nix/modules/hive-c0re.nix

@@ -1104,19 +1104,13 @@ in
         NoNewPrivileges = true; # already runs as unprivileged user
         PrivateTmp = true; # uses StateDirectory for tmpfiles, not /tmp
         ProtectHome = true; # HOME = /var/lib/hyperhive; no /home/* access needed
-        # "strict" makes the entire filesystem read-only except for
-        # StateDirectory (/var/lib/hyperhive) and RuntimeDirectory
-        # (/run/hyperhive), which systemd keeps writable. No
-        # ReadWritePaths needed beyond the managed directories because:
-        # - nix is invoked directly (lifecycle, meta, flake_check), but
-        #   NIX_REMOTE=daemon routes all store writes through the host
-        #   daemon — hive-c0re never writes to /nix itself.
-        # - flake.lock ops land in the meta worktree under StateDirectory
-        #   (kept writable by systemd).
-        # - nix build worktrees live in PrivateTmp, not /tmp.
-        # - /etc writes (bind-mount edits) go through hive-priv via the
-        #   privileged socket; /etc/hyperhive/serve.json is read-only.
-        ProtectSystem = "strict";
+        # "full" makes /usr, /etc, /boot read-only. Safe: c0re never
+        # writes to any of those paths directly — all /etc writes (e.g.
+        # /etc/nixos-containers) go through hive-priv, and reads from
+        # /etc/hyperhive/serve.json are read-only. "strict" (everything
+        # read-only) requires carefully auditing ReadWritePaths for every
+        # nix store path c0re touches and is deferred to a follow-up.
+        ProtectSystem = "full";
         ProtectKernelTunables = true; # no sysctl writes
         ProtectKernelLogs = true; # reads logs via systemd-journal group, not /dev/kmsg
         ProtectControlGroups = true; # cgroup writes go through hive-priv, not c0re directly