MalformedPolicyDocumentException while creating IAM policy using Boto

Question

I am working on a boto script to create an IAM policy using a python function. The policy has been converted to JSON format using "json.dumps()", but AWS would still not consider it as a valid format. The function is:

##### Global variables ####
region="us-east-2"
instance_type="t2.micro"
ebs_volume_size="20"
meta_template_name="ec2_policy_meta_template"
###############################

start_time_1 = input("What's the start time")
end_time1 = input("What's the end time")
def create_aws_iam_policy_template(**kwargs):
  template_data = {}
  template_data["region"] = kwargs.get('region')
  template_data["start_time"] = kwargs.get('end_time')
  template_data["end_time"] = kwargs.get('start_time')
  template_data["instance_type"] = kwargs.get('instance_type')
  template_data["ebs_volume_size"] = kwargs.get('ebs_volume_size')
  template_data["meta_template_name"] = kwargs.get('meta_template_name')

  meta_template_dict = getattr(meta_templates, template_data["meta_template_name"])
  meta_template_json = json.dumps(meta_template_dict)
  template_json = Template(meta_template_json).render(template_data)
  return template_json  


template_json = create_aws_iam_policy_template(
  region=region,
  instance_type=instance_type,
  ebs_volume_size=ebs_volume_size,
  meta_template_name=meta_template_name,
  start_time = start_time_1,
  end_time = end_time1
)

This is what I am using to convert dict to JSON:

app_json = json.dumps(template_json)
print(app_json)

This is the output of the IAM policy:

"{"Version": "2012-10-17", "Statement": [{"Sid": "VisualEditor0", "Effect": "Allow", "Action": "ec2:RunInstances", "Resource": ["arn:aws:ec2:us-east-2::instance/", "arn:aws:ec2:us-east-2::network-interface/", "arn:aws:ec2:us-east-2::key-pair/", "arn:aws:ec2:us-east-2::security-group/", "arn:aws:ec2:us-east-2::subnet/", "arn:aws:ec2:us-east-2::volume/", "arn:aws:ec2:us-east-2::image/ami-"], "Condition": {"ForAllValues:NumericLessThanEquals": {"ec2:VolumeSize": "20"}, "ForAllValues:StringEquals": {"ec2:InstanceType": "t2.micro"}}}, {"Sid": "VisualEditor1", "Effect": "Allow", "Action": ["ec2:TerminateInstances", "ec2:StartInstances", "ec2:StopInstances"], "Resource": "arn:aws:ec2:us-east-2::instance/", "Condition": {"ForAllValues:StringEquals": {"ec2:InstanceType": "t2.micro"}}}, {"Sid": "VisualEditor2", "Effect": "Allow", "Action": ["ec2:Describe*", "ec2:GetConsole*", "cloudwatch:DescribeAlarms", "iam:ListInstanceProfiles", "cloudwatch:GetMetricStatistics", "ec2:DescribeKeyPairs", "ec2:CreateKeyPair"], "Resource": "*", "Condition": {"DateGreaterThan": {"aws:CurrentTime": "2020-06-30T23:59:59Z"}, "DateLessThanEquals": {"aws:CurrentTime": "2020-04-01T00:00:00Z"}}}]}" This is the error I am getting while trying to create an IAM policy:

botocore.errorfactory.MalformedPolicyDocumentException: An error occurred (MalformedPolicyDocument) when calling the CreatePolicy operation: Syntax errors in policy.

Can you provide more complete example code? Where and how do you generate template_json and call CreatePolicy? — Marcin

samtoddler samtoddler · Accepted Answer · 2021-02-09T13:59:34

The policy overall has too many warnings, even though I was able to create it via the console.

For example, aws:CurrentTime should be somethink like below:

                "DateGreaterThan": {"aws:CurrentTime": "2020-04-01T00:00:00Z"},
                "DateLessThan": {"aws:CurrentTime": "2020-06-30T23:59:59Z"}

ec2:InstanceType condition doesnt have the corresponding condition's value specified.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "VisualEditor0",
      "Effect": "Allow",
      "Action": "ec2:RunInstances",
      "Resource": [
        "arn:aws:ec2:us-east-2::instance/",
        "arn:aws:ec2:us-east-2::network-interface/",
        "arn:aws:ec2:us-east-2::key-pair/",
        "arn:aws:ec2:us-east-2::security-group/",
        "arn:aws:ec2:us-east-2::subnet/",
        "arn:aws:ec2:us-east-2::volume/",
        "arn:aws:ec2:us-east-2::image/ami-"
      ],
      "Condition": {
        "ForAllValues:NumericLessThanEquals": {
          "ec2:VolumeSize": "20"
        },
        "ForAllValues:StringEquals": {
          "ec2:InstanceType": ""
        }
      }
    },
    {
      "Sid": "VisualEditor1",
      "Effect": "Allow",
      "Action": [
        "ec2:TerminateInstances",
        "ec2:StartInstances",
        "ec2:StopInstances"
      ],
      "Resource": "arn:aws:ec2:us-east-2::instance/",
      "Condition": {
        "ForAllValues:StringEquals": {
          "ec2:InstanceType": ""
        }
      }
    },
    {
      "Sid": "VisualEditor2",
      "Effect": "Allow",
      "Action": [
        "ec2:Describe*",
        "ec2:GetConsole*",
        "cloudwatch:DescribeAlarms",
        "iam:ListInstanceProfiles",
        "cloudwatch:GetMetricStatistics",
        "ec2:DescribeKeyPairs",
        "ec2:CreateKeyPair"
      ],
      "Resource": "*",
      "Condition": {
        "DateGreaterThan": {
          "aws:CurrentTime": "30"
        },
        "DateLessThanEquals": {
          "aws:CurrentTime": "20"
        }
      }
    }
  ]
}

MalformedPolicyDocumentException while creating IAM policy using Boto

1 Answers