Merge pull request #2 from ccamel/add-recaptcha-support

Add reCaptcha support

.gitignore

@@ -1,2 +1,3 @@
 .vscode
+.idea
 hugo-mx-gateway

README.md

@@ -166,6 +166,7 @@ Regardless of the deployment platform (Google App Engine, Kubernetes, Docker), t
 * `CONTACT_REPLY_BCC_EMAIL`: Sets an email address for bcc copy of the email sent to the user. This is useful for tracking and follow up.
 * `DEMO_URL`: Specific for demo forms, it can be used to set the URL of the demo site that will be included to the user reply email (e.g. `https://demo.example.com/`). 
 * `ALLOWED_ORIGINS`: Set a list of comma-separated domains that the `hugo-mx-gateway` App shoudl trust. This is for security reason to filter requests. Only requests with an `Origin` header belonging to the defined origins will be accepted, through it's only required that the request has a valid `Referer` header. It's expected in the future to these request filtering and admission rules.
+* `RECAPTCHA_PRIVATE_KEY` (optional): The [reCaptcha](https://www.google.com/recaptcha/intro/v3.html) private key.
 * `TEMPLATE_DEMO_REQUEST_REPLY` (optional): Specify the path of the template to reply a demo request. The default templare is `templates/template_reply_demo_request.html`
 * `TEMPLATE_CONTACT_REQUEST_REPLY` (optional): Specify the path of the template to reply a contact request. The default templare is `templates/template_reply_contact_request.html`.
 

go.mod

@@ -3,6 +3,7 @@ module hugo-mx-gateway
 go 1.13
 
 require (
+	github.com/dpapathanasiou/go-recaptcha v0.0.0-20190121160230-be5090b17804
 	github.com/gorilla/mux v1.7.4
 	github.com/sirupsen/logrus v1.2.0
 	github.com/spf13/viper v1.7.0

go.sum

@@ -36,6 +36,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
+github.com/dpapathanasiou/go-recaptcha v0.0.0-20190121160230-be5090b17804 h1:gFnPvL9HX+Nrb4M2AwzFYqcwGStxYZpuDpFAqpViBG4=
+github.com/dpapathanasiou/go-recaptcha v0.0.0-20190121160230-be5090b17804/go.mod h1:eovtlS/D2AGk8vy2a9sO4XzOyHMHb8jM+WPsf9pkgFo=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=

main.go

@@ -27,10 +27,10 @@ import (
 )
 
 type Route struct {
-	Name        string
-	Method      string
-	Pattern     string
-	HandlerFunc http.HandlerFunc
+	Name    string
+	Method  string
+	Pattern string
+	Handler http.Handler
 }
 
 type Routes []Route
@@ -40,13 +40,15 @@ var routes = Routes{
 		"SendMail",
 		"POST",
 		"/sendmail",
-		SendMail,
+		MuxSecAllowedDomainsHandler(
+			MuxSecReCaptchaHandler(
+				http.HandlerFunc(SendMail))),
 	},
 	Route{
 		"Healthz",
 		"GET",
 		"/healthz",
-		Healthz,
+		http.HandlerFunc(Healthz),
 	},
 }
 
@@ -67,9 +69,7 @@ func MuxLoggerHandler(inner http.Handler, name string) http.Handler {
 func NewRouter() *mux.Router {
 	router := mux.NewRouter().StrictSlash(true)
 	for _, route := range routes {
-		var handler http.Handler
-		handler = route.HandlerFunc
-		handler = MuxLoggerHandler(handler, route.Name)
+		handler := MuxLoggerHandler(route.Handler, route.Name)
 
 		router.
 			Methods(route.Method).

samples/hugo-partial-contact-form.html

@@ -3,6 +3,9 @@
    <fieldset>
       <legend>Please fill in the form to submit your request</legend>
       <form action="https://contact-request-endpoint/" method="post">
+         <!-- uncomment this div block when enabling reCaptcha
+         <script src="https://www.google.com/recaptcha/api.js"></script>
+         -->
          <div class="form-item">
             <label for="name">Name</label>
             <input type="text" name="name" id="name"  placeholder="Mr. Smith" />
@@ -15,7 +18,7 @@
             <label for="organization">Organization</label>
             <input type="text" name="organization" id="organization"  placeholder="Company, Inc." />
          </div>
-         {{ if in .Params.tags "contact" }}  
+         {{ if in .Params.tags "contact" }}
          <div class="form-item">
             <label for="subject">Subject</label>
             <input type="text" name="subject" id="subject"  value="" placeholder="Need help or expertise?" />
@@ -25,12 +28,15 @@
             <label for="message">Message</label>
             <textarea  rows="6" name="message" id="message"  placeholder="Please add details concerning your request."></textarea>
          </div>
-         {{ else }}    
+         {{ else }}
          <div class="form-item">
             <input type="hidden" name="subject" id="subject"  value="Your Access to Product Demo!" />
             <input type="hidden" name="target" id="target"  value="demo" />
          </div>
          {{ end }}
+         <!-- uncomment the below div when enabling reCaptcha
+         <div class="g-recaptcha" data-sitekey="{{.Site.Params.reCaptchaPrivateKey}}"></div>
+         -->
          <input  class="button"  type="submit" value="Submit">
       </form>
    </fieldset>

sendmail.go

@@ -4,7 +4,7 @@ Copyright 2020 Rodrigue Chakode and contributors.
 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
@@ -28,6 +28,7 @@ import (
 	"net/url"
 	"strings"
 
+	"github.com/dpapathanasiou/go-recaptcha"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
 )
@@ -149,32 +150,71 @@ func (m *SendMailRequest) ParseTemplate(templateFileName string, data interface{
 	return nil
 }
 
-// SendMail handles HTTP request to send email
-func SendMail(httpResp http.ResponseWriter, httpReq *http.Request) {
+// MuxSecAllowedDomainsHandler is a security middleware which controls allowed domains.
+func MuxSecAllowedDomainsHandler(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		allowedDomains := strings.Split(viper.GetString("ALLOWED_ORIGINS"), ",")
+		allowedOrigins := make(map[string]bool)
+
+		for _, domain := range allowedDomains {
+			domainTrimmed := strings.TrimSpace(domain)
+			allowedOrigins[fmt.Sprintf("http://%s", domainTrimmed)] = true
+			allowedOrigins[fmt.Sprintf("https://%s", domainTrimmed)] = true
+			allowedOrigins[fmt.Sprintf("http://www.%s", domainTrimmed)] = true
+			allowedOrigins[fmt.Sprintf("https://www.%s", domainTrimmed)] = true
+		}
 
-	allowedDomains := strings.Split(viper.GetString("ALLOWED_ORIGINS"), ",")
-	allowedOrigins := make(map[string]bool)
-	for _, domain := range allowedDomains {
-		domainTrimmed := strings.TrimSpace(domain)
-		allowedOrigins[fmt.Sprintf("http://%s", domainTrimmed)] = true
-		allowedOrigins[fmt.Sprintf("https://%s", domainTrimmed)] = true
-		allowedOrigins[fmt.Sprintf("http://www.%s", domainTrimmed)] = true
-		allowedOrigins[fmt.Sprintf("https://www.%s", domainTrimmed)] = true
-	}
-	if len(httpReq.Header["Origin"]) == 0 || len(httpReq.Header["Referer"]) == 0 {
-		rawHeader, _ := json.Marshal(httpReq.Header)
-		log.Infoln("request with unexpected headers", string(rawHeader))
-		httpResp.WriteHeader(http.StatusForbidden)
-		return
-	}
+		if len(r.Header["Origin"]) == 0 || len(r.Header["Referer"]) == 0 {
+			rawHeader, _ := json.Marshal(r.Header)
+			log.Infoln("request with unexpected headers", string(rawHeader))
+			w.WriteHeader(http.StatusForbidden)
+			return
+		}
 
-	reqOrigin := httpReq.Header["Origin"][0]
-	if _, domainFound := allowedOrigins[reqOrigin]; !domainFound {
-		log.Errorln("not allowed origin", reqOrigin)
-		httpResp.WriteHeader(http.StatusForbidden)
-		return
-	}
+		reqOrigin := r.Header["Origin"][0]
+		if _, domainFound := allowedOrigins[reqOrigin]; !domainFound {
+			log.Errorln("not allowed origin", reqOrigin)
+			w.WriteHeader(http.StatusForbidden)
+			return
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+// MuxSecReCaptchaHandler is a security middleware which verifies the challenge code from
+// the reCaptcha human verification system (provided by Google).
+func MuxSecReCaptchaHandler(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		recaptchaResponse, found := r.Form["g-recaptcha-response"]
+
+		if found {
+			remoteIp, _, _ := net.SplitHostPort(r.RemoteAddr)
+			recaptchaPrivateKey := viper.GetString("RECAPTCHA_PRIVATE_KEY")
+
+			recaptcha.Init(recaptchaPrivateKey)
+
+			result, err := recaptcha.Confirm(remoteIp, recaptchaResponse[0])
+			if err != nil {
+				log.WithFields(log.Fields{
+					"error": err,
+				}).Errorln("reCaptcha server error")
+				w.WriteHeader(http.StatusForbidden)
+				return
+			}
+
+			if !result {
+				w.WriteHeader(http.StatusForbidden)
+				return
+			}
+		}
+
+		next.ServeHTTP(w, r)
+	})
+}
 
+// SendMail handles HTTP request to send email
+func SendMail(httpResp http.ResponseWriter, httpReq *http.Request) {
 	httpReq.ParseForm()
 
 	contactRequest := ContactRequest{
@@ -227,12 +267,12 @@ func SendMail(httpResp http.ResponseWriter, httpReq *http.Request) {
 
 	replyTplFile := ""
 	if contactRequest.RequestTarget == "demo" {
-		replyTplFile = viper.GetString("TEMPLATE_DEMO_REQUEST_REPLY");
+		replyTplFile = viper.GetString("TEMPLATE_DEMO_REQUEST_REPLY")
 		if replyTplFile == "" {
 			replyTplFile = "./templates/template_reply_demo_request.html"
 		}
 	} else {
-		replyTplFile = viper.GetString("TEMPLATE_CONTACT_REQUEST_REPLY");
+		replyTplFile = viper.GetString("TEMPLATE_CONTACT_REQUEST_REPLY")
 		if replyTplFile == "" {
 			replyTplFile = "./templates/template_reply_contact_request.html"
 		}

vendor/modules.txt

@@ -1,3 +1,5 @@
+# github.com/dpapathanasiou/go-recaptcha v0.0.0-20190121160230-be5090b17804
+github.com/dpapathanasiou/go-recaptcha
 # github.com/fsnotify/fsnotify v1.4.7
 github.com/fsnotify/fsnotify
 # github.com/gorilla/mux v1.7.4