AIによるAWS操作を安全に。Kiro CLIで作るsudo的なIAM権限昇格

AWSTemplateFormatVersion: '2010-09-09'
Description: Kiro agent role switching test - EC2 with minimal permissions and AssumeRole chain

Parameters:
  Subnet:
    Type: AWS::EC2::Subnet::Id
    Description: Subnet ID for the EC2 instance
  SecurityGroup:
    Type: AWS::EC2::SecurityGroup::Id
    Description: Security Group ID for the EC2 instance (Must allow SSM)
  AmiId:
    Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
    Default: /aws/service/ami-amazon-linux-latest/al2023-ami-kernel-default-arm64

Resources:
  ReadOnlyRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub kiro-readonly-${AWS::StackName}
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              AWS: !Sub arn:aws:iam::${AWS::AccountId}:root
            Action: sts:AssumeRole
            Condition:
              ArnEquals:
                aws:PrincipalArn: !Sub arn:aws:iam::${AWS::AccountId}:role/kiro-ec2-${AWS::StackName}
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/ReadOnlyAccess
      Policies:
        - PolicyName: AllowAssumeElevated
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action: sts:AssumeRole
                Resource: !Sub arn:aws:iam::${AWS::AccountId}:role/kiro-elevated-${AWS::StackName}

  ElevatedRole:
    Type: AWS::IAM::Role
    DependsOn: ReadOnlyRole
    Properties:
      RoleName: !Sub kiro-elevated-${AWS::StackName}
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              AWS: !Sub arn:aws:iam::${AWS::AccountId}:root
            Action: sts:AssumeRole
            Condition:
              ArnEquals:
                aws:PrincipalArn: !Sub arn:aws:iam::${AWS::AccountId}:role/kiro-readonly-${AWS::StackName}
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/PowerUserAccess

  Ec2Role:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub kiro-ec2-${AWS::StackName}
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service: ec2.amazonaws.com
            Action: sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore
      Policies:
        - PolicyName: AllowAssumeReadOnly
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action: sts:AssumeRole
                Resource: !Sub arn:aws:iam::${AWS::AccountId}:role/kiro-readonly-${AWS::StackName}

  InstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      InstanceProfileName: !Sub kiro-ec2-${AWS::StackName}
      Roles:
        - !Ref Ec2Role

  Ec2Instance:
    Type: AWS::EC2::Instance
    DependsOn: InstanceProfile
    Properties:
      InstanceType: t4g.small
      ImageId: !Ref AmiId
      SubnetId: !Ref Subnet
      SecurityGroupIds:
        - !Ref SecurityGroup
      IamInstanceProfile: !Ref InstanceProfile
      MetadataOptions:
        HttpTokens: required
        HttpEndpoint: enabled
      BlockDeviceMappings:
        - DeviceName: /dev/xvda
          Ebs:
            VolumeSize: 10
            VolumeType: gp3
      Tags:
        - Key: Name
          Value: !Sub kiro-${AWS::StackName}
      UserData:
        Fn::Base64: !Sub |
          #!/bin/bash
          set -eux

          dnf install -y unzip

          # swap 512MB
          dd if=/dev/zero of=/swapfile bs=1M count=512
          chmod 600 /swapfile
          mkswap /swapfile
          swapon /swapfile
          echo '/swapfile swap swap defaults 0 0' >> /etc/fstab

          mkdir -p /home/ec2-user/.kiro/agents
          mkdir -p /home/ec2-user/.aws

          su - ec2-user -c '
            curl --proto "=https" --tlsv1.2 -sSf "https://desktop-release.q.us-east-1.amazonaws.com/latest/kirocli-aarch64-linux.zip" -o "/tmp/kirocli.zip"
            cd /tmp && unzip -o kirocli.zip
            /tmp/kirocli/install.sh --no-confirm
          '

          # AWS CLI config - ネイティブ AssumeRole
          printf '[default]\nregion = ${AWS::Region}\n\n[profile kiro-readonly]\nrole_arn = ${ReadOnlyRole.Arn}\ncredential_source = Ec2InstanceMetadata\nrole_session_name = kiro-readonly-session\nregion = ${AWS::Region}\n\n[profile kiro-elevated]\nrole_arn = ${ElevatedRole.Arn}\nsource_profile = kiro-readonly\nrole_session_name = kiro-elevated-session\nregion = ${AWS::Region}\n' > /home/ec2-user/.aws/config

          # エージェント設定: readonly
          printf '{\n  "name": "readonly",\n  "description": "ReadOnly agent - reference only",\n  "prompt": "You are a read-only agent. Always use the kiro-readonly profile for all AWS operations via use_aws. Never perform create, update, delete, or any mutating operations.",\n  "tools": ["@builtin"],\n  "resources": []\n}\n' > /home/ec2-user/.kiro/agents/readonly.json

          # エージェント設定: elevated
          printf '{\n  "name": "elevated",\n  "description": "Elevated agent for AWS changes",\n  "prompt": "You are an elevated agent with change permissions. Always use the kiro-elevated profile for all AWS operations via use_aws. Confirm with the user before any mutating operation.",\n  "tools": ["@builtin"],\n  "resources": []\n}\n' > /home/ec2-user/.kiro/agents/elevated.json

          chown -R ec2-user:ec2-user /home/ec2-user/.kiro /home/ec2-user/.aws

Outputs:
  InstanceId:
    Value: !Ref Ec2Instance
  Ec2RoleArn:
    Value: !GetAtt Ec2Role.Arn
  ReadOnlyRoleArn:
    Value: !GetAtt ReadOnlyRole.Arn
  ElevatedRoleArn:
    Value: !GetAtt ElevatedRole.Arn
  SsmConnectCommand:
    Value: !Sub aws ssm start-session --target ${Ec2Instance} --region ${AWS::Region}

aws cloudformation create-stack \
  --stack-name kiro-agent-test \
  --template-body file://cfn-kiro-test.yaml \
  --capabilities CAPABILITY_NAMED_IAM \
  --parameters \
    ParameterKey=Subnet,ParameterValue=<YOUR_SUBNET_ID> \
    ParameterKey=SecurityGroup,ParameterValue=<YOUR_SG_ID> \
  --region us-west-2

aws cloudformation delete-stack --stack-name kiro-agent-test --region us-west-2