From 3c6ab9aad940e8571745004cf3e4aff8b8a91ed6 Mon Sep 17 00:00:00 2001
From: Nils Larsch <nils@openssl.org>
Date: Sun, 17 Jul 2005 16:08:21 +0000
Subject: [PATCH] bugfix: 0 - w (w != 0) is actually negative

---
 crypto/bn/bn_word.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/crypto/bn/bn_word.c b/crypto/bn/bn_word.c
index 1bcb37e292..bc5905fef4 100644
--- a/crypto/bn/bn_word.c
+++ b/crypto/bn/bn_word.c
@@ -175,7 +175,13 @@ int BN_sub_word(BIGNUM *a, BN_ULONG w)
 	/* degenerate case: w is zero */
 	if (!w) return 1;
 	/* degenerate case: a is zero */
-	if(BN_is_zero(a)) return BN_set_word(a,w);
+	if(BN_is_zero(a))
+		{
+		i = BN_set_word(a,w);
+		if (i != 0)
+			BN_set_negative(a, 1);
+		return i;
+		}
 	/* handle 'a' when negative */
 	if (a->neg)
 		{
-- 
2.25.1