prototype copyparty reverse proxy config

guests/copyparty.nix

@@ -43,6 +43,10 @@ in
           enable = true;
           inherit (cfg) accountName stateDir;
           passwordFile = "/run/secrets/${cfg.passwordSecret}";
+          reverseProxy = {
+            enable = cfg.reverseProxy.enable;
+            inherit (cfg.reverseProxy) trustedSources;
+          };
           volumes = lib.mapAttrs (_urlPath: volume: {
             inherit (volume) path access flags;
           }) cfg.volumes;
@@ -77,6 +81,12 @@ in
       description = "Host path bind-mounted as Copyparty's state directory.";
     };
 
+    reverseProxy.trustedSources = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ ];
+      description = "IP ranges that may supply Copyparty's forwarded client IP header.";
+    };
+
     volumes = lib.mkOption {
       type = lib.types.attrsOf volumeType;
       default = { };

hosts/pikachu/default.nix

@@ -101,6 +101,7 @@
       enable = true;
       host = "files.alexion.dev";
       backend = "http://10.23.20.126:3923";
+      trustedSources = [ "10.23.20.109/32" ];
     };
     volumes = {
       "/inbox" = {

modules/services/copyparty.nix

@@ -48,6 +48,14 @@ let
     ''}
   '';
 
+  renderTrustedSource = source: "  xff-src: ${source}";
+
+  renderedReverseProxy = lib.optionalString cfg.reverseProxy.enable ''
+      rproxy: 1
+      xff-hdr: x-forwarded-for
+    ${lib.concatStringsSep "\n" (map renderTrustedSource cfg.reverseProxy.trustedSources)}
+  '';
+
   renderedVolumes = lib.concatStringsSep "\n" (lib.mapAttrsToList renderVolume cfg.volumes);
 
   configScript = pkgs.writeShellScript "copyparty-config" ''
@@ -68,7 +76,7 @@ let
       ses-db: ${cfg.stateDir}/sessions.db
       chpw-db: ${cfg.stateDir}/chpw.json
       shr-db: ${cfg.stateDir}/shares.db
-
+    ${renderedReverseProxy}
     [accounts]
       ${cfg.accountName}: $password
 
@@ -128,6 +136,16 @@ in
       default = { };
       description = "Copyparty volumes keyed by their URL path.";
     };
+
+    reverseProxy = {
+      enable = lib.mkEnableOption "reverse-proxy trust settings for Copyparty";
+
+      trustedSources = lib.mkOption {
+        type = lib.types.listOf lib.types.str;
+        default = [ ];
+        description = "IP ranges that may supply Copyparty's forwarded client IP header.";
+      };
+    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -136,6 +154,10 @@ in
         assertion = cfg.volumes != { };
         message = "modules.services.copyparty.volumes must declare at least one served volume.";
       }
+      {
+        assertion = !cfg.reverseProxy.enable || cfg.reverseProxy.trustedSources != [ ];
+        message = "modules.services.copyparty.reverseProxy.trustedSources must name at least one trusted proxy source when reverse-proxy support is enabled.";
+      }
     ];
 
     users.users.${cfg.user} = {

prototypes/copyparty-rproxy-config/run.sh

@@ -0,0 +1,105 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+bold=$'\033[1m'
+reset=$'\033[0m'
+
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT
+mkdir -p "$tmp/state" "$tmp/root"
+
+printf '%sQuestion%s\n' "$bold" "$reset"
+printf 'Does the proposed copyparty reverse-proxy config parse and make a proxied HTTPS-origin login-shaped request pass the CORS gate?\n\n'
+
+printf '%sNix-generated config fragment%s\n' "$bold" "$reset"
+config_script=$(nix eval --raw '.#nixosConfigurations.pikachu.config.containers.copyparty.config.systemd.services.copyparty.serviceConfig.ExecStartPre')
+awk '/\[global\]/{show=1} /\[accounts\]/{show=0} show {print}' "$config_script" | grep -E 'rproxy|xff-hdr|xff-src' || true
+
+pkg=$(nix eval --raw '.#nixosConfigurations.pikachu.config.containers.copyparty.config.modules.services.copyparty.package.outPath')
+
+make_conf() {
+  local file=$1 port=$2 rproxy=$3
+  cat > "$file" <<EOF
+[global]
+  i: 127.0.0.1
+  p: $port
+  usernames
+  http-only
+  no-crt
+  no-thumb
+  no-snap
+  no-rescan
+  ses-db: $tmp/state/sessions-$port.db
+  chpw-db: $tmp/state/chpw-$port.json
+  shr-db: $tmp/state/shares-$port.db
+$rproxy
+
+[accounts]
+  alexion: prototype-password
+
+[/]
+  $tmp/root
+  accs:
+    A: alexion
+EOF
+}
+
+start_server() {
+  local conf=$1 log=$2
+  "$pkg/bin/copyparty" -c "$conf" >"$log" 2>&1 &
+  local pid=$!
+  for _ in {1..50}; do
+    if grep -q 'listening' "$log"; then
+      printf '%s' "$pid"
+      return 0
+    fi
+    sleep 0.1
+  done
+  cat "$log"
+  kill "$pid" 2>/dev/null || true
+  return 1
+}
+
+request() {
+  local label=$1 port=$2 host=$3 proto=${4:-}
+  local headers="$tmp/$label.headers"
+  local body="$tmp/$label.body"
+  local args=(
+    -sS
+    -D "$headers"
+    -o "$body"
+    -X POST
+    -H "Host: $host"
+    -H 'Origin: https://files.alexion.dev'
+    -H 'X-Forwarded-For: 10.23.20.20'
+  )
+  if [[ -n "$proto" ]]; then
+    args+=(-H "X-Forwarded-Proto: $proto")
+  fi
+  curl "${args[@]}" "http://127.0.0.1:$port/?pw=alexion:prototype-password" >/dev/null || true
+  printf '%-24s %s %s\n' "$label" "$(head -1 "$headers" | tr -d '\r')" "$(head -1 "$body")"
+}
+
+rproxy_config='  rproxy: 1
+  xff-hdr: x-forwarded-for
+  xff-src: 127.0.0.1/32'
+make_conf "$tmp/rproxy.conf" 39234 "$rproxy_config"
+pid=$(start_server "$tmp/rproxy.conf" "$tmp/rproxy.log")
+
+printf '\n%sCORS gate probes%s\n' "$bold" "$reset"
+request with-forwarded-https 39234 files.alexion.dev https
+request missing-forwarded-proto 39234 files.alexion.dev
+request wrong-forwarded-host 39234 '10.23.20.126:3923' https
+
+kill "$pid" 2>/dev/null || true
+wait "$pid" 2>/dev/null || true
+
+printf '\n%sRelevant server log%s\n' "$bold" "$reset"
+grep -E 'cors-reject|POST|http405|got proxied request|untrusted source|listening' "$tmp/rproxy.log" || true
+
+printf '\n%sNginx proxy headers%s\n' "$bold" "$reset"
+toplevel=$(nix build --print-out-paths '.#nixosConfigurations.pikachu.config.containers.reverse-proxy.config.system.build.toplevel' --no-link)
+nginx_conf=$(readlink -f "$toplevel/etc/nginx/nginx.conf")
+include_path=$(awk '/server_name files\.alexion\.dev;/{in_server=1} in_server && /include .*recommended-proxy_set_header/{print $2; exit}' "$nginx_conf" | tr -d ';')
+cat "$include_path"