From: Andy Polyakov <appro@openssl.org>
Date: Wed, 25 Jul 2018 08:29:51 +0000 (+0200)
Subject: bn/bn_mod.c: harmonize BN_mod_add_quick with original implementation.
X-Git-Tag: OpenSSL_1_1_0i~23
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=ed04bcf67426888e8f8556b9eb37e9e2cf4eb04b;p=oweals%2Fopenssl.git

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/6796)

(cherry picked from commit 70a579ae2f37437a1e02331eeaa84e1b68ba021e)
---

diff --git a/crypto/bn/bn_mod.c b/crypto/bn/bn_mod.c
index 99929f9278..e33e3f3eb9 100644
--- a/crypto/bn/bn_mod.c
+++ b/crypto/bn/bn_mod.c
@@ -83,6 +83,7 @@ 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);