From 8db7c14e5632cb139ecdb0eeceaabddc9f00d7a8 Mon Sep 17 00:00:00 2001
From: Thomas Strobel <ts468@cam.ac.uk>
Date: Thu, 10 Sep 2015 18:04:04 +0200
Subject: [PATCH] namecoind nixos module: security enhancements

---
 nixos/modules/misc/ids.nix                    |  2 +-
 .../modules/services/networking/namecoind.nix | 24 ++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/misc/ids.nix b/nixos/modules/misc/ids.nix
index 8ee92f695b46..0d7b1c4f222f 100644
--- a/nixos/modules/misc/ids.nix
+++ b/nixos/modules/misc/ids.nix
@@ -437,7 +437,7 @@
       riak = 205;
       #shout = 206; #unused
       gateone = 207;
-      #namecoin = 208; #unused
+      namecoin = 208;
 
       # When adding a gid, make sure it doesn't match an existing
       # uid. Users and groups with the same name should have equal
diff --git a/nixos/modules/services/networking/namecoind.nix b/nixos/modules/services/networking/namecoind.nix
index 4851abc47481..83fc1ec66679 100644
--- a/nixos/modules/services/networking/namecoind.nix
+++ b/nixos/modules/services/networking/namecoind.nix
@@ -45,7 +45,8 @@ in
         type = types.path;
         example = "/etc/namecoin/wallet.dat";
         description = ''
-          Wallet file.
+          Wallet file. The ownership of the file has to be
+          namecoin:namecoin, and the permissions must be 0640.
         '';
       };
 
@@ -61,6 +62,8 @@ in
           USER=namecoin
           PASSWORD=secret
           </literal>
+          The ownership of the file has to be namecoin:namecoin,
+          and the permissions must be 0640.
         '';
       };
 
@@ -107,10 +110,29 @@ in
         createHome = true;
       };
 
+    users.extraGroups = singleton
+      { name = "namecoin";
+        gid = config.ids.gids.namecoin;
+      };
+
     systemd.services.namecoind = {
         description = "Namecoind Daemon";
         after = [ "network.target" ];
         wantedBy = [ "multi-user.target" ];
+        preStart = ''
+          if [  "$(stat --printf '%u' ${cfg.userFile})" != "${toString config.ids.uids.namecoin}" \
+             -o "$(stat --printf '%g' ${cfg.userFile})" != "${toString config.ids.gids.namecoin}" \
+             -o "$(stat --printf '%a' ${cfg.userFile})" != "640" ]; then
+             echo "ERROR: bad ownership or rights on ${cfg.userFile}" >&2
+             exit 1
+          fi
+          if [  "$(stat --printf '%u' ${cfg.wallet})" != "${toString config.ids.uids.namecoin}" \
+             -o "$(stat --printf '%g' ${cfg.wallet})" != "${toString config.ids.gids.namecoin}" \
+             -o "$(stat --printf '%a' ${cfg.wallet})" != "640" ]; then
+             echo "ERROR: bad ownership or rights on ${cfg.wallet}" >&2
+             exit 1
+          fi
+        '';
         serviceConfig = {
           Type = "simple";
           User = "namecoin";