Merge remote-tracking branch '0xacab/0.9.8' into 8802_drawer

1 files changed, 927 insertions, 0 deletions

diff --git a/app/src/main/java/se/leap/bitmaskclient/ProviderApiManagerBase.java b/app/src/main/java/se/leap/bitmaskclient/ProviderApiManagerBase.java
new file mode 100644
index 00000000..9f5fdc2d
--- /dev/null
+++ b/app/src/main/java/se/leap/bitmaskclient/ProviderApiManagerBase.java
@@ -0,0 +1,927 @@
+/**
+ * Copyright (c) 2018 LEAP Encryption Access Project and contributers
+ *
+ * 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package se.leap.bitmaskclient;
+
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.content.res.Resources;
+import android.os.Bundle;
+import android.os.ResultReceiver;
+import android.support.annotation.NonNull;
+import android.util.Base64;
+import android.util.Pair;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.IOException;
+import java.math.BigInteger;
+import java.net.ConnectException;
+import java.net.MalformedURLException;
+import java.net.SocketTimeoutException;
+import java.net.UnknownHostException;
+import java.net.UnknownServiceException;
+import java.security.NoSuchAlgorithmException;
+import java.security.cert.CertificateEncodingException;
+import java.security.cert.CertificateException;
+import java.security.cert.CertificateExpiredException;
+import java.security.cert.CertificateNotYetValidException;
+import java.security.cert.X509Certificate;
+import java.security.interfaces.RSAPrivateKey;
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.net.ssl.SSLHandshakeException;
+
+import okhttp3.OkHttpClient;
+import se.leap.bitmaskclient.userstatus.SessionDialog;
+import se.leap.bitmaskclient.userstatus.User;
+import se.leap.bitmaskclient.userstatus.UserStatus;
+
+import static se.leap.bitmaskclient.ConfigHelper.getFingerprintFromCertificate;
+import static se.leap.bitmaskclient.DownloadFailedDialog.DOWNLOAD_ERRORS.ERROR_CERTIFICATE_PINNING;
+import static se.leap.bitmaskclient.DownloadFailedDialog.DOWNLOAD_ERRORS.ERROR_CORRUPTED_PROVIDER_JSON;
+import static se.leap.bitmaskclient.DownloadFailedDialog.DOWNLOAD_ERRORS.ERROR_INVALID_CERTIFICATE;
+import static se.leap.bitmaskclient.Provider.MAIN_URL;
+import static se.leap.bitmaskclient.ProviderAPI.CORRECTLY_DOWNLOADED_CERTIFICATE;
+import static se.leap.bitmaskclient.ProviderAPI.CORRECTLY_DOWNLOADED_EIP_SERVICE;
+import static se.leap.bitmaskclient.ProviderAPI.CURRENT_PROGRESS;
+import static se.leap.bitmaskclient.ProviderAPI.DOWNLOAD_CERTIFICATE;
+import static se.leap.bitmaskclient.ProviderAPI.DOWNLOAD_EIP_SERVICE;
+import static se.leap.bitmaskclient.ProviderAPI.ERRORID;
+import static se.leap.bitmaskclient.ProviderAPI.ERRORS;
+import static se.leap.bitmaskclient.ProviderAPI.FAILED_LOGIN;
+import static se.leap.bitmaskclient.ProviderAPI.FAILED_SIGNUP;
+import static se.leap.bitmaskclient.ProviderAPI.INCORRECTLY_DOWNLOADED_CERTIFICATE;
+import static se.leap.bitmaskclient.ProviderAPI.INCORRECTLY_DOWNLOADED_EIP_SERVICE;
+import static se.leap.bitmaskclient.ProviderAPI.LOGOUT_FAILED;
+import static se.leap.bitmaskclient.ProviderAPI.LOG_IN;
+import static se.leap.bitmaskclient.ProviderAPI.LOG_OUT;
+import static se.leap.bitmaskclient.ProviderAPI.PARAMETERS;
+import static se.leap.bitmaskclient.ProviderAPI.PROVIDER_NOK;
+import static se.leap.bitmaskclient.ProviderAPI.PROVIDER_OK;
+import static se.leap.bitmaskclient.ProviderAPI.RECEIVER_KEY;
+import static se.leap.bitmaskclient.ProviderAPI.RESULT_KEY;
+import static se.leap.bitmaskclient.ProviderAPI.SET_UP_PROVIDER;
+import static se.leap.bitmaskclient.ProviderAPI.SIGN_UP;
+import static se.leap.bitmaskclient.ProviderAPI.SUCCESSFUL_LOGIN;
+import static se.leap.bitmaskclient.ProviderAPI.SUCCESSFUL_LOGOUT;
+import static se.leap.bitmaskclient.ProviderAPI.SUCCESSFUL_SIGNUP;
+import static se.leap.bitmaskclient.ProviderAPI.UPDATE_PROGRESSBAR;
+import static se.leap.bitmaskclient.ProviderAPI.UPDATE_PROVIDER_DETAILS;
+import static se.leap.bitmaskclient.R.string.certificate_error;
+import static se.leap.bitmaskclient.R.string.error_io_exception_user_message;
+import static se.leap.bitmaskclient.R.string.error_json_exception_user_message;
+import static se.leap.bitmaskclient.R.string.error_no_such_algorithm_exception_user_message;
+import static se.leap.bitmaskclient.R.string.malformed_url;
+import static se.leap.bitmaskclient.R.string.server_unreachable_message;
+import static se.leap.bitmaskclient.R.string.service_is_down_error;
+import static se.leap.bitmaskclient.R.string.warning_corrupted_provider_cert;
+import static se.leap.bitmaskclient.R.string.warning_corrupted_provider_details;
+import static se.leap.bitmaskclient.R.string.warning_expired_provider_cert;
+
+/**
+ * Implements the logic of the http api calls. The methods of this class needs to be called from
+ * a background thread.
+ */
+
+public abstract class ProviderApiManagerBase {
+
+    public interface ProviderApiServiceCallback {
+        void broadcastProgress(Intent intent);
+    }
+
+    private ProviderApiServiceCallback serviceCallback;
+
+    protected static volatile boolean
+            CA_CERT_DOWNLOADED = false,
+            PROVIDER_JSON_DOWNLOADED = false,
+            EIP_SERVICE_JSON_DOWNLOADED = false;
+
+    protected static String lastProviderMainUrl;
+    protected static boolean go_ahead = true;
+    protected static SharedPreferences preferences;
+    protected static String providerApiUrl;
+    protected static String providerCaCertFingerprint;
+    protected static String providerCaCert;
+    protected static JSONObject providerDefinition;
+    protected Resources resources;
+    protected OkHttpClientGenerator clientGenerator;
+
+    public static void stop() {
+        go_ahead = false;
+    }
+
+    public static String lastProviderMainUrl() {
+        return lastProviderMainUrl;
+    }
+
+    public ProviderApiManagerBase(SharedPreferences preferences, Resources resources, OkHttpClientGenerator clientGenerator, ProviderApiServiceCallback callback) {
+        this.preferences = preferences;
+        this.resources = resources;
+        this.serviceCallback = callback;
+        this.clientGenerator = clientGenerator;
+    }
+
+    public void handleIntent(Intent command) {
+        final ResultReceiver receiver = command.getParcelableExtra(RECEIVER_KEY);
+        String action = command.getAction();
+        Bundle parameters = command.getBundleExtra(PARAMETERS);
+
+        if (providerApiUrl == null && preferences.contains(Provider.KEY)) {
+            try {
+                JSONObject provider_json = new JSONObject(preferences.getString(Provider.KEY, ""));
+                providerApiUrl = provider_json.getString(Provider.API_URL) + "/" + provider_json.getString(Provider.API_VERSION);
+                go_ahead = true;
+            } catch (JSONException e) {
+                go_ahead = false;
+            }
+        }
+
+        if (action.equals(UPDATE_PROVIDER_DETAILS)) {
+            resetProviderDetails();
+            Bundle task = new Bundle();
+            task.putString(MAIN_URL, lastProviderMainUrl);
+            Bundle result = setUpProvider(task);
+            if (result.getBoolean(RESULT_KEY)) {
+                receiver.send(PROVIDER_OK, result);
+            } else {
+                receiver.send(PROVIDER_NOK, result);
+            }
+        } else if (action.equalsIgnoreCase(SET_UP_PROVIDER)) {
+            Bundle result = setUpProvider(parameters);
+            if (go_ahead) {
+                if (result.getBoolean(RESULT_KEY)) {
+                    receiver.send(PROVIDER_OK, result);
+                } else {
+                    receiver.send(PROVIDER_NOK, result);
+                }
+            }
+        } else if (action.equalsIgnoreCase(SIGN_UP)) {
+            UserStatus.updateStatus(UserStatus.SessionStatus.SIGNING_UP, resources);
+            Bundle result = tryToRegister(parameters);
+            if (result.getBoolean(RESULT_KEY)) {
+                receiver.send(SUCCESSFUL_SIGNUP, result);
+            } else {
+                receiver.send(FAILED_SIGNUP, result);
+            }
+        } else if (action.equalsIgnoreCase(LOG_IN)) {
+            UserStatus.updateStatus(UserStatus.SessionStatus.LOGGING_IN, resources);
+            Bundle result = tryToAuthenticate(parameters);
+            if (result.getBoolean(RESULT_KEY)) {
+                receiver.send(SUCCESSFUL_LOGIN, result);
+                UserStatus.updateStatus(UserStatus.SessionStatus.LOGGED_IN, resources);
+            } else {
+                receiver.send(FAILED_LOGIN, result);
+                UserStatus.updateStatus(UserStatus.SessionStatus.NOT_LOGGED_IN, resources);
+            }
+        } else if (action.equalsIgnoreCase(LOG_OUT)) {
+            UserStatus.updateStatus(UserStatus.SessionStatus.LOGGING_OUT, resources);
+            if (logOut()) {
+                receiver.send(SUCCESSFUL_LOGOUT, Bundle.EMPTY);
+                UserStatus.updateStatus(UserStatus.SessionStatus.LOGGED_OUT, resources);
+            } else {
+                receiver.send(LOGOUT_FAILED, Bundle.EMPTY);
+                UserStatus.updateStatus(UserStatus.SessionStatus.DIDNT_LOG_OUT, resources);
+            }
+        } else if (action.equalsIgnoreCase(DOWNLOAD_CERTIFICATE)) {
+            if (updateVpnCertificate()) {
+                receiver.send(CORRECTLY_DOWNLOADED_CERTIFICATE, Bundle.EMPTY);
+            } else {
+                receiver.send(INCORRECTLY_DOWNLOADED_CERTIFICATE, Bundle.EMPTY);
+            }
+        } else if (action.equalsIgnoreCase(DOWNLOAD_EIP_SERVICE)) {
+            Bundle result = getAndSetEipServiceJson();
+            if (result.getBoolean(RESULT_KEY)) {
+                receiver.send(CORRECTLY_DOWNLOADED_EIP_SERVICE, result);
+            } else {
+                receiver.send(INCORRECTLY_DOWNLOADED_EIP_SERVICE, result);
+            }
+        }
+    }
+
+    protected void resetProviderDetails() {
+        CA_CERT_DOWNLOADED = PROVIDER_JSON_DOWNLOADED = false;
+        deleteProviderDetailsFromPreferences(providerDefinition);
+        providerCaCert = "";
+        providerDefinition = new JSONObject();
+    }
+
+    protected String formatErrorMessage(final int toastStringId) {
+        return formatErrorMessage(resources.getString(toastStringId));
+    }
+
+    private String formatErrorMessage(String errorMessage) {
+        return "{ \"" + ERRORS + "\" : \"" + errorMessage + "\" }";
+    }
+
+    private JSONObject getErrorMessageAsJson(final int toastStringId) {
+        try {
+            return new JSONObject(formatErrorMessage(toastStringId));
+        } catch (JSONException e) {
+            e.printStackTrace();
+            return new JSONObject();
+        }
+    }
+
+    protected void addErrorMessageToJson(JSONObject jsonObject, String errorMessage) {
+        try {
+            jsonObject.put(ERRORS, errorMessage);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+    }
+
+    protected void addErrorMessageToJson(JSONObject jsonObject, String errorMessage, String errorId) {
+        try {
+            jsonObject.put(ERRORS, errorMessage);
+            jsonObject.put(ERRORID, errorId);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+    }
+
+
+
+
+    private Bundle tryToRegister(Bundle task) {
+        Bundle result = new Bundle();
+        int progress = 0;
+
+        String username = User.userName();
+        String password = task.getString(SessionDialog.PASSWORD);
+
+        if (validUserLoginData(username, password)) {
+            result = register(username, password);
+            broadcastProgress(progress++);
+        } else {
+            if (!wellFormedPassword(password)) {
+                result.putBoolean(RESULT_KEY, false);
+                result.putString(SessionDialog.USERNAME, username);
+                result.putBoolean(SessionDialog.ERRORS.PASSWORD_INVALID_LENGTH.toString(), true);
+            }
+            if (!validUsername(username)) {
+                result.putBoolean(RESULT_KEY, false);
+                result.putBoolean(SessionDialog.ERRORS.USERNAME_MISSING.toString(), true);
+            }
+        }
+
+        return result;
+    }
+
+    private Bundle register(String username, String password) {
+        JSONObject stepResult = null;
+        OkHttpClient okHttpClient = clientGenerator.initSelfSignedCAHttpClient(stepResult);
+        if (okHttpClient == null) {
+            return authFailedNotification(stepResult, username);
+        }
+
+        LeapSRPSession client = new LeapSRPSession(username, password);
+        byte[] salt = client.calculateNewSalt();
+
+        BigInteger password_verifier = client.calculateV(username, password, salt);
+
+        JSONObject api_result = sendNewUserDataToSRPServer(providerApiUrl, username, new BigInteger(1, salt).toString(16), password_verifier.toString(16), okHttpClient);
+
+        Bundle result = new Bundle();
+        if (api_result.has(ERRORS))
+            result = authFailedNotification(api_result, username);
+        else {
+            result.putString(SessionDialog.USERNAME, username);
+            result.putString(SessionDialog.PASSWORD, password);
+            result.putBoolean(RESULT_KEY, true);
+        }
+
+        return result;
+    }
+
+    /**
+     * Starts the authentication process using SRP protocol.
+     *
+     * @param task containing: username, password and api url.
+     * @return a bundle with a boolean value mapped to a key named RESULT_KEY, and which is true if authentication was successful.
+     */
+    private Bundle tryToAuthenticate(Bundle task) {
+        Bundle result = new Bundle();
+        int progress = 0;
+
+        String username = User.userName();
+        String password = task.getString(SessionDialog.PASSWORD);
+        if (validUserLoginData(username, password)) {
+            result = authenticate(username, password);
+            broadcastProgress(progress++);
+        } else {
+            if (!wellFormedPassword(password)) {
+                result.putBoolean(RESULT_KEY, false);
+                result.putString(SessionDialog.USERNAME, username);
+                result.putBoolean(SessionDialog.ERRORS.PASSWORD_INVALID_LENGTH.toString(), true);
+            }
+            if (!validUsername(username)) {
+                result.putBoolean(RESULT_KEY, false);
+                result.putBoolean(SessionDialog.ERRORS.USERNAME_MISSING.toString(), true);
+            }
+        }
+
+        return result;
+    }
+
+    private Bundle authenticate(String username, String password) {
+        Bundle result = new Bundle();
+        JSONObject stepResult = new JSONObject();
+        OkHttpClient okHttpClient = clientGenerator.initSelfSignedCAHttpClient(stepResult);
+        if (okHttpClient == null) {
+            return authFailedNotification(stepResult, username);
+        }
+
+        LeapSRPSession client = new LeapSRPSession(username, password);
+        byte[] A = client.exponential();
+
+        JSONObject step_result = sendAToSRPServer(providerApiUrl, username, new BigInteger(1, A).toString(16), okHttpClient);
+        try {
+            String salt = step_result.getString(LeapSRPSession.SALT);
+            byte[] Bbytes = new BigInteger(step_result.getString("B"), 16).toByteArray();
+            byte[] M1 = client.response(new BigInteger(salt, 16).toByteArray(), Bbytes);
+            if (M1 != null) {
+                step_result = sendM1ToSRPServer(providerApiUrl, username, M1, okHttpClient);
+                setTokenIfAvailable(step_result);
+                byte[] M2 = new BigInteger(step_result.getString(LeapSRPSession.M2), 16).toByteArray();
+                if (client.verify(M2)) {
+                    result.putBoolean(RESULT_KEY, true);
+                } else {
+                    authFailedNotification(step_result, username);
+                }
+            } else {
+                result.putBoolean(RESULT_KEY, false);
+                result.putString(SessionDialog.USERNAME, username);
+                result.putString(resources.getString(R.string.user_message), resources.getString(R.string.error_srp_math_error_user_message));
+            }
+        } catch (JSONException e) {
+            result = authFailedNotification(step_result, username);
+            e.printStackTrace();
+        }
+
+        return result;
+    }
+
+    private boolean setTokenIfAvailable(JSONObject authentication_step_result) {
+        try {
+            LeapSRPSession.setToken(authentication_step_result.getString(LeapSRPSession.TOKEN));
+        } catch (JSONException e) {
+            return false;
+        }
+        return true;
+    }
+
+    private Bundle authFailedNotification(JSONObject result, String username) {
+        Bundle userNotificationBundle = new Bundle();
+        Object baseErrorMessage = result.opt(ERRORS);
+        if (baseErrorMessage != null) {
+            if (baseErrorMessage instanceof JSONObject) {
+                try {
+                    JSONObject errorMessage = result.getJSONObject(ERRORS);
+                    String errorType = errorMessage.keys().next().toString();
+                    String message = errorMessage.get(errorType).toString();
+                    userNotificationBundle.putString(resources.getString(R.string.user_message), message);
+                } catch (JSONException e) {
+                    e.printStackTrace();
+                }
+            } else if (baseErrorMessage instanceof String) {
+                try {
+                    String errorMessage = result.getString(ERRORS);
+                    userNotificationBundle.putString(resources.getString(R.string.user_message), errorMessage);
+                } catch (JSONException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+
+        if (!username.isEmpty())
+            userNotificationBundle.putString(SessionDialog.USERNAME, username);
+        userNotificationBundle.putBoolean(RESULT_KEY, false);
+
+        return userNotificationBundle;
+    }
+
+    /**
+     * Sets up an intent with the progress value passed as a parameter
+     * and sends it as a broadcast.
+     *
+     * @param progress
+     */
+    protected void broadcastProgress(int progress) {
+        Intent intentUpdate = new Intent();
+        intentUpdate.setAction(UPDATE_PROGRESSBAR);
+        intentUpdate.addCategory(Intent.CATEGORY_DEFAULT);
+        intentUpdate.putExtra(CURRENT_PROGRESS, progress);
+        serviceCallback.broadcastProgress(intentUpdate);
+        //sendBroadcast(intentUpdate);
+    }
+
+    /**
+     * Validates parameters entered by the user to log in
+     *
+     * @param username
+     * @param password
+     * @return true if both parameters are present and the entered password length is greater or equal to eight (8).
+     */
+    private boolean validUserLoginData(String username, String password) {
+        return validUsername(username) && wellFormedPassword(password);
+    }
+
+    private boolean validUsername(String username) {
+        return username != null && !username.isEmpty();
+    }
+
+    /**
+     * Validates a password
+     *
+     * @param password
+     * @return true if the entered password length is greater or equal to eight (8).
+     */
+    private boolean wellFormedPassword(String password) {
+        return password != null && password.length() >= 8;
+    }
+
+    /**
+     * Sends an HTTP POST request to the authentication server with the SRP Parameter A.
+     *
+     * @param server_url
+     * @param username
+     * @param clientA    First SRP parameter sent
+     * @param okHttpClient
+     * @return response from authentication server
+     */
+    private JSONObject sendAToSRPServer(String server_url, String username, String clientA, OkHttpClient okHttpClient) {
+        SrpCredentials srpCredentials = new SrpCredentials(username, clientA);
+        return sendToServer(server_url + "/sessions.json", "POST", srpCredentials.toString(), okHttpClient);
+    }
+
+    /**
+     * Sends an HTTP PUT request to the authentication server with the SRP Parameter M1 (or simply M).
+     *
+     * @param server_url
+     * @param username
+     * @param m1         Second SRP parameter sent
+     * @param okHttpClient
+     * @return response from authentication server
+     */
+    private JSONObject sendM1ToSRPServer(String server_url, String username, byte[] m1, OkHttpClient okHttpClient) {
+        String m1json = "{\"client_auth\":\"" + new BigInteger(1, ConfigHelper.trim(m1)).toString(16)+ "\"}";
+        return sendToServer(server_url + "/sessions/" + username + ".json", "PUT", m1json, okHttpClient);
+    }
+
+    /**
+     * Sends an HTTP POST request to the api server to register a new user.
+     *
+     * @param server_url
+     * @param username
+     * @param salt
+     * @param password_verifier
+     * @param okHttpClient
+     * @return response from authentication server
+     */
+    private JSONObject sendNewUserDataToSRPServer(String server_url, String username, String salt, String password_verifier, OkHttpClient okHttpClient) {
+        return sendToServer(server_url + "/users.json", "POST", new SrpRegistrationData(username, salt, password_verifier).toString(), okHttpClient);
+    }
+
+    /**
+     * Executes an HTTP request expecting a JSON response.
+     *
+     * @param url
+     * @param request_method
+     * @return response from authentication server
+     */
+    private JSONObject sendToServer(String url, String request_method, String jsonString, OkHttpClient okHttpClient) {
+        return requestJsonFromServer(url, request_method, jsonString, null, okHttpClient);
+    }
+
+    protected String sendGetStringToServer(@NonNull String url, @NonNull List<Pair<String, String>> headerArgs, @NonNull OkHttpClient okHttpClient) {
+        return requestStringFromServer(url, "GET", null, headerArgs, okHttpClient);
+    }
+
+
+
+    private JSONObject requestJsonFromServer(@NonNull String url, @NonNull String request_method, String jsonString, @NonNull List<Pair<String, String>> headerArgs, @NonNull OkHttpClient okHttpClient)  {
+        JSONObject responseJson;
+        String plain_response = requestStringFromServer(url, request_method, jsonString, headerArgs, okHttpClient);
+
+        try {
+            responseJson = new JSONObject(plain_response);
+        } catch (JSONException e) {
+            e.printStackTrace();
+            responseJson = getErrorMessageAsJson(error_json_exception_user_message);
+        }
+        return responseJson;
+
+    }
+
+    private String requestStringFromServer(@NonNull String url, @NonNull String request_method, String jsonString, @NonNull List<Pair<String, String>> headerArgs, @NonNull OkHttpClient okHttpClient) {
+        String plainResponseBody = null;
+
+        try {
+
+            plainResponseBody = ProviderApiConnector.requestStringFromServer(url, request_method, jsonString, headerArgs, okHttpClient);
+
+        } catch (NullPointerException npe) {
+            plainResponseBody = formatErrorMessage(error_json_exception_user_message);
+        } catch (UnknownHostException | SocketTimeoutException e) {
+            plainResponseBody = formatErrorMessage(server_unreachable_message);
+        } catch (MalformedURLException e) {
+            plainResponseBody = formatErrorMessage(malformed_url);
+        } catch (SSLHandshakeException e) {
+            plainResponseBody = formatErrorMessage(certificate_error);
+        } catch (ConnectException e) {
+            plainResponseBody = formatErrorMessage(service_is_down_error);
+        } catch (IllegalArgumentException e) {
+            plainResponseBody = formatErrorMessage(error_no_such_algorithm_exception_user_message);
+        } catch (UnknownServiceException e) {
+            //unable to find acceptable protocols - tlsv1.2 not enabled?
+            plainResponseBody = formatErrorMessage(error_no_such_algorithm_exception_user_message);
+        } catch (IOException e) {
+            plainResponseBody = formatErrorMessage(error_io_exception_user_message);
+        }
+
+        return plainResponseBody;
+    }
+
+    private boolean canConnect(String caCert, JSONObject providerDefinition, Bundle result) {
+        JSONObject errorJson = new JSONObject();
+        String baseUrl = getApiUrl(providerDefinition);
+
+        OkHttpClient okHttpClient = clientGenerator.initSelfSignedCAHttpClient(errorJson, caCert);
+        if (okHttpClient == null) {
+            result.putString(ERRORS, errorJson.toString());
+            return false;
+        }
+
+        try {
+
+            return ProviderApiConnector.canConnect(okHttpClient, baseUrl);
+
+        }  catch (UnknownHostException | SocketTimeoutException e) {
+            setErrorResult(result, server_unreachable_message, null);
+        } catch (MalformedURLException e) {
+            setErrorResult(result, malformed_url, null);
+        } catch (SSLHandshakeException e) {
+            setErrorResult(result, warning_corrupted_provider_cert, ERROR_INVALID_CERTIFICATE.toString());
+        } catch (ConnectException e) {
+            setErrorResult(result, service_is_down_error, null);
+        } catch (IllegalArgumentException e) {
+            setErrorResult(result, error_no_such_algorithm_exception_user_message, null);
+        } catch (UnknownServiceException e) {
+            //unable to find acceptable protocols - tlsv1.2 not enabled?
+            setErrorResult(result, error_no_such_algorithm_exception_user_message, null);
+        } catch (IOException e) {
+            setErrorResult(result, error_io_exception_user_message, null);
+        }
+        return false;
+    }
+
+    /**
+     * Downloads a provider.json from a given URL, adding a new provider using the given name.
+     *
+     * @param task containing a boolean meaning if the provider is custom or not, another boolean meaning if the user completely trusts this provider, the provider name and its provider.json url.
+     * @return a bundle with a boolean value mapped to a key named RESULT_KEY, and which is true if the update was successful.
+     */
+    protected abstract Bundle setUpProvider(Bundle task);
+
+    /**
+     * Downloads the eip-service.json from a given URL, and saves eip service capabilities including the offered gateways
+     * @return a bundle with a boolean value mapped to a key named RESULT_KEY, and which is true if the download was successful.
+     */
+    protected abstract Bundle getAndSetEipServiceJson();
+
+    /**
+     * Downloads a new OpenVPN certificate, attaching authenticated cookie for authenticated certificate.
+     *
+     * @return true if certificate was downloaded correctly, false if provider.json is not present in SharedPreferences, or if the certificate url could not be parsed as a URI, or if there was an SSL error.
+     */
+    protected abstract boolean updateVpnCertificate();
+
+
+    protected static boolean caCertDownloaded() {
+        return CA_CERT_DOWNLOADED;
+    }
+
+    protected boolean isValidJson(String jsonString) {
+        try {
+            new JSONObject(jsonString);
+            return true;
+        } catch(JSONException e) {
+            return false;
+        } catch(NullPointerException e) {
+            e.printStackTrace();
+            return false;
+        }
+    }
+
+    protected boolean validCertificate(String cert_string) {
+        boolean result = false;
+        if (!ConfigHelper.checkErroneousDownload(cert_string)) {
+            X509Certificate certificate = ConfigHelper.parseX509CertificateFromString(cert_string);
+            try {
+                if (certificate != null) {
+                    JSONObject provider_json = new JSONObject(preferences.getString(Provider.KEY, ""));
+                    String fingerprint = provider_json.getString(Provider.CA_CERT_FINGERPRINT);
+                    String encoding = fingerprint.split(":")[0];
+                    String expected_fingerprint = fingerprint.split(":")[1];
+                    String real_fingerprint = getFingerprintFromCertificate(certificate, encoding);
+
+                    result = real_fingerprint.trim().equalsIgnoreCase(expected_fingerprint.trim());
+                } else
+                    result = false;
+            } catch (JSONException | NoSuchAlgorithmException | CertificateEncodingException e) {
+                result = false;
+            }
+        }
+
+        return result;
+    }
+
+    protected void checkPersistedProviderUpdates() {
+        String providerDomain = getDomainFromMainURL(lastProviderMainUrl);
+        if (hasUpdatedProviderDetails(providerDomain)) {
+            providerCaCert = getPersistedProviderCA(providerDomain);
+            providerDefinition = getPersistedProviderDefinition(providerDomain);
+            providerCaCertFingerprint = getPersistedCaCertFingerprint(providerDomain);
+            providerApiUrl = getApiUrlWithVersion(providerDefinition);
+        }
+    }
+
+    protected Bundle validateProviderDetails() {
+        Bundle result = validateCertificateForProvider(providerCaCert, providerDefinition, lastProviderMainUrl);
+
+        //invalid certificate or no certificate
+        if (result.containsKey(ERRORS) || (result.containsKey(RESULT_KEY) && !result.getBoolean(RESULT_KEY)) ) {
+            return result;
+        }
+
+        //valid certificate: skip download, save loaded provider CA cert and provider definition directly
+        try {
+            preferences.edit().putString(Provider.KEY, providerDefinition.toString()).
+                    putBoolean(Constants.PROVIDER_ALLOW_ANONYMOUS, providerDefinition.getJSONObject(Provider.SERVICE).getBoolean(Constants.PROVIDER_ALLOW_ANONYMOUS)).
+                    putBoolean(Constants.PROVIDER_ALLOWED_REGISTERED, providerDefinition.getJSONObject(Provider.SERVICE).getBoolean(Constants.PROVIDER_ALLOWED_REGISTERED)).
+                    putString(Provider.CA_CERT, providerCaCert).commit();
+            CA_CERT_DOWNLOADED = true;
+            PROVIDER_JSON_DOWNLOADED = true;
+            result.putBoolean(RESULT_KEY, true);
+        } catch (JSONException e) {
+            e.printStackTrace();
+            setErrorResult(result, warning_corrupted_provider_details, ERROR_CORRUPTED_PROVIDER_JSON.toString());
+        }
+
+        return result;
+    }
+
+    protected Bundle validateCertificateForProvider(String cert_string, JSONObject providerDefinition, String mainUrl) {
+        Bundle result = new Bundle();
+        result.putBoolean(RESULT_KEY, false);
+
+        if (ConfigHelper.checkErroneousDownload(cert_string)) {
+            return result;
+        }
+
+        X509Certificate certificate = ConfigHelper.parseX509CertificateFromString(cert_string);
+        if (certificate == null) {
+            return setErrorResult(result, warning_corrupted_provider_cert, ERROR_INVALID_CERTIFICATE.toString());
+        }
+        try {
+            certificate.checkValidity();
+            String fingerprint = getCaCertFingerprint(providerDefinition);
+            String encoding = fingerprint.split(":")[0];
+            String expected_fingerprint = fingerprint.split(":")[1];
+            String real_fingerprint = getFingerprintFromCertificate(certificate, encoding);
+            if (!real_fingerprint.trim().equalsIgnoreCase(expected_fingerprint.trim())) {
+                return setErrorResult(result, warning_corrupted_provider_cert, ERROR_CERTIFICATE_PINNING.toString());
+            }
+
+
+            if (!hasApiUrlExpectedDomain(providerDefinition, mainUrl)){
+                return setErrorResult(result, warning_corrupted_provider_details, ERROR_CORRUPTED_PROVIDER_JSON.toString());
+            }
+
+            if (!canConnect(cert_string, providerDefinition, result)) {
+                return result;
+            }
+        } catch (NoSuchAlgorithmException e ) {
+            return setErrorResult(result, error_no_such_algorithm_exception_user_message, null);
+        } catch (ArrayIndexOutOfBoundsException e) {
+            return setErrorResult(result, warning_corrupted_provider_details, ERROR_CORRUPTED_PROVIDER_JSON.toString());
+        } catch (CertificateEncodingException | CertificateNotYetValidException | CertificateExpiredException e) {
+            return setErrorResult(result, warning_expired_provider_cert, ERROR_INVALID_CERTIFICATE.toString());
+        }
+
+        result.putBoolean(RESULT_KEY, true);
+        return result;
+    }
+
+    protected Bundle setErrorResult(Bundle result, int errorMessageId, String errorId) {
+        JSONObject errorJson = new JSONObject();
+        if (errorId != null) {
+            addErrorMessageToJson(errorJson, resources.getString(errorMessageId), errorId);
+        } else {
+            addErrorMessageToJson(errorJson, resources.getString(errorMessageId));
+        }
+        result.putString(ERRORS, errorJson.toString());
+        result.putBoolean(RESULT_KEY, false);
+        return result;
+    }
+
+    /**
+     * This method aims to prevent attacks where the provider.json file got manipulated by a third party.
+     * The main url is visible to the provider when setting up a new provider.
+     * The user is responsible to check that this is the provider main url he intends to connect to.
+     *
+     * @param providerDefinition
+     * @param mainUrlString
+     * @return
+     */
+    private boolean hasApiUrlExpectedDomain(JSONObject providerDefinition, String mainUrlString) {
+        //  fix against "api_uri": "https://calyx.net.malicious.url.net:4430",
+        String apiUrlString = getApiUrl(providerDefinition);
+        String providerDomain = getProviderDomain(providerDefinition);
+        if (mainUrlString.contains(providerDomain) && apiUrlString.contains(providerDomain  + ":")) {
+            return true;
+        }
+        return false;
+    }
+
+    protected String getCaCertFingerprint(JSONObject providerDefinition) {
+        try {
+            return providerDefinition.getString(Provider.CA_CERT_FINGERPRINT);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+        return "";
+    }
+
+    protected String getApiUrl(JSONObject providerDefinition) {
+        try {
+            return providerDefinition.getString(Provider.API_URL);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+        return "";
+    }
+
+    protected String getApiUrlWithVersion(JSONObject providerDefinition) {
+        try {
+            return providerDefinition.getString(Provider.API_URL) + "/" + providerDefinition.getString(Provider.API_VERSION);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+        return "";
+    }
+
+    protected void deleteProviderDetailsFromPreferences(JSONObject providerDefinition) {
+        String providerDomain = getProviderDomain(providerDefinition);
+
+        if (preferences.contains(Provider.KEY + "." + providerDomain)) {
+            preferences.edit().remove(Provider.KEY + "." + providerDomain).apply();
+        }
+        if (preferences.contains(Provider.CA_CERT + "." + providerDomain)) {
+            preferences.edit().remove(Provider.CA_CERT + "." + providerDomain).apply();
+        }
+        if (preferences.contains(Provider.CA_CERT_FINGERPRINT + "." + providerDomain)) {
+            preferences.edit().remove(Provider.CA_CERT_FINGERPRINT + "." + providerDomain).apply();
+        }
+    }
+
+    protected String getPersistedCaCertFingerprint(String providerDomain) {
+        try {
+            return getPersistedProviderDefinition(providerDomain).getString(Provider.CA_CERT_FINGERPRINT);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+        return "";
+    }
+
+    protected JSONObject getPersistedProviderDefinition(String providerDomain) {
+        try {
+            return new JSONObject(preferences.getString(Provider.KEY + "." + providerDomain, ""));
+        } catch (JSONException e) {
+            e.printStackTrace();
+            return new JSONObject();
+        }
+    }
+
+    protected String getPersistedProviderCA(String providerDomain) {
+        return preferences.getString(Provider.CA_CERT + "." + providerDomain, "");
+    }
+
+    protected String getProviderDomain(JSONObject providerDefinition) {
+        try {
+            return providerDefinition.getString(Provider.DOMAIN);
+        } catch (JSONException e) {
+            e.printStackTrace();
+        }
+
+        return "";
+    }
+
+    protected boolean hasUpdatedProviderDetails(String domain) {
+        return preferences.contains(Provider.KEY + "." + domain) && preferences.contains(Provider.CA_CERT + "." + domain);
+    }
+
+    protected String getDomainFromMainURL(String mainUrl) {
+        return mainUrl.replaceFirst("http[s]?://", "").replaceFirst("/.*", "");
+
+    }
+
+    /**
+     * Interprets the error message as a JSON object and extract the "errors" keyword pair.
+     * If the error message is not a JSON object, then it is returned untouched.
+     *
+     * @param string_json_error_message
+     * @return final error message
+     */
+    protected String pickErrorMessage(String string_json_error_message) {
+        String error_message = "";
+        try {
+            JSONObject json_error_message = new JSONObject(string_json_error_message);
+            error_message = json_error_message.getString(ERRORS);
+        } catch (JSONException e) {
+            // TODO Auto-generated catch block
+            error_message = string_json_error_message;
+        } catch (NullPointerException e) {
+            //do nothing
+        }
+
+        return error_message;
+    }
+
+    @NonNull
+    protected List<Pair<String, String>> getAuthorizationHeader() {
+        List<Pair<String, String>> headerArgs = new ArrayList<>();
+        if (!LeapSRPSession.getToken().isEmpty()) {
+            Pair<String, String> authorizationHeaderPair = new Pair<>(LeapSRPSession.AUTHORIZATION_HEADER, "Token token=" + LeapSRPSession.getToken());
+            headerArgs.add(authorizationHeaderPair);
+        }
+        return headerArgs;
+    }
+
+    private boolean logOut() {
+        OkHttpClient okHttpClient = clientGenerator.initSelfSignedCAHttpClient(new JSONObject());
+        if (okHttpClient == null) {
+            return false;
+        }
+
+        String deleteUrl = providerApiUrl + "/logout";
+        int progress = 0;
+
+        if (ProviderApiConnector.delete(okHttpClient, deleteUrl)) {
+            broadcastProgress(progress++);
+            LeapSRPSession.setToken("");
+            return true;
+        }
+        return false;
+    }
+
+    //FIXME: don't save private keys in shared preferences! use the keystore
+    protected boolean loadCertificate(String cert_string) {
+        if (cert_string == null) {
+            return false;
+        }
+
+        try {
+            // API returns concatenated cert & key.  Split them for OpenVPN options
+            String certificateString = null, keyString = null;
+            String[] certAndKey = cert_string.split("(?<=-\n)");
+            for (int i = 0; i < certAndKey.length - 1; i++) {
+                if (certAndKey[i].contains("KEY")) {
+                    keyString = certAndKey[i++] + certAndKey[i];
+                } else if (certAndKey[i].contains("CERTIFICATE")) {
+                    certificateString = certAndKey[i++] + certAndKey[i];
+                }
+            }
+
+            RSAPrivateKey key = ConfigHelper.parseRsaKeyFromString(keyString);
+            keyString = Base64.encodeToString(key.getEncoded(), Base64.DEFAULT);
+            preferences.edit().putString(Constants.PROVIDER_PRIVATE_KEY, "-----BEGIN RSA PRIVATE KEY-----\n" + keyString + "-----END RSA PRIVATE KEY-----").commit();
+
+            X509Certificate certificate = ConfigHelper.parseX509CertificateFromString(certificateString);
+            certificateString = Base64.encodeToString(certificate.getEncoded(), Base64.DEFAULT);
+            preferences.edit().putString(Constants.PROVIDER_VPN_CERTIFICATE, "-----BEGIN CERTIFICATE-----\n" + certificateString + "-----END CERTIFICATE-----").commit();
+            return true;
+        } catch (CertificateException e) {
+            // TODO Auto-generated catch block
+            e.printStackTrace();
+            return false;
+        }
+    }
+}