Cron job can't access Documents - "Tar: Desktop: Couldn't visit directory: Unknown error: -1"

I have an automated backup script that runs from a cron job. It basically tars up my home directory and pipes it to a command that writes the tarball to Amazon S3. tar zcvf - -X BACKUP_EXCLUDE | /usr/local/bin/aws s3 cp - ... It works fine if I run from the command line, but from a cron job it fails with: tar: /Users/falk/Desktop: Couldn't visit directory: Unknown error: -1 tar: Error exit delayed from previous errors. I'm guessing this is some sort of security thing, likely "Full Disk Access". (Adding Desktop to my "BACKUP_EXCLUDE" file didn't seem to help.) Is there a way to whitelist tar to access all my files from cron? Or give cron jobs the same access as the same command executed from the terminal?