android: Add repository for managed user certificates

src/frontends/android/app/src/main/java/org/strongswan/android/data/ManagedUserCertificateRepository.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2023 Relution GmbH
+ *
+ * Copyright (C) secunet Security Networks AG
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+package org.strongswan.android.data;
+
+import android.app.admin.DevicePolicyManager;
+import android.database.Cursor;
+import android.os.Build;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+public class ManagedUserCertificateRepository extends ManagedCertificateRepository<ManagedUserCertificate>
+{
+	private static final DatabaseHelper.DbTable TABLE = DatabaseHelper.TABLE_USER_CERTIFICATE;
+
+	@NonNull
+	private final DevicePolicyManager devicePolicyManager;
+
+	public ManagedUserCertificateRepository(
+		@NonNull final ManagedConfigurationService managedConfigurationService,
+		@NonNull final DevicePolicyManager devicePolicyManager,
+		@NonNull final DatabaseHelper databaseHelper)
+	{
+		super(managedConfigurationService, databaseHelper, TABLE);
+		this.devicePolicyManager = devicePolicyManager;
+	}
+
+	@Nullable
+	@Override
+	protected ManagedUserCertificate getCertificate(@NonNull ManagedVpnProfile vpnProfile)
+	{
+		return vpnProfile.getUserCertificate();
+	}
+
+	@NonNull
+	@Override
+	protected ManagedUserCertificate createCertificate(@NonNull Cursor cursor)
+	{
+		return new ManagedUserCertificate(cursor);
+	}
+
+	@Override
+	protected boolean isInstalled(@NonNull ManagedUserCertificate certificate)
+	{
+		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S)
+		{
+			return devicePolicyManager.hasKeyPair(certificate.getAlias());
+		}
+		/* We don't know, so we assume a certificate we installed may have been removed by the
+		 * user, so we install it again to make sure it's still there */
+		return false;
+	}
+}