There aren't any maximum file upload size constraints that you can place on an S3 bucket, per se. As far as I can find, there aren't any AWS policy provisions for that.
But S3 supports CORS, which is what s3_file_field
uses to make this direct upload work. If S3 supports the content-length-range
policy element of CORS, you can add that and then are probably covered.
Also s3_file_field is actually an extension of jQuery File Upload, and that has various validation options, including max_file_size
as documented here. In s3_file_field
the default max_file_size
is 500 megabytes and it appears you can override it.
Either way, if a user disables javascript, then they won't be able to run JQuery File Upload, which means they shouldn't be able to upload anything at all via CORS.
Just make sure you specify the AllowedOrigin
in production, as stated in the s3_file_field
docs.