Pinning connection to provider.json

Using AndroidPinning library from Moxie, I make sure the provider.json
file Bitmask downloads is fetched from a pinned https connection, so
that the api certificate fingerprint is the good one.

8 files changed, 159 insertions, 71 deletions

diff --git a/app/src/debug/java/se/leap/bitmaskclient/ConfigurationWizard.java b/app/src/debug/java/se/leap/bitmaskclient/ConfigurationWizard.java
index 59d77d83..8910891a 100644
--- a/app/src/debug/java/se/leap/bitmaskclient/ConfigurationWizard.java
+++ b/app/src/debug/java/se/leap/bitmaskclient/ConfigurationWizard.java
@@ -126,7 +126,7 @@ public class ConfigurationWizard extends Activity
 
         if (fragment_manager.findFragmentByTag(ProviderDetailFragment.TAG) == null && setting_up_provider) {
             if (selected_provider != null)
-                onItemSelectedUi(selected_provider);
+                onItemSelectedUi();
             if (progress > 0)
                 mProgressBar.setProgress(progress);
         }
@@ -231,20 +231,18 @@ public class ConfigurationWizard extends Activity
     void onItemSelected(int position) {
         //TODO Code 2 pane view
         selected_provider = adapter.getItem(position);
-        onItemSelectedLogic(selected_provider);
-        onItemSelectedUi(selected_provider);
+        onItemSelectedLogic();
+        onItemSelectedUi();
     }
 
-    private void onItemSelectedLogic(Provider selected_provider) {
-        boolean danger_on = true;
-        if (preferences.contains(ProviderItem.DANGER_ON))
-            danger_on = preferences.getBoolean(ProviderItem.DANGER_ON, false);
-        setUpProvider(selected_provider.mainUrl(), danger_on);
+    private void onItemSelectedLogic() {
+        boolean danger_on = preferences.getBoolean(ProviderItem.DANGER_ON, false);
+        setUpProvider(danger_on);
     }
 
-    private void onItemSelectedUi(Provider provider) {
+    private void onItemSelectedUi() {
         startProgressBar();
-        adapter.hideAllBut(adapter.indexOf(provider));
+        adapter.hideAllBut(adapter.indexOf(selected_provider));
     }
 
     @Override
@@ -383,21 +381,21 @@ public class ConfigurationWizard extends Activity
     private void autoSelectProvider(Provider provider, boolean danger_on) {
         preferences.edit().putBoolean(ProviderItem.DANGER_ON, danger_on).apply();
         selected_provider = provider;
-        onItemSelectedLogic(selected_provider);
-        onItemSelectedUi(selected_provider);
+        onItemSelectedLogic();
+        onItemSelectedUi();
     }
 
     /**
      * Asks ProviderAPI to download a new provider.json file
      *
-     * @param provider_main_url
      * @param danger_on         tells if HTTPS client should bypass certificate errors
      */
-    public void setUpProvider(URL provider_main_url, boolean danger_on) {
+    public void setUpProvider(boolean danger_on) {
         Intent provider_API_command = new Intent(this, ProviderAPI.class);
         Bundle parameters = new Bundle();
-        parameters.putString(Provider.MAIN_URL, provider_main_url.toString());
+        parameters.putString(Provider.MAIN_URL, selected_provider.mainUrl().toString());
         parameters.putBoolean(ProviderItem.DANGER_ON, danger_on);
+        parameters.putString(Provider.CA_CERT_FINGERPRINT, selected_provider.certificatePin());
 
         provider_API_command.setAction(ProviderAPI.SET_UP_PROVIDER);
         provider_API_command.putExtra(ProviderAPI.PARAMETERS, parameters);
diff --git a/app/src/debug/java/se/leap/bitmaskclient/ProviderAPI.java b/app/src/debug/java/se/leap/bitmaskclient/ProviderAPI.java
index 9b5601a9..6c57fca2 100644
--- a/app/src/debug/java/se/leap/bitmaskclient/ProviderAPI.java
+++ b/app/src/debug/java/se/leap/bitmaskclient/ProviderAPI.java
@@ -22,6 +22,10 @@ import android.content.res.*;
 import android.os.*;
 import android.util.*;
 
+import org.apache.http.client.*;
+import org.json.*;
+import org.thoughtcrime.ssl.pinning.util.*;
+
 import java.io.*;
 import java.math.*;
 import java.net.*;
@@ -32,10 +36,7 @@ import java.util.*;
 
 import javax.net.ssl.*;
 
-import org.apache.http.client.*;
-import org.json.*;
-
-import se.leap.bitmaskclient.ProviderListContent.ProviderItem;
+import se.leap.bitmaskclient.ProviderListContent.*;
 import se.leap.bitmaskclient.eip.*;
 
 /**
@@ -88,6 +89,7 @@ public class ProviderAPI extends IntentService {
     private static boolean go_ahead = true;
     private static SharedPreferences preferences;
     private static String provider_api_url;
+    private static String provider_ca_cert_fingerprint;
     private Resources resources;
 
     public static void stop() {
@@ -102,6 +104,7 @@ public class ProviderAPI extends IntentService {
     public void onCreate() {
         super.onCreate();
 
+
         preferences = getSharedPreferences(Dashboard.SHARED_PREFERENCES, MODE_PRIVATE);
         resources = getResources();
         CookieHandler.setDefault(new CookieManager(null, CookiePolicy.ACCEPT_ORIGINAL_SERVER));
@@ -124,7 +127,7 @@ public class ProviderAPI extends IntentService {
         final ResultReceiver receiver = command.getParcelableExtra(RECEIVER_KEY);
         String action = command.getAction();
         Bundle parameters = command.getBundleExtra(PARAMETERS);
-        if (provider_api_url == null) {
+        if (provider_api_url == null && preferences.contains(Provider.KEY)) {
             try {
                 JSONObject provider_json = new JSONObject(preferences.getString(Provider.KEY, "no provider"));
                 provider_api_url = provider_json.getString(Provider.API_URL) + "/" + provider_json.getString(Provider.API_VERSION);
@@ -136,12 +139,10 @@ public class ProviderAPI extends IntentService {
 
         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);
-                }
+            if (result.getBoolean(RESULT_KEY)) {
+                receiver.send(PROVIDER_OK, result);
+            } else {
+                receiver.send(PROVIDER_NOK, result);
             }
         } else if (action.equalsIgnoreCase(SIGN_UP)) {
             UserSessionStatus.updateStatus(UserSessionStatus.SessionStatus.SIGNING_UP, resources);
@@ -511,15 +512,20 @@ public class ProviderAPI extends IntentService {
         int progress = 0;
         Bundle current_download = new Bundle();
 
-        if (task != null && task.containsKey(ProviderItem.DANGER_ON) && task.containsKey(Provider.MAIN_URL)) {
-            last_danger_on = task.getBoolean(ProviderItem.DANGER_ON);
-            last_provider_main_url = task.getString(Provider.MAIN_URL);
+        if (task != null) {
+            last_danger_on = task.containsKey(ProviderItem.DANGER_ON) && task.getBoolean(ProviderItem.DANGER_ON);
+            last_provider_main_url = task.containsKey(Provider.MAIN_URL) ?
+                    task.getString(Provider.MAIN_URL) :
+                    "";
+            provider_ca_cert_fingerprint = task.containsKey(Provider.CA_CERT_FINGERPRINT) ?
+                    task.getString(Provider.CA_CERT_FINGERPRINT) :
+                    "";
             CA_CERT_DOWNLOADED = PROVIDER_JSON_DOWNLOADED = EIP_SERVICE_JSON_DOWNLOADED = false;
             go_ahead = true;
         }
 
         if (!PROVIDER_JSON_DOWNLOADED)
-            current_download = getAndSetProviderJson(last_provider_main_url, last_danger_on);
+            current_download = getAndSetProviderJson(last_provider_main_url, last_danger_on, provider_ca_cert_fingerprint);
         if (PROVIDER_JSON_DOWNLOADED || (current_download.containsKey(RESULT_KEY) && current_download.getBoolean(RESULT_KEY))) {
             broadcastProgress(progress++);
             PROVIDER_JSON_DOWNLOADED = true;
@@ -608,11 +614,15 @@ public class ProviderAPI extends IntentService {
         return hexData.toString();
     }
 
-    private Bundle getAndSetProviderJson(String provider_main_url, boolean danger_on) {
+    private Bundle getAndSetProviderJson(String provider_main_url, boolean danger_on, String provider_ca_cert_fingerprint) {
         Bundle result = new Bundle();
 
         if (go_ahead) {
-            String provider_dot_json_string = downloadWithCommercialCA(provider_main_url + "/provider.json", danger_on);
+            String provider_dot_json_string;
+            if(provider_ca_cert_fingerprint.isEmpty())
+                provider_dot_json_string = downloadWithCommercialCA(provider_main_url + "/provider.json", danger_on);
+            else
+                provider_dot_json_string = downloadWithCommercialCA(provider_main_url + "/provider.json", danger_on, provider_ca_cert_fingerprint);
 
             try {
                 JSONObject provider_json = new JSONObject(provider_dot_json_string);
@@ -678,6 +688,29 @@ public class ProviderAPI extends IntentService {
         return error_message;
     }
 
+    private String downloadWithCommercialCA(String url_string, boolean danger_on, String ca_cert_fingerprint) {
+        String result = "";
+
+        int seconds_of_timeout = 2;
+        String[] pins = new String[] {ca_cert_fingerprint};
+        try {
+            URL url = new URL(url_string);
+            HttpsURLConnection connection = PinningHelper.getPinnedHttpsURLConnection(Dashboard.getContext(), pins, url);
+            connection.setConnectTimeout(seconds_of_timeout * 1000);
+            if (!LeapSRPSession.getToken().isEmpty())
+                connection.addRequestProperty(LeapSRPSession.AUTHORIZATION_HEADER, "Token token = " + LeapSRPSession.getToken());
+            result = new Scanner(connection.getInputStream()).useDelimiter("\\A").next();
+        } catch (IOException e) {
+            if(e instanceof SSLHandshakeException) {
+                result = danger_on ? downloadWithoutCA(url_string) :
+                        formatErrorMessage(R.string.error_security_pinnedcertificate);
+            } else
+                result = formatErrorMessage(R.string.error_io_exception_user_message);
+        }
+
+        return result;
+    }
+
     /**
      * Tries to download the contents of the provided url using commercially validated CA certificate from chosen provider.
      * <p/>
@@ -696,6 +729,7 @@ public class ProviderAPI extends IntentService {
         try {
             provider_url = new URL(string_url);
             URLConnection url_connection = provider_url.openConnection();
+
             url_connection.setConnectTimeout(seconds_of_timeout * 1000);
             if (!LeapSRPSession.getToken().isEmpty())
                 url_connection.addRequestProperty(LeapSRPSession.AUTHORIZATION_HEADER, "Token token = " + LeapSRPSession.getToken());
diff --git a/app/src/main/java/se/leap/bitmaskclient/Provider.java b/app/src/main/java/se/leap/bitmaskclient/Provider.java
index ee06a586..54bfcc19 100644
--- a/app/src/main/java/se/leap/bitmaskclient/Provider.java
+++ b/app/src/main/java/se/leap/bitmaskclient/Provider.java
@@ -32,6 +32,7 @@ public final class Provider implements Parcelable {
 
     private JSONObject definition; // Represents our Provider's provider.json
     private URL main_url;
+    private String certificate_pin;
 
     final public static String
             API_URL = "api_uri",
@@ -62,8 +63,9 @@ public final class Provider implements Parcelable {
         this.main_url = main_url;
     }
 
-    public Provider(File provider_file) {
-
+    public Provider(URL main_url, String certificate_pin) {
+        this.main_url = main_url;
+        this.certificate_pin = certificate_pin;
     }
 
     public static final Parcelable.Creator<Provider> CREATOR
@@ -81,11 +83,9 @@ public final class Provider implements Parcelable {
         try {
             main_url = new URL(in.readString());
             String definition_string = in.readString();
-            if (definition_string != null)
+            if (!definition_string.isEmpty())
                 definition = new JSONObject((definition_string));
-        } catch (MalformedURLException e) {
-            e.printStackTrace();
-        } catch (JSONException e) {
+        } catch (MalformedURLException | JSONException e) {
             e.printStackTrace();
         }
     }
@@ -106,6 +106,8 @@ public final class Provider implements Parcelable {
         return main_url;
     }
 
+    protected String certificatePin() { return certificate_pin; }
+
     protected String getName() {
         // Should we pass the locale in, or query the system here?
         String lang = Locale.getDefault().getLanguage();
diff --git a/app/src/main/java/se/leap/bitmaskclient/ProviderManager.java b/app/src/main/java/se/leap/bitmaskclient/ProviderManager.java
index 40fe8b5a..220a71c8 100644
--- a/app/src/main/java/se/leap/bitmaskclient/ProviderManager.java
+++ b/app/src/main/java/se/leap/bitmaskclient/ProviderManager.java
@@ -49,11 +49,14 @@ public class ProviderManager implements AdapteeCollection<Provider> {
         Set<Provider> providers = new HashSet<Provider>();
         try {
             for (String file : relative_file_paths) {
-                String main_url = extractMainUrlFromInputStream(assets_manager.open(directory + "/" + file));
-                providers.add(new Provider(new URL(main_url)));
+                InputStream provider_file = assets_manager.open(directory + "/" + file);
+                String main_url = extractMainUrlFromInputStream(provider_file);
+                String certificate_pin = extractCertificatePinFromInputStream(provider_file);
+                if(certificate_pin.isEmpty())
+                    providers.add(new Provider(new URL(main_url)));
+                else
+                    providers.add(new Provider(new URL(main_url), certificate_pin));
             }
-        } catch (MalformedURLException e) {
-            e.printStackTrace();
         } catch (IOException e) {
             e.printStackTrace();
         }
@@ -75,30 +78,43 @@ public class ProviderManager implements AdapteeCollection<Provider> {
                 String main_url = extractMainUrlFromInputStream(new FileInputStream(external_files_dir.getAbsolutePath() + "/" + file));
                 providers.add(new Provider(new URL(main_url)));
             }
-        } catch (MalformedURLException e) {
-            e.printStackTrace();
-        } catch (FileNotFoundException e) {
+        } catch (MalformedURLException | FileNotFoundException e) {
             e.printStackTrace();
         }
 
         return providers;
     }
 
-    private String extractMainUrlFromInputStream(InputStream input_stream_file_contents) {
+    private String extractMainUrlFromInputStream(InputStream input_stream) {
         String main_url = "";
-        byte[] bytes = new byte[0];
+
+        JSONObject file_contents = inputStreamToJson(input_stream);
+        if(file_contents != null)
+            main_url = file_contents.optString(Provider.MAIN_URL);
+        return main_url;
+    }
+
+    private String extractCertificatePinFromInputStream(InputStream input_stream) {
+        String certificate_pin = "";
+
+        JSONObject file_contents = inputStreamToJson(input_stream);
+        if(file_contents != null)
+            certificate_pin = file_contents.optString(Provider.CA_CERT_FINGERPRINT);
+
+        return certificate_pin;
+    }
+
+    private JSONObject inputStreamToJson(InputStream input_stream) {
+        JSONObject json = null;
         try {
-            bytes = new byte[input_stream_file_contents.available()];
-            if (input_stream_file_contents.read(bytes) > 0) {
-                JSONObject file_contents = new JSONObject(new String(bytes));
-                main_url = file_contents.getString(Provider.MAIN_URL);
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
-        } catch (JSONException e) {
+            byte[] bytes = new byte[input_stream.available()];
+            if (input_stream.read(bytes) > 0)
+                json = new JSONObject(new String(bytes));
+            input_stream.reset();
+        } catch (IOException | JSONException e) {
             e.printStackTrace();
         }
-        return main_url;
+        return json;
     }
 
     public Set<Provider> providers() {
diff --git a/app/src/main/res/values-es/strings.xml b/app/src/main/res/values-es/strings.xml
index 7ab5150e..82ca44e9 100644
--- a/app/src/main/res/values-es/strings.xml
+++ b/app/src/main/res/values-es/strings.xml
@@ -48,6 +48,7 @@
     <string name="setup_error_close_button">Salir</string>
     <string name="setup_error_text">Sucedió un error configurando Bitmask con tu proveedor elegido.\n\nPuedes volver a intentarlo, o elegir otro proveedor.</string>
     <string name="server_unreachable_message">No se ha detectado red para hablar con el servidor, inténtalo de nuevo.</string>
+    <string name="error.security.pinnedcertificate">Error de seguridad, actualiza la aplicación o elige otro proveedor.</string>
     <string name="malformed_url">No parece que sea un proveedor de Bitmask.</string>
     <string name="certificate_error">No es un proveedor de Bitmak de confianza.</string>
     <string name="service_is_down_error">El servicio está caído.</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index ac6191a9..bcfd3a2c 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -47,6 +47,7 @@
     <string name="setup_error_close_button">Exit</string>
     <string name="setup_error_text">There was an error configuring Bitmask with your chosen provider.\n\nYou may choose to reconfigure, or exit and configure a provider upon next launch.</string>
     <string name="server_unreachable_message">Server is unreachable, please try again.</string>
+    <string name="error.security.pinnedcertificate">Security error, update the app or choose another provider.</string>
     <string name="malformed_url">It doesn\'t seem to be a Bitmask provider.</string>
     <string name="certificate_error">This is not a trusted Bitmask provider.</string>
     <string name="service_is_down_error">Service is down.</string>
diff --git a/app/src/release/java/se/leap/bitmaskclient/ConfigurationWizard.java b/app/src/release/java/se/leap/bitmaskclient/ConfigurationWizard.java
index 19ba1ba8..68ff9e47 100644
--- a/app/src/release/java/se/leap/bitmaskclient/ConfigurationWizard.java
+++ b/app/src/release/java/se/leap/bitmaskclient/ConfigurationWizard.java
@@ -126,7 +126,7 @@ public class ConfigurationWizard extends Activity
 
         if (fragment_manager.findFragmentByTag(ProviderDetailFragment.TAG) == null && setting_up_provider) {
             if (selected_provider != null)
-                onItemSelectedUi(selected_provider);
+                onItemSelectedUi();
             if (progress > 0)
                 mProgressBar.setProgress(progress);
         }
@@ -229,17 +229,17 @@ public class ConfigurationWizard extends Activity
     void onItemSelected(int position) {
         //TODO Code 2 pane view
         selected_provider = adapter.getItem(position);
-        onItemSelectedUi(selected_provider);
-        onItemSelectedLogic(selected_provider);
+        onItemSelectedUi();
+        onItemSelectedLogic();
     }
 
-    private void onItemSelectedLogic(Provider selected_provider) {
-        setUpProvider(selected_provider.mainUrl());
+    private void onItemSelectedLogic() {
+        setUpProvider();
     }
 
-    private void onItemSelectedUi(Provider provider) {
+    private void onItemSelectedUi() {
         startProgressBar();
-        adapter.hideAllBut(adapter.indexOf(provider));
+        adapter.hideAllBut(adapter.indexOf(selected_provider));
     }
 
     @Override
@@ -379,8 +379,8 @@ public class ConfigurationWizard extends Activity
 
     private void autoSelectProvider(Provider provider) {
         selected_provider = provider;
-        onItemSelectedUi(selected_provider);
-        onItemSelectedLogic(selected_provider);
+        onItemSelectedUi();
+        onItemSelectedLogic();
     }
 
     /**
@@ -389,10 +389,11 @@ public class ConfigurationWizard extends Activity
      * @param provider_name
      * @param provider_main_url
      */
-    public void setUpProvider(URL provider_main_url) {
+    public void setUpProvider() {
         Intent provider_API_command = new Intent(this, ProviderAPI.class);
         Bundle parameters = new Bundle();
-        parameters.putString(Provider.MAIN_URL, provider_main_url.toString());
+        parameters.putString(Provider.MAIN_URL, selected_provider.mainUrl().toString());
+        parameters.putString(Provider.CA_CERT_FINGERPRINT, selected_provider.certificatePin());
 
         provider_API_command.setAction(ProviderAPI.SET_UP_PROVIDER);
         provider_API_command.putExtra(ProviderAPI.PARAMETERS, parameters);
diff --git a/app/src/release/java/se/leap/bitmaskclient/ProviderAPI.java b/app/src/release/java/se/leap/bitmaskclient/ProviderAPI.java
index 890262ce..a96556bc 100644
--- a/app/src/release/java/se/leap/bitmaskclient/ProviderAPI.java
+++ b/app/src/release/java/se/leap/bitmaskclient/ProviderAPI.java
@@ -34,6 +34,7 @@ import javax.net.ssl.*;
 
 import org.apache.http.client.*;
 import org.json.*;
+import org.thoughtcrime.ssl.pinning.util.*;
 
 import se.leap.bitmaskclient.ProviderListContent.ProviderItem;
 import se.leap.bitmaskclient.eip.*;
@@ -87,6 +88,7 @@ public class ProviderAPI extends IntentService {
     private static boolean go_ahead = true;
     private static SharedPreferences preferences;
     private static String provider_api_url;
+    private static String provider_ca_cert_fingerprint;
     private Resources resources;
 
     public static void stop() {
@@ -504,13 +506,19 @@ public class ProviderAPI extends IntentService {
         Bundle current_download = new Bundle();
 
         if (task != null && task.containsKey(Provider.MAIN_URL)) {
-            last_provider_main_url = task.getString(Provider.MAIN_URL);
+            last_provider_main_url = task.containsKey(Provider.MAIN_URL) ?
+                    task.getString(Provider.MAIN_URL) :
+                    "";
+            provider_ca_cert_fingerprint = task.containsKey(Provider.CA_CERT_FINGERPRINT) ?
+                    task.getString(Provider.CA_CERT_FINGERPRINT) :
+                    "";
+
             CA_CERT_DOWNLOADED = PROVIDER_JSON_DOWNLOADED = EIP_SERVICE_JSON_DOWNLOADED = false;
             go_ahead = true;
         }
 
         if (!PROVIDER_JSON_DOWNLOADED)
-            current_download = getAndSetProviderJson(last_provider_main_url);
+            current_download = getAndSetProviderJson(last_provider_main_url, provider_ca_cert_fingerprint);
         if (PROVIDER_JSON_DOWNLOADED || (current_download.containsKey(RESULT_KEY) && current_download.getBoolean(RESULT_KEY))) {
             broadcastProgress(progress++);
             PROVIDER_JSON_DOWNLOADED = true;
@@ -602,11 +610,16 @@ public class ProviderAPI extends IntentService {
         return hexData.toString();
     }
 
-    private Bundle getAndSetProviderJson(String provider_main_url) {
+    private Bundle getAndSetProviderJson(String provider_main_url, String provider_ca_cert_fingerprint) {
         Bundle result = new Bundle();
 
         if (go_ahead) {
-            String provider_dot_json_string = downloadWithCommercialCA(provider_main_url + "/provider.json");
+            String provider_dot_json_string;
+
+            if(provider_ca_cert_fingerprint.isEmpty())
+                provider_dot_json_string = downloadWithCommercialCA(provider_main_url + "/provider.json");
+            else
+                provider_dot_json_string = downloadWithCommercialCA(provider_main_url + "/provider.json", provider_ca_cert_fingerprint);
 
             try {
                 JSONObject provider_json = new JSONObject(provider_dot_json_string);
@@ -672,6 +685,28 @@ public class ProviderAPI extends IntentService {
         return error_message;
     }
 
+    private String downloadWithCommercialCA(String url_string, String ca_cert_fingerprint) {
+        String result = "";
+
+        int seconds_of_timeout = 2;
+        String[] pins = new String[] {ca_cert_fingerprint};
+        try {
+            URL url = new URL(url_string);
+            HttpsURLConnection connection = PinningHelper.getPinnedHttpsURLConnection(Dashboard.getContext(), pins, url);
+            connection.setConnectTimeout(seconds_of_timeout * 1000);
+            if (!LeapSRPSession.getToken().isEmpty())
+                connection.addRequestProperty(LeapSRPSession.AUTHORIZATION_HEADER, "Token token = " + LeapSRPSession.getToken());
+            result = new Scanner(connection.getInputStream()).useDelimiter("\\A").next();
+        } catch (IOException e) {
+            if(e instanceof SSLHandshakeException)
+                result = formatErrorMessage(R.string.error_security_pinnedcertificate);
+            else
+                result = formatErrorMessage(R.string.error_io_exception_user_message);
+        }
+
+        return result;
+    }
+
     /**
      * Tries to download the contents of the provided url using commercially validated CA certificate from chosen provider.
      *