NfcOtpActivity is back - this time with app link enabled (allows users to enter https://keepass2android.crocoll.net/neo/ as NDEF payload and should work on all recent Android devices with NFC). Closes #603

src/keepass2android/NfcOtpActivity.cs

@@ -0,0 +1,115 @@
+using System;
+using Android.App;
+using Android.Content;
+using Android.Content.PM;
+using Android.Nfc;
+using Android.OS;
+using Android.Widget;
+using Java.Util;
+using Java.Util.Regex;
+using Keepass2android.Yubiclip.Scancode;
+
+namespace keepass2android
+{
+	[Activity(Label = "@string/app_name",
+			   ConfigurationChanges = ConfigChanges.Orientation |
+			   ConfigChanges.KeyboardHidden,
+			   NoHistory = true,
+			   ExcludeFromRecents = true,
+			   Theme = "@android:style/Theme.Dialog")]
+	[IntentFilter(new[] { "android.nfc.action.NDEF_DISCOVERED" },
+		Label = "@string/app_name",
+		Categories = new[] { Intent.CategoryDefault },
+		DataHost = "my.yubico.com",
+		DataPathPrefix = "/neo",
+		DataScheme = "https")]
+	[IntentFilter(new[] { "android.nfc.action.NDEF_DISCOVERED", Android.Content.Intent.ActionView },
+	    Label = "@string/app_name",
+	    Categories = new[] { Intent.CategoryDefault, Intent.CategoryBrowsable },
+	    DataHost = "keepass2android.crocoll.net",
+	    DataPathPrefix = "/neo",
+	    DataScheme = "https",
+        AutoVerify=true)]
+    public class NfcOtpActivity : Activity
+	{
+		private String GetOtpFromIntent(Intent intent)
+		{
+			String data = intent.DataString;
+			Matcher matcher = OtpPattern.Matcher(data);
+			if (matcher.Matches())
+			{
+				String otp = matcher.Group(1);
+				return otp;
+			}
+			else
+			{
+				IParcelable[] raw = Intent.GetParcelableArrayExtra(NfcAdapter.ExtraNdefMessages);
+				
+				byte[] bytes = ((NdefMessage) raw[0]).ToByteArray();
+				bytes = Arrays.CopyOfRange(bytes, DATA_OFFSET, bytes.Length);
+				String layout = "US";
+				KeyboardLayout kbd = KeyboardLayout.ForName(layout);
+				String otp = kbd.FromScanCodes(bytes);
+				return otp;
+			}
+			return null;
+		}
+
+
+		//private static readonly Java.Util.Regex.Pattern OtpPattern = Java.Util.Regex.Pattern.Compile("^https://my\\.yubico\\.com/neo/(.+)$");
+		private static readonly Java.Util.Regex.Pattern OtpPattern = Java.Util.Regex.Pattern.Compile("^https://my\\.yubico\\.com/neo/([a-zA-Z0-9!]+)$");
+		private const int DATA_OFFSET = 23;
+
+		private ActivityDesign _design;
+
+		public NfcOtpActivity()
+		{
+			_design = new ActivityDesign(this);
+		}
+
+		protected override void OnCreate(Bundle bundle)
+		{
+			_design.ApplyTheme();
+			base.OnCreate(bundle);
+			
+
+			Intent i = new Intent(this, typeof (PasswordActivity));
+			i.SetAction(Intents.StartWithOtp);
+			
+			//things to consider:
+			// PasswordActivity should be resumed if currently active -> this is why single top is used and why PasswordActivity is started
+			// If PasswordActivity is not open already, it may be the wrong place to send our OTP to because maybe the user first needs to select 
+			//  a file (which might require UI action like entering credentials, all of which is handled in FileSelectActivity)
+			// FileSelectActivity is not on the back stack, it finishes itself.
+			// -> PasswordActivity needs to handle this and return to FSA.
+			
+			
+			i.SetFlags(ActivityFlags.NewTask | ActivityFlags.SingleTop | ActivityFlags.ClearTop);
+			try
+			{
+				string otp = GetOtpFromIntent(Intent);
+				if (otp == null)
+					throw new Exception("Otp must not be null!");
+				i.PutExtra(Intents.OtpExtraKey, otp);
+			}
+			catch (Exception e)
+			{
+				Kp2aLog.LogUnexpectedError(e);
+				Toast.MakeText(this, "No Yubikey OTP found!", ToastLength.Long).Show();
+				Finish();
+				return;
+			}
+
+			StartActivity(i);				
+			Finish();
+
+		}
+
+		protected override void OnResume()
+		{
+			base.OnResume();
+			_design.ReapplyTheme();
+		}
+
+	}
+}

src/keepass2android/keepass2android.csproj

@@ -225,6 +225,7 @@
     <Compile Include="FixedDrawerLayout.cs" />
     <Compile Include="KpEntryTemplatedEdit.cs" />
     <Compile Include="MeasuringRelativeLayout.cs" />
+    <Compile Include="NfcOtpActivity.cs" />
     <Compile Include="PasswordFont.cs" />
     <Compile Include="pluginhost\PluginArrayAdapter.cs" />
     <Compile Include="pluginhost\PluginDatabase.cs" />