From 3ec7b082be76aaedb91e4a99915a00cd0c50231c Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Thu, 25 Aug 2022 11:41:05 +0200
Subject: [PATCH] Prevent NPEs in file walker

---
 .../backend/FileBasedCertificateDirectoryBackend.java     | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/pgp-cert-d-java/src/main/java/pgp/cert_d/backend/FileBasedCertificateDirectoryBackend.java b/pgp-cert-d-java/src/main/java/pgp/cert_d/backend/FileBasedCertificateDirectoryBackend.java
index def57e6..1ffc550 100644
--- a/pgp-cert-d-java/src/main/java/pgp/cert_d/backend/FileBasedCertificateDirectoryBackend.java
+++ b/pgp-cert-d-java/src/main/java/pgp/cert_d/backend/FileBasedCertificateDirectoryBackend.java
@@ -217,6 +217,10 @@ public class FileBasedCertificateDirectoryBackend implements PGPCertificateDirec
                     }
                 });
 
+                if (subdirectories == null) {
+                    subdirectories = new File[0];
+                }
+
                 for (File subdirectory : subdirectories) {
                     File[] files = subdirectory.listFiles(new FileFilter() {
                         @Override
@@ -225,6 +229,10 @@ public class FileBasedCertificateDirectoryBackend implements PGPCertificateDirec
                         }
                     });
 
+                    if (files == null) {
+                        files = new File[0];
+                    }
+
                     for (File certFile : files) {
                         certificateQueue.add(new Lazy<Certificate>() {
                             @Override