From 6a815969776e3329fdffcc12c77e047e3a15be78 Mon Sep 17 00:00:00 2001
From: Andy Polyakov <appro@openssl.org>
Date: Wed, 25 Jul 2018 10:29:51 +0200
Subject: [PATCH] bn/bn_mod.c: harmonize BN_mod_add_quick with original
 implementation.

New implementation failed to correctly reset r->neg flag. Spotted by
OSSFuzz.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6810)

(cherry picked from commit 70a579ae2f37437a1e02331eeaa84e1b68ba021e)
---
 crypto/bn/bn_mod.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/crypto/bn/bn_mod.c b/crypto/bn/bn_mod.c
index df6f1e2452..23ddd4805d 100644
--- a/crypto/bn/bn_mod.c
+++ b/crypto/bn/bn_mod.c
@@ -197,6 +197,7 @@ int bn_mod_add_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
         ((volatile BN_ULONG *)tp)[i] = 0;
     }
     r->top = mtop;
+    r->neg = 0;
 
     if (tp != storage)
         OPENSSL_free(tp);
-- 
2.25.1