X-Git-Url: https://git.openssl.org/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_exp2.c;h=b3f43cec8c1c1cc949f24c051c5cb7934f65e443;hp=0b3e13f6bc394f7e69c14820db8c4f3745a43b85;hb=c86f2054f39c7005bc03f91db2d7bcf38f0a92ac;hpb=dc434bbcb0f63e03c64be1d977fae6c9411bfc5c

diff --git a/crypto/bn/bn_exp2.c b/crypto/bn/bn_exp2.c
index 0b3e13f6bc..b3f43cec8c 100644
--- a/crypto/bn/bn_exp2.c
+++ b/crypto/bn/bn_exp2.c
@@ -115,14 +115,16 @@
 
 #define TABLE_SIZE	32
 
-int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
-	     BIGNUM *p2, BIGNUM *m, BN_CTX *ctx, BN_MONT_CTX *in_mont)
+int BN_mod_exp2_mont(BIGNUM *rr, const BIGNUM *a1, const BIGNUM *p1,
+	const BIGNUM *a2, const BIGNUM *p2, const BIGNUM *m,
+	BN_CTX *ctx, BN_MONT_CTX *in_mont)
 	{
 	int i,j,bits,b,bits1,bits2,ret=0,wpos1,wpos2,window1,window2,wvalue1,wvalue2;
-	int r_is_one=1,ts1=0,ts2=0;
+	int r_is_one=1;
 	BIGNUM *d,*r;
-	BIGNUM *a_mod_m;
-	BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
+	const BIGNUM *a_mod_m;
+	/* Tables of variables obtained from 'ctx' */
+	BIGNUM *val1[TABLE_SIZE], *val2[TABLE_SIZE];
 	BN_MONT_CTX *mont=NULL;
 
 	bn_check_top(a1);
@@ -140,15 +142,18 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 	bits2=BN_num_bits(p2);
 	if ((bits1 == 0) && (bits2 == 0))
 		{
-		BN_one(rr);
-		return(1);
+		ret = BN_one(rr);
+		return ret;
 		}
+	
 	bits=(bits1 > bits2)?bits1:bits2;
 
 	BN_CTX_start(ctx);
 	d = BN_CTX_get(ctx);
 	r = BN_CTX_get(ctx);
-	if (d == NULL || r == NULL) goto err;
+	val1[0] = BN_CTX_get(ctx);
+	val2[0] = BN_CTX_get(ctx);
+	if(!d || !r || !val1[0] || !val2[0]) goto err;
 
 	if (in_mont != NULL)
 		mont=in_mont;
@@ -164,58 +169,67 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 	/*
 	 * Build table for a1:   val1[i] := a1^(2*i + 1) mod m  for i = 0 .. 2^(window1-1)
 	 */
-	BN_init(&val1[0]);
-	ts1=1;
-	if (BN_ucmp(a1,m) >= 0)
+	if (a1->neg || BN_ucmp(a1,m) >= 0)
 		{
-		if (!BN_mod(&(val1[0]),a1,m,ctx))
+		if (!BN_mod(val1[0],a1,m,ctx))
 			goto err;
-		a_mod_m = &(val1[0]);
+		a_mod_m = val1[0];
 		}
 	else
 		a_mod_m = a1;
-	if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err;
+	if (BN_is_zero(a_mod_m))
+		{
+		BN_zero(rr);
+		ret = 1;
+		goto err;
+		}
+
+	if (!BN_to_montgomery(val1[0],a_mod_m,mont,ctx)) goto err;
 	if (window1 > 1)
 		{
-		if (!BN_mod_mul_montgomery(d,&(val1[0]),&(val1[0]),mont,ctx)) goto err;
+		if (!BN_mod_mul_montgomery(d,val1[0],val1[0],mont,ctx)) goto err;
 
 		j=1<<(window1-1);
 		for (i=1; i<j; i++)
 			{
-			BN_init(&(val1[i]));
-			if (!BN_mod_mul_montgomery(&(val1[i]),&(val1[i-1]),d,mont,ctx))
+			if(((val1[i] = BN_CTX_get(ctx)) == NULL) ||
+					!BN_mod_mul_montgomery(val1[i],val1[i-1],
+						d,mont,ctx))
 				goto err;
 			}
-		ts1=i;
 		}
 
 
 	/*
 	 * Build table for a2:   val2[i] := a2^(2*i + 1) mod m  for i = 0 .. 2^(window2-1)
 	 */
-	BN_init(&val2[0]);
-	ts2=1;
-	if (BN_ucmp(a2,m) >= 0)
+	if (a2->neg || BN_ucmp(a2,m) >= 0)
 		{
-		if (!BN_mod(&(val2[0]),a2,m,ctx))
+		if (!BN_mod(val2[0],a2,m,ctx))
 			goto err;
-		a_mod_m = &(val2[0]);
+		a_mod_m = val2[0];
 		}
 	else
 		a_mod_m = a2;
-	if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err;
+	if (BN_is_zero(a_mod_m))
+		{
+		BN_zero(rr);
+		ret = 1;
+		goto err;
+		}
+	if (!BN_to_montgomery(val2[0],a_mod_m,mont,ctx)) goto err;
 	if (window2 > 1)
 		{
-		if (!BN_mod_mul_montgomery(d,&(val2[0]),&(val2[0]),mont,ctx)) goto err;
+		if (!BN_mod_mul_montgomery(d,val2[0],val2[0],mont,ctx)) goto err;
 
 		j=1<<(window2-1);
 		for (i=1; i<j; i++)
 			{
-			BN_init(&(val2[i]));
-			if (!BN_mod_mul_montgomery(&(val2[i]),&(val2[i-1]),d,mont,ctx))
+			if(((val2[i] = BN_CTX_get(ctx)) == NULL) ||
+					!BN_mod_mul_montgomery(val2[i],val2[i-1],
+						d,mont,ctx))
 				goto err;
 			}
-		ts2=i;
 		}
 
 
@@ -240,7 +254,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 				{
 				/* consider bits b-window1+1 .. b for this window */
 				i = b-window1+1;
-				while (!BN_is_bit_set(p1, i))
+				while (!BN_is_bit_set(p1, i)) /* works for i<0 */
 					i++;
 				wpos1 = i;
 				wvalue1 = 1;
@@ -272,7 +286,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 		if (wvalue1 && b == wpos1)
 			{
 			/* wvalue1 is odd and < 2^window1 */
-			if (!BN_mod_mul_montgomery(r,r,&(val1[wvalue1>>1]),mont,ctx))
+			if (!BN_mod_mul_montgomery(r,r,val1[wvalue1>>1],mont,ctx))
 				goto err;
 			wvalue1 = 0;
 			r_is_one = 0;
@@ -281,7 +295,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 		if (wvalue2 && b == wpos2)
 			{
 			/* wvalue2 is odd and < 2^window2 */
-			if (!BN_mod_mul_montgomery(r,r,&(val2[wvalue2>>1]),mont,ctx))
+			if (!BN_mod_mul_montgomery(r,r,val2[wvalue2>>1],mont,ctx))
 				goto err;
 			wvalue2 = 0;
 			r_is_one = 0;
@@ -292,9 +306,6 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 err:
 	if ((in_mont == NULL) && (mont != NULL)) BN_MONT_CTX_free(mont);
 	BN_CTX_end(ctx);
-	for (i=0; i<ts1; i++)
-		BN_clear_free(&(val1[i]));
-	for (i=0; i<ts2; i++)
-		BN_clear_free(&(val2[i]));
+	bn_check_top(rr);
 	return(ret);
 	}