Merge pull request #14339 from karalabe/faucet-block-banned-users

cmd/faucet: further user validations and bot protection

cmd/faucet/faucet.go

@@ -29,6 +29,7 @@ import (
 	"io/ioutil"
 	"math/big"
 	"net/http"
+	"net/url"
 	"os"
 	"path/filepath"
 	"strings"
@@ -73,6 +74,9 @@ var (
 	githubUser  = flag.String("github.user", "", "GitHub user to authenticate with for Gist access")
 	githubToken = flag.String("github.token", "", "GitHub personal token to access Gists with")
 
+	captchaToken  = flag.String("captcha.token", "", "Recaptcha site key to authenticate client side")
+	captchaSecret = flag.String("captcha.secret", "", "Recaptcha secret key to authenticate server side")
+
 	logFlag = flag.Int("loglevel", 3, "Log level to use for Ethereum and the faucet")
 )
 
@@ -96,9 +100,10 @@ func main() {
 	}
 	website := new(bytes.Buffer)
 	template.Must(template.New("").Parse(string(tmpl))).Execute(website, map[string]interface{}{
-		"Network": *netnameFlag,
-		"Amount":  *payoutFlag,
-		"Period":  period,
+		"Network":   *netnameFlag,
+		"Amount":    *payoutFlag,
+		"Period":    period,
+		"Recaptcha": *captchaToken,
 	})
 	// Load and parse the genesis block requested by the user
 	blob, err := ioutil.ReadFile(*genesisFlag)
@@ -297,7 +302,8 @@ func (f *faucet) apiHandler(conn *websocket.Conn) {
 	for {
 		// Fetch the next funding request and validate against github
 		var msg struct {
-			URL string `json:"url"`
+			URL     string `json:"url"`
+			Captcha string `json:"captcha"`
 		}
 		if err := websocket.JSON.Receive(conn, &msg); err != nil {
 			return
@@ -308,6 +314,33 @@ func (f *faucet) apiHandler(conn *websocket.Conn) {
 		}
 		log.Info("Faucet funds requested", "gist", msg.URL)
 
+		// If captcha verifications are enabled, make sure we're not dealing with a robot
+		if *captchaToken != "" {
+			form := url.Values{}
+			form.Add("secret", *captchaSecret)
+			form.Add("response", msg.Captcha)
+
+			res, err := http.PostForm("https://www.google.com/recaptcha/api/siteverify", form)
+			if err != nil {
+				websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
+				continue
+			}
+			var result struct {
+				Success bool            `json:"success"`
+				Errors  json.RawMessage `json:"error-codes"`
+			}
+			err = json.NewDecoder(res.Body).Decode(&result)
+			res.Body.Close()
+			if err != nil {
+				websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
+				continue
+			}
+			if !result.Success {
+				log.Warn("Captcha verification failed", "err", string(result.Errors))
+				websocket.JSON.Send(conn, map[string]string{"error": "Beep-boop, you're a robot!"})
+				continue
+			}
+		}
 		// Retrieve the gist from the GitHub Gist APIs
 		parts := strings.Split(msg.URL, "/")
 		req, _ := http.NewRequest("GET", "https://api.github.com/gists/"+parts[len(parts)-1], nil)
@@ -334,7 +367,7 @@ func (f *faucet) apiHandler(conn *websocket.Conn) {
 			continue
 		}
 		if gist.Owner.Login == "" {
-			websocket.JSON.Send(conn, map[string]string{"error": "Nice try ;)"})
+			websocket.JSON.Send(conn, map[string]string{"error": "Anonymous Gists not allowed"})
 			continue
 		}
 		// Iterate over all the files and look for Ethereum addresses
@@ -348,6 +381,17 @@ func (f *faucet) apiHandler(conn *websocket.Conn) {
 			websocket.JSON.Send(conn, map[string]string{"error": "No Ethereum address found to fund"})
 			continue
 		}
+		// Validate the user's existence since the API is unhelpful here
+		if res, err = http.Head("https://github.com/" + gist.Owner.Login); err != nil {
+			websocket.JSON.Send(conn, map[string]string{"error": err.Error()})
+			continue
+		}
+		res.Body.Close()
+
+		if res.StatusCode != 200 {
+			websocket.JSON.Send(conn, map[string]string{"error": "Invalid user... boom!"})
+			continue
+		}
 		// Ensure the user didn't request funds too recently
 		f.lock.Lock()
 		var (

cmd/faucet/faucet.html

@@ -51,9 +51,10 @@
 						<div class="input-group">
 							<input id="gist" type="text" class="form-control" placeholder="GitHub Gist URL containing your Ethereum address...">
 							<span class="input-group-btn">
-								<button class="btn btn-default" type="button" onclick="submit()">Give me Ether!</button>
+								<button class="btn btn-default" type="button" onclick="{{if .Recaptcha}}grecaptcha.execute(){{else}}submit(){{end}}">Give me Ether!</button>
 							</span>
-						</div>
+						</div>{{if .Recaptcha}}
+						<div class="g-recaptcha" data-sitekey="{{.Recaptcha}}" data-callback="submit" data-size="invisible"></div>{{end}}
 					</div>
 				</div>
 				<div class="row" style="margin-top: 32px;">
@@ -76,7 +77,7 @@
 				<div class="row" style="margin-top: 32px;">
 					<div class="col-lg-12">
 						<h3>How does this work?</h3>
-						<p>This Ether faucet is running on the {{.Network}} network. To prevent malicious actors from exhausting all available funds or accumulating enough Ether to mount long running spam attacks, requests are tied to GitHub accounts. Anyone having a GitHub account may request funds within the permitted limit of <strong>{{.Amount}} Ether(s) / {{.Period}}</strong>.</p>
+						<p>This Ether faucet is running on the {{.Network}} network. To prevent malicious actors from exhausting all available funds or accumulating enough Ether to mount long running spam attacks, requests are tied to GitHub accounts. Anyone having a GitHub account may request funds within the permitted limit of <strong>{{.Amount}} Ether(s) / {{.Period}}</strong>.{{if .Recaptcha}} The faucet is running invisible reCaptcha protection against bots.{{end}}</p>
 						<p>To request funds, simply create a <a href="https://gist.github.com/" target="_about:blank">GitHub Gist</a> with your Ethereum address pasted into the contents (the file name doesn't matter), copy paste the gists URL into the above input box and fire away! You can track the current pending requests below the input field to see how much you have to wait until your turn comes.</p>
 					</div>
 				</div>
@@ -89,8 +90,9 @@
 			var server;
 
 			// Define the function that submits a gist url to the server
-			var submit = function() {
-				server.send(JSON.stringify({url: $("#gist")[0].value}));
+			var submit = function({{if .Recaptcha}}captcha{{end}}) {
+				server.send(JSON.stringify({url: $("#gist")[0].value{{if .Recaptcha}}, captcha: captcha{{end}}}));{{if .Recaptcha}}
+				grecaptcha.reset();{{end}}
 			};
 			// Define a method to reconnect upon server loss
 			var reconnect = function() {
@@ -134,10 +136,10 @@
 					}
 				}
 				server.onclose = function() { setTimeout(reconnect, 3000); };
-				server.onerror = function() { setTimeout(reconnect, 3000); };
 			}
 			// Establish a websocket connection to the API server
 			reconnect();
-		</script>
+		</script>{{if .Recaptcha}}
+		<script src="https://www.google.com/recaptcha/api.js" async defer></script>{{end}}
 	</body>
 </html>

cmd/puppeth/module_faucet.go

@@ -54,6 +54,7 @@ CMD [ \
 	"/faucet", "--genesis", "/genesis.json", "--network", "{{.NetworkID}}", "--bootnodes", "{{.Bootnodes}}", "--ethstats", "{{.Ethstats}}",            \
 	"--ethport", "{{.EthPort}}", "--faucet.name", "{{.FaucetName}}", "--faucet.amount", "{{.FaucetAmount}}", "--faucet.minutes", "{{.FaucetMinutes}}", \
 	"--github.user", "{{.GitHubUser}}", "--github.token", "{{.GitHubToken}}", "--account.json", "/account.json", "--account.pass", "/account.pass"     \
+	{{if .CaptchaToken}}, "--captcha.token", "{{.CaptchaToken}}", "--captcha.secret", "{{.CaptchaSecret}}"{{end}}                                      \
 ]`
 
 // faucetComposefile is the docker-compose.yml file required to deploy and maintain
@@ -75,7 +76,9 @@ services:
       - FAUCET_AMOUNT={{.FaucetAmount}}
       - FAUCET_MINUTES={{.FaucetMinutes}}
       - GITHUB_USER={{.GitHubUser}}
-      - GITHUB_TOKEN={{.GitHubToken}}{{if .VHost}}
+      - GITHUB_TOKEN={{.GitHubToken}}
+      - CAPTCHA_TOKEN={{.CaptchaToken}}
+      - CAPTCHA_SECRET={{.CaptchaSecret}}{{if .VHost}}
       - VIRTUAL_HOST={{.VHost}}
       - VIRTUAL_PORT=8080{{end}}
     restart: always
@@ -97,6 +100,8 @@ func deployFaucet(client *sshClient, network string, bootnodes []string, config
 		"EthPort":       config.node.portFull,
 		"GitHubUser":    config.githubUser,
 		"GitHubToken":   config.githubToken,
+		"CaptchaToken":  config.captchaToken,
+		"CaptchaSecret": config.captchaSecret,
 		"FaucetName":    strings.Title(network),
 		"FaucetAmount":  config.amount,
 		"FaucetMinutes": config.minutes,
@@ -113,6 +118,8 @@ func deployFaucet(client *sshClient, network string, bootnodes []string, config
 		"EthName":       config.node.ethstats[:strings.Index(config.node.ethstats, ":")],
 		"GitHubUser":    config.githubUser,
 		"GitHubToken":   config.githubToken,
+		"CaptchaToken":  config.captchaToken,
+		"CaptchaSecret": config.captchaSecret,
 		"FaucetAmount":  config.amount,
 		"FaucetMinutes": config.minutes,
 	})
@@ -135,18 +142,20 @@ func deployFaucet(client *sshClient, network string, bootnodes []string, config
 // faucetInfos is returned from an faucet status check to allow reporting various
 // configuration parameters.
 type faucetInfos struct {
-	node        *nodeInfos
-	host        string
-	port        int
-	amount      int
-	minutes     int
-	githubUser  string
-	githubToken string
+	node          *nodeInfos
+	host          string
+	port          int
+	amount        int
+	minutes       int
+	githubUser    string
+	githubToken   string
+	captchaToken  string
+	captchaSecret string
 }
 
 // String implements the stringer interface.
 func (info *faucetInfos) String() string {
-	return fmt.Sprintf("host=%s, api=%d, eth=%d, amount=%d, minutes=%d, github=%s, ethstats=%s", info.host, info.port, info.node.portFull, info.amount, info.minutes, info.githubUser, info.node.ethstats)
+	return fmt.Sprintf("host=%s, api=%d, eth=%d, amount=%d, minutes=%d, github=%s, captcha=%v, ethstats=%s", info.host, info.port, info.node.portFull, info.amount, info.minutes, info.githubUser, info.captchaToken != "", info.node.ethstats)
 }
 
 // checkFaucet does a health-check against an faucet server to verify whether
@@ -200,11 +209,13 @@ func checkFaucet(client *sshClient, network string) (*faucetInfos, error) {
 			keyJSON:  keyJSON,
 			keyPass:  keyPass,
 		},
-		host:        host,
-		port:        port,
-		amount:      amount,
-		minutes:     minutes,
-		githubUser:  infos.envvars["GITHUB_USER"],
-		githubToken: infos.envvars["GITHUB_TOKEN"],
+		host:          host,
+		port:          port,
+		amount:        amount,
+		minutes:       minutes,
+		githubUser:    infos.envvars["GITHUB_USER"],
+		githubToken:   infos.envvars["GITHUB_TOKEN"],
+		captchaToken:  infos.envvars["CAPTCHA_TOKEN"],
+		captchaSecret: infos.envvars["CAPTCHA_SECRET"],
 	}, nil
 }

cmd/puppeth/wizard_faucet.go

@@ -71,7 +71,7 @@ func (w *wizard) deployFaucet() {
 	// Accessing GitHub gists requires API authorization, retrieve it
 	if infos.githubUser != "" {
 		fmt.Println()
-		fmt.Printf("Reused previous (%s) GitHub API authorization (y/n)? (default = yes)\n", infos.githubUser)
+		fmt.Printf("Reuse previous (%s) GitHub API authorization (y/n)? (default = yes)\n", infos.githubUser)
 		if w.readDefaultString("y") != "y" {
 			infos.githubUser, infos.githubToken = "", ""
 		}
@@ -109,6 +109,29 @@ func (w *wizard) deployFaucet() {
 			return
 		}
 	}
+	// Accessing the reCaptcha service requires API authorizations, request it
+	if infos.captchaToken != "" {
+		fmt.Println()
+		fmt.Println("Reuse previous reCaptcha API authorization (y/n)? (default = yes)")
+		if w.readDefaultString("y") != "y" {
+			infos.captchaToken, infos.captchaSecret = "", ""
+		}
+	}
+	if infos.captchaToken == "" {
+		// No previous authorization (or old one discarded)
+		fmt.Println()
+		fmt.Println("Enable reCaptcha protection against robots (y/n)? (default = no)")
+		if w.readDefaultString("n") == "y" {
+			// Captcha protection explicitly requested, read the site and secret keys
+			fmt.Println()
+			fmt.Printf("What is the reCaptcha site key to authenticate human users?\n")
+			infos.captchaToken = w.readString()
+
+			fmt.Println()
+			fmt.Printf("What is the reCaptcha secret key to verify authentications? (won't be echoed)\n")
+			infos.captchaSecret = w.readPassword()
+		}
+	}
 	// Figure out where the user wants to store the persistent data
 	fmt.Println()
 	if infos.node.datadir == "" {