X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=crypto%2Fbn%2Fbn_recp.c;h=2e8efb8dae29ac2f5473299ae2bcb9e4752c1f5c;hb=03c4a3a4740f8814130f99cc3c2a983dad556ef8;hp=3ace566b552e4dc88168b5a55f25533526a0f114;hpb=e03ddfae7ea7c27193d3f7c0eaa1d01704647d77;p=oweals%2Fopenssl.git

diff --git a/crypto/bn/bn_recp.c b/crypto/bn/bn_recp.c
index 3ace566b55..2e8efb8dae 100644
--- a/crypto/bn/bn_recp.c
+++ b/crypto/bn/bn_recp.c
@@ -60,8 +60,7 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-void BN_RECP_CTX_init(recp)
-BN_RECP_CTX *recp;
+void BN_RECP_CTX_init(BN_RECP_CTX *recp)
 	{
 	BN_init(&(recp->N));
 	BN_init(&(recp->Nr));
@@ -69,11 +68,11 @@ BN_RECP_CTX *recp;
 	recp->flags=0;
 	}
 
-BN_RECP_CTX *BN_RECP_CTX_new()
+BN_RECP_CTX *BN_RECP_CTX_new(void)
 	{
 	BN_RECP_CTX *ret;
 
-	if ((ret=(BN_RECP_CTX *)Malloc(sizeof(BN_RECP_CTX))) == NULL)
+	if ((ret=(BN_RECP_CTX *)OPENSSL_malloc(sizeof(BN_RECP_CTX))) == NULL)
 		return(NULL);
 
 	BN_RECP_CTX_init(ret);
@@ -81,8 +80,7 @@ BN_RECP_CTX *BN_RECP_CTX_new()
 	return(ret);
 	}
 
-void BN_RECP_CTX_free(recp)
-BN_RECP_CTX *recp;
+void BN_RECP_CTX_free(BN_RECP_CTX *recp)
 	{
 	if(recp == NULL)
 	    return;
@@ -90,76 +88,69 @@ BN_RECP_CTX *recp;
 	BN_free(&(recp->N));
 	BN_free(&(recp->Nr));
 	if (recp->flags & BN_FLG_MALLOCED)
-		Free(recp);
+		OPENSSL_free(recp);
 	}
 
-int BN_RECP_CTX_set(recp,d,ctx)
-BN_RECP_CTX *recp;
-BIGNUM *d;
-BN_CTX *ctx;
+int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)
 	{
-	BN_copy(&(recp->N),d);
+	if (!BN_copy(&(recp->N),d)) return 0;
 	BN_zero(&(recp->Nr));
 	recp->num_bits=BN_num_bits(d);
 	recp->shift=0;
 	return(1);
 	}
 
-int BN_mod_mul_reciprocal(r, x, y, recp, ctx)
-BIGNUM *r;
-BIGNUM *x;
-BIGNUM *y;
-BN_RECP_CTX *recp;
-BN_CTX *ctx;
+int BN_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y,
+	BN_RECP_CTX *recp, BN_CTX *ctx)
 	{
 	int ret=0;
 	BIGNUM *a;
+	const BIGNUM *ca;
 
-	a= &(ctx->bn[ctx->tos++]);
+	BN_CTX_start(ctx);
+	if ((a = BN_CTX_get(ctx)) == NULL) goto err;
 	if (y != NULL)
 		{
 		if (x == y)
 			{ if (!BN_sqr(a,x,ctx)) goto err; }
 		else
 			{ if (!BN_mul(a,x,y,ctx)) goto err; }
+		ca = a;
 		}
 	else
-		a=x; /* Just do the mod */
+		ca=x; /* Just do the mod */
 
-	BN_div_recp(NULL,r,a,recp,ctx);
-	ret=1;
+	ret = BN_div_recp(NULL,r,ca,recp,ctx);
 err:
-	ctx->tos--;
+	BN_CTX_end(ctx);
+	bn_check_top(r);
 	return(ret);
 	}
 
-int BN_div_recp(dv,rem,m,recp,ctx)
-BIGNUM *dv;
-BIGNUM *rem;
-BIGNUM *m;
-BN_RECP_CTX *recp;
-BN_CTX *ctx;
+int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
+	BN_RECP_CTX *recp, BN_CTX *ctx)
 	{
-	int i,j,tos,ret=0,ex;
+	int i,j,ret=0;
 	BIGNUM *a,*b,*d,*r;
 
-	tos=ctx->tos;
-	a= &(ctx->bn[ctx->tos++]);
-	b= &(ctx->bn[ctx->tos++]);
+	BN_CTX_start(ctx);
+	a=BN_CTX_get(ctx);
+	b=BN_CTX_get(ctx);
 	if (dv != NULL)
 		d=dv;
 	else
-		d= &(ctx->bn[ctx->tos++]);
+		d=BN_CTX_get(ctx);
 	if (rem != NULL)
 		r=rem;
 	else
-		r= &(ctx->bn[ctx->tos++]);
+		r=BN_CTX_get(ctx);
+	if (a == NULL || b == NULL || d == NULL || r == NULL) goto err;
 
 	if (BN_ucmp(m,&(recp->N)) < 0)
 		{
 		BN_zero(d);
-		BN_copy(r,m);
-		ctx->tos=tos;
+		if (!BN_copy(r,m)) return 0;
+		BN_CTX_end(ctx);
 		return(1);
 		}
 
@@ -168,40 +159,39 @@ BN_CTX *ctx;
 	 * we need multiply ABCDEF by 3 digests of the reciprocal of ab
 	 *
 	 */
-	i=BN_num_bits(m);
-
-	j=recp->num_bits*2;
-	if (j > i)
-		{
-		i=j;
-		ex=0;
-		}
-	else
-		{
-		ex=(i-j)/2;
-		}
 
-	j=i/2;
+	/* i := max(BN_num_bits(m), 2*BN_num_bits(N)) */
+	i=BN_num_bits(m);
+	j=recp->num_bits<<1;
+	if (j>i) i=j;
 
+	/* Nr := round(2^i / N) */
 	if (i != recp->shift)
 		recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N),
-			i,ctx);
+			i,ctx); /* BN_reciprocal returns i, or -1 for an error */
+	if (recp->shift == -1) goto err;
 
-	if (!BN_rshift(a,m,j-ex)) goto err;
+	/* d := |round(round(m / 2^BN_num_bits(N)) * recp->Nr / 2^(i - BN_num_bits(N)))|
+	 *    = |round(round(m / 2^BN_num_bits(N)) * round(2^i / N) / 2^(i - BN_num_bits(N)))|
+	 *   <= |(m / 2^BN_num_bits(N)) * (2^i / N) * (2^BN_num_bits(N) / 2^i)|
+	 *    = |m/N|
+	 */
+	if (!BN_rshift(a,m,recp->num_bits)) 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-recp->num_bits)) 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)
 			{
-			BNerr(BN_F_BN_MOD_MUL_RECIPROCAL,BN_R_BAD_RECIPROCAL);
+			BNerr(BN_F_BN_DIV_RECP,BN_R_BAD_RECIPROCAL);
 			goto err;
 			}
 		if (!BN_usub(r,r,&(recp->N))) goto err;
@@ -213,7 +203,9 @@ BN_CTX *ctx;
 	d->neg=m->neg^recp->N.neg;
 	ret=1;
 err:
-	ctx->tos=tos;
+	BN_CTX_end(ctx);
+	bn_check_top(dv);
+	bn_check_top(rem);
 	return(ret);
 	} 
 
@@ -221,24 +213,22 @@ err:
  * We actually calculate with an extra word of precision, so
  * we can do faster division if the remainder is not required.
  */
-int BN_reciprocal(r,m,len,ctx)
-BIGNUM *r;
-BIGNUM *m;
-int len;
-BN_CTX *ctx;
+/* r := 2^len / m */
+int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx)
 	{
 	int ret= -1;
-	BIGNUM t;
+	BIGNUM *t;
+
+	BN_CTX_start(ctx);
+	if((t = BN_CTX_get(ctx)) == NULL) goto err;
 
-	BN_init(&t);
+	if (!BN_set_bit(t,len)) goto err;
 
-	BN_zero(&t);
-	if (!BN_set_bit(&t,len)) goto err;
+	if (!BN_div(r,NULL,t,m,ctx)) goto err;
 
-	if (!BN_div(r,NULL,&t,m,ctx)) goto err;
 	ret=len;
 err:
-	BN_free(&t);
+	bn_check_top(r);
+	BN_CTX_end(ctx);
 	return(ret);
 	}
-