From c86f2054f39c7005bc03f91db2d7bcf38f0a92ac Mon Sep 17 00:00:00 2001 From: Geoff Thorpe Date: Thu, 25 Mar 2004 04:32:24 +0000 Subject: [PATCH] Adjust various bignum functions to use BN_CTX for variables instead of locally initialising their own. NB: I've removed the "BN_clear_free()" loops for the exit-paths in some of these functions, and that may be a major part of the performance improvements we're seeing. The "free" part can be removed because we're using BN_CTX. The "clear" part OTOH can be removed because BN_CTX destruction automatically performs this task, so performing it inside functions that may be called repeatedly is wasteful. This is currently safe within openssl due to the fact that BN_CTX objects are never created for longer than a single high-level operation. However, that is only because there's currently no mechanism in openssl for thread-local storage. Beyond that, this might be an issue for applications using the bignum API directly and caching their own BN_CTX objects. The solution is to introduce a flag to BN_CTX_start() that allows its variables to be automatically sanitised on release during BN_CTX_end(). This way any higher-level function (and perhaps the application) can specify this flag in its own BN_CTX_start()/BN_CTX_end() pair, and this will cause inner-loop functions specifying the flag to be ignored so that sanitisation is handled only once back out at the higher level. I will be implementing this in the near future. --- crypto/bn/bn_exp.c | 84 ++++++++++++++++++++------------------------ crypto/bn/bn_exp2.c | 50 ++++++++++++-------------- crypto/bn/bn_mont.c | 35 +++++++++--------- crypto/bn/bn_prime.c | 17 +++++---- crypto/bn/bn_recp.c | 11 +++--- 5 files changed, 95 insertions(+), 102 deletions(-) diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index c11e5afd32..d6bb2b4397 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -231,9 +231,10 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, const BIGNUM *m, BN_CTX *ctx) { int i,j,bits,ret=0,wstart,wend,window,wvalue; - int start=1,ts=0; + int start=1; BIGNUM *aa; - BIGNUM val[TABLE_SIZE]; + /* Table of variables obtained from 'ctx' */ + BIGNUM *val[TABLE_SIZE]; BN_RECP_CTX recp; bits=BN_num_bits(p); @@ -245,7 +246,9 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, } BN_CTX_start(ctx); - if ((aa = BN_CTX_get(ctx)) == NULL) goto err; + aa = BN_CTX_get(ctx); + val[0] = BN_CTX_get(ctx); + if(!aa || !val[0]) goto err; BN_RECP_CTX_init(&recp); if (m->neg) @@ -260,11 +263,8 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, if (BN_RECP_CTX_set(&recp,m,ctx) <= 0) goto err; } - BN_init(&(val[0])); - ts=1; - - if (!BN_nnmod(&(val[0]),a,m,ctx)) goto err; /* 1 */ - if (BN_is_zero(&(val[0]))) + if (!BN_nnmod(val[0],a,m,ctx)) goto err; /* 1 */ + if (BN_is_zero(val[0])) { BN_zero(r); ret = 1; @@ -274,16 +274,16 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, window = BN_window_bits_for_exponent_size(bits); if (window > 1) { - if (!BN_mod_mul_reciprocal(aa,&(val[0]),&(val[0]),&recp,ctx)) + if (!BN_mod_mul_reciprocal(aa,val[0],val[0],&recp,ctx)) goto err; /* 2 */ j=1<<(window-1); for (i=1; i>1]),&recp,ctx)) + if (!BN_mod_mul_reciprocal(r,r,val[wvalue>>1],&recp,ctx)) goto err; /* move the 'window' down further */ @@ -347,8 +347,6 @@ int BN_mod_exp_recp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, ret=1; err: BN_CTX_end(ctx); - for (i=0; ineg || BN_ucmp(a,m) >= 0) { - if (!BN_nnmod(&(val[0]),a,m,ctx)) + if (!BN_nnmod(val[0],a,m,ctx)) goto err; - aa= &(val[0]); + aa= val[0]; } else aa=a; @@ -414,20 +411,20 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, ret = 1; goto err; } - if (!BN_to_montgomery(&(val[0]),aa,mont,ctx)) goto err; /* 1 */ + if (!BN_to_montgomery(val[0],aa,mont,ctx)) goto err; /* 1 */ window = BN_window_bits_for_exponent_size(bits); if (window > 1) { - if (!BN_mod_mul_montgomery(d,&(val[0]),&(val[0]),mont,ctx)) goto err; /* 2 */ + if (!BN_mod_mul_montgomery(d,val[0],val[0],mont,ctx)) goto err; /* 2 */ j=1<<(window-1); for (i=1; i>1]),mont,ctx)) + if (!BN_mod_mul_montgomery(r,r,val[wvalue>>1],mont,ctx)) goto err; /* move the 'window' down further */ @@ -494,8 +491,6 @@ int BN_mod_exp_mont(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, err: if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); BN_CTX_end(ctx); - for (i=0; i 1) { - if (!BN_mod_mul(d,&(val[0]),&(val[0]),m,ctx)) + if (!BN_mod_mul(d,val[0],val[0],m,ctx)) goto err; /* 2 */ j=1<<(window-1); for (i=1; i>1]),m,ctx)) + if (!BN_mod_mul(r,r,val[wvalue>>1],m,ctx)) goto err; /* move the 'window' down further */ @@ -750,8 +744,6 @@ int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, ret=1; err: BN_CTX_end(ctx); - for (i=0; ineg || BN_ucmp(a1,m) >= 0) { - if (!BN_mod(&(val1[0]),a1,m,ctx)) + if (!BN_mod(val1[0],a1,m,ctx)) goto err; - a_mod_m = &(val1[0]); + a_mod_m = val1[0]; } else a_mod_m = a1; @@ -184,32 +184,30 @@ int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1, goto err; } - if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err; + if (!BN_to_montgomery(val1[0],a_mod_m,mont,ctx)) goto err; if (window1 > 1) { - if (!BN_mod_mul_montgomery(d,&(val1[0]),&(val1[0]),mont,ctx)) goto err; + if (!BN_mod_mul_montgomery(d,val1[0],val1[0],mont,ctx)) goto err; j=1<<(window1-1); for (i=1; ineg || BN_ucmp(a2,m) >= 0) { - if (!BN_mod(&(val2[0]),a2,m,ctx)) + if (!BN_mod(val2[0],a2,m,ctx)) goto err; - a_mod_m = &(val2[0]); + a_mod_m = val2[0]; } else a_mod_m = a2; @@ -219,19 +217,19 @@ int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1, ret = 1; goto err; } - if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err; + if (!BN_to_montgomery(val2[0],a_mod_m,mont,ctx)) goto err; if (window2 > 1) { - if (!BN_mod_mul_montgomery(d,&(val2[0]),&(val2[0]),mont,ctx)) goto err; + if (!BN_mod_mul_montgomery(d,val2[0],val2[0],mont,ctx)) goto err; j=1<<(window2-1); for (i=1; i>1]),mont,ctx)) + if (!BN_mod_mul_montgomery(r,r,val1[wvalue1>>1],mont,ctx)) goto err; wvalue1 = 0; r_is_one = 0; @@ -297,7 +295,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1, if (wvalue2 && b == wpos2) { /* wvalue2 is odd and < 2^window2 */ - if (!BN_mod_mul_montgomery(r,r,&(val2[wvalue2>>1]),mont,ctx)) + if (!BN_mod_mul_montgomery(r,r,val2[wvalue2>>1],mont,ctx)) goto err; wvalue2 = 0; r_is_one = 0; @@ -308,10 +306,6 @@ int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1, err: if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont); BN_CTX_end(ctx); - for (i=0; iRR); /* grab RR as a temp */ BN_copy(&(mont->N),mod); /* Set N */ mont->N.neg = 0; @@ -294,22 +296,21 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) tmod.dmax=2; tmod.neg=0; /* Ri = R^-1 mod N*/ - if ((BN_mod_inverse(&Ri,R,&tmod,ctx)) == NULL) + 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_lshift(Ri,Ri,BN_BITS2)) goto err; /* R*Ri */ + if (!BN_is_zero(Ri)) { - if (!BN_sub_word(&Ri,1)) goto err; + 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_set_word(Ri,BN_MASK2)) goto err; /* Ri-- (mod word size) */ } - if (!BN_div(&Ri,NULL,&Ri,&tmod,ctx)) goto err; + if (!BN_div(Ri,NULL,Ri,&tmod,ctx)) goto err; /* Ni = (R*Ri-1)/N, * keep only least significant word: */ - mont->n0 = (Ri.top > 0) ? Ri.d[0] : 0; - BN_free(&Ri); + mont->n0 = (Ri->top > 0) ? Ri->d[0] : 0; } #else /* !MONT_WORD */ { /* bignum version */ @@ -317,13 +318,12 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) 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) + 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; + 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; - BN_free(&Ri); + if (!BN_div(&(mont->Ni),NULL,Ri,&mont->N,ctx)) goto err; } #endif @@ -332,9 +332,10 @@ int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx) if (!BN_set_bit(&(mont->RR),mont->ri*2)) goto err; if (!BN_mod(&(mont->RR),&(mont->RR),&(mont->N),ctx)) goto err; - return(1); + ret = 1; err: - return(0); + BN_CTX_end(ctx); + return ret; } BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from) diff --git a/crypto/bn/bn_prime.c b/crypto/bn/bn_prime.c index 4430e90df5..d03403a600 100644 --- a/crypto/bn/bn_prime.c +++ b/crypto/bn/bn_prime.c @@ -159,15 +159,17 @@ int BN_GENCB_call(BN_GENCB *cb, int a, int b) int BN_generate_prime_ex(BIGNUM *ret, int bits, int safe, const BIGNUM *add, const BIGNUM *rem, BN_GENCB *cb) { - BIGNUM t; + BIGNUM *t; int found=0; int i,j,c1=0; BN_CTX *ctx; int checks = BN_prime_checks_for_size(bits); - BN_init(&t); ctx=BN_CTX_new(); if (ctx == NULL) goto err; + BN_CTX_start(ctx); + t = BN_CTX_get(ctx); + if(!t) goto err; loop: /* make a random number and set the top and bottom bits */ if (add == NULL) @@ -204,7 +206,7 @@ loop: * check that (p-1)/2 is prime. * Since a prime is odd, We just * need to divide by 2 */ - if (!BN_rshift1(&t,ret)) goto err; + if (!BN_rshift1(t,ret)) goto err; for (i=0; i