adds check for TEE backed KeyStore

app/src/main/java/com/besendorf/androidsecurityscanner/MainActivity.java

@@ -31,6 +31,7 @@ import android.media.MediaDrm;
 import android.os.Build;
 import android.os.Bundle;
 import android.security.keystore.KeyGenParameterSpec;
+import android.security.keystore.KeyInfo;
 import android.security.keystore.KeyProperties;
 import android.security.keystore.StrongBoxUnavailableException;
 import android.text.TextUtils;
@@ -55,13 +56,17 @@ import java.io.InputStreamReader;
 import java.lang.reflect.Method;
 import java.math.BigInteger;
 import java.security.InvalidAlgorithmParameterException;
+import java.security.Key;
 import java.security.KeyStore;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
 import java.security.NoSuchProviderException;
+import java.security.spec.InvalidKeySpecException;
 import java.util.UUID;
 
 import javax.crypto.KeyGenerator;
+import javax.crypto.SecretKey;
+import javax.crypto.SecretKeyFactory;
 
 //import androidx.biometric.BiometricPrompt;
 
@@ -150,6 +155,7 @@ public class MainActivity extends AppCompatActivity {
             json.put("ro.boot.verifiedbootstate", getProp("ro.boot.verifiedbootstate"));
             json.put("ro.boot.veritymode", getProp("ro.boot.veritymode"));
             json.put("KeyStore", keyStorePresence());
+            json.put("TEE", TEE());
             json.put("Strongbox", isStrongbox());
             json.put("StrongboxPM", isStrongboxPM());
             json.put("DeviceAdmin", deviceAdmin());
@@ -274,6 +280,48 @@ public class MainActivity extends AppCompatActivity {
         }
     }
 
+    private boolean TEE(){
+        //generates a key and then uses keyInfo.isInsideSecureHardware() to check wheter it is stored in a TEE (or an SE)
+        KeyGenerator kg = null;
+        try {
+            kg = KeyGenerator.getInstance(
+                    KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
+        } catch (NoSuchAlgorithmException | NoSuchProviderException e) {
+            return false;
+        }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            try {
+                kg.init(new KeyGenParameterSpec.Builder("keystore1", 0)
+                        .setCertificateSerialNumber(BigInteger.valueOf(1L))
+                        .build());
+            } catch (InvalidAlgorithmParameterException e) {
+                e.printStackTrace();
+            }
+        } else {
+            return false;
+        }
+        SecretKey key = kg.generateKey();
+
+        SecretKeyFactory factory = null;
+        try {
+            factory = SecretKeyFactory.getInstance(key.getAlgorithm(), "AndroidKeyStore");
+        } catch (NoSuchAlgorithmException | NoSuchProviderException e) {
+            e.printStackTrace();
+            return false;
+        }
+        KeyInfo keyInfo = null;
+        try {
+            keyInfo = (KeyInfo) factory.getKeySpec(key, KeyInfo.class);
+        } catch (InvalidKeySpecException e) {
+            // Not an Android KeyStore key.
+            e.printStackTrace();
+        }
+        if (keyInfo != null){
+            return keyInfo.isInsideSecureHardware();
+        }
+        return false;
+    }
+
     private boolean isStrongbox() {
         // similar to keyStorePresence we use .setIsStrongBoxBacked to make using Strongbox
         // mandatory for a dummy Key Generation which will result in