Amazon s3 user policies - amazon-s3

Question

I'm trying to define a policy for a specific user.
I have several buckets in my S3 but I want to give the user access to some of them.
I created the following policy:
{
"Version":"2012-10-17",
"Statement":[
{
"Sid":"AddPerm",
"Effect":"Allow",
"Principal": "*",
"Action":["s3:GetObject",
"s3:ListBucket",
"s3:ListAllMyBuckets",
"s3:GetBucketLocation",
"s3:PutObject"],
"Resource":["arn:aws:s3:::examplebucket"]
}
when I try to add a list of resources like this:
"Resource":["arn:aws:s3:::examplebucket1","arn:aws:s3:::examplebucket2"]
I get access denied
The only option that works for me (I get buckets lists) is:
"Resource": ["arn:aws:s3:::*"]
whats the problem?

Answer 1

Some Amazon S3 API calls operate at the Bucket-level, while some operate at the Object-level. Therefore, you will need a policy like:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": ["s3:ListBucket"],
"Resource": ["arn:aws:s3:::test"]
},
{
"Effect": "Allow",
"Action": [
"s3:PutObject",
"s3:GetObject",
"s3:DeleteObject"
],
"Resource": ["arn:aws:s3:::test/*"]
}
]
}
See: AWS Security Blog - Writing IAM Policies: How to Grant Access to an Amazon S3 Bucket

Answer 2

I found that its an AWS limitation.
There is no option get filtered list of buckets.
Once you give permissions to ListAllMyBuckets like this:
{
"Sid": "AllowUserToSeeBucketListInTheConsole",
"Action": ["s3:GetBucketLocation", "s3:ListAllMyBuckets"],
"Effect": "Allow",
"Resource": ["arn:aws:s3:::*"]
}
you get the list of all bucket (including buckets that you don't have permissions to it).
More info could be found here: https://aws.amazon.com/blogs/security/writing-iam-policies-grant-access-to-user-specific-folders-in-an-amazon-s3-bucket/
Few workarounds could be found here: Is there an S3 policy for limiting access to only see/access one bucket?