diff --git a/src/libstrongswan/asn1/asn1.c b/src/libstrongswan/asn1/asn1.c
index 6dd90b7e5..85695bbea 100644
--- a/src/libstrongswan/asn1/asn1.c
+++ b/src/libstrongswan/asn1/asn1.c
@@ -341,7 +341,7 @@ time_t asn1_to_time(const chunk_t *utctime, asn1_t type)
 	tc = mktime(&t);
 
 	/* if no conversion overflow occurred, compensate timezone */
-	return (tc == -1) ? TIME_MAX : tc - timezone - tz_offset;
+	return (tc == -1) ? TIME_MAX : (tc - timezone - tz_offset);
 }
 
 /**
diff --git a/src/pluto/asn1.c b/src/pluto/asn1.c
index f7519d253..30a0dba23 100644
--- a/src/pluto/asn1.c
+++ b/src/pluto/asn1.c
@@ -426,7 +426,7 @@ asn1totime(const chunk_t *utctime, asn1_t type)
     tc = mktime(&t);
 
     /* if no conversion overflow occurred, compensate timezone */
-    return (tc == -1) ? TIME_MAX : tc - timezone - tz_offset;
+    return (tc == -1) ? TIME_MAX : (tc - timezone - tz_offset);
 }
 
 /*