AWS EC2 IAM role access denied on S3

Question

I have launched an EC2 instance with IAM role "webapp". role is attached and i can confirm it using

curl http://169.254.169.254/latest/meta-data/iam/security-credentials/webapp
{
  "Code" : "Success",
  "LastUpdated" : "2016-01-04T06:44:50Z",
  "Type" : "AWS-HMAC",
  "AccessKeyId" : "xxx",
  "SecretAccessKey" : "xxx",
  "Token" : "xxx",
  "Expiration" : "2016-01-04T12:46:27Z"
}

webapp Role has an attached policy for S3

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:*",
      "Resource": "*"
    }
  ]
}

But I am unable to access objects on S3. I am using aws-php-sdk

require_once 'vendor/autoload.php';
use Aws\S3\S3Client;

$client = S3Client::factory(array('region'  => 'us-west-2','version'=>'2006-03-01'));
  $result = $client->getObject(array(
    'Bucket' => 'test-bkt88767',
    'Key'    => "file.txt",
  ));
echo $result['Body'] . "\n";

I am getting a 403 forbidden

PHP Fatal error:  Uncaught exception 'Aws\S3\Exception\S3Exception' with message 'Error executing "GetObject" on "https://s3-us-west-2.amazonaws.com/test-bkt88767/file.txt"; AWS HTTP error: Client error: `GET https://s3-us-west-2.amazonaws.com/test-bkt88767/file.txt` resulted in a `403 Forbidden` response:
<?xml version="1.0" encoding="UTF-8"?>
<Error><Code>AccessDenied</Code><Message>Access Denied</Message><RequestId>995F9A (truncated...)
 AccessDenied (client): Access Denied - <?xml version="1.0" encoding="UTF-8"?>
<Error><Code>AccessDenied</Code><Message>Access Denied</Message><RequestId>995F9AC51CC2164F</RequestId><HostId>JPKyfP1LBLW5ky2wH9t2CEjHrKT0tI9zgyXHU/qcJWvBoOwhK7O0dzl1wCjjzV58UhKZVHXvFFg=</HostId></Error>'

do I need to change bucket permissions as well? or I am doing something wrong with the conf. of EC2?

Does aws-php-sdk automatically use the instance role? I don't see any explicit reference to it in the code. — Michael - sqlbot
Check the bucket policy on the s3 bucket, make sure there are no denies on it as well. — strongjz

Nic Nic · Accepted Answer · 2018-01-29T03:11:47

Check your webapp role in IAM, it should say something like this:

{
    "Action": [
        "s3:ListBucket"
    ],
    "Resource": "arn:aws:s3:::your_bucket",
    "Effect": "Allow"
},
{
    "Action": [
        "s3:GetObject"
    ],
    "Resource": "arn:aws:s3:::your_bucket/*",
    "Effect": "Allow"
}

AWS EC2 IAM role access denied on S3

2 Answers