Serverless IAM Requirements

Policy

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "cloudformation:CreateStack",
                "cloudformation:UpdateStack",
                "cloudformation:DescribeStacks",
                "cloudformation:ListStacks",
                "cloudformation:DescribeStackEvents",
                "cloudformation:DescribeStackResource",
                "cloudformation:DescribeStackResources",
                "iam:GetRole",
                "iam:CreateRole",
                "iam:CreatePolicy",
                "iam:PutRolePolicy",
                "iam:PassRole",
                "lambda:GetFunction",
                "lambda:ListVersionsByFunction",
                "lambda:CreateFunction",
                "lambda:UpdateFunctionCode",
                "lambda:UpdateFunctionConfig",
                "lambda:GetFunctionConfiguration",
                "lambda:AddPermission",
                "lambda:PublishVersion",
                "s3:DeleteObject",
                "s3:GetObject",
                "s3:CreateBucket",
                "s3:ListBucket",
                "s3:PutObject",
                "apigateway:POST",
                "apigateway:GetResources",
                "apigateway:GET",
                "apigateway:PUT",
                "apigateway:DELETE"
            ],
            "Resource": "*"
        }
    ]
}

Warning: iam:PutRolePolicy will allow the user of this policy to create any role they like in IAM