Those uploader decides rules are wild. Does that mean someone with a website poorly configured enough can have user content uploaded to, and later served from amazon glacier? (assuming a sufficiently motivated user)
https://docs.aws.amazon.com/service-authorization/latest/ref...
The condition keys specifically are here and you can see keys to control access to storage class, tagging, etc.
https://docs.aws.amazon.com/service-authorization/latest/ref...