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BN_div_recp fix. I've ran divtest for 10 mins and it didn't exhibit a

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single fault:-) Needless to mention that bnbug.c posted couple of days
ago passes as well...
This commit is contained in:
Andy Polyakov 2000-02-26 16:20:05 +00:00
parent 6ee6fdf555
commit 63933136ab
1 changed files with 8 additions and 18 deletions
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26
crypto/bn/bn_recp.c
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@ -128,7 +128,7 @@ err:
int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp, int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp,
BN_CTX *ctx) BN_CTX *ctx)
{ {
int i,j,ret=0,ex; int i,j,ret=0;
BIGNUM *a,*b,*d,*r; BIGNUM *a,*b,*d,*r;
BN_CTX_start(ctx); BN_CTX_start(ctx);
@ -158,40 +158,30 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp,
* *
*/ */
i=BN_num_bits(m); i=BN_num_bits(m);
if (i%2) i--;
j=recp->num_bits*2; j=recp->num_bits<<1;
if (j > i) if (j>i) i=j;
{ j>>=1;
i=j;
ex=0;
}
else
{
ex=(i-j)/2;
}
j=i/2;
if (i != recp->shift) if (i != recp->shift)
recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N), recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N),
i,ctx); i,ctx);
if (!BN_rshift(a,m,j-ex)) goto err; if (!BN_rshift(a,m,j)) goto err;
if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err; if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err;
if (!BN_rshift(d,b,j+ex)) goto err; if (!BN_rshift(d,b,i-j)) goto err;
d->neg=0; d->neg=0;
if (!BN_mul(b,&(recp->N),d,ctx)) goto err; if (!BN_mul(b,&(recp->N),d,ctx)) goto err;
if (!BN_usub(r,m,b)) goto err; if (!BN_usub(r,m,b)) goto err;
r->neg=0; r->neg=0;
j=0;
#if 1 #if 1
j=0;
while (BN_ucmp(r,&(recp->N)) >= 0) while (BN_ucmp(r,&(recp->N)) >= 0)
{ {
if (j++ > 2) if (j++ > 2)
{ {
#if 1 #if 0
/* work around some bug: /* work around some bug:
-1CC0E177F93042B29D309839F8019DB93404D7A395F1E162 -1CC0E177F93042B29D309839F8019DB93404D7A395F1E162
5383BF622A20B17E1BAA999336988B82B93F5FB77B55B4B68 5383BF622A20B17E1BAA999336988B82B93F5FB77B55B4B68