AIによるAWS操作を安全に。Claude Code × Bedrockで作るsudo的なIAM権限昇格

AWSTemplateFormatVersion: '2010-09-09'
Description: Claude Code + Bedrock with IAM profile switching (ReadOnly / Elevated)

Parameters:
  Subnet:
    Type: AWS::EC2::Subnet::Id
  SecurityGroup:
    Type: AWS::EC2::SecurityGroup::Id
  InstanceType:
    Type: String
    Default: t4g.small
  VolumeSize:
    Type: Number
    Default: 10
  AmiId:
    Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
    Default: /aws/service/ami-amazon-linux-latest/al2023-ami-kernel-default-arm64

Resources:
  BedrockPolicy:
    Type: AWS::IAM::ManagedPolicy
    Properties:
      ManagedPolicyName: !Sub claudecode-bedrock-${AWS::StackName}
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action:
              - bedrock:InvokeModel
              - bedrock:InvokeModelWithResponseStream
              - bedrock:ListFoundationModels
              - bedrock:ListInferenceProfiles
            Resource: '*'

  ReadOnlyRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub claudecode-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::${AWS::AccountId}:role/claudecode-ec2-${AWS::StackName}
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/ReadOnlyAccess
        - !Ref BedrockPolicy
      Policies:
        - PolicyName: AllowAssumeElevated
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action: sts:AssumeRole
                Resource: !Sub arn:aws:iam::${AWS::AccountId}:role/claudecode-elevated-${AWS::StackName}

  ElevatedRole:
    Type: AWS::IAM::Role
    DependsOn: ReadOnlyRole
    Properties:
      RoleName: !Sub claudecode-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::${AWS::AccountId}:role/claudecode-readonly-${AWS::StackName}
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/PowerUserAccess
        - !Ref BedrockPolicy

  Ec2Role:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub claudecode-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/claudecode-readonly-${AWS::StackName}

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

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

          dnf install -y unzip git jq nodejs docker

          # Claude Code
          npm install -g @anthropic-ai/claude-code

          # Docker
          usermod -aG docker ec2-user
          systemctl enable docker
          systemctl start docker

          # 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

          # Bedrock 環境変数
          printf '#!/bin/bash\nexport CLAUDE_CODE_USE_BEDROCK=1\nexport ANTHROPIC_MODEL=us.anthropic.claude-sonnet-4-6\nexport AWS_REGION=${AWS::Region}\n' > /etc/profile.d/claude-bedrock.sh
          chmod 644 /etc/profile.d/claude-bedrock.sh

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

          # エイリアス
          printf '\nalias claude-ro="AWS_PROFILE=claudecode-readonly claude"\nalias claude-el="AWS_PROFILE=claudecode-elevated claude"\n' >> /home/ec2-user/.bashrc

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

Outputs:
  InstanceId:
    Value: !Ref Ec2Instance
  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 claudecode-profile-test \
  --template-body file://cfn-claudecode.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 claudecode-profile-test --region us-west-2