Commit 6defae04 authored by Geoff Thorpe's avatar Geoff Thorpe
Browse files

Fix some handling in bn_word. This also resolves the issues observed in 

ticket 697 (though uses a different solution than the proposed one). This
problem was initially raised by Otto Moerbeek.

PR: 697
Submitted by: Nils Larsch
Reviewed by: Geoff Thorpe
parent e1064adf

crypto/bn/bn_word.c

+19 −6
Original line number Diff line number Diff line
@@ -85,12 +85,17 @@ BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w) 


BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)

	{

	BN_ULONG ret;

	BN_ULONG ret = 0;

	int i;



	if (a->top == 0) return(0);

	ret=0;

	w &= BN_MASK2;



	if (!w)

		/* actually this an error (division by zero) */

		return 0;

	if (a->top == 0)

		return 0;



	for (i=a->top-1; i>=0; i--)

		{

		BN_ULONG l,d;
@@ -111,6 +116,11 @@ int BN_add_word(BIGNUM *a, BN_ULONG w) 
	BN_ULONG l;

	int i;



	w &= BN_MASK2;



	if (!w)

		return 1;



	if (a->neg)

		{

		a->neg=0;
@@ -119,7 +129,6 @@ int BN_add_word(BIGNUM *a, BN_ULONG w) 
			a->neg=!(a->neg);

		return(i);

		}

	w&=BN_MASK2;

	if (bn_wexpand(a,a->top+1) == NULL) return(0);

	i=0;

	for (;;)
@@ -145,6 +154,11 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w) 
	{

	int i;



	w &= BN_MASK2;



	if (!w)

		return 1;



	if (BN_is_zero(a) || a->neg)

		{

		a->neg=0;
@@ -153,7 +167,6 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w) 
		return(i);

		}



	w&=BN_MASK2;

	if ((a->top == 1) && (a->d[0] < w))

		{

		a->d[0]=w-a->d[0];