amazon s3 - Getting Access Denied when calling the PutObject operation with bucket-level permission

Question

I followed the example on http://docs.aws.amazon.com/IAM/latest/UserGuide/access_policies_examples.html#iam-policy-example-s3 for how to grant a user access to just one bucket.

I then tested the config using the W3 Total Cache Wordpress plugin. The test failed.

I also tried reproducing the problem using

aws s3 cp --acl=public-read --cache-control='max-age=604800, public' ./test.txt s3://my-bucket/

and that failed with

upload failed: ./test.txt to s3://my-bucket/test.txt A client error (AccessDenied) occurred when calling the PutObject operation: Access Denied

Why can't I upload to my bucket?

Answer 1

To answer my own question:

The example policy granted PutObject access, but I also had to grant PutObjectAcl access.

I had to change

"s3:PutObject",
"s3:GetObject",
"s3:DeleteObject"

from the example to:

"s3:PutObject",
"s3:PutObjectAcl",
"s3:GetObject",
"s3:GetObjectAcl",
"s3:DeleteObject"

You also need to make sure your bucket is configured for clients to set a public-accessible ACL by unticking these two boxes: