core: add new ReadOnlySystem= and ProtectedHome= settings for service units

ReadOnlySystem= uses fs namespaces to mount /usr and /boot read-only for
a service.

ProtectedHome= uses fs namespaces to mount /home and /run/user
inaccessible or read-only for a service.

This patch also enables these settings for all our long-running services.

Together they should be good building block for a minimal service
sandbox, removing the ability for services to modify the operating
system or access the user's private data.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/test/test-ns.c b/src/test/test-ns.c
index ad0d0419c4..71581934cb 100644
--- a/src/test/test-ns.c
+++ b/src/test/test-ns.c
@@ -60,6 +60,8 @@ int main(int argc, char *argv[]) {
                             tmp_dir,
                             var_tmp_dir,
                             true,
+                            PROTECTED_HOME_NO,
+                            false,
                             0);
         if (r < 0) {
                 log_error("Failed to setup namespace: %s", strerror(-r));