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// Copyright 2019 Parminder Singh <parmsingh129@gmail.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package routing
import (
"fmt"
"html/template"
"net/http"
"github.com/matrix-org/dendrite/clientapi/auth/authtypes"
"github.com/matrix-org/dendrite/setup/config"
"github.com/matrix-org/util"
)
// recaptchaTemplate is an HTML webpage template for recaptcha auth
const recaptchaTemplate = `
<html>
<head>
<title>Authentication</title>
<meta name='viewport' content='width=device-width, initial-scale=1,
user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
<script src="{{.apiJsUrl}}" async defer></script>
<script src="//code.jquery.com/jquery-1.11.2.min.js"></script>
<script>
function captchaDone() {
$('#registrationForm').submit();
}
</script>
</head>
<body>
<form id="registrationForm" method="post" action="{{.myUrl}}">
<div>
<p>
Hello! We need to prevent computer programs and other automated
things from creating accounts on this server.
</p>
<p>
Please verify that you're not a robot.
</p>
<input type="hidden" name="session" value="{{.session}}" />
<div class="{{.sitekeyClass}}"
data-sitekey="{{.sitekey}}"
data-callback="captchaDone">
</div>
<noscript>
<input type="submit" value="All Done" />
</noscript>
</div>
</div>
</form>
</body>
</html>
`
// successTemplate is an HTML template presented to the user after successful
// recaptcha completion
const successTemplate = `
<html>
<head>
<title>Success!</title>
<meta name='viewport' content='width=device-width, initial-scale=1,
user-scalable=no, minimum-scale=1.0, maximum-scale=1.0'>
<script>
if (window.onAuthDone) {
window.onAuthDone();
} else if (window.opener && window.opener.postMessage) {
window.opener.postMessage("authDone", "*");
}
</script>
</head>
<body>
<div>
<p>Thank you!</p>
<p>You may now close this window and return to the application.</p>
</div>
</body>
</html>
`
// serveTemplate fills template data and serves it using http.ResponseWriter
func serveTemplate(w http.ResponseWriter, templateHTML string, data map[string]string) {
t := template.Must(template.New("response").Parse(templateHTML))
if err := t.Execute(w, data); err != nil {
panic(err)
}
}
// AuthFallback implements GET and POST /auth/{authType}/fallback/web?session={sessionID}
func AuthFallback(
w http.ResponseWriter, req *http.Request, authType string,
cfg *config.ClientAPI,
) {
// We currently only support "m.login.recaptcha", so fail early if that's not requested
if authType == authtypes.LoginTypeRecaptcha {
if !cfg.RecaptchaEnabled {
writeHTTPMessage(w, req,
"Recaptcha login is disabled on this Homeserver",
http.StatusBadRequest,
)
return
}
} else {
writeHTTPMessage(w, req, fmt.Sprintf("Unknown authtype %q", authType), http.StatusNotImplemented)
return
}
sessionID := req.URL.Query().Get("session")
if sessionID == "" {
writeHTTPMessage(w, req,
"Session ID not provided",
http.StatusBadRequest,
)
return
}
serveRecaptcha := func() {
data := map[string]string{
"myUrl": req.URL.String(),
"session": sessionID,
"apiJsUrl": cfg.RecaptchaApiJsUrl,
"sitekey": cfg.RecaptchaPublicKey,
"sitekeyClass": cfg.RecaptchaSitekeyClass,
"formField": cfg.RecaptchaFormField,
}
serveTemplate(w, recaptchaTemplate, data)
}
serveSuccess := func() {
data := map[string]string{}
serveTemplate(w, successTemplate, data)
}
if req.Method == http.MethodGet {
// Handle Recaptcha
serveRecaptcha()
return
} else if req.Method == http.MethodPost {
// Handle Recaptcha
clientIP := req.RemoteAddr
err := req.ParseForm()
if err != nil {
util.GetLogger(req.Context()).WithError(err).Error("req.ParseForm failed")
w.WriteHeader(http.StatusBadRequest)
serveRecaptcha()
return
}
response := req.Form.Get(cfg.RecaptchaFormField)
err = validateRecaptcha(cfg, response, clientIP)
switch err {
case ErrMissingResponse:
w.WriteHeader(http.StatusBadRequest)
serveRecaptcha() // serve the initial page again, instead of nothing
return
case ErrInvalidCaptcha:
w.WriteHeader(http.StatusUnauthorized)
serveRecaptcha()
return
case nil:
default: // something else failed
util.GetLogger(req.Context()).WithError(err).Error("failed to validate recaptcha")
serveRecaptcha()
return
}
// Success. Add recaptcha as a completed login flow
sessions.addCompletedSessionStage(sessionID, authtypes.LoginTypeRecaptcha)
serveSuccess()
return
}
writeHTTPMessage(w, req, "Bad method", http.StatusMethodNotAllowed)
}
// writeHTTPMessage writes the given header and message to the HTTP response writer.
// Returns an error JSONResponse obtained through httputil.LogThenError if the writing failed, otherwise nil.
func writeHTTPMessage(
w http.ResponseWriter, req *http.Request,
message string, header int,
) {
w.WriteHeader(header)
_, err := w.Write([]byte(message))
if err != nil {
util.GetLogger(req.Context()).WithError(err).Error("w.Write failed")
}
}
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