1 files changed, 26 insertions, 13 deletions

diff --git a/crypto/bn/bn_gcd.c b/crypto/bn/bn_gcd.c
index 071bba3b4b..c80cecdc8d 100644
--- a/crypto/bn/bn_gcd.c
+++ b/crypto/bn/bn_gcd.c
@@ -73,8 +73,11 @@ BN_CTX *ctx;
 	BIGNUM *a,*b,*t;
 	int ret=0;
 
-	a=ctx->bn[ctx->tos];
-	b=ctx->bn[ctx->tos+1];
+	bn_check_top(in_a);
+	bn_check_top(in_b);
+
+	a= &(ctx->bn[ctx->tos]);
+	b= &(ctx->bn[ctx->tos+1]);
 
 	if (BN_copy(a,in_a) == NULL) goto err;
 	if (BN_copy(b,in_b) == NULL) goto err;
@@ -95,6 +98,9 @@ BIGNUM *a,*b;
 	BIGNUM *t;
 	int shifts=0;
 
+	bn_check_top(a);
+	bn_check_top(b);
+
 	for (;;)
 		{
 		if (BN_is_zero(b))
@@ -142,23 +148,30 @@ err:
 	}
 
 /* solves ax == 1 (mod n) */
-BIGNUM *BN_mod_inverse(a, n, ctx)
+BIGNUM *BN_mod_inverse(in, a, n, ctx)
+BIGNUM *in;
 BIGNUM *a;
 BIGNUM *n;
 BN_CTX *ctx;
 	{
 	BIGNUM *A,*B,*X,*Y,*M,*D,*R;
-	BIGNUM *ret=NULL,*T;
+	BIGNUM *T,*ret=NULL;
 	int sign;
 
-	A=ctx->bn[ctx->tos];
-	B=ctx->bn[ctx->tos+1];
-	X=ctx->bn[ctx->tos+2];
-	D=ctx->bn[ctx->tos+3];
-	M=ctx->bn[ctx->tos+4];
-	Y=ctx->bn[ctx->tos+5];
+	bn_check_top(a);
+	bn_check_top(n);
+
+	A= &(ctx->bn[ctx->tos]);
+	B= &(ctx->bn[ctx->tos+1]);
+	X= &(ctx->bn[ctx->tos+2]);
+	D= &(ctx->bn[ctx->tos+3]);
+	M= &(ctx->bn[ctx->tos+4]);
+	Y= &(ctx->bn[ctx->tos+5]);
 	ctx->tos+=6;
-	R=BN_new();
+	if (in == NULL)
+		R=BN_new();
+	else
+		R=in;
 	if (R == NULL) goto err;
 
 	BN_zero(X);
@@ -175,7 +188,7 @@ BN_CTX *ctx;
 		B=M;
 		/* T has a struct, M does not */
 
-		if (!BN_mul(T,D,X)) goto err;
+		if (!BN_mul(T,D,X,ctx)) goto err;
 		if (!BN_add(T,T,Y)) goto err;
 		M=Y;
 		Y=X;
@@ -196,7 +209,7 @@ BN_CTX *ctx;
 		}
 	ret=R;
 err:
-	if ((ret == NULL) && (R != NULL)) BN_free(R);
+	if ((ret == NULL) && (in == NULL)) BN_free(R);
 	ctx->tos-=6;
 	return(ret);
 	}