X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=crypto%2Fbn%2Fbn_recp.c;h=2e8efb8dae29ac2f5473299ae2bcb9e4752c1f5c;hb=22cd982566135496f6f6f804559dfa45b9a02067;hp=72cd69d3fc9c76efbf06c43df8724a221dba6226;hpb=78414a6a897db42c9bcf06aa21c705811ab33921;p=oweals%2Fopenssl.git

diff --git a/crypto/bn/bn_recp.c b/crypto/bn/bn_recp.c
index 72cd69d3fc..2e8efb8dae 100644
--- a/crypto/bn/bn_recp.c
+++ b/crypto/bn/bn_recp.c
@@ -60,66 +60,175 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-int BN_mod_mul_reciprocal(r, x, y, m, i, nb, ctx)
-BIGNUM *r;
-BIGNUM *x;
-BIGNUM *y;
-BIGNUM *m;
-BIGNUM *i;
-int nb;
-BN_CTX *ctx;
+void BN_RECP_CTX_init(BN_RECP_CTX *recp)
 	{
-	int ret=0,j;
-	BIGNUM *a,*b,*c,*d;
+	BN_init(&(recp->N));
+	BN_init(&(recp->Nr));
+	recp->num_bits=0;
+	recp->flags=0;
+	}
+
+BN_RECP_CTX *BN_RECP_CTX_new(void)
+	{
+	BN_RECP_CTX *ret;
+
+	if ((ret=(BN_RECP_CTX *)OPENSSL_malloc(sizeof(BN_RECP_CTX))) == NULL)
+		return(NULL);
+
+	BN_RECP_CTX_init(ret);
+	ret->flags=BN_FLG_MALLOCED;
+	return(ret);
+	}
+
+void BN_RECP_CTX_free(BN_RECP_CTX *recp)
+	{
+	if(recp == NULL)
+	    return;
+
+	BN_free(&(recp->N));
+	BN_free(&(recp->Nr));
+	if (recp->flags & BN_FLG_MALLOCED)
+		OPENSSL_free(recp);
+	}
 
-	a=ctx->bn[ctx->tos++];
-	b=ctx->bn[ctx->tos++];
-	c=ctx->bn[ctx->tos++];
-	d=ctx->bn[ctx->tos++];
+int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)
+	{
+	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(BIGNUM *r, const BIGNUM *x, const BIGNUM *y,
+	BN_RECP_CTX *recp, BN_CTX *ctx)
+	{
+	int ret=0;
+	BIGNUM *a;
+	const BIGNUM *ca;
 
-	if (x == y)
-		{ if (!BN_sqr(a,x,ctx)) goto err; }
+	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
-		{ if (!BN_mul(a,x,y)) goto err; }
-	if (!BN_rshift(d,a,nb)) goto err;
-	if (!BN_mul(b,d,i)) goto err;
-	if (!BN_rshift(c,b,nb)) goto err;
-	if (!BN_mul(b,m,c)) goto err;
-	if (!BN_sub(r,a,b)) goto err;
+		ca=x; /* Just do the mod */
+
+	ret = BN_div_recp(NULL,r,ca,recp,ctx);
+err:
+	BN_CTX_end(ctx);
+	bn_check_top(r);
+	return(ret);
+	}
+
+int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
+	BN_RECP_CTX *recp, BN_CTX *ctx)
+	{
+	int i,j,ret=0;
+	BIGNUM *a,*b,*d,*r;
+
+	BN_CTX_start(ctx);
+	a=BN_CTX_get(ctx);
+	b=BN_CTX_get(ctx);
+	if (dv != NULL)
+		d=dv;
+	else
+		d=BN_CTX_get(ctx);
+	if (rem != NULL)
+		r=rem;
+	else
+		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);
+		if (!BN_copy(r,m)) return 0;
+		BN_CTX_end(ctx);
+		return(1);
+		}
+
+	/* We want the remainder
+	 * Given input of ABCDEF / ab
+	 * we need multiply ABCDEF by 3 digests of the reciprocal of ab
+	 *
+	 */
+
+	/* 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); /* BN_reciprocal returns i, or -1 for an error */
+	if (recp->shift == -1) 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,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;
+
+#if 1
 	j=0;
-	while (BN_cmp(r,m) >= 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_sub(r,r,m)) goto err;
+		if (!BN_usub(r,r,&(recp->N))) goto err;
+		if (!BN_add_word(d,1)) goto err;
 		}
+#endif
 
+	r->neg=BN_is_zero(r)?0:m->neg;
+	d->neg=m->neg^recp->N.neg;
 	ret=1;
 err:
-	ctx->tos-=4;
+	BN_CTX_end(ctx);
+	bn_check_top(dv);
+	bn_check_top(rem);
 	return(ret);
-	}
+	} 
 
-int BN_reciprocal(r, m,ctx)
-BIGNUM *r;
-BIGNUM *m;
-BN_CTX *ctx;
+/* len is the expected size of the result
+ * We actually calculate with an extra word of precision, so
+ * we can do faster division if the remainder is not required.
+ */
+/* r := 2^len / m */
+int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx)
 	{
-	int nm,ret= -1;
+	int ret= -1;
 	BIGNUM *t;
 
-	t=ctx->bn[ctx->tos++];
+	BN_CTX_start(ctx);
+	if((t = BN_CTX_get(ctx)) == NULL) goto err;
 
-	nm=BN_num_bits(m);
-	if (!BN_lshift(t,BN_value_one(),nm*2)) goto err;
+	if (!BN_set_bit(t,len)) goto err;
 
 	if (!BN_div(r,NULL,t,m,ctx)) goto err;
-	ret=nm;
+
+	ret=len;
 err:
-	ctx->tos--;
+	bn_check_top(r);
+	BN_CTX_end(ctx);
 	return(ret);
 	}
-