Fog, S3 and iam instance profile: Excon Forbidden

Question

I am trying to list the contents of an S3 bucket with Fog, but get constant errors:

The request signature we calculated does not match the signature you provided. Check your key and signing method.

Details of the setup

EC2 Instance

IAM Role "S3BucketAccess":

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "s3:Get*",
        "s3:List*"
      ],
      "Resource": [
        "arn:aws:s3:::*",
        "arn:aws:s3:::mybucket/*",
        "arn:aws:s3:::mybucket/deploy",
        "arn:aws:s3:::mybucket/deploy/*"
      ]
    },
    {
      "Effect": "Allow",
      "Action": "s3:ListAllMyBuckets",
      "Resource": "arn:aws:s3:::*"
    }
  ]
}

169.254.169.254/latest/meta-data/iam/security-credentials/S3BucketAccess

{
  "Code" : "Success",
  "LastUpdated" : "2013-06-28T11:54:08Z",
  "Type" : "AWS-HMAC",
  "AccessKeyId" : "XXXXXXXXXX",
  "SecretAccessKey" : "YYYYYYYYYY",
  "Token" : "ALongToken",
  "Expiration" : "2013-06-28T18:15:09Z"
}

The Ruby code:

require 'rubygems'
require 'fog'
connection = Fog::Storage::AWS.new({:use_iam_profile => true})
p connection.directories

Get a nasty error message / stack trace with the above mentioned error code.

Answer 1

fog 1.14.0 was published on 07-19-2013 which has the resolution (issue 1923 is a result of https://github.com/fog/fog/pull/1940). The update resolves the issue.

Answer 2

What version of fog are you using? Could you grab and share the body from the error? It often has an "expected" vs "received" signature thing which can help greatly with signature problems. Thanks!