restrict umask of htpasswd file

changelog/unreleased/issue-318

@@ -0,0 +1,13 @@
+Security: Fix world-readable permissions on new `.htpasswd` files
+
+On startup the rest-server Docker container creates an empty `.htpasswd` file
+if none exists yet. This file was world-readable by default, which can be
+a security risk, even though the file only contains hashed passwords.
+
+This has been fixed such that new `.htpasswd` files are no longer world-readabble.
+
+The permissions of existing `.htpasswd` files must be manually changed
+if relevant in your setup.
+
+https://github.com/restic/rest-server/issues/318
+https://github.com/restic/rest-server/pull/340

docker/entrypoint.sh

@@ -6,7 +6,7 @@ if [ -n "$DISABLE_AUTHENTICATION" ]; then
     OPTIONS="--no-auth $OPTIONS"
 else
     if [ ! -f "$PASSWORD_FILE" ]; then
-        touch "$PASSWORD_FILE"
+        ( umask 027 && touch "$PASSWORD_FILE" )
     fi
 
     if [ ! -s "$PASSWORD_FILE" ]; then