From: Jeffrey Walton <noloader@gmail.com>
Date: Thu, 5 Mar 2020 21:13:09 +0000 (-0500)
Subject: Fix UBsan finding (GH #71)
X-Git-Tag: 1.8.0-rc.1~62^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ae65df048d7359951fa2ddabc7ae52c7270641e6;p=thirdparty%2Fldns.git

Fix UBsan finding (GH #71)
Also see https://github.com/NLnetLabs/unbound/commit/57bbbfc0e6d9, where Unbound clared a similar finding with uint32_t casts.
---

diff --git a/util.c b/util.c
index 1216134f..fb129e12 100644
--- a/util.c
+++ b/util.c
@@ -295,11 +295,11 @@ ldns_gmtime64_r(int64_t clock, struct tm *result)
 static int64_t
 ldns_serial_arithmitics_time(int32_t time, time_t now)
 {
-	int32_t offset = time - (int32_t) now;
+	/* Casting due to https://github.com/NLnetLabs/ldns/issues/71 */
+	int32_t offset = (int32_t) ((uint32_t) time - (uint32_t) now);
 	return (int64_t) now + offset;
 }
 
-
 struct tm *
 ldns_serial_arithmitics_gmtime_r(int32_t time, time_t now, struct tm *result)
 {