X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_recp.c;h=3ab486bf59ca82aa348a2139a9c091c6640e8dd5;hp=97ca857ed1b2463428b1504c79e248ecb1d65d5a;hb=b4faea50c35;hpb=dfeab0689f69c0b4bd3480ffd37a9cacc2f17d9c diff --git a/crypto/bn/bn_recp.c b/crypto/bn/bn_recp.c index 97ca857ed1..3ab486bf59 100644 --- a/crypto/bn/bn_recp.c +++ b/crypto/bn/bn_recp.c @@ -5,21 +5,21 @@ * 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: @@ -34,10 +34,10 @@ * 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 + * 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 @@ -49,193 +49,198 @@ * 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.] */ -#include #include "cryptlib.h" #include "bn_lcl.h" -void BN_RECP_CTX_init(recp) -BN_RECP_CTX *recp; - { - BN_init(&(recp->N)); - BN_init(&(recp->Nr)); - recp->num_bits=0; - recp->flags=0; - } - -BN_RECP_CTX *BN_RECP_CTX_new() - { - BN_RECP_CTX *ret; - - if ((ret=(BN_RECP_CTX *)Malloc(sizeof(BN_RECP_CTX))) == NULL) - return(NULL); - - BN_RECP_CTX_init(ret); - ret->flags=BN_FLG_MALLOCED; - return(ret); - } - -void BN_RECP_CTX_free(recp) -BN_RECP_CTX *recp; - { - BN_free(&(recp->N)); - BN_free(&(recp->Nr)); - if (recp->flags & BN_FLG_MALLOCED) - Free(recp); - } - -int BN_RECP_CTX_set(recp,d,ctx) -BN_RECP_CTX *recp; -BIGNUM *d; -BN_CTX *ctx; - { - BN_copy(&(recp->N),d); - BN_zero(&(recp->Nr)); - recp->num_bits=BN_num_bits(d); - recp->shift=0; - return(1); - } - -int BN_mod_mul_reciprocal(r, x, y, recp, ctx) -BIGNUM *r; -BIGNUM *x; -BIGNUM *y; -BN_RECP_CTX *recp; -BN_CTX *ctx; - { - int ret=0; - BIGNUM *a; - - a= &(ctx->bn[ctx->tos++]); - if (y != NULL) - { - if (x == y) - { if (!BN_sqr(a,x,ctx)) goto err; } - else - { if (!BN_mul(a,x,y,ctx)) goto err; } - } - else - a=x; /* Just do the mod */ - - BN_div_recp(NULL,r,a,recp,ctx); - ret=1; -err: - ctx->tos--; - return(ret); - } - -int BN_div_recp(dv,rem,m,recp,ctx) -BIGNUM *dv; -BIGNUM *rem; -BIGNUM *m; -BN_RECP_CTX *recp; -BN_CTX *ctx; - { - int i,j,tos,ret=0,ex; - BIGNUM *a,*b,*d,*r; - - tos=ctx->tos; - a= &(ctx->bn[ctx->tos++]); - b= &(ctx->bn[ctx->tos++]); - if (dv != NULL) - d=dv; - else - d= &(ctx->bn[ctx->tos++]); - if (rem != NULL) - r=rem; - else - r= &(ctx->bn[ctx->tos++]); - - if (BN_ucmp(m,&(recp->N)) < 0) - { - BN_zero(d); - BN_copy(r,m); - ctx->tos=tos; - return(1); - } - - /* We want the remainder - * Given input of ABCDEF / ab - * we need multiply ABCDEF by 3 digests of the reciprocal of ab - * - */ - i=BN_num_bits(m); - - j=recp->num_bits*2; - if (j > i) - { - i=j; - ex=0; - } - else - { - ex=(i-j)/2; - } - - j=i/2; - - if (i != recp->shift) - recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N), - i,ctx); - - if (!BN_rshift(a,m,j-ex)) goto err; - if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err; - if (!BN_rshift(d,b,j+ex)) goto err; - d->neg=0; - if (!BN_mul(b,&(recp->N),d,ctx)) goto err; - if (!BN_usub(r,m,b)) goto err; - r->neg=0; - - j=0; -#if 1 - while (BN_ucmp(r,&(recp->N)) >= 0) - { - if (j++ > 2) - { - BNerr(BN_F_BN_MOD_MUL_RECIPROCAL,BN_R_BAD_RECIPROCAL); - goto err; - } - if (!BN_usub(r,r,&(recp->N))) goto err; - if (!BN_add_word(d,1)) goto err; - } -#endif - - r->neg=BN_is_zero(r)?0:m->neg; - d->neg=m->neg^recp->N.neg; - ret=1; -err: - ctx->tos=tos; - return(ret); - } - -/* len is the expected size of the result - * We actually calculate with an extra word of precision, so - * we can do faster division if the remainder is not required. +void BN_RECP_CTX_init(BN_RECP_CTX *recp) +{ + BN_init(&(recp->N)); + BN_init(&(recp->Nr)); + recp->num_bits = 0; + recp->flags = 0; +} + +BN_RECP_CTX *BN_RECP_CTX_new(void) +{ + BN_RECP_CTX *ret; + + if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) + return (NULL); + + BN_RECP_CTX_init(ret); + ret->flags = BN_FLG_MALLOCED; + return (ret); +} + +void BN_RECP_CTX_free(BN_RECP_CTX *recp) +{ + if (recp == NULL) + return; + + BN_free(&(recp->N)); + BN_free(&(recp->Nr)); + if (recp->flags & BN_FLG_MALLOCED) + OPENSSL_free(recp); +} + +int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx) +{ + if (!BN_copy(&(recp->N), d)) + return 0; + BN_zero(&(recp->Nr)); + recp->num_bits = BN_num_bits(d); + recp->shift = 0; + return (1); +} + +int BN_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y, + BN_RECP_CTX *recp, BN_CTX *ctx) +{ + int ret = 0; + BIGNUM *a; + const BIGNUM *ca; + + BN_CTX_start(ctx); + if ((a = BN_CTX_get(ctx)) == NULL) + goto err; + if (y != NULL) { + if (x == y) { + if (!BN_sqr(a, x, ctx)) + goto err; + } else { + if (!BN_mul(a, x, y, ctx)) + goto err; + } + ca = a; + } else + ca = x; /* Just do the mod */ + + ret = BN_div_recp(NULL, r, ca, recp, ctx); + err: + BN_CTX_end(ctx); + bn_check_top(r); + return (ret); +} + +int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, + BN_RECP_CTX *recp, BN_CTX *ctx) +{ + int i, j, ret = 0; + BIGNUM *a, *b, *d, *r; + + BN_CTX_start(ctx); + a = BN_CTX_get(ctx); + b = BN_CTX_get(ctx); + if (dv != NULL) + d = dv; + else + d = BN_CTX_get(ctx); + if (rem != NULL) + r = rem; + else + r = BN_CTX_get(ctx); + if (a == NULL || b == NULL || d == NULL || r == NULL) + goto err; + + if (BN_ucmp(m, &(recp->N)) < 0) { + BN_zero(d); + if (!BN_copy(r, m)) + return 0; + BN_CTX_end(ctx); + return (1); + } + + /* + * We want the remainder Given input of ABCDEF / ab we need multiply + * ABCDEF by 3 digests of the reciprocal of ab + */ + + /* i := max(BN_num_bits(m), 2*BN_num_bits(N)) */ + i = BN_num_bits(m); + j = recp->num_bits << 1; + if (j > i) + i = j; + + /* Nr := round(2^i / N) */ + if (i != recp->shift) + recp->shift = BN_reciprocal(&(recp->Nr), &(recp->N), i, ctx); + /* BN_reciprocal could have returned -1 for an error */ + if (recp->shift == -1) + goto err; + + /*- + * d := |round(round(m / 2^BN_num_bits(N)) * recp->Nr / 2^(i - BN_num_bits(N)))| + * = |round(round(m / 2^BN_num_bits(N)) * round(2^i / N) / 2^(i - BN_num_bits(N)))| + * <= |(m / 2^BN_num_bits(N)) * (2^i / N) * (2^BN_num_bits(N) / 2^i)| + * = |m/N| + */ + if (!BN_rshift(a, m, recp->num_bits)) + goto err; + if (!BN_mul(b, a, &(recp->Nr), ctx)) + goto err; + if (!BN_rshift(d, b, i - recp->num_bits)) + goto err; + d->neg = 0; + + if (!BN_mul(b, &(recp->N), d, ctx)) + goto err; + if (!BN_usub(r, m, b)) + goto err; + r->neg = 0; + + j = 0; + while (BN_ucmp(r, &(recp->N)) >= 0) { + if (j++ > 2) { + BNerr(BN_F_BN_DIV_RECP, BN_R_BAD_RECIPROCAL); + goto err; + } + if (!BN_usub(r, r, &(recp->N))) + goto err; + if (!BN_add_word(d, 1)) + goto err; + } + + r->neg = BN_is_zero(r) ? 0 : m->neg; + d->neg = m->neg ^ recp->N.neg; + ret = 1; + err: + BN_CTX_end(ctx); + bn_check_top(dv); + bn_check_top(rem); + return (ret); +} + +/* + * len is the expected size of the result We actually calculate with an extra + * word of precision, so we can do faster division if the remainder is not + * required. */ -int BN_reciprocal(r,m,len,ctx) -BIGNUM *r; -BIGNUM *m; -int len; -BN_CTX *ctx; - { - int ret= -1; - BIGNUM t; - - BN_init(&t); - - BN_zero(&t); - if (!BN_set_bit(&t,len)) goto err; - - if (!BN_div(r,NULL,&t,m,ctx)) goto err; - ret=len; -err: - BN_free(&t); - return(ret); - } - +/* r := 2^len / m */ +int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx) +{ + int ret = -1; + BIGNUM *t; + + BN_CTX_start(ctx); + if ((t = BN_CTX_get(ctx)) == NULL) + goto err; + + if (!BN_set_bit(t, len)) + goto err; + + if (!BN_div(r, NULL, t, m, ctx)) + goto err; + + ret = len; + err: + bn_check_top(r); + BN_CTX_end(ctx); + return (ret); +}