diff --git a/lib/isc/openssl_shim.c b/lib/isc/openssl_shim.c
index 1dcc921f01..3d6cbeed89 100644
--- a/lib/isc/openssl_shim.c
+++ b/lib/isc/openssl_shim.c
@@ -174,7 +174,7 @@ OPENSSL_cleanup(void) {
 
 int
 X509_STORE_up_ref(X509_STORE *store) {
-	return (CRYPTO_add(&store->references, 1, CRYPTO_LOCK_X509_STORE));
+	return (CRYPTO_add(&store->references, 1, CRYPTO_LOCK_X509_STORE) > 0);
 }
 
 #endif /* !HAVE_OPENSSL_CLEANUP */