4 files changed, 276 insertions, 0 deletions
diff --git a/fun/watchblob/README.md b/fun/watchblob/README.md
new file mode 100644
index 000000000000..712c96cd95d4
--- /dev/null
+++ b/fun/watchblob/README.md
@@ -0,0 +1,35 @@
+Watchblob - WatchGuard VPN on Linux
+===================================
+
+This tiny helper tool makes it possible to use WatchGuard / Firebox / <<whatever
+they are actually called>> VPNs that use multi-factor authentication on Linux.
+
+Rather than using OpenVPN's built-in dynamic challenge/response protocol, WatchGuard
+has opted for a separate implementation negotiating credentials outside of the
+OpenVPN protocol, which makes it impossible to start those connections solely by
+using the `openvpn` CLI and configuration files.
+
+What this application does has been reverse-engineered from the "WatchGuard Mobile VPN
+with SSL" application on OS X.
+
+I've published a [blog post](https://www.tazj.in/en/1486830338) describing the process
+and what is actually going on in this protocol.
+
+## Installation
+
+Make sure you have Go installed and `GOPATH` configured, then simply
+`go get github.com/tazjin/watchblob/...`.
+
+## Usage
+
+Right now the usage is very simple. Make sure you have the correct OpenVPN client
+config ready (this is normally supplied by the WatchGuard UI) simply run:
+
+```
+watchblob vpnserver.somedomain.org username p4ssw0rd
+```
+
+The server responds with a challenge which is displayed to the user, wait until you
+receive the SMS code or whatever and enter it. `watchblob` then completes the
+credential negotiation and you may proceed to log in with OpenVPN using your username
+and *the OTP token* (**not**  your password) as credentials.
diff --git a/fun/watchblob/main.go b/fun/watchblob/main.go
new file mode 100644
index 000000000000..a7ab65d3d196
--- /dev/null
+++ b/fun/watchblob/main.go
@@ -0,0 +1,108 @@
+package main
+
+import (
+	"bufio"
+	"encoding/xml"
+	"fmt"
+	"golang.org/x/crypto/ssh/terminal"
+	"net/http"
+	"os"
+	"strings"
+	"syscall"
+)
+
+// The XML response returned by the WatchGuard server
+type Resp struct {
+	Action      string `xml:"action"`
+	LogonStatus int    `xml:"logon_status"`
+	LogonId     int    `xml:"logon_id"`
+	Error       string `xml:"errStr"`
+	Challenge   string `xml:"chaStr"`
+}
+
+func main() {
+	args := os.Args[1:]
+
+	if len(args) != 1 {
+		fmt.Fprintln(os.Stderr, "Usage: watchblob <vpn-host>")
+		os.Exit(1)
+	}
+
+	host := args[0]
+
+	username, password, err := readCredentials()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Could not read credentials: %v\n", err)
+	}
+
+	fmt.Printf("Requesting challenge from %s as user %s\n", host, username)
+	challenge, err := triggerChallengeResponse(&host, &username, &password)
+
+	if err != nil || challenge.LogonStatus != 4 {
+		fmt.Fprintln(os.Stderr, "Did not receive challenge from server")
+		fmt.Fprintf(os.Stderr, "Response: %v\nError: %v\n", challenge, err)
+		os.Exit(1)
+	}
+
+	token := getToken(&challenge)
+	err = logon(&host, &challenge, &token)
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Logon failed: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Login succeeded, you may now (quickly) authenticate OpenVPN with %s as your password\n", token)
+}
+
+func readCredentials() (string, string, error) {
+	fmt.Printf("Username: ")
+	reader := bufio.NewReader(os.Stdin)
+	username, err := reader.ReadString('\n')
+
+	fmt.Printf("Password: ")
+	password, err := terminal.ReadPassword(syscall.Stdin)
+	fmt.Println()
+
+	// If an error occured, I don't care about which one it is.
+	return strings.TrimSpace(username), strings.TrimSpace(string(password)), err
+}
+
+func triggerChallengeResponse(host *string, username *string, password *string) (r Resp, err error) {
+	return request(templateUrl(host, templateChallengeTriggerUri(username, password)))
+}
+
+func getToken(challenge *Resp) string {
+	fmt.Println(challenge.Challenge)
+
+	reader := bufio.NewReader(os.Stdin)
+	token, _ := reader.ReadString('\n')
+
+	return strings.TrimSpace(token)
+}
+
+func logon(host *string, challenge *Resp, token *string) (err error) {
+	resp, err := request(templateUrl(host, templateResponseUri(challenge.LogonId, token)))
+	if err != nil {
+		return
+	}
+
+	if resp.LogonStatus != 1 {
+		err = fmt.Errorf("Challenge/response authentication failed: %v", resp)
+	}
+
+	return
+}
+
+func request(url string) (r Resp, err error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return
+	}
+
+	defer resp.Body.Close()
+	decoder := xml.NewDecoder(resp.Body)
+
+	err = decoder.Decode(&r)
+	return
+}
diff --git a/fun/watchblob/main_test.go b/fun/watchblob/main_test.go
new file mode 100644
index 000000000000..1af52d0cd4eb
--- /dev/null
+++ b/fun/watchblob/main_test.go
@@ -0,0 +1,96 @@
+package main
+
+import (
+	"encoding/xml"
+	"reflect"
+	"testing"
+)
+
+func TestUnmarshalChallengeRespones(t *testing.T) {
+	var testXml string = `
+<?xml version="1.0" encoding="UTF-8"?>
+<resp>
+  <action>sslvpn_logon</action>
+  <logon_status>4</logon_status>
+  <auth-domain-list>
+    <auth-domain>
+      <name>RADIUS</name>
+    </auth-domain>
+  </auth-domain-list>
+  <logon_id>441</logon_id>
+  <chaStr>Enter Your 6 Digit Passcode </chaStr>
+</resp>`
+
+	var r Resp
+	xml.Unmarshal([]byte(testXml), &r)
+
+	expected := Resp{
+		Action:      "sslvpn_logon",
+		LogonStatus: 4,
+		LogonId:     441,
+		Challenge:   "Enter Your 6 Digit Passcode ",
+	}
+
+	assertEqual(t, expected, r)
+}
+
+func TestUnmarshalLoginError(t *testing.T) {
+	var testXml string = `
+<?xml version="1.0" encoding="UTF-8"?>
+<resp>
+  <action>sslvpn_logon</action>
+  <logon_status>2</logon_status>
+  <auth-domain-list>
+    <auth-domain>
+      <name>RADIUS</name>
+    </auth-domain>
+  </auth-domain-list>
+  <errStr>501</errStr>
+</resp>`
+
+	var r Resp
+	xml.Unmarshal([]byte(testXml), &r)
+
+	expected := Resp{
+		Action:      "sslvpn_logon",
+		LogonStatus: 2,
+		Error:       "501",
+	}
+
+	assertEqual(t, expected, r)
+}
+
+func TestUnmarshalLoginSuccess(t *testing.T) {
+	var testXml string = `
+<?xml version="1.0" encoding="UTF-8"?>
+<resp>
+  <action>sslvpn_logon</action>
+  <logon_status>1</logon_status>
+  <auth-domain-list>
+    <auth-domain>
+      <name>RADIUS</name>
+    </auth-domain>
+  </auth-domain-list>
+</resp>
+`
+	var r Resp
+	xml.Unmarshal([]byte(testXml), &r)
+
+	expected := Resp{
+		Action:      "sslvpn_logon",
+		LogonStatus: 1,
+	}
+
+	assertEqual(t, expected, r)
+}
+
+func assertEqual(t *testing.T, expected interface{}, result interface{}) {
+	if !reflect.DeepEqual(expected, result) {
+		t.Errorf(
+			"Unmarshaled values did not match.\nExpected: %v\nResult: %v\n",
+			expected, result,
+		)
+
+		t.Fail()
+	}
+}
diff --git a/fun/watchblob/urls.go b/fun/watchblob/urls.go
new file mode 100644
index 000000000000..37f65e0faef4
--- /dev/null
+++ b/fun/watchblob/urls.go
@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+	"net/url"
+	"strconv"
+)
+
+const urlFormat string = "https://%s%s"
+const uriFormat = "/?%s"
+
+func templateChallengeTriggerUri(username *string, password *string) string {
+	v := url.Values{}
+	v.Set("action", "sslvpn_logon")
+	v.Set("style", "fw_logon_progress.xsl")
+	v.Set("fw_logon_type", "logon")
+	v.Set("fw_domain", "Firebox-DB")
+	v.Set("fw_username", *username)
+	v.Set("fw_password", *password)
+
+	return fmt.Sprintf(uriFormat, v.Encode())
+}
+
+func templateResponseUri(logonId int, token *string) string {
+	v := url.Values{}
+	v.Set("action", "sslvpn_logon")
+	v.Set("style", "fw_logon_progress.xsl")
+	v.Set("fw_logon_type", "response")
+	v.Set("response", *token)
+	v.Set("fw_logon_id", strconv.Itoa(logonId))
+
+	return fmt.Sprintf(uriFormat, v.Encode())
+}
+
+func templateUrl(baseUrl *string, uri string) string {
+	return fmt.Sprintf(urlFormat, *baseUrl, uri)
+}