From: Dr. Stephen Henson <steve@openssl.org>
Date: Fri, 10 May 2002 22:18:13 +0000 (+0000)
Subject: Fallback to normal multiply if n2 == 8 and dna or dnb is not zero
X-Git-Tag: BEFORE_COMPAQ_PATCH~18
X-Git-Url: https://git.openssl.org/?p=openssl.git;a=commitdiff_plain;h=dc014d43af330e2c492b80db0ce0abaa351e17dc;ds=sidebyside

Fallback to normal multiply if n2 == 8 and dna or dnb is not zero
in bn_mul_recursive.

This is (hopefully) what was triggering bignum errors on 64 bit
platforms and causing the BN_mod_mul test to fail.
---

diff --git a/CHANGES b/CHANGES
index ed2bcead6c..6721f046e3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -55,6 +55,11 @@
  
  Changes between 0.9.6d and 0.9.7  [XX xxx 2002]
 
+  *) Check the values of dna and dnb in bn_mul_recursive before calling
+     bn_mul_comba (a non zero value means the a or b arrays do not contain
+     n2 elements) and fallback to bn_mul_normal if either is not zero.
+     [Steve Henson]
+
   *) Fix escaping of non-ASCII characters when using the -subj option
      of the "openssl req" command line tool. (Robert Joop <joop@fokus.gmd.de>)
      [Lutz Jaenicke]
diff --git a/crypto/bn/bn_mul.c b/crypto/bn/bn_mul.c
index 41ea925b8d..7bffc9c16a 100644
--- a/crypto/bn/bn_mul.c
+++ b/crypto/bn/bn_mul.c
@@ -408,16 +408,22 @@ void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
 		return;
 		}
 #  endif
-	if (n2 == 8)
+	/* Only call bn_mul_comba 8 if n2 == 8 and the
+	 * two arrays are complete [steve]
+	 */
+	if (n2 == 8 && dna == 0 && dnb == 0)
 		{
 		bn_mul_comba8(r,a,b);
 		return; 
 		}
 # endif /* BN_MUL_COMBA */
+	/* Else do normal multiply */
 	if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL)
 		{
-		/* This should not happen */
-		bn_mul_normal(r,a,n2,b,n2);
+		bn_mul_normal(r,a,n2+dna,b,n2+dnb);
+		if ((dna + dnb) < 0)
+			memset(&r[2*n2 + dna + dnb], 0,
+				sizeof(BN_ULONG) * -(dna + dnb));
 		return;
 		}
 	/* r=(a[0]-a[1])*(b[1]-b[0]) */