Merge pull request #85900 from rnhmjoj/dnscrypt

nixos/dnscrypt-wrapper: use dnscrypt-proxy1

nixos/modules/services/networking/dnscrypt-wrapper.nix

@@ -5,12 +5,20 @@ let
   cfg     = config.services.dnscrypt-wrapper;
   dataDir = "/var/lib/dnscrypt-wrapper";
 
+  mkPath = path: default:
+    if path != null
+      then toString path
+      else default;
+
+  publicKey = mkPath cfg.providerKey.public "${dataDir}/public.key";
+  secretKey = mkPath cfg.providerKey.secret "${dataDir}/secret.key";
+
   daemonArgs = with cfg; [
     "--listen-address=${address}:${toString port}"
     "--resolver-address=${upstream.address}:${toString upstream.port}"
     "--provider-name=${providerName}"
-    "--provider-publickey-file=public.key"
+    "--provider-publickey-file=${publicKey}"
-    "--provider-secretkey-file=secret.key"
+    "--provider-secretkey-file=${secretKey}"
     "--provider-cert-file=${providerName}.crt"
     "--crypt-secretkey-file=${providerName}.key"
   ];
@@ -24,17 +32,19 @@ let
       dnscrypt-wrapper --gen-cert-file \
         --crypt-secretkey-file=${cfg.providerName}.key \
         --provider-cert-file=${cfg.providerName}.crt \
-        --provider-publickey-file=public.key \
+        --provider-publickey-file=${publicKey} \
-        --provider-secretkey-file=secret.key \
+        --provider-secretkey-file=${secretKey} \
         --cert-file-expire-days=${toString cfg.keys.expiration}
     }
 
     cd ${dataDir}
 
     # generate provider keypair (first run only)
-    if [ ! -f public.key ] || [ ! -f secret.key ]; then
+    ${optionalString (cfg.providerKey.public == null || cfg.providerKey.secret == null) ''
+      if [ ! -f ${publicKey} ] || [ ! -f ${secretKey} ]; then
         dnscrypt-wrapper --gen-provider-keypair
       fi
+    ''}
 
     # generate new keys for rotation
     if [ ! -f ${cfg.providerName}.key ] || [ ! -f ${cfg.providerName}.crt ]; then
@@ -64,6 +74,47 @@ let
     fi
   '';
 
+
+  # This is the fork of the original dnscrypt-proxy maintained by Dyne.org.
+  # dnscrypt-proxy2 doesn't provide the `--test` feature that is needed to
+  # correctly implement key rotation of dnscrypt-wrapper ephemeral keys.
+  dnscrypt-proxy1 = pkgs.callPackage
+    ({ stdenv, fetchFromGitHub, autoreconfHook
+    , pkgconfig, libsodium, ldns, openssl, systemd }:
+
+    stdenv.mkDerivation rec {
+      pname = "dnscrypt-proxy";
+      version = "2019-08-20";
+
+      src = fetchFromGitHub {
+        owner = "dyne";
+        repo = "dnscrypt-proxy";
+        rev = "07ac3825b5069adc28e2547c16b1d983a8ed8d80";
+        sha256 = "0c4mq741q4rpmdn09agwmxap32kf0vgfz7pkhcdc5h54chc3g3xy";
+      };
+
+      configureFlags = optional stdenv.isLinux "--with-systemd";
+
+      nativeBuildInputs = [ autoreconfHook pkgconfig ];
+
+      # <ldns/ldns.h> depends on <openssl/ssl.h>
+      buildInputs = [ libsodium openssl.dev ldns ] ++ optional stdenv.isLinux systemd;
+
+      postInstall = ''
+        # Previous versions required libtool files to load plugins; they are
+        # now strictly optional.
+        rm $out/lib/dnscrypt-proxy/*.la
+      '';
+
+      meta = {
+        description = "A tool for securing communications between a client and a DNS resolver";
+        homepage = "https://github.com/dyne/dnscrypt-proxy";
+        license = licenses.isc;
+        maintainers = with maintainers; [ rnhmjoj ];
+        platforms = platforms.linux;
+      };
+    }) { };
+
 in {
 
 
@@ -98,6 +149,26 @@ in {
       '';
     };
 
+    providerKey.public = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      example = "/etc/secrets/public.key";
+      description = ''
+        The filepath to the provider public key. If not given a new
+        provider key pair will be generated on the first run.
+      '';
+    };
+
+    providerKey.secret = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      example = "/etc/secrets/secret.key";
+      description = ''
+        The filepath to the provider secret key. If not given a new
+        provider key pair will be generated on the first run.
+      '';
+    };
+
     upstream.address = mkOption {
       type = types.str;
       default = "127.0.0.1";
@@ -179,7 +250,7 @@ in {
       requires = [ "dnscrypt-wrapper.service" ];
       description = "Rotates DNSCrypt wrapper keys if soon to expire";
 
-      path   = with pkgs; [ dnscrypt-wrapper dnscrypt-proxy gawk ];
+      path   = with pkgs; [ dnscrypt-wrapper dnscrypt-proxy1 gawk ];
       script = rotateKeys;
       serviceConfig.User = "dnscrypt-wrapper";
     };
@@ -196,6 +267,13 @@ in {
       };
     };
 
+    assertions = with cfg; [
+      { assertion = (providerKey.public == null && providerKey.secret == null) ||
+                    (providerKey.secret != null && providerKey.public != null);
+        message = "The secret and public provider key must be set together.";
+      }
+    ];
+
   };
 
   meta.maintainers = with lib.maintainers; [ rnhmjoj ];

nixos/tests/all-tests.nix

@@ -70,6 +70,7 @@ in
   deluge = handleTest ./deluge.nix {};
   dhparams = handleTest ./dhparams.nix {};
   dnscrypt-proxy2 = handleTestOn ["x86_64-linux"] ./dnscrypt-proxy2.nix {};
+  dnscrypt-wrapper = handleTestOn ["x86_64-linux"] ./dnscrypt-wrapper {};
   doas = handleTest ./doas.nix {};
   docker = handleTestOn ["x86_64-linux"] ./docker.nix {};
   oci-containers = handleTestOn ["x86_64-linux"] ./oci-containers.nix {};

nixos/tests/dnscrypt-wrapper/default.nix

@@ -0,0 +1,71 @@
+import ../make-test-python.nix ({ pkgs, ... }: {
+  name = "dnscrypt-wrapper";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ rnhmjoj ];
+  };
+
+  nodes = {
+    server = { lib, ... }:
+      { services.dnscrypt-wrapper = with builtins;
+          { enable = true;
+            address = "192.168.1.1";
+            keys.expiration = 5; # days
+            keys.checkInterval = 2;  # min
+            # The keypair was generated by the command:
+            # dnscrypt-wrapper --gen-provider-keypair \
+            #  --provider-name=2.dnscrypt-cert.server \
+            #  --ext-address=192.168.1.1:5353
+            providerKey.public = toFile "public.key" (readFile ./public.key);
+            providerKey.secret = toFile "secret.key" (readFile ./secret.key);
+          };
+        services.tinydns.enable = true;
+        services.tinydns.data = ''
+          ..:192.168.1.1:a
+          +it.works:1.2.3.4
+        '';
+        networking.firewall.allowedUDPPorts = [ 5353 ];
+        networking.firewall.allowedTCPPorts = [ 5353 ];
+        networking.interfaces.eth1.ipv4.addresses = lib.mkForce
+          [ { address = "192.168.1.1"; prefixLength = 24; } ];
+      };
+
+    client = { lib, ... }:
+      { services.dnscrypt-proxy2.enable = true;
+        services.dnscrypt-proxy2.settings = {
+          server_names = [ "server" ];
+          static.server.stamp = "sdns://AQAAAAAAAAAAEDE5Mi4xNjguMS4xOjUzNTMgFEHYOv0SCKSuqR5CDYa7-58cCBuXO2_5uTSVU9wNQF0WMi5kbnNjcnlwdC1jZXJ0LnNlcnZlcg";
+        };
+        networking.nameservers = [ "127.0.0.1" ];
+        networking.interfaces.eth1.ipv4.addresses = lib.mkForce
+          [ { address = "192.168.1.2"; prefixLength = 24; } ];
+      };
+
+  };
+
+  testScript = ''
+    start_all()
+
+    with subtest("The server can generate the ephemeral keypair"):
+        server.wait_for_unit("dnscrypt-wrapper")
+        server.wait_for_file("/var/lib/dnscrypt-wrapper/2.dnscrypt-cert.server.key")
+        server.wait_for_file("/var/lib/dnscrypt-wrapper/2.dnscrypt-cert.server.crt")
+
+    with subtest("The client can connect to the server"):
+        server.wait_for_unit("tinydns")
+        client.wait_for_unit("dnscrypt-proxy2")
+        assert "1.2.3.4" in client.succeed(
+            "host it.works"
+        ), "The IP address of 'it.works' does not match 1.2.3.4"
+
+    with subtest("The server rotates the ephemeral keys"):
+        # advance time by a little less than 5 days
+        server.succeed("date -s \"$(date --date '4 days 6 hours')\"")
+        client.succeed("date -s \"$(date --date '4 days 6 hours')\"")
+        server.wait_for_file("/var/lib/dnscrypt-wrapper/oldkeys")
+
+    with subtest("The client can still connect to the server"):
+        server.wait_for_unit("dnscrypt-wrapper")
+        client.succeed("host it.works")
+  '';
+})
+

nixos/tests/dnscrypt-wrapper/public.key

@@ -0,0 +1 @@
+A<>:<3A><08><><EFBFBD>B
<0A><><EFBFBD><EFBFBD><1B>;o<><6F>4<EFBFBD>S<EFBFBD>
@]

nixos/tests/dnscrypt-wrapper/secret.key

@@ -0,0 +1 @@
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 ל>׀א¥(ׂ²‡¼J•«÷=<3D>„<EFBFBD>ֱ<EFBFBD>lלA״:‎₪®©B
†»<E280A0><C2BB>—;oש¹4•S<E280A2>
@]