Added limitation for decryption files. | #118.

Author: DenBond7

FlowCrypt/src/main/java/com/flowcrypt/email/Constants.java

@@ -44,4 +44,14 @@ public class Constants {
 
     public static final String PREFERENCES_KEY_TEMP_LAST_AUTH_CREDENTIALS =
             "preferences_key_temp_last_auth_credentials";
+
+    /**
+     * The max total size off all attachment which can be send via the app.
+     */
+    public static final int MAX_TOTAL_ATTACHMENT_SIZE_IN_BYTES = 1024 * 1024 * 3;
+
+    /**
+     * The max size off an attachment which can be decrypted via the app.
+     */
+    public static final int MAX_ATTACHMENT_SIZE_WHICH_CAN_BE_DECRYPTED = 1024 * 1024 * 3;
 }

FlowCrypt/src/main/java/com/flowcrypt/email/service/attachment/AttachmentDownloadManagerService.java

@@ -26,6 +26,7 @@
 import android.widget.Toast;
 
 import com.flowcrypt.email.BuildConfig;
+import com.flowcrypt.email.Constants;
 import com.flowcrypt.email.R;
 import com.flowcrypt.email.api.email.JavaEmailConstants;
 import com.flowcrypt.email.api.email.model.AttachmentInfo;
@@ -463,6 +464,8 @@ public void run() {
             AccountDao accountDao = new AccountDaoSource().getAccountInformation(context, attachmentInfo.getEmail());
 
             try {
+                checkMaxDecryptedFileSize();
+
                 Session session = OpenStoreHelper.getAttachmentSession(accountDao);
                 Store store = OpenStoreHelper.openAndConnectToStore(context, accountDao, session);
                 IMAPFolder imapFolder = (IMAPFolder) store.getFolder(new ImapLabelsDaoSource()
@@ -542,6 +545,23 @@ public void setOnDownloadAttachmentListener(OnDownloadAttachmentListener onDownl
             this.onDownloadAttachmentListener = onDownloadAttachmentListener;
         }
 
+        /**
+         * Check is decrypted file has size not more than
+         * {@link Constants#MAX_ATTACHMENT_SIZE_WHICH_CAN_BE_DECRYPTED}. If the file greater then
+         * {@link Constants#MAX_ATTACHMENT_SIZE_WHICH_CAN_BE_DECRYPTED} we throw an exception. This is only for files
+         * with the "pgp" extension.
+         */
+        private void checkMaxDecryptedFileSize() {
+            if ("pgp".equalsIgnoreCase(FilenameUtils.getExtension(attachmentInfo.getName()))) {
+                if (attachmentInfo.getEncodedSize() > Constants.MAX_ATTACHMENT_SIZE_WHICH_CAN_BE_DECRYPTED) {
+                    throw new IllegalArgumentException(context.getString(R.string
+                                    .template_warning_max_attachments_size_for_decryption,
+                            FileUtils.byteCountToDisplaySize(Constants
+                                    .MAX_ATTACHMENT_SIZE_WHICH_CAN_BE_DECRYPTED)));
+                }
+            }
+        }
+
         /**
          * Do decryption of the downloaded file if it need.
          *
@@ -594,10 +614,12 @@ private File decryptFileIfNeed(Context context, File file) throws IOException {
          * @param attachmentFile The file which will be removed.
          */
         private void removeNotCompleteDownloadFile(File attachmentFile) {
-            if (!attachmentFile.delete()) {
-                Log.d(TAG, "Cannot delete file: " + attachmentFile);
-            } else {
-                Log.d(TAG, "Canceled attachment \"" + attachmentFile + "\" was deleted");
+            if (attachmentFile != null && attachmentFile.exists()) {
+                if (!attachmentFile.delete()) {
+                    Log.d(TAG, "Cannot delete file: " + attachmentFile);
+                } else {
+                    Log.d(TAG, "Canceled attachment \"" + attachmentFile + "\" was deleted");
+                }
             }
         }
 

FlowCrypt/src/main/java/com/flowcrypt/email/ui/activity/fragment/base/CreateMessageFragment.java

@@ -31,6 +31,7 @@
 import android.widget.TextView;
 import android.widget.Toast;
 
+import com.flowcrypt.email.Constants;
 import com.flowcrypt.email.R;
 import com.flowcrypt.email.api.email.FoldersManager;
 import com.flowcrypt.email.api.email.model.AttachmentInfo;
@@ -78,8 +79,6 @@ public class CreateMessageFragment extends BaseGmailFragment implements View.OnF
     private static final int REQUEST_CODE_IMPORT_PUBLIC_KEY = 101;
     private static final int REQUEST_CODE_GET_CONTENT_FOR_SENDING = 102;
 
-    private static final int MAX_TOTAL_ATTACHMENT_SIZE_IN_BYTES = 1024 * 1024 * 3;
-
     private Js js;
     private OnMessageSendListener onMessageSendListener;
     private OnChangeMessageEncryptedTypeListener onChangeMessageEncryptedTypeListener;
@@ -236,7 +235,8 @@ public void onActivityResult(int requestCode, int resultCode, Intent data) {
                             } else {
                                 showInfoSnackbar(getView(),
                                         getString(R.string.template_warning_max_total_attachments_size,
-                                                FileUtils.byteCountToDisplaySize(MAX_TOTAL_ATTACHMENT_SIZE_IN_BYTES)),
+                                                FileUtils.byteCountToDisplaySize(
+                                                        Constants.MAX_TOTAL_ATTACHMENT_SIZE_IN_BYTES)),
                                         Snackbar.LENGTH_LONG);
                             }
                         } else {
@@ -679,7 +679,7 @@ private boolean isAttachmentCanBeAdded(AttachmentInfo newAttachmentInfo) {
 
         totalSizeOfAttachments += newAttachmentInfo.getEncodedSize();
 
-        return totalSizeOfAttachments < MAX_TOTAL_ATTACHMENT_SIZE_IN_BYTES;
+        return totalSizeOfAttachments < Constants.MAX_TOTAL_ATTACHMENT_SIZE_IN_BYTES;
     }
 
     /**

FlowCrypt/src/main/res/values/strings.xml

@@ -201,4 +201,5 @@
     <string name="simulate_app_crash">Simulate app crash</string>
     <string name="attachments">Attachments</string>
     <string name="download_attachments_notification_channel">The download attachments notification channel</string>
+    <string name="template_warning_max_attachments_size_for_decryption">The app cannot decrypt an attachment greater than %1$s</string>
 </resources>