From cf41b524b0a0c005946817c157299c50dfd8de39 Mon Sep 17 00:00:00 2001
From: Kyle Spearrin <kyle.spearrin@gmail.com>
Date: Tue, 27 Jun 2017 23:33:13 -0400
Subject: [PATCH] read yubikey otp via nfc

---
 src/Android/MainActivity.cs                | 40 ++++++++++++++++++++++
 src/Android/Properties/AndroidManifest.xml |  1 +
 2 files changed, 41 insertions(+)

diff --git a/src/Android/MainActivity.cs b/src/Android/MainActivity.cs
index 643a7b7ef..8acccc73a 100644
--- a/src/Android/MainActivity.cs
+++ b/src/Android/MainActivity.cs
@@ -15,6 +15,7 @@ using Xamarin.Forms;
 using System.Threading.Tasks;
 using Bit.App.Models.Page;
 using Bit.App;
+using Android.Nfc;
 
 namespace Bit.Android
 {
@@ -26,6 +27,7 @@ namespace Bit.Android
     {
         private const string HockeyAppId = "d3834185b4a643479047b86c65293d42";
         private DateTime? _lastAction;
+        private Java.Util.Regex.Pattern _otpPattern = Java.Util.Regex.Pattern.Compile("^.*?([cbdefghijklnrtuv]{32,64})$");
 
         protected override void OnCreate(Bundle bundle)
         {
@@ -102,6 +104,12 @@ namespace Bit.Android
             {
                 LaunchApp(args);
             });
+
+            MessagingCenter.Subscribe<Xamarin.Forms.Application>(
+                Xamarin.Forms.Application.Current, "ListenYubiKeyOTP", (sender) =>
+            {
+                ListenYubiKey();
+            });
         }
 
         private void ReturnCredentials(VaultListPageModel.Login login)
@@ -228,5 +236,37 @@ namespace Bit.Android
                 StartActivity(launchIntent);
             }
         }
+
+        private void ListenYubiKey()
+        {
+            var intent = new Intent(this, Class);
+            intent.AddFlags(ActivityFlags.SingleTop);
+            var pendingIntent = PendingIntent.GetActivity(this, 0, intent, 0);
+
+            // register for all NDEF tags starting with http och https
+            var ndef = new IntentFilter(NfcAdapter.ActionNdefDiscovered);
+            ndef.AddDataScheme("http");
+            ndef.AddDataScheme("https");
+
+            // register for foreground dispatch so we'll receive tags according to our intent filters
+            var adapter = NfcAdapter.GetDefaultAdapter(this);
+            adapter.EnableForegroundDispatch(this, pendingIntent, new IntentFilter[] { ndef }, null);
+
+            var data = Intent.DataString;
+            if(data != null)
+            {
+                var otpMatch = _otpPattern.Matcher(data);
+                if(otpMatch.Matches())
+                {
+                    var otp = otpMatch.Group(1);
+                    Console.WriteLine("Got OTP: " + otp);
+                    MessagingCenter.Send(Xamarin.Forms.Application.Current, "GotYubiKeyOTP", otp);
+                }
+                else
+                {
+                    Console.WriteLine("Data from ndef didn't match, it was: " + data);
+                }
+            }
+        }
     }
 }
diff --git a/src/Android/Properties/AndroidManifest.xml b/src/Android/Properties/AndroidManifest.xml
index 80aa9a2fc..12298232d 100644
--- a/src/Android/Properties/AndroidManifest.xml
+++ b/src/Android/Properties/AndroidManifest.xml
@@ -3,6 +3,7 @@
   <uses-sdk android:minSdkVersion="19" android:targetSdkVersion="23" />
 
   <uses-permission android:name="android.permission.INTERNET" />
+  <uses-permission android:name="android.permission.NFC" />
   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
   <uses-permission android:name="android.permission.USE_FINGERPRINT" />
   <uses-permission android:name="com.samsung.android.providers.context.permission.WRITE_USE_APP_FEATURE_SURVEY" />