Added client authentication

basicswap/bin/prepare.py

@@ -1711,6 +1711,8 @@ def printHelp():
     print(
         "--dashv20compatible      Generate the same DASH wallet seed as for DASH v20 - Use only when importing an existing seed."
     )
+    print("--client-auth-password=  Set or update the password to protect the web UI.")
+    print("--disable-client-auth    Remove password protection from the web UI.")
 
     active_coins = []
     for coin_name in known_coins.keys():
@@ -2114,6 +2116,8 @@ def main():
     disable_tor = False
     initwalletsonly = False
     tor_control_password = None
+    client_auth_pwd_value = None
+    disable_client_auth_flag = False
     extra_opts = {}
 
     if os.getenv("SSL_CERT_DIR", "") == "" and GUIX_SSL_CERT_DIR is not None:
@@ -2246,7 +2250,15 @@ def main():
             if name == "trustremotenode":
                 extra_opts["trust_remote_node"] = toBool(s[1])
                 continue
+            if name == "client-auth-password":
+                client_auth_pwd_value = s[1].strip('"')
+                continue
 
+        if name == "disable-client-auth":
+            disable_client_auth_flag = True
+            continue
+        if len(s) != 2:
+            exitWithError("Unknown argument {}".format(v))
         exitWithError("Unknown argument {}".format(v))
 
     if print_versions:
@@ -2276,6 +2288,34 @@ def main():
         os.makedirs(data_dir)
     config_path = os.path.join(data_dir, cfg.CONFIG_FILENAME)
 
+    config_exists = os.path.exists(config_path)
+    if config_exists and (
+        client_auth_pwd_value is not None or disable_client_auth_flag
+    ):
+        try:
+            settings = load_config(config_path)
+            modified = False
+            if client_auth_pwd_value is not None:
+                settings["client_auth_hash"] = rfc2440_hash_password(
+                    client_auth_pwd_value
+                )
+                logger.info("Client authentication password updated.")
+                modified = True
+            elif disable_client_auth_flag:
+                if "client_auth_hash" in settings:
+                    del settings["client_auth_hash"]
+                    logger.info("Client authentication disabled.")
+                    modified = True
+                else:
+                    logger.info("Client authentication is already disabled.")
+
+            if modified:
+                with open(config_path, "w") as fp:
+                    json.dump(settings, fp, indent=4)
+            return 0
+        except Exception as e:
+            exitWithError(f"Failed to update client auth settings: {e}")
+
     if use_tor_proxy and extra_opts.get("no_tor_proxy", False):
         exitWithError("Can't use --usetorproxy and --notorproxy together")
 
@@ -2916,6 +2956,10 @@ def main():
         tor_control_password = generate_salt(24)
         addTorSettings(settings, tor_control_password)
 
+    if client_auth_pwd_value is not None:
+        settings["client_auth_hash"] = rfc2440_hash_password(client_auth_pwd_value)
+        logger.info("Client authentication password set.")
+
     if not no_cores:
         for c in with_coins:
             prepareCore(c, known_coins[c], settings, data_dir, extra_opts)

basicswap/http_server.py

@@ -1,13 +1,15 @@
 # -*- coding: utf-8 -*-
 
 # Copyright (c) 2019-2024 tecnovert
-# Copyright (c) 2024 The Basicswap developers
+# Copyright (c) 2024-2025 The Basicswap developers
 # Distributed under the MIT software license, see the accompanying
 # file LICENSE or http://www.opensource.org/licenses/mit-license.php.
 
 import os
+import cgi
 import json
 import shlex
+import secrets
 import traceback
 import threading
 import http.client
@@ -16,6 +18,8 @@ from http.server import BaseHTTPRequestHandler, HTTPServer
 from jinja2 import Environment, PackageLoader
 from socket import error as SocketError
 from urllib import parse
+from datetime import datetime, timedelta, timezone
+from http.cookies import SimpleCookie
 
 from . import __version__
 from .util import (
@@ -32,14 +36,14 @@ from .basicswap_util import (
     strTxState,
     strBidState,
 )
+from .util.rfc2440 import verify_rfc2440_password
+
 from .js_server import (
     js_error,
     js_url_to_function,
 )
 from .ui.util import (
     getCoinName,
-    get_data_entry,
-    get_data_entry_or,
     listAvailableCoins,
 )
 from .ui.page_automation import (
@@ -58,6 +62,9 @@ from .ui.page_identity import page_identity
 from .ui.page_smsgaddresses import page_smsgaddresses
 from .ui.page_debug import page_debug
 
+SESSION_COOKIE_NAME = "basicswap_session_id"
+SESSION_DURATION_MINUTES = 60
+
 env = Environment(loader=PackageLoader("basicswap", "templates"))
 env.filters["formatts"] = format_timestamp
 
@@ -120,6 +127,57 @@ def parse_cmd(cmd: str, type_map: str):
 
 
 class HttpHandler(BaseHTTPRequestHandler):
+    def _get_session_cookie(self):
+        if "Cookie" in self.headers:
+            cookie = SimpleCookie(self.headers["Cookie"])
+            if SESSION_COOKIE_NAME in cookie:
+                return cookie[SESSION_COOKIE_NAME].value
+        return None
+
+    def _set_session_cookie(self, session_id):
+        cookie = SimpleCookie()
+        cookie[SESSION_COOKIE_NAME] = session_id
+        cookie[SESSION_COOKIE_NAME]["path"] = "/"
+        cookie[SESSION_COOKIE_NAME]["httponly"] = True
+        cookie[SESSION_COOKIE_NAME]["samesite"] = "Lax"
+        expires = datetime.now(timezone.utc) + timedelta(
+            minutes=SESSION_DURATION_MINUTES
+        )
+        cookie[SESSION_COOKIE_NAME]["expires"] = expires.strftime(
+            "%a, %d %b %Y %H:%M:%S GMT"
+        )
+        return ("Set-Cookie", cookie.output(header="").strip())
+
+    def _clear_session_cookie(self):
+        cookie = SimpleCookie()
+        cookie[SESSION_COOKIE_NAME] = ""
+        cookie[SESSION_COOKIE_NAME]["path"] = "/"
+        cookie[SESSION_COOKIE_NAME]["httponly"] = True
+        cookie[SESSION_COOKIE_NAME]["expires"] = "Thu, 01 Jan 1970 00:00:00 GMT"
+        return ("Set-Cookie", cookie.output(header="").strip())
+
+    def is_authenticated(self):
+        swap_client = self.server.swap_client
+        client_auth_hash = swap_client.settings.get("client_auth_hash")
+
+        if not client_auth_hash:
+            return True
+
+        session_id = self._get_session_cookie()
+        if not session_id:
+            return False
+
+        session_data = self.server.active_sessions.get(session_id)
+        if session_data and session_data["expires"] > datetime.now(timezone.utc):
+            session_data["expires"] = datetime.now(timezone.utc) + timedelta(
+                minutes=SESSION_DURATION_MINUTES
+            )
+            return True
+
+        if session_id in self.server.active_sessions:
+            del self.server.active_sessions[session_id]
+        return False
+
     def log_error(self, format, *args):
         super().log_message(format, *args)
 
@@ -131,18 +189,32 @@ class HttpHandler(BaseHTTPRequestHandler):
         return os.urandom(8).hex()
 
     def checkForm(self, post_string, name, messages):
-        if post_string == "":
+        if not post_string:
             return None
-        form_data = parse.parse_qs(post_string)
-        form_id = form_data[b"formid"][0].decode("utf-8")
-        if self.server.last_form_id.get(name, None) == form_id:
-            messages.append("Prevented double submit for form {}.".format(form_id))
+        post_data_str = (
+            post_string.decode("utf-8")
+            if isinstance(post_string, bytes)
+            else post_string
+        )
+        form_data = parse.parse_qs(post_data_str)
+        form_id_list = form_data.get("formid", [])
+        if not form_id_list:
+            return form_data
+
+        form_id = form_id_list[0]
+        if form_id == self.server.last_form_id.get(name):
+            messages.append("Form already submitted.")
             return None
         self.server.last_form_id[name] = form_id
         return form_data
 
     def render_template(
-        self, template, args_dict, status_code=200, version=__version__
+        self,
+        template,
+        args_dict,
+        status_code=200,
+        version=__version__,
+        extra_headers=None,
     ):
         swap_client = self.server.swap_client
         if swap_client.ws_server:
@@ -153,7 +225,6 @@ class HttpHandler(BaseHTTPRequestHandler):
             args_dict["debug_ui_mode"] = True
         if swap_client.use_tor_proxy:
             args_dict["use_tor_proxy"] = True
-            # TODO: Cache value?
             try:
                 tor_state = get_tor_established_state(swap_client)
                 args_dict["tor_established"] = True if tor_state == "1" else False
@@ -202,7 +273,7 @@ class HttpHandler(BaseHTTPRequestHandler):
 
         args_dict["version"] = version
 
-        self.putHeaders(status_code, "text/html")
+        self.putHeaders(status_code, "text/html", extra_headers=extra_headers)
         return bytes(
             template.render(
                 title=self.server.title,
@@ -214,6 +285,7 @@ class HttpHandler(BaseHTTPRequestHandler):
         )
 
     def render_simple_template(self, template, args_dict):
+        self.putHeaders(200, "text/html")
         return bytes(
             template.render(
                 title=self.server.title,
@@ -222,7 +294,7 @@ class HttpHandler(BaseHTTPRequestHandler):
             "UTF-8",
         )
 
-    def page_info(self, info_str, post_string=None):
+    def page_info(self, info_str, post_string=None, extra_headers=None):
         template = env.get_template("info.html")
         swap_client = self.server.swap_client
         summary = swap_client.getSummary()
@@ -233,6 +305,7 @@ class HttpHandler(BaseHTTPRequestHandler):
                 "message_str": info_str,
                 "summary": summary,
             },
+            extra_headers=extra_headers,
         )
 
     def page_error(self, error_str, post_string=None):
@@ -248,6 +321,68 @@ class HttpHandler(BaseHTTPRequestHandler):
             },
         )
 
+    def page_login(self, url_split, post_string):
+        swap_client = self.server.swap_client
+        template = env.get_template("login.html")
+        err_messages = []
+        extra_headers = []
+
+        if post_string:
+            from io import BytesIO
+
+            fs = cgi.FieldStorage(
+                fp=BytesIO(post_string),
+                headers=self.headers,
+                environ={
+                    "REQUEST_METHOD": "POST",
+                    "CONTENT_TYPE": self.headers["Content-Type"],
+                },
+            )
+            password = fs.getvalue("password")
+
+            client_auth_hash = swap_client.settings.get("client_auth_hash")
+
+            if (
+                client_auth_hash
+                and password
+                and verify_rfc2440_password(client_auth_hash, password)
+            ):
+                session_id = secrets.token_urlsafe(32)
+                expires = datetime.now(timezone.utc) + timedelta(
+                    minutes=SESSION_DURATION_MINUTES
+                )
+                self.server.active_sessions[session_id] = {"expires": expires}
+                cookie_header = self._set_session_cookie(session_id)
+
+                self.send_response(302)
+                self.send_header("Location", "/offers")
+                self.send_header(cookie_header[0], cookie_header[1])
+                self.end_headers()
+                return b""
+            else:
+                err_messages.append("Invalid password.")
+                clear_cookie_header = self._clear_session_cookie()
+                extra_headers.append(clear_cookie_header)
+
+        if swap_client.settings.get("client_auth_hash") and self.is_authenticated():
+            self.send_response(302)
+            self.send_header("Location", "/offers")
+            self.end_headers()
+            return b""
+
+        return self.render_template(
+            template,
+            {
+                "title_str": "Login",
+                "err_messages": err_messages,
+                "summary": {},
+                "encrypted": False,
+                "locked": False,
+            },
+            status_code=401 if post_string and err_messages else 200,
+            extra_headers=extra_headers,
+        )
+
     def page_explorers(self, url_split, post_string):
         swap_client = self.server.swap_client
         swap_client.checkSystemStatus()
@@ -259,16 +394,12 @@ class HttpHandler(BaseHTTPRequestHandler):
         messages = []
         err_messages = []
         form_data = self.checkForm(post_string, "explorers", err_messages)
-        if form_data:
+        if form_data and form_data is not None:
 
-            explorer = form_data[b"explorer"][0].decode("utf-8")
-            action = form_data[b"action"][0].decode("utf-8")
+            explorer = form_data.get("explorer", ["-1"])[0]
+            action = form_data.get("action", ["-1"])[0]
+            args = form_data.get("args", [""])[0]
 
-            args = (
-                ""
-                if b"args" not in form_data
-                else form_data[b"args"][0].decode("utf-8")
-            )
             try:
                 c, e = explorer.split("_")
                 exp = swap_client.coin_clients[Coins(int(c))]["explorers"][int(e)]
@@ -316,12 +447,12 @@ class HttpHandler(BaseHTTPRequestHandler):
         messages = []
         err_messages = []
         form_data = self.checkForm(post_string, "rpc", err_messages)
-        if form_data:
+        if form_data and form_data is not None:  # Check if not None (double submit)
             try:
-                call_type = get_data_entry_or(form_data, "call_type", "cli")
-                type_map = get_data_entry_or(form_data, "type_map", "")
+                call_type = form_data.get("call_type", ["cli"])[0]
+                type_map = form_data.get("type_map", [""])[0]
                 try:
-                    coin_type_selected = get_data_entry(form_data, "coin_type")
+                    coin_type_selected = form_data.get("coin_type", ["-1"])[0]
                     coin_type_split = coin_type_selected.split(",")
                     coin_type = Coins(int(coin_type_split[0]))
                     coin_variant = int(coin_type_split[1])
@@ -332,7 +463,7 @@ class HttpHandler(BaseHTTPRequestHandler):
                     call_type = "http"
 
                 try:
-                    cmd = get_data_entry(form_data, "cmd")
+                    cmd = form_data.get("cmd", [""])[0]
                 except Exception:
                     raise ValueError("Invalid command")
                 if coin_type in (Coins.XMR, Coins.WOW):
@@ -457,6 +588,7 @@ class HttpHandler(BaseHTTPRequestHandler):
 
     def page_shutdown(self, url_split, post_string):
         swap_client = self.server.swap_client
+        extra_headers = []
 
         if len(url_split) > 2:
             token = url_split[2]
@@ -464,9 +596,15 @@ class HttpHandler(BaseHTTPRequestHandler):
             if token != expect_token:
                 return self.page_info("Unexpected token, still running.")
 
+        session_id = self._get_session_cookie()
+        if session_id and session_id in self.server.active_sessions:
+            del self.server.active_sessions[session_id]
+        clear_cookie_header = self._clear_session_cookie()
+        extra_headers.append(clear_cookie_header)
+
         swap_client.stopRunning()
 
-        return self.page_info("Shutting down")
+        return self.page_info("Shutting down", extra_headers=extra_headers)
 
     def page_index(self, url_split):
         swap_client = self.server.swap_client
@@ -487,20 +625,36 @@ class HttpHandler(BaseHTTPRequestHandler):
             },
         )
 
-    def putHeaders(self, status_code, content_type):
+    def putHeaders(self, status_code, content_type, extra_headers=None):
         self.send_response(status_code)
         if self.server.allow_cors:
             self.send_header("Access-Control-Allow-Origin", "*")
         self.send_header("Content-Type", content_type)
+        if extra_headers:
+            for header_tuple in extra_headers:
+                self.send_header(header_tuple[0], header_tuple[1])
         self.end_headers()
 
-    def handle_http(self, status_code, path, post_string="", is_json=False):
+    def handle_http(self, status_code, path, post_string=b"", is_json=False):
         swap_client = self.server.swap_client
         parsed = parse.urlparse(self.path)
         url_split = parsed.path.split("/")
-        if post_string == "" and len(parsed.query) > 0:
-            post_string = parsed.query
-        if len(url_split) > 1 and url_split[1] == "json":
+        page = url_split[1] if len(url_split) > 1 else ""
+
+        exempt_pages = ["login", "static", "json", "error", "info"]
+        if page not in exempt_pages:
+            if not self.is_authenticated():
+                self.send_response(302)
+                self.send_header("Location", "/login")
+                clear_cookie_header = self._clear_session_cookie()
+                self.send_header(clear_cookie_header[0], clear_cookie_header[1])
+                self.end_headers()
+                return b""
+
+        if not post_string and len(parsed.query) > 0:
+            post_string = parsed.query.encode("utf-8")
+
+        if page == "json":
             try:
                 self.putHeaders(status_code, "text/plain")
                 func = js_url_to_function(url_split)
@@ -508,20 +662,23 @@ class HttpHandler(BaseHTTPRequestHandler):
             except Exception as ex:
                 if swap_client.debug is True:
                     swap_client.log.error(traceback.format_exc())
+                self.putHeaders(500, "text/plain")
                 return js_error(self, str(ex))
 
-        if len(url_split) > 1 and url_split[1] == "static":
+        if page == "static":
             try:
                 static_path = os.path.join(os.path.dirname(__file__), "static")
+                content = None
+                mime_type = ""
+                filepath = ""
                 if len(url_split) > 3 and url_split[2] == "sequence_diagrams":
-                    with open(
-                        os.path.join(static_path, "sequence_diagrams", url_split[3]),
-                        "rb",
-                    ) as fp:
-                        self.putHeaders(status_code, "image/svg+xml")
-                        return fp.read()
+                    filepath = os.path.join(
+                        static_path, "sequence_diagrams", url_split[3]
+                    )
+                    mime_type = "image/svg+xml"
                 elif len(url_split) > 3 and url_split[2] == "images":
                     filename = os.path.join(*url_split[3:])
+                    filepath = os.path.join(static_path, "images", filename)
                     _, extension = os.path.splitext(filename)
                     mime_type = {
                         ".svg": "image/svg+xml",
@@ -530,25 +687,25 @@ class HttpHandler(BaseHTTPRequestHandler):
                         ".gif": "image/gif",
                         ".ico": "image/x-icon",
                     }.get(extension, "")
-                    if mime_type == "":
-                        raise ValueError("Unknown file type " + filename)
-                    with open(
-                        os.path.join(static_path, "images", filename), "rb"
-                    ) as fp:
-                        self.putHeaders(status_code, mime_type)
-                        return fp.read()
                 elif len(url_split) > 3 and url_split[2] == "css":
                     filename = os.path.join(*url_split[3:])
-                    with open(os.path.join(static_path, "css", filename), "rb") as fp:
-                        self.putHeaders(status_code, "text/css; charset=utf-8")
-                        return fp.read()
+                    filepath = os.path.join(static_path, "css", filename)
+                    mime_type = "text/css; charset=utf-8"
                 elif len(url_split) > 3 and url_split[2] == "js":
                     filename = os.path.join(*url_split[3:])
-                    with open(os.path.join(static_path, "js", filename), "rb") as fp:
-                        self.putHeaders(status_code, "application/javascript")
-                        return fp.read()
+                    filepath = os.path.join(static_path, "js", filename)
+                    mime_type = "application/javascript"
                 else:
                     return self.page_404(url_split)
+
+                if mime_type == "" or not filepath:
+                    raise ValueError("Unknown file type or path")
+
+                with open(filepath, "rb") as fp:
+                    content = fp.read()
+                self.putHeaders(status_code, mime_type)
+                return content
+
             except FileNotFoundError:
                 return self.page_404(url_split)
             except Exception as ex:
@@ -560,6 +717,8 @@ class HttpHandler(BaseHTTPRequestHandler):
             if len(url_split) > 1:
                 page = url_split[1]
 
+                if page == "login":
+                    return self.page_login(url_split, post_string)
                 if page == "active":
                     return self.page_active(url_split, post_string)
                 if page == "wallets":
@@ -632,7 +791,8 @@ class HttpHandler(BaseHTTPRequestHandler):
             self.server.swap_client.log.debug(f"do_GET SocketError {e}")
 
     def do_POST(self):
-        post_string = self.rfile.read(int(self.headers.get("Content-Length")))
+        content_length = int(self.headers.get("Content-Length", 0))
+        post_string = self.rfile.read(content_length)
 
         is_json = True if "json" in self.headers.get("Content-Type", "") else False
         response = self.handle_http(200, self.path, post_string, is_json)
@@ -664,6 +824,7 @@ class HttpThread(threading.Thread, HTTPServer):
         self.title = "BasicSwap - " + __version__
         self.last_form_id = dict()
         self.session_tokens = dict()
+        self.active_sessions = {}
         self.env = env
         self.msg_id_counter = 0
 
@@ -673,18 +834,22 @@ class HttpThread(threading.Thread, HTTPServer):
     def stop(self):
         self.stop_event.set()
 
-        # Send fake request
-        conn = http.client.HTTPConnection(self.host_name, self.port_no)
-        conn.connect()
-        conn.request("GET", "/none")
-        response = conn.getresponse()
-        _ = response.read()
-        conn.close()
+        try:
+            conn = http.client.HTTPConnection(self.host_name, self.port_no, timeout=0.5)
+            conn.request("GET", "/shutdown_ping")
+            conn.close()
+        except Exception:
+            pass
 
     def serve_forever(self):
+        self.timeout = 1
         while not self.stop_event.is_set():
             self.handle_request()
         self.socket.close()
+        self.swap_client.log.info("HTTP server stopped.")
 
     def run(self):
+        self.swap_client.log.info(
+            f"Starting HTTP server on {self.host_name}:{self.port_no}"
+        )
         self.serve_forever()

basicswap/templates/login.html

@@ -0,0 +1,72 @@
+{% from 'style.html' import circular_error_messages_svg %}
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <link type="text/css" media="all" href="/static/css/libs/flowbite.min.css" rel="stylesheet" />
+    <link type="text/css" media="all" href="/static/css/libs/tailwind.min.css" rel="stylesheet">
+    <link type="text/css" media="all" href="/static/css/style.css" rel="stylesheet">
+    <script>
+      const isDarkMode = localStorage.getItem('color-theme') === 'dark' || (!localStorage.getItem('color-theme') && window.matchMedia('(prefers-color-scheme: dark)').matches);
+      if (isDarkMode) {
+        document.documentElement.classList.add('dark');
+      }
+    </script>
+    <link rel=icon sizes="32x32" type="image/png" href="/static/images/favicon/favicon-32.png">
+    <title>(BSX) BasicSwap - Login - v{{ version }}</title>
+</head>
+<body class="dark:bg-gray-700">
+    <section class="py-24 md:py-32">
+        <div class="container px-4 mx-auto">
+            <div class="max-w-sm mx-auto">
+                <div class="mb-6 text-center">
+                     <a class="inline-block mb-6" href="#">
+                       <img src="/static/images/logos/basicswap-logo.svg" class="h-20 imageshow dark-image" style="display: none;">
+                       <img src="/static/images/logos/basicswap-logo-dark.svg" class="h-20 imageshow light-image" style="display: block;">
+                     </a>
+                    <h3 class="mb-4 text-2xl md:text-3xl font-bold dark:text-white">Login Required</h3>
+                    <p class="text-lg text-coolGray-500 font-medium dark:text-gray-300">Please enter the password to access BasicSwap.</p>
+                </div>
+
+                {% for m in err_messages %}
+                <section class="py-4" id="err_messages_{{ m[0] }}" role="alert">
+                  <div class="container px-4 mx-auto">
+                    <div class="p-4 text-red-800 rounded-lg bg-red-50 border border-red-400 dark:bg-gray-600 dark:text-red-300 rounded-md">
+                      <div class="flex flex-wrap items-center -m-1">
+                        <div class="w-auto p-1"> {{ circular_error_messages_svg | safe }} </div>
+                        <p class="ml-2 font-medium text-sm">{{ m[1] }}</p>
+                      </div>
+                    </div>
+                  </div>
+                </section>
+                {% endfor %}
+
+                <form method="post" action="/login" autocomplete="off">
+                    <div class="mb-6">
+                        <label class="block mb-2 text-coolGray-800 font-medium dark:text-white" for="password">Password</label>
+                        <input class="appearance-none block w-full p-3 leading-5 text-coolGray-900 border border-coolGray-200 rounded-lg shadow-md placeholder-coolGray-400 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-opacity-50 dark:bg-gray-600 dark:border-gray-500 dark:text-white"
+                               type="password" name="password" id="password" required autocomplete="current-password">
+                    </div>
+                    <button class="inline-block py-3 px-7 mb-6 w-full text-base text-blue-50 font-medium text-center leading-6 bg-blue-500 hover:bg-blue-600 rounded-md shadow-sm"
+                            type="submit">Login</button>
+                     <p class="text-center">
+                       <span class="text-xs font-medium text-coolGray-500 dark:text-gray-500">{{ title }}</span>
+                     </p>
+                </form>
+            </div>
+        </div>
+    </section>
+    <script>
+      document.addEventListener('DOMContentLoaded', () => {
+        function toggleImages() {
+          const isDark = document.documentElement.classList.contains('dark');
+          const darkImages = document.querySelectorAll('.dark-image');
+          const lightImages = document.querySelectorAll('.light-image');
+          darkImages.forEach(img => img.style.display = isDark ? 'block' : 'none');
+          lightImages.forEach(img => img.style.display = isDark ? 'none' : 'block');
+        }
+        toggleImages();
+      });
+    </script>
+</body>
+</html>

basicswap/util/rfc2440.py

@@ -29,3 +29,51 @@ def rfc2440_hash_password(password, salt=None):
         break
     rv = "16:" + salt.hex() + "60" + h.hexdigest()
     return rv.upper()
+
+
+def verify_rfc2440_password(stored_hash, provided_password):
+    """
+    Verifies a password against a hash generated by rfc2440_hash_password.
+
+    Args:
+        stored_hash (str): The hash string stored (e.g., "16:<salt>60<hash>").
+        provided_password (str): The password attempt to verify.
+
+    Returns:
+        bool: True if the password matches the hash, False otherwise.
+    """
+    try:
+        parts = stored_hash.upper().split(":")
+        if len(parts) != 2 or parts[0] != "16":
+            return False
+
+        salt_hex_plus_hash_hex = parts[1]
+        separator_index = salt_hex_plus_hash_hex.find("60")
+        if separator_index != 16:
+            return False
+
+        salt_hex = salt_hex_plus_hash_hex[:separator_index]
+        expected_hash_hex = salt_hex_plus_hash_hex[separator_index + 2 :]
+
+        salt = bytes.fromhex(salt_hex)
+    except (ValueError, IndexError):
+        return False
+
+    EXPBIAS = 6
+    c = 96
+    count = (16 + (c & 15)) << ((c >> 4) + EXPBIAS)
+
+    hashbytes = salt + provided_password.encode("utf-8")
+    len_hashbytes = len(hashbytes)
+    h = hashlib.sha1()
+
+    while count > 0:
+        if count >= len_hashbytes:
+            h.update(hashbytes)
+            count -= len_hashbytes
+            continue
+        h.update(hashbytes[:count])
+        break
+
+    calculated_hash_hex = h.hexdigest().upper()
+    return secrets.compare_digest(calculated_hash_hex, expected_hash_hex)

doc/install.md

@@ -66,6 +66,10 @@ Adjust `--withcoins` and `--withoutcoins` as desired, eg: `--withcoins=monero,bi
 Append `--usebtcfastsync` to the below command to optionally initialise the Bitcoin datadir with a chain snapshot from btcpayserver FastSync.<br>
 [FastSync README.md](https://github.com/btcpayserver/btcpayserver-docker/blob/master/contrib/FastSync/README.md)
 
+##### FastSync
+
+Append `--client-auth-password=<YOUR_PASSWORD>` to the below command to optionally enable client authentication to protect your web UI from unauthorized access.<br>
+
 
 Setup with a local Monero daemon (recommended):
 
@@ -200,7 +204,7 @@ Prepare the datadir:
     OR using a remote/public XMR daemon (not recommended):
     XMR_RPC_HOST="node.xmr.to" XMR_RPC_PORT=18081 basicswap-prepare --datadir=$SWAP_DATADIR --withcoins=monero --xmrrestoreheight=$CURRENT_XMR_HEIGHT
 
-
+Append `--client-auth-password=<YOUR_PASSWORD>` to the above command to optionally enable client authentication to protect your web UI from unauthorized access.<br>
 Record the mnemonic from the output of the above command.
 
 Start Basicswap: