (rounded up + to the word size) */ + al=ri=mont->ri/BN_BITS2; + + nl=n->top; + if ((al == 0) || (nl == 0)) { ret->top=0; return(1); } + + max=(nl+al+1); /* allow for overflow (no?) XXX */ + if (bn_wexpand(r,max) == NULL) return(0); + + r->neg^=n->neg; + np=n->d; + rp=r->d; + nrp= &(r->d[nl]); + + /* clear the top words of T */ +#if 1 + for (i=r->top; i<max; i++) /* memset? XXX */ + r->d[i]=0; +#else + memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); +#endif + + r->top=max; + n0=mont->n0[0]; + +#ifdef BN_COUNT + fprintf(stderr,"word BN_from_montgomery_word %d * %d\n",nl,nl); +#endif + for (i=0; i<nl; i++) + { +#ifdef __TANDEM + { + long long t1; + long long t2; + long long t3; + t1 = rp[0] * (n0 & 0177777); + t2 = 037777600000l; + t2 = n0 & t2; + t3 = rp[0] & 0177777; + t2 = (t3 * t2) & BN_MASK2; + t1 = t1 + t2; + v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1); + } +#else + v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2); +#endif + nrp++; + rp++; + if (((nrp[-1]+=v)&BN_MASK2) >= v) + continue; + else + { + if (((++nrp[0])&BN_MASK2) != 0) continue; + if (((++nrp[1])&BN_MASK2) != 0) continue; + for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ; + } + } + bn_correct_top(r); + + /* mont->ri will be a multiple of the word size and below code + * is kind of BN_rshift(ret,r,mont->ri) equivalent */ + if (r->top <= ri) + { + ret->top=0; + return(1); + } + al=r->top-ri; + +#define BRANCH_FREE 1 +#if BRANCH_FREE + if (bn_wexpand(ret,ri) == NULL) return(0); + x=0-(((al-ri)>>(sizeof(al)*8-1))&1); + ret->top=x=(ri&~x)|(al&x); /* min(ri,al) */ + ret->neg=r->neg; + + rp=ret->d; + ap=&(r->d[ri]); + + { + size_t m1,m2; + + v=bn_sub_words(rp,ap,np,ri); + /* this ----------------^^ works even in al<ri case + * thanks to zealous zeroing of top of the vector in the + * beginning. */ + + /* if (al==ri && !v) || al>ri) nrp=rp; else nrp=ap; */ + /* in other words if subtraction result is real, then + * trick unconditional memcpy below to perform in-place + * "refresh" instead of actual copy. */ + m1=0-(size_t)(((al-ri)>>(sizeof(al)*8-1))&1); /* al<ri */ + m2=0-(size_t)(((ri-al)>>(sizeof(al)*8-1))&1); /* al>ri */ + m1|=m2; /* (al!=ri) */ + m1|=(0-(size_t)v); /* (al!=ri || v) */ + m1&=~m2; /* (al!=ri || v) && !al>ri */ + nrp=(BN_ULONG *)(((PTR_SIZE_INT)rp&~m1)|((PTR_SIZE_INT)ap&m1)); + } + + /* 'i<ri' is chosen to eliminate dependency on input data, even + * though it results in redundant copy in al<ri case. */ + for (i=0,ri-=4; i<ri; i+=4) + { + BN_ULONG t1,t2,t3,t4; + + t1=nrp[i+0]; + t2=nrp[i+1]; + t3=nrp[i+2]; ap[i+0]=0; + t4=nrp[i+3]; ap[i+1]=0; + rp[i+0]=t1; ap[i+2]=0; + rp[i+1]=t2; ap[i+3]=0; + rp[i+2]=t3; + rp[i+3]=t4; + } + for (ri+=4; i<ri; i++) + rp[i]=nrp[i], ap[i]=0; + bn_correct_top(r); + bn_correct_top(ret); +#else + if (bn_wexpand(ret,al) == NULL) return(0); + ret->top=al; + ret->neg=r->neg; + + rp=ret->d; + ap=&(r->d[ri]); + al-=4; + for (i=0; i<al; i+=4) + { + BN_ULONG t1,t2,t3,t4; + + t1=ap[i+0]; + t2=ap[i+1]; + t3=ap[i+2]; + t4=ap[i+3]; + rp[i+0]=t1; + rp[i+1]=t2; + rp[i+2]=t3; + rp[i+3]=t4; + } + al+=4; + for (; i<al; i++) + rp[i]=ap[i]; + + if (BN_ucmp(ret, &(mont->N)) >= 0) + { + if (!BN_usub(ret,ret,&(mont->N))) return(0); + } +#endif + bn_check_top(ret); + + return(1); + } +#endif /* MONT_WORD */ + +int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, + BN_CTX *ctx) + { + int retn=0; +#ifdef MONT_WORD + BIGNUM *t; + + BN_CTX_start(ctx); + if ((t = BN_CTX_get(ctx)) && BN_copy(t,a)) + retn = BN_from_montgomery_word(ret,t,mont); + BN_CTX_end(ctx); +#else /* !MONT_WORD */ + BIGNUM *t1,*t2; + + BN_CTX_start(ctx); + t1 = BN_CTX_get(ctx); + t2 = BN_CTX_get(ctx); + if (t1 == NULL || t2 == NULL) goto err; + + if (!BN_copy(t1,a)) goto err; + BN_mask_bits(t1,mont->ri); + + if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err; + BN_mask_bits(t2,mont->ri); + + if (!BN_mul(t1,t2,&mont->N,ctx)) goto err; + if (!BN_add(t2,a,t1)) goto err; + if (!BN_rshift(ret,t2,mont->ri)) goto err; + + if (BN_ucmp(ret, &(mont->N)) >= 0) + { + if (!BN_usub(ret,ret,&(mont->N))) goto err; + } + retn=1; + bn_check_top(ret); + err: + BN_CTX_end(ctx); +#endif /* MONT_WORD */ + return(retn); + } + +BN_MONT_CTX *BN_MONT_CTX_new(void) + { + BN_MONT_CTX *ret; + + if ((ret=(BN_MONT_CTX *)OPENSSL_malloc(sizeof(BN_MONT_CTX))) == NULL) + return(NULL); + + BN_MONT_CTX_init(ret); + ret->flags=BN_FLG_MALLOCED; + return(ret); + } + +void BN_MONT_CTX_init(BN_MONT_CTX *ctx) + { + ctx->ri=0; + BN_init(&(ctx->RR)); + BN_init(&(ctx->N)); + BN_init(&(ctx->Ni)); + ctx->n0[0] = ctx->n0[1] = 0; + ctx->flags=0; + } + +void BN_MONT_CTX_free(BN_MONT_CTX *mont) + { + if(mont == NULL) + return; + + BN_free(&(mont->RR)); + BN_free(&(mont->N)); + BN_free(&(mont->Ni)); + if (mont->flags & BN_FLG_MALLOCED) + OPENSSL_free(mont); + } + +int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) + { + int ret = 0; + BIGNUM *Ri,*R; + + BN_CTX_start(ctx); + if((Ri = BN_CTX_get(ctx)) == NULL) goto err; + R= &(mont->RR); /* grab RR as a temp */ + if (!BN_copy(&(mont->N),mod)) goto err; /* Set N */ + mont->N.neg = 0; + +#ifdef MONT_WORD + { + BIGNUM tmod; + BN_ULONG buf[2]; + + BN_init(&tmod); + tmod.d=buf; + tmod.dmax=2; + tmod.neg=0; + + mont->ri=(BN_num_bits(mod)+(BN_BITS2-1))/BN_BITS2*BN_BITS2; + +#if defined(OPENSSL_BN_ASM_MONT) && (BN_BITS2<=32) + /* Only certain BN_BITS2<=32 platforms actually make use of + * n0[1], and we could use the #else case (with a shorter R + * value) for the others. However, currently only the assembler + * files do know which is which. */ + + BN_zero(R); + if (!(BN_set_bit(R,2*BN_BITS2))) goto err; + + tmod.top=0; + if ((buf[0] = mod->d[0])) tmod.top=1; + if ((buf[1] = mod->top>1 ? mod->d[1] : 0)) tmod.top=2; + + if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL) + goto err; + if (!BN_lshift(Ri,Ri,2*BN_BITS2)) goto err; /* R*Ri */ + if (!BN_is_zero(Ri)) + { + if (!BN_sub_word(Ri,1)) goto err; + } + else /* if N mod word size == 1 */ + { + if (bn_expand(Ri,(int)sizeof(BN_ULONG)*2) == NULL) + goto err; + /* Ri-- (mod double word size) */ + Ri->neg=0; + Ri->d[0]=BN_MASK2; + Ri->d[1]=BN_MASK2; + Ri->top=2; + } + if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; + /* Ni = (R*Ri-1)/N, + * keep only couple of least significant words: */ + mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; + mont->n0[1] = (Ri->top > 1) ? Ri->d[1] : 0; +#else + BN_zero(R); + if (!(BN_set_bit(R,BN_BITS2))) goto err; /* R */ + + buf[0]=mod->d[0]; /* tmod = N mod word size */ + buf[1]=0; + tmod.top = buf[0] != 0 ? 1 : 0; + /* Ri = R^-1 mod N*/ + if ((BN_mod_inverse(Ri,R,&tmod,ctx)) == NULL) + goto err; + if (!BN_lshift(Ri,Ri,BN_BITS2)) goto err; /* R*Ri */ + if (!BN_is_zero(Ri)) + { + if (!BN_sub_word(Ri,1)) goto err; + } + else /* if N mod word size == 1 */ + { + if (!BN_set_word(Ri,BN_MASK2)) goto err; /* Ri-- (mod word size) */ + } + if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; + /* Ni = (R*Ri-1)/N, + * keep only least significant word: */ + mont->n0[0] = (Ri->top > 0) ? Ri->d[0] : 0; + mont->n0[1] = 0; +#endif + } +#else /* !MONT_WORD */ + { /* bignum version */ + mont->ri=BN_num_bits(&mont->N); + BN_zero(R); + if (!BN_set_bit(R,mont->ri)) goto err; /* R = 2^ri */ + /* Ri = R^-1 mod N*/ + if ((BN_mod_inverse(Ri,R,&mont->N,ctx)) == NULL) + goto err; + if (!BN_lshift(Ri,Ri,mont->ri)) goto err; /* R*Ri */ + if (!BN_sub_word(Ri,1)) goto err; + /* Ni = (R*Ri-1) / N */ + if (!BN_div(&(mont->Ni),NULL,Ri,&mont->N,ctx)) goto err; + } +#endif + + /* setup RR for conversions */ + BN_zero(&(mont->RR)); + if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err; + if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err; + + ret = 1; +err: + BN_CTX_end(ctx); + return ret; + } + +BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) + { + if (to == from) return(to); + + if (!BN_copy(&(to->RR),&(from->RR))) return NULL; + if (!BN_copy(&(to->N),&(from->N))) return NULL; + if (!BN_copy(&(to->Ni),&(from->Ni))) return NULL; + to->ri=from->ri; + to->n0[0]=from->n0[0]; + to->n0[1]=from->n0[1]; + return(to); + } + +BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock, + const BIGNUM *mod, BN_CTX *ctx) + { + int got_write_lock = 0; + BN_MONT_CTX *ret; + + CRYPTO_r_lock(lock); + if (!*pmont) + { + CRYPTO_r_unlock(lock); + CRYPTO_w_lock(lock); + got_write_lock = 1; + + if (!*pmont) + { + ret = BN_MONT_CTX_new(); + if (ret && !BN_MONT_CTX_set(ret, mod, ctx)) + BN_MONT_CTX_free(ret); + else + *pmont = ret; + } + } + + ret = *pmont; + + if (got_write_lock) + CRYPTO_w_unlock(lock); + else + CRYPTO_r_unlock(lock); + + return ret; + } |