From b64270d1e45fe7f3241e4c9b6ce60d5ac89bc2e9 Mon Sep 17 00:00:00 2001
From: beck <>
Date: Wed, 15 May 2002 02:29:21 +0000
Subject: OpenSSL 0.9.7 stable 2002 05 08 merge

---
 src/lib/libcrypto/bn/bn_exp2.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

(limited to 'src/lib/libcrypto/bn/bn_exp2.c')

diff --git a/src/lib/libcrypto/bn/bn_exp2.c b/src/lib/libcrypto/bn/bn_exp2.c
index 29029f4c72..73ccd58a83 100644
--- a/src/lib/libcrypto/bn/bn_exp2.c
+++ b/src/lib/libcrypto/bn/bn_exp2.c
@@ -115,13 +115,14 @@
 
 #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;
 	BIGNUM *d,*r;
-	BIGNUM *a_mod_m;
+	const BIGNUM *a_mod_m;
 	BIGNUM val1[TABLE_SIZE], val2[TABLE_SIZE];
 	BN_MONT_CTX *mont=NULL;
 
@@ -140,9 +141,10 @@ 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);
@@ -166,7 +168,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 	 */
 	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))
 			goto err;
@@ -174,6 +176,12 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 		}
 	else
 		a_mod_m = a1;
+	if (BN_is_zero(a_mod_m))
+		{
+		ret = BN_zero(rr);
+		goto err;
+		}
+
 	if (!BN_to_montgomery(&(val1[0]),a_mod_m,mont,ctx)) goto err;
 	if (window1 > 1)
 		{
@@ -195,7 +203,7 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 	 */
 	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))
 			goto err;
@@ -203,6 +211,11 @@ int BN_mod_exp2_mont(BIGNUM *rr, BIGNUM *a1, BIGNUM *p1, BIGNUM *a2,
 		}
 	else
 		a_mod_m = a2;
+	if (BN_is_zero(a_mod_m))
+		{
+		ret = BN_zero(rr);
+		goto err;
+		}
 	if (!BN_to_montgomery(&(val2[0]),a_mod_m,mont,ctx)) goto err;
 	if (window2 > 1)
 		{
-- 
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