Merge pull request #22356 from Ekleog/redsocks

Redsocks

nixos/modules/module-list.nix

@@ -446,6 +446,7 @@
   ./services/networking/radicale.nix
   ./services/networking/radvd.nix
   ./services/networking/rdnssd.nix
+  ./services/networking/redsocks.nix
   ./services/networking/rpcbind.nix
   ./services/networking/sabnzbd.nix
   ./services/networking/searx.nix

nixos/modules/services/networking/redsocks.nix

@@ -0,0 +1,270 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+  cfg = config.services.redsocks;
+in
+{
+  ##### interface
+  options = {
+    services.redsocks = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Whether to enable redsocks.";
+      };
+
+      log_debug = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Log connection progress.";
+      };
+
+      log_info = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Log start and end of client sessions.";
+      };
+
+      log = mkOption {
+        type = types.str;
+        default = "stderr";
+        description =
+          ''
+            Where to send logs.
+
+            Possible values are:
+              - stderr
+              - file:/path/to/file
+              - syslog:FACILITY where FACILITY is any of "daemon", "local0",
+              etc.
+          '';
+      };
+
+      chroot = mkOption {
+        type = with types; nullOr str;
+        default = null;
+        description =
+          ''
+            Chroot under which to run redsocks. Log file is opened before
+            chroot, but if logging to syslog /etc/localtime may be required.
+          '';
+      };
+
+      redsocks = mkOption {
+        description =
+          ''
+            Local port to proxy associations to be performed.
+
+            The example shows how to configure a proxy to handle port 80 as HTTP
+            relay, and all other ports as HTTP connect.
+          '';
+        example = [
+          { port = 23456; proxy = "1.2.3.4:8080"; type = "http-relay";
+            redirectCondition = "--dport 80";
+            doNotRedirect = [ "-d 1.2.0.0/16" ];
+          }
+          { port = 23457; proxy = "1.2.3.4:8080"; type = "http-connect";
+            redirectCondition = true;
+            doNotRedirect = [ "-d 1.2.0.0/16" ];
+          }
+        ];
+        type = types.listOf (types.submodule { options = {
+          ip = mkOption {
+            type = types.str;
+            default = "127.0.0.1";
+            description =
+              ''
+                IP on which redsocks should listen. Defaults to 127.0.0.1 for
+                security reasons.
+              '';
+          };
+
+          port = mkOption {
+            type = types.int;
+            default = 12345;
+            description = "Port on which redsocks should listen.";
+          };
+
+          proxy = mkOption {
+            type = types.str;
+            description =
+              ''
+                Proxy through which redsocks should forward incoming traffic.
+                Example: "example.org:8080"
+              '';
+          };
+
+          type = mkOption {
+            type = types.enum [ "socks4" "socks5" "http-connect" "http-relay" ];
+            description = "Type of proxy.";
+          };
+
+          login = mkOption {
+            type = with types; nullOr str;
+            default = null;
+            description = "Login to send to proxy.";
+          };
+
+          password = mkOption {
+            type = with types; nullOr str;
+            default = null;
+            description =
+              ''
+                Password to send to proxy. WARNING, this will end up
+                world-readable in the store! Awaiting
+                https://github.com/NixOS/nix/issues/8 to be able to fix.
+              '';
+          };
+
+          disclose_src = mkOption {
+            type = types.enum [ "false" "X-Forwarded-For" "Forwarded_ip"
+                                "Forwarded_ipport" ];
+            default = "false";
+            description =
+              ''
+                Way to disclose client IP to the proxy.
+                  - "false": do not disclose
+                http-connect supports the following ways:
+                  - "X-Forwarded-For": add header "X-Forwarded-For: IP"
+                  - "Forwarded_ip": add header "Forwarded: for=IP" (see RFC7239)
+                  - "Forwarded_ipport": add header 'Forwarded: for="IP:port"'
+              '';
+          };
+
+          redirectInternetOnly = mkOption {
+            type = types.bool;
+            default = true;
+            description = "Exclude all non-globally-routable IPs from redsocks";
+          };
+
+          doNotRedirect = mkOption {
+            type = with types; listOf str;
+            default = [];
+            description =
+              ''
+                Iptables filters that if matched will get the packet off of
+                redsocks.
+              '';
+            example = [ "-d 1.2.3.4" ];
+          };
+
+          redirectCondition = mkOption {
+            type = with types; either bool str;
+            default = false;
+            description =
+              ''
+                Conditions to make outbound packets go through this redsocks
+                instance.
+
+                If set to false, no packet will be forwarded. If set to true,
+                all packets will be forwarded (except packets excluded by
+                redirectInternetOnly).
+
+                If set to a string, this is an iptables filter that will be
+                matched against packets before getting them into redsocks. For
+                example, setting it to "--dport 80" will only send
+                packets to port 80 to redsocks. Note "-p tcp" is always
+                implicitly added, as udp can only be proxied through redudp or
+                the like.
+              '';
+          };
+        };});
+      };
+
+      # TODO: Add support for redudp and dnstc
+    };
+  };
+
+  ##### implementation
+  config = let
+    redsocks_blocks = concatMapStrings (block:
+      let proxy = splitString ":" block.proxy; in
+      ''
+        redsocks {
+          local_ip = ${block.ip};
+          local_port = ${toString block.port};
+
+          ip = ${elemAt proxy 0};
+          port = ${elemAt proxy 1};
+          type = ${block.type};
+
+          ${optionalString (block.login != null) "login = \"${block.login}\";"}
+          ${optionalString (block.password != null) "password = \"${block.password}\";"}
+
+          disclose_src = ${block.disclose_src};
+        }
+      '') cfg.redsocks;
+    configfile = pkgs.writeText "redsocks.conf"
+      ''
+        base {
+          log_debug = ${if cfg.log_debug then "on" else "off" };
+          log_info = ${if cfg.log_info then "on" else "off" };
+          log = ${cfg.log};
+
+          daemon = off;
+          redirector = iptables;
+
+          user = redsocks;
+          group = redsocks;
+          ${optionalString (cfg.chroot != null) "chroot = ${cfg.chroot};"}
+        }
+
+        ${redsocks_blocks}
+      '';
+    internetOnly = [ # TODO: add ipv6-equivalent
+      "-d 0.0.0.0/8"
+      "-d 10.0.0.0/8"
+      "-d 127.0.0.0/8"
+      "-d 169.254.0.0/16"
+      "-d 172.16.0.0/12"
+      "-d 192.168.0.0/16"
+      "-d 224.168.0.0/4"
+      "-d 240.168.0.0/4"
+    ];
+    redCond = block:
+      optionalString (isString block.redirectCondition) block.redirectCondition;
+    iptables = concatImapStrings (idx: block:
+      let chain = "REDSOCKS${toString idx}"; doNotRedirect =
+        concatMapStringsSep "\n"
+          (f: "ip46tables -t nat -A ${chain} ${f} -j RETURN 2>/dev/null || true")
+          (block.doNotRedirect ++ (optionals block.redirectInternetOnly internetOnly));
+      in
+      optionalString (block.redirectCondition != false)
+        ''
+          ip46tables -t nat -F ${chain} 2>/dev/null || true
+          ip46tables -t nat -N ${chain} 2>/dev/null || true
+          ${doNotRedirect}
+          ip46tables -t nat -A ${chain} -p tcp -j REDIRECT --to-ports ${toString block.port}
+
+          # TODO: show errors, when it will be easily possible by a switch to
+          # iptables-restore
+          ip46tables -t nat -A OUTPUT -p tcp ${redCond block} -j ${chain} 2>/dev/null || true
+        ''
+    ) cfg.redsocks;
+  in
+    mkIf cfg.enable {
+      users.groups.redsocks = {};
+      users.users.redsocks = {
+        description = "Redsocks daemon";
+        group = "redsocks";
+        isSystemUser = true;
+      };
+
+      systemd.services.redsocks = {
+        description = "Redsocks";
+        after = [ "network.target" ];
+        wantedBy = [ "multi-user.target" ];
+        script = "${pkgs.redsocks}/bin/redsocks -c ${configfile}";
+      };
+
+      networking.firewall.extraCommands = iptables;
+
+      networking.firewall.extraStopCommands =
+        concatImapStringsSep "\n" (idx: block:
+          let chain = "REDSOCKS${toString idx}"; in
+          optionalString (block.redirectCondition != false)
+            "ip46tables -t nat -D OUTPUT -p tcp ${redCond block} -j ${chain} 2>/dev/null || true"
+        ) cfg.redsocks;
+    };
+}

pkgs/tools/networking/redsocks/default.nix

@@ -0,0 +1,33 @@
+{ stdenv, fetchFromGitHub, libevent }:
+
+let
+  pkg = "redsocks";
+  version = "0.5";
+in
+stdenv.mkDerivation rec {
+  name = "${pkg}-${version}";
+
+  src = fetchFromGitHub {
+    owner = "darkk";
+    repo = pkg;
+    rev = "release-${version}";
+    sha256 = "170cpvvivb6y2kwsqj9ppx5brgds9gkn8mixrnvj8z9c15xhvplm";
+  };
+
+  installPhase =
+    ''
+      mkdir -p $out/{bin,share}
+      mv redsocks $out/bin
+      mv doc $out/share
+    '';
+
+  buildInputs = [ libevent ];
+
+  meta = {
+    description = "Transparent redirector of any TCP connection to proxy";
+    homepage = http://darkk.net.ru/redsocks/;
+    license = stdenv.lib.licenses.asl20;
+    maintainers = [ ];
+    platforms = stdenv.lib.platforms.all;
+  };
+}

pkgs/top-level/all-packages.nix

@@ -3583,6 +3583,8 @@ with pkgs;
 
   redmine = callPackage ../applications/version-management/redmine { };
 
+  redsocks = callPackage ../tools/networking/redsocks { };
+
   rt = callPackage ../servers/rt { };
 
   rtmpdump = callPackage ../tools/video/rtmpdump { };