FileSender Shredding deleted files

FileSender 2.0 can execute shred or other long running tasks to securely delete user files when they are discarded by the user. Explicit support was added in FileSender 2.0 beta 4 for this functionality.

The problem with shredding files right at the time the user deletes a transfer is that a secure shredding on a large file may take a very long time. A user may not be interested in waiting for this shredding to complete before continuing to use the FileSender Web interface.

If you wish to run shred at the time a user deletes a file simply continue to use shred in the storage_filesystem_file_deletion_command configuration directive. Otherwise, the new storage_filesystem_file_shred_command can be set which will also enable the new shredding functionality.

If you are using this shredding support, when a user deletes a transfer files are renamed into the directory specified by the storage_filesystem_shred_path configuration directive. For best, and most secure, results you should have storage_filesystem_shred_path on the same filesystem as storage_filesystem_path. On security grounds, the code may reject configurations where these two paths are not on the same filesystem in the future.

Files that are moved to storage_filesystem_shred_path have a new file name and are inserted into the shredfiles table in the database. That table has a synthetic tuple id, the file name, and an optional errormessage field. To actually shred the files you should arrange to execute the scripts/task/cron-handle-shred-files.php script on a regular basis. This script will perform the actual shredding of the files and remove them from the database after a successful shred.

If shredding failed then the output of storage_filesystem_file_shred_command is inserted into the errormessage field to help the system administrator to track down the problem. Each time your run the cron-handle-shred-files.php script every file in the shredfiles table will be attempted to be shredded. So if you have had a problem shredding a file and have changed things such as file permissions to fix the problem simply rerun the cron-handle-shred-files.php script and an attempt will be made to shred all files in the shredfiles table.

Configuration directives of interest

• storage_filesystem_file_shred_command
• storage_filesystem_shred_path
• storage_filesystem_path (Note: should be on same filesystem as storage_filesystem_shred_path).