AWS STS SDK for Python (Boto3) を使用した の例

MFA トークンを必要とする IAMロールを引き受け、一時的な認証情報を使用してアカウントの Amazon S3 バケットを一覧表示します。

def list_buckets_from_assumed_role_with_mfa(
    assume_role_arn, session_name, mfa_serial_number, mfa_totp, sts_client
):
    """
    Assumes a role from another account and uses the temporary credentials from
    that role to list the Amazon S3 buckets that are owned by the other account.
    Requires an MFA device serial number and token.

    The assumed role must grant permission to list the buckets in the other account.

    :param assume_role_arn: The Amazon Resource Name (ARN) of the role that
                            grants access to list the other account's buckets.
    :param session_name: The name of the STS session.
    :param mfa_serial_number: The serial number of the MFA device. For a virtual MFA
                              device, this is an ARN.
    :param mfa_totp: A time-based, one-time password issued by the MFA device.
    :param sts_client: A Boto3 STS instance that has permission to assume the role.
    """
    response = sts_client.assume_role(
        RoleArn=assume_role_arn,
        RoleSessionName=session_name,
        SerialNumber=mfa_serial_number,
        TokenCode=mfa_totp,
    )
    temp_credentials = response["Credentials"]
    print(f"Assumed role {assume_role_arn} and got temporary credentials.")

    s3_resource = boto3.resource(
        "s3",
        aws_access_key_id=temp_credentials["AccessKeyId"],
        aws_secret_access_key=temp_credentials["SecretAccessKey"],
        aws_session_token=temp_credentials["SessionToken"],
    )

    print(f"Listing buckets for the assumed role's account:")
    for bucket in s3_resource.buckets.all():
        print(bucket.name)

トークンを渡してセッションMFAトークンを取得し、それを使用してアカウントの Amazon S3 バケットを一覧表示します。

def list_buckets_with_session_token_with_mfa(mfa_serial_number, mfa_totp, sts_client):
    """
    Gets a session token with MFA credentials and uses the temporary session
    credentials to list Amazon S3 buckets.

    Requires an MFA device serial number and token.

    :param mfa_serial_number: The serial number of the MFA device. For a virtual MFA
                              device, this is an Amazon Resource Name (ARN).
    :param mfa_totp: A time-based, one-time password issued by the MFA device.
    :param sts_client: A Boto3 STS instance that has permission to assume the role.
    """
    if mfa_serial_number is not None:
        response = sts_client.get_session_token(
            SerialNumber=mfa_serial_number, TokenCode=mfa_totp
        )
    else:
        response = sts_client.get_session_token()
    temp_credentials = response["Credentials"]

    s3_resource = boto3.resource(
        "s3",
        aws_access_key_id=temp_credentials["AccessKeyId"],
        aws_secret_access_key=temp_credentials["SecretAccessKey"],
        aws_session_token=temp_credentials["SessionToken"],
    )

    print(f"Buckets for the account:")
    for bucket in s3_resource.buckets.all():
        print(bucket.name)

IAM ユーザーを作成し、MFAデバイスを登録し、S3 バケットを一覧表示するアクセス許可を付与するロールを作成します。ユーザーには、ロールの引き受けのみ権限があります。

def setup(iam_resource):
    """
    Creates a new user with no permissions.
    Creates a new virtual MFA device.
    Displays the QR code to seed the device.
    Asks for two codes from the MFA device.
    Registers the MFA device for the user.
    Creates an access key pair for the user.
    Creates a role with a policy that lets the user assume the role and requires MFA.
    Creates a policy that allows listing Amazon S3 buckets.
    Attaches the policy to the role.
    Creates an inline policy for the user that lets the user assume the role.

    For demonstration purposes, the user is created in the same account as the role,
    but in practice the user would likely be from another account.

    Any MFA device that can scan a QR code will work with this demonstration.
    Common choices are mobile apps like LastPass Authenticator,
    Microsoft Authenticator, or Google Authenticator.

    :param iam_resource: A Boto3 AWS Identity and Access Management (IAM) resource
                         that has permissions to create users, roles, and policies
                         in the account.
    :return: The newly created user, user key, virtual MFA device, and role.
    """
    user = iam_resource.create_user(UserName=unique_name("user"))
    print(f"Created user {user.name}.")

    virtual_mfa_device = iam_resource.create_virtual_mfa_device(
        VirtualMFADeviceName=unique_name("mfa")
    )
    print(f"Created virtual MFA device {virtual_mfa_device.serial_number}")

    print(
        f"Showing the QR code for the device. Scan this in the MFA app of your "
        f"choice."
    )
    with open("qr.png", "wb") as qr_file:
        qr_file.write(virtual_mfa_device.qr_code_png)
    webbrowser.open(qr_file.name)

    print(f"Enter two consecutive code from your MFA device.")
    mfa_code_1 = input("Enter the first code: ")
    mfa_code_2 = input("Enter the second code: ")
    user.enable_mfa(
        SerialNumber=virtual_mfa_device.serial_number,
        AuthenticationCode1=mfa_code_1,
        AuthenticationCode2=mfa_code_2,
    )
    os.remove(qr_file.name)
    print(f"MFA device is registered with the user.")

    user_key = user.create_access_key_pair()
    print(f"Created access key pair for user.")

    print(f"Wait for user to be ready.", end="")
    progress_bar(10)

    role = iam_resource.create_role(
        RoleName=unique_name("role"),
        AssumeRolePolicyDocument=json.dumps(
            {
                "Version": "2012-10-17",
                "Statement": [
                    {
                        "Effect": "Allow",
                        "Principal": {"AWS": user.arn},
                        "Action": "sts:AssumeRole",
                        "Condition": {"Bool": {"aws:MultiFactorAuthPresent": True}},
                    }
                ],
            }
        ),
    )
    print(f"Created role {role.name} that requires MFA.")

    policy = iam_resource.create_policy(
        PolicyName=unique_name("policy"),
        PolicyDocument=json.dumps(
            {
                "Version": "2012-10-17",
                "Statement": [
                    {
                        "Effect": "Allow",
                        "Action": "s3:ListAllMyBuckets",
                        "Resource": "arn:aws:s3:::*",
                    }
                ],
            }
        ),
    )
    role.attach_policy(PolicyArn=policy.arn)
    print(f"Created policy {policy.policy_name} and attached it to the role.")

    user.create_policy(
        PolicyName=unique_name("user-policy"),
        PolicyDocument=json.dumps(
            {
                "Version": "2012-10-17",
                "Statement": [
                    {
                        "Effect": "Allow",
                        "Action": "sts:AssumeRole",
                        "Resource": role.arn,
                    }
                ],
            }
        ),
    )
    print(
        f"Created an inline policy for {user.name} that lets the user assume "
        f"the role."
    )

    print("Give AWS time to propagate these new resources and connections.", end="")
    progress_bar(10)

    return user, user_key, virtual_mfa_device, role

MFA トークンなしでロールを引き受けることは許可されていないことを示します。

def try_to_assume_role_without_mfa(assume_role_arn, session_name, sts_client):
    """
    Shows that attempting to assume the role without sending MFA credentials results
    in an AccessDenied error.

    :param assume_role_arn: The Amazon Resource Name (ARN) of the role to assume.
    :param session_name: The name of the STS session.
    :param sts_client: A Boto3 STS instance that has permission to assume the role.
    """
    print(f"Trying to assume the role without sending MFA credentials...")
    try:
        sts_client.assume_role(RoleArn=assume_role_arn, RoleSessionName=session_name)
        raise RuntimeError("Expected AccessDenied error.")
    except ClientError as error:
        if error.response["Error"]["Code"] == "AccessDenied":
            print("Got AccessDenied.")
        else:
            raise

S3 バケットを一覧表示し、必要なMFAトークンを渡して、バケットを一覧表示できることを示すアクセス許可を付与するロールを引き受けます。

def list_buckets_from_assumed_role_with_mfa(
    assume_role_arn, session_name, mfa_serial_number, mfa_totp, sts_client
):
    """
    Assumes a role from another account and uses the temporary credentials from
    that role to list the Amazon S3 buckets that are owned by the other account.
    Requires an MFA device serial number and token.

    The assumed role must grant permission to list the buckets in the other account.

    :param assume_role_arn: The Amazon Resource Name (ARN) of the role that
                            grants access to list the other account's buckets.
    :param session_name: The name of the STS session.
    :param mfa_serial_number: The serial number of the MFA device. For a virtual MFA
                              device, this is an ARN.
    :param mfa_totp: A time-based, one-time password issued by the MFA device.
    :param sts_client: A Boto3 STS instance that has permission to assume the role.
    """
    response = sts_client.assume_role(
        RoleArn=assume_role_arn,
        RoleSessionName=session_name,
        SerialNumber=mfa_serial_number,
        TokenCode=mfa_totp,
    )
    temp_credentials = response["Credentials"]
    print(f"Assumed role {assume_role_arn} and got temporary credentials.")

    s3_resource = boto3.resource(
        "s3",
        aws_access_key_id=temp_credentials["AccessKeyId"],
        aws_secret_access_key=temp_credentials["SecretAccessKey"],
        aws_session_token=temp_credentials["SessionToken"],
    )

    print(f"Listing buckets for the assumed role's account:")
    for bucket in s3_resource.buckets.all():
        print(bucket.name)

デモ用に作成されたリソースを破棄します。

def teardown(user, virtual_mfa_device, role):
    """
    Removes all resources created during setup.

    :param user: The demo user.
    :param role: The demo role.
    """
    for attached in role.attached_policies.all():
        policy_name = attached.policy_name
        role.detach_policy(PolicyArn=attached.arn)
        attached.delete()
        print(f"Detached and deleted {policy_name}.")
    role.delete()
    print(f"Deleted {role.name}.")
    for user_pol in user.policies.all():
        user_pol.delete()
        print("Deleted inline user policy.")
    for key in user.access_keys.all():
        key.delete()
        print("Deleted user's access key.")
    for mfa in user.mfa_devices.all():
        mfa.disassociate()
    virtual_mfa_device.delete()
    user.delete()
    print(f"Deleted {user.name}.")

このシナリオは、前に定義した関数を使用して実行します。

def usage_demo():
    """Drives the demonstration."""
    print("-" * 88)
    print(
        f"Welcome to the AWS Security Token Service assume role demo, "
        f"starring multi-factor authentication (MFA)!"
    )
    print("-" * 88)
    iam_resource = boto3.resource("iam")
    user, user_key, virtual_mfa_device, role = setup(iam_resource)
    print(f"Created {user.name} and {role.name}.")
    try:
        sts_client = boto3.client(
            "sts", aws_access_key_id=user_key.id, aws_secret_access_key=user_key.secret
        )
        try_to_assume_role_without_mfa(role.arn, "demo-sts-session", sts_client)
        mfa_totp = input("Enter the code from your registered MFA device: ")
        list_buckets_from_assumed_role_with_mfa(
            role.arn,
            "demo-sts-session",
            virtual_mfa_device.serial_number,
            mfa_totp,
            sts_client,
        )
    finally:
        teardown(user, virtual_mfa_device, role)
        print("Thanks for watching!")

現在のアカウントの Amazon S3 リソースに対する読み取り専用アクセス権限を付与するロールを作成します。

def setup(iam_resource):
    """
    Creates a role that can be assumed by the current user.
    Attaches a policy that allows only Amazon S3 read-only access.

    :param iam_resource: A Boto3 AWS Identity and Access Management (IAM) instance
                         that has the permission to create a role.
    :return: The newly created role.
    """
    role = iam_resource.create_role(
        RoleName=unique_name("role"),
        AssumeRolePolicyDocument=json.dumps(
            {
                "Version": "2012-10-17",
                "Statement": [
                    {
                        "Effect": "Allow",
                        "Principal": {"AWS": iam_resource.CurrentUser().arn},
                        "Action": "sts:AssumeRole",
                    }
                ],
            }
        ),
    )
    role.attach_policy(PolicyArn="arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess")
    print(f"Created role {role.name}.")

    print("Give AWS time to propagate these new resources and connections.", end="")
    progress_bar(10)

    return role

AWS フェデレーションエンドポイントからセキュリティトークンを取得し、フェデレーション認証情報を使用してコンソールにアクセスするためにURL使用できる を構築します。

def construct_federated_url(assume_role_arn, session_name, issuer, sts_client):
    """
    Constructs a URL that gives federated users direct access to the AWS Management
    Console.

    1. Acquires temporary credentials from AWS Security Token Service (AWS STS) that
       can be used to assume a role with limited permissions.
    2. Uses the temporary credentials to request a sign-in token from the
       AWS federation endpoint.
    3. Builds a URL that can be used in a browser to navigate to the AWS federation
       endpoint, includes the sign-in token for authentication, and redirects to
       the AWS Management Console with permissions defined by the role that was
       specified in step 1.

    :param assume_role_arn: The role that specifies the permissions that are granted.
                            The current user must have permission to assume the role.
    :param session_name: The name for the STS session.
    :param issuer: The organization that issues the URL.
    :param sts_client: A Boto3 STS instance that can assume the role.
    :return: The federated URL.
    """
    response = sts_client.assume_role(
        RoleArn=assume_role_arn, RoleSessionName=session_name
    )
    temp_credentials = response["Credentials"]
    print(f"Assumed role {assume_role_arn} and got temporary credentials.")

    session_data = {
        "sessionId": temp_credentials["AccessKeyId"],
        "sessionKey": temp_credentials["SecretAccessKey"],
        "sessionToken": temp_credentials["SessionToken"],
    }
    aws_federated_signin_endpoint = "https://signin.aws.amazon.com/federation"

    # Make a request to the AWS federation endpoint to get a sign-in token.
    # The requests.get function URL-encodes the parameters and builds the query string
    # before making the request.
    response = requests.get(
        aws_federated_signin_endpoint,
        params={
            "Action": "getSigninToken",
            "SessionDuration": str(datetime.timedelta(hours=12).seconds),
            "Session": json.dumps(session_data),
        },
    )
    signin_token = json.loads(response.text)
    print(f"Got a sign-in token from the AWS sign-in federation endpoint.")

    # Make a federated URL that can be used to sign into the AWS Management Console.
    query_string = urllib.parse.urlencode(
        {
            "Action": "login",
            "Issuer": issuer,
            "Destination": "https://console.aws.amazon.com/",
            "SigninToken": signin_token["SigninToken"],
        }
    )
    federated_url = f"{aws_federated_signin_endpoint}?{query_string}"
    return federated_url

デモ用に作成されたリソースを破棄します。

def teardown(role):
    """
    Removes all resources created during setup.

    :param role: The demo role.
    """
    for attached in role.attached_policies.all():
        role.detach_policy(PolicyArn=attached.arn)
        print(f"Detached {attached.policy_name}.")
    role.delete()
    print(f"Deleted {role.name}.")

このシナリオは、前に定義した関数を使用して実行します。

def usage_demo():
    """Drives the demonstration."""
    print("-" * 88)
    print(f"Welcome to the AWS Security Token Service federated URL demo.")
    print("-" * 88)
    iam_resource = boto3.resource("iam")
    role = setup(iam_resource)
    sts_client = boto3.client("sts")
    try:
        federated_url = construct_federated_url(
            role.arn, "AssumeRoleDemoSession", "example.org", sts_client
        )
        print(
            "Constructed a federated URL that can be used to connect to the "
            "AWS Management Console with role-defined permissions:"
        )
        print("-" * 88)
        print(federated_url)
        print("-" * 88)
        _ = input(
            "Copy and paste the above URL into a browser to open the AWS "
            "Management Console with limited permissions. When done, press "
            "Enter to clean up and complete this demo."
        )
    finally:
        teardown(role)
        print("Thanks for watching!")

ユーザーを作成しIAM、MFAデバイスを登録し、MFA認証情報が使用されている場合にのみ S3 バケットを一覧表示するアクセス許可をユーザーに付与するロールを作成します。

def setup(iam_resource):
    """
    Creates a new user with no permissions.
    Creates a new virtual multi-factor authentication (MFA) device.
    Displays the QR code to seed the device.
    Asks for two codes from the MFA device.
    Registers the MFA device for the user.
    Creates an access key pair for the user.
    Creates an inline policy for the user that lets the user list Amazon S3 buckets,
    but only when MFA credentials are used.

    Any MFA device that can scan a QR code will work with this demonstration.
    Common choices are mobile apps like LastPass Authenticator,
    Microsoft Authenticator, or Google Authenticator.

    :param iam_resource: A Boto3 AWS Identity and Access Management (IAM) resource
                         that has permissions to create users, MFA devices, and
                         policies in the account.
    :return: The newly created user, user key, and virtual MFA device.
    """
    user = iam_resource.create_user(UserName=unique_name("user"))
    print(f"Created user {user.name}.")

    virtual_mfa_device = iam_resource.create_virtual_mfa_device(
        VirtualMFADeviceName=unique_name("mfa")
    )
    print(f"Created virtual MFA device {virtual_mfa_device.serial_number}")

    print(
        f"Showing the QR code for the device. Scan this in the MFA app of your "
        f"choice."
    )
    with open("qr.png", "wb") as qr_file:
        qr_file.write(virtual_mfa_device.qr_code_png)
    webbrowser.open(qr_file.name)

    print(f"Enter two consecutive code from your MFA device.")
    mfa_code_1 = input("Enter the first code: ")
    mfa_code_2 = input("Enter the second code: ")
    user.enable_mfa(
        SerialNumber=virtual_mfa_device.serial_number,
        AuthenticationCode1=mfa_code_1,
        AuthenticationCode2=mfa_code_2,
    )
    os.remove(qr_file.name)
    print(f"MFA device is registered with the user.")

    user_key = user.create_access_key_pair()
    print(f"Created access key pair for user.")

    print(f"Wait for user to be ready.", end="")
    progress_bar(10)

    user.create_policy(
        PolicyName=unique_name("user-policy"),
        PolicyDocument=json.dumps(
            {
                "Version": "2012-10-17",
                "Statement": [
                    {
                        "Effect": "Allow",
                        "Action": "s3:ListAllMyBuckets",
                        "Resource": "arn:aws:s3:::*",
                        "Condition": {"Bool": {"aws:MultiFactorAuthPresent": True}},
                    }
                ],
            }
        ),
    )
    print(
        f"Created an inline policy for {user.name} that lets the user list buckets, "
        f"but only when MFA credentials are present."
    )

    print("Give AWS time to propagate these new resources and connections.", end="")
    progress_bar(10)

    return user, user_key, virtual_mfa_device

MFA トークンを渡して一時的なセッション認証情報を取得し、その認証情報を使用してアカウントの S3 バケットを一覧表示します。

def list_buckets_with_session_token_with_mfa(mfa_serial_number, mfa_totp, sts_client):
    """
    Gets a session token with MFA credentials and uses the temporary session
    credentials to list Amazon S3 buckets.

    Requires an MFA device serial number and token.

    :param mfa_serial_number: The serial number of the MFA device. For a virtual MFA
                              device, this is an Amazon Resource Name (ARN).
    :param mfa_totp: A time-based, one-time password issued by the MFA device.
    :param sts_client: A Boto3 STS instance that has permission to assume the role.
    """
    if mfa_serial_number is not None:
        response = sts_client.get_session_token(
            SerialNumber=mfa_serial_number, TokenCode=mfa_totp
        )
    else:
        response = sts_client.get_session_token()
    temp_credentials = response["Credentials"]

    s3_resource = boto3.resource(
        "s3",
        aws_access_key_id=temp_credentials["AccessKeyId"],
        aws_secret_access_key=temp_credentials["SecretAccessKey"],
        aws_session_token=temp_credentials["SessionToken"],
    )

    print(f"Buckets for the account:")
    for bucket in s3_resource.buckets.all():
        print(bucket.name)

デモ用に作成されたリソースを破棄します。

def teardown(user, virtual_mfa_device):
    """
    Removes all resources created during setup.

    :param user: The demo user.
    :param role: The demo MFA device.
    """
    for user_pol in user.policies.all():
        user_pol.delete()
        print("Deleted inline user policy.")
    for key in user.access_keys.all():
        key.delete()
        print("Deleted user's access key.")
    for mfa in user.mfa_devices.all():
        mfa.disassociate()
    virtual_mfa_device.delete()
    user.delete()
    print(f"Deleted {user.name}.")

このシナリオは、前に定義した関数を使用して実行します。

def usage_demo():
    """Drives the demonstration."""
    print("-" * 88)
    print(
        f"Welcome to the AWS Security Token Service assume role demo, "
        f"starring multi-factor authentication (MFA)!"
    )
    print("-" * 88)
    iam_resource = boto3.resource("iam")
    user, user_key, virtual_mfa_device = setup(iam_resource)
    try:
        sts_client = boto3.client(
            "sts", aws_access_key_id=user_key.id, aws_secret_access_key=user_key.secret
        )
        try:
            print("Listing buckets without specifying MFA credentials.")
            list_buckets_with_session_token_with_mfa(None, None, sts_client)
        except ClientError as error:
            if error.response["Error"]["Code"] == "AccessDenied":
                print("Got expected AccessDenied error.")
        mfa_totp = input("Enter the code from your registered MFA device: ")
        list_buckets_with_session_token_with_mfa(
            virtual_mfa_device.serial_number, mfa_totp, sts_client
        )
    finally:
        teardown(user, virtual_mfa_device)
        print("Thanks for watching!")