Cannot perform `ec2:CreateSecurityGroup` on non-default vpc with `aws:ResourceTag` conditions in IAM policy

Question

I have the following policy snippet in IAM:
```json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ec2:CreateSecurityGroup"
            ],
            "Resource": "*",
            "Condition": {
                "StringEquals": {
                    "aws:RequestTag/CreatedBy": "Controller"
                }
            }
        }
    ]
}
```
This works for the default VPC, allowing the user to create a security group, only if the tag `CreatedBy` is set to the correct value.
```shell
$ aws ec2 create-security-group --group-name test-sg-2  --description "test" --region us-west-2 --profile controller-test --tag-specification 'ResourceType=security-group,Tags=[{Key=CreatedBy,Value=Controller}]'
{
  "GroupId": "sg-XXXXXXXXXXXXXX",
  "Tags": [
    {
      "Key": "CreatedBy",
      "Value": "Controller"
    }
  ]
}
```
However, when running against a non-default VPC, an opaque permission denied error is returned
```shell
$ aws ec2 create-security-group --vpc-id vpc-XXXXXXXXXX --group-name test-sg-2  --description "test" --region us-west-2 --profile controller-test --tag-specification 'ResourceType=security-group,Tags=[{Key=CreatedBy,Value=Controller}]'
An error occurred (UnauthorizedOperation) when calling the CreateSecurityGroup operation: You are not authorized to perform this operation. User: arn:aws:iam::XXXXXXXXX:user/test-controller is not authorized to perform: ec2:CreateSecurityGroup on resource: arn:aws:ec2:us-west-2:XXXXXXXX:vpc/vpc-XXXXXXXXX because no identity-based policy allows the ec2:CreateSecurityGroup action.
```

Removing the condition for request tags allows the user to create the SG as you'd expect. The policy simulator claims that this policy _should_ work, but for some reason it isn't.

![Policy sim showing it should work](/media/postImages/original/IM0aWRQA9CTIePTC4nidLGog)

I've tried adding an explicit permission grant to the VPC with `Resources=["arn:aws:ec2:::security-group/*","arn:aws:ec2:::vpc/vpc-XXXXXXXX"]` in the policy, various tweaks to the condition block, and half a dozen other things I've forgotten at this point, but as far as I can tell having a condition on `RequestTag` just breaks non-default VPC deployment, even though it's listed as a supported condition in the [IAM conditions list](https://docs.aws.amazon.com/IAM/latest/UserGuide/list_amazonec2.html)

What am I missing here?

Accepted Answer

After talking with support, the issue is that `CreateSecurityGroup` in a non-default VPC requires that the requester be authorized to call `CreateSecurityGroup` on that VPC. The VPC component of `CreateSecurityGroup` does not, however, support filtering on `aws:RequestTag`. The solution is to use two seperate statements, one which grants `CreateSecurityGroup` on `security-group/*` and one which grants `CreateSecurityGroup` on the VPC(s).

```json
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": "ec2:CreateSecurityGroup",
            "Resource": "arn:aws:ec2:*:XXXXXXXXX:security-group/*",
            "Condition": {
                "StringEquals": {
                    "aws:RequestTag/CreatedBy": "Controller"
                }
            }
        },
        {
            "Sid": "VisualEditor1",
            "Effect": "Allow",
            "Action": "ec2:CreateSecurityGroup",
            "Resource": "arn:aws:ec2:*:XXXXXXXXX:vpc/vpc-XXXXXXXXX"
        }
        {
            "Sid": "VisualEditor2",
            "Effect": "Allow",
            "Action": [
                "ec2:Describe*",
                "ec2:CreateTags"
            ],
            "Resource": "*"
        }
    ]
}
```

Answer

It states the required permission also needed is ec2:CreateTags

Does this user have the permission to CreateTags also?

Cannot perform `ec2:CreateSecurityGroup` on non-default vpc with `aws:ResourceTag` conditions in IAM policy

相關內容