Commit 63933136 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

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

single fault:-) Needless to mention that bnbug.c posted couple of days
ago passes as well...
parent 6ee6fdf5

crypto/bn/bn_recp.c

+8 −18
Original line number Diff line number Diff line
@@ -128,7 +128,7 @@ err: 
int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp,

	     BN_CTX *ctx)

	{

	int i,j,ret=0,ex;

	int i,j,ret=0;

	BIGNUM *a,*b,*d,*r;



	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);

	if (i%2) i--;



	j=recp->num_bits*2;

	if (j > i)

		{

		i=j;

		ex=0;

		}

	else

		{

		ex=(i-j)/2;

		}



	j=i/2;

	j=recp->num_bits<<1;

	if (j>i) i=j;

	j>>=1;



	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_rshift(a,m,j)) 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;

	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

	j=0;

	while (BN_ucmp(r,&(recp->N)) >= 0)

		{

		if (j++ > 2)

			{

#if 1

#if 0

			/* work around some bug:

			   -1CC0E177F93042B29D309839F8019DB93404D7A395F1E162

			   5383BF622A20B17E1BAA999336988B82B93F5FB77B55B4B68