S3 user cannot access objects in his own bucket if created by another user Why

Question

An external user added a file to the S3 bucket. But when I tried downloading it, I got 403 error. I attempted to change the permission of the object but got a message "You do not have permission to view this bucket".

How do I solve it?

Answer 1

I think you have to  re-write the object specifying bucket owner full control or you have to get the object owner to update the ACL or. The simplest way to experiment with this is using the CLI:

aws s3api put-object-acl --acl bucket-owner-full-control --bucket some-bucket --key path/to/unreadable.txt

This has to be done once for each object