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Managing a bucket policy

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Updated at May 5, 2025

Object Storage incorporates several access management mechanisms. To learn how these mechanisms interact, see Access management methods in Object Storage: Overview.

Bucket policies set permissions for operations with buckets, objects, and object groups.

For examples of bucket policies for specific use cases, see Configuration examples.

Warning

If you want to assign an access policy to a bucket and connect to this bucket from a Hive Metastore or Yandex Managed Service for Apache Airflow™ cluster, you will need some additional infrastructure setup. For more information, see these guides for Metastore and Managed Service for Apache Airflow™.

Applying or updating a policy

The minimum role required to apply or update a bucket policy is storage.configurer. For more information, see the role description.

Note

If the bucket already had a bucket policy configured, it will be completely overwritten once you apply the changes.

To apply or update a bucket policy:

  1. In the management console, select Object Storage from the list of services and go to the bucket whose policy you need to configure.

  2. In the left-hand panel, select Security and go to the Access policy tab.

  3. Click Configure access.

  4. Enter a bucket policy ID.

  5. Set up a rule:

    1. Enter a rule ID.

    2. Configure rule settings:

      • Result: Allow or deny.

      • Selection principle: Include or exclude users.

      • User: Select all users or list specific subjects.

        To list specific subjects:

        • Select Select users.

        • Select the subjects you need from the list. To do this, place the cursor in the subject input field, then select the required user, service account, user group, system group, or public group in the form that appears. If required, use the relevant tabs in the form or the search bar to find a subject by name or email address.

          You can select multiple subjects; to do this, select them one by one.

      • Action for which you are creating the rule. You can also enable All actions.

      • Resource: Defaults to the selected bucket. To add other resources to the rule, click Add resource.

        Note

        A bucket resource does not include resources of all its objects. To make sure a bucket policy rule refers to the bucket and all the objects, specify them as separate resources, e.g., samplebucket and samplebucket/*.

    3. If required, add a condition for the rule:

      • Select Key from the list.
      • Select Operator from the list. If you want the operator to apply solely to the existing fields, select Apply if the field exists. This way, if the field is missing, the condition will be considered met.
      • Specify Value.
      • Click Add value to add another value to the condition.

      You can set multiple conditions for a rule and specify multiple keys for each condition. These conditions and their keys will be checked using the logical AND, i.e., the request must meet all the specified criteria at once.

      You can set multiple values for each condition key at the same time. These values will be checked using the logical OR, i.e., the request must match any of the specified condition key values.

  6. Add and configure rules as required.

  7. Click Save.

If you do not have the Yandex Cloud CLI yet, install and initialize it.

The folder specified when creating the CLI profile is used by default. To change the default folder, use the yc config set folder-id <folder_ID> command. You can specify a different folder using the --folder-name or --folder-id parameter.

  1. See the description of the CLI command for editing a bucket ACL:

    yc storage bucket update --help

  2. Describe your bucket policy configuration as a JSON data schema:

    {
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Principal": "*",
    "Action": "s3:GetObject",
    "Resource": "arn:aws:s3:::<bucket_name>/*",
    "Condition": {
      "Bool": {
        "aws:SecureTransport": "true"
      }
    }
  }
}

    Where:

    • Version: Version of the bucket policy description. This is an optional parameter.
    • Statement: Bucket policy rules:

      • Effect: Deny or allow the requested action. The possible values are Allow and Deny.

      • Principal: Requested permission subject ID. You can request permissions for a user, service account, or user group. Possible values: * and <subject_ID>. This is an optional parameter.

        You can get the IDs in the following ways:

      • Action: Action to allow when the policy is triggered. The possible values are s3:GetObject, s3:PutObject, and * (if you need to apply the policy to all actions).

      • Resource: Resource to apply the rule to.

      • Condition: Condition to check. This is an optional parameter.

        You can set multiple conditions for a rule and specify multiple keys for each condition. These conditions and their keys will be checked using the logical AND, i.e., the request must meet all the specified criteria at once.

        You can set multiple values for each condition key at the same time. These values will be checked using the logical OR, i.e., the request must match any of the specified condition key values.

  3. Run this command:

    yc storage bucket update \
  --name <bucket_name> \
  --policy-from-file <policy_file_path>

    Result:

    name: my-bucket
folder_id: csgeoelk7fl1********
default_storage_class: STANDARD
versioning: VERSIONING_SUSPENDED
max_size: "10737418240"
policy:
    Statement:
      Action: s3:GetObject
      Condition:
        Bool:
          aws:SecureTransport: "true"
        Effect: Allow
        Principal: '*'
        Resource: arn:aws:s3:::my-bucket
      Version: "2012-10-17"
acl: {}
created_at: "2022-12-14T08:42:16.273717Z"

Note

To manage a policy using the AWS CLI, a service account needs the storage.admin role.

If you do not have the AWS CLI yet, install and configure it.

  1. Describe your bucket policy configuration as a JSON data schema:

    {
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Principal": "*",
    "Action": "s3:GetObject",
    "Resource": "arn:aws:s3:::<bucket_name>/*",
    "Condition": {
      "Bool": {
        "aws:SecureTransport": "true"
      }
    }
  }
}

    Where:

    • Version: Version of the bucket policy description. This is an optional parameter.
    • Statement: Bucket policy rules:

      • Effect: Deny or allow the requested action. The possible values are Allow and Deny.

      • Principal: Requested permission subject ID. You can request permissions for a user, service account, or user group. Possible values: * and <subject_ID>. This is an optional parameter.

        You can get the IDs in the following ways:

      • Action: Action to allow when the policy is triggered. The possible values are s3:GetObject, s3:PutObject, and * (if you need to apply the policy to all actions).

      • Resource: Resource to apply the rule to.

      • Condition: Condition to check. This is an optional parameter.

        You can set multiple conditions for a rule and specify multiple keys for each condition. These conditions and their keys will be checked using the logical AND, i.e., the request must meet all the specified criteria at once.

        You can set multiple values for each condition key at the same time. These values will be checked using the logical OR, i.e., the request must match any of the specified condition key values.

    Once the configuration is complete, save it to a file named policy.json.

  2. Run this command:

    aws s3api put-bucket-policy \
  --endpoint https://storage.yandexcloud.net \
  --bucket <bucket_name> \
  --policy file://policy.json

Note

Terraform uses a service account to interact with Object Storage. Assign to the service account the required role, e.g., storage.admin, for the folder where you are going to create resources.

If you do not have Terraform yet, install it and configure its Yandex Cloud provider.

Retrieve static access keys: a secret key and key ID used for Object Storage authentication.

Note

In addition to static access keys, you can use an IAM token for authentication in Object Storage. For more details, see Creating a bucket and the relevant provider documentation.

  1. In the configuration file, describe the resources you want to create:

    
resource "yandex_iam_service_account" "sa" {
  name = "<service_account_name>"
}

// Assigning a role to a service account
resource "yandex_resourcemanager_folder_iam_member" "sa-admin" {
  folder_id = "<folder_ID>"
  role      = "storage.admin"
  member    = "serviceAccount:${yandex_iam_service_account.sa.id}"
}

// Creating a static access key
resource "yandex_iam_service_account_static_access_key" "sa-static-key" {
  service_account_id = yandex_iam_service_account.sa.id
  description        = "static access key for object storage"
}

resource "yandex_storage_bucket" "b" {
  access_key = "yandex_iam_service_account_static_access_key.sa-static-key.access_key"
  secret_key = "yandex_iam_service_account_static_access_key.sa-static-key.secret_key"
  bucket     = "my-policy-bucket"
  policy     = <<POLICY
 {
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": "*",
      "Action": "s3:*",
      "Resource": [
        "arn:aws:s3:::my-policy-bucket/*",
        "arn:aws:s3:::my-policy-bucket"
      ]
    },
    {
      "Effect": "Deny",
      "Principal": "*",
      "Action": "s3:PutObject",
      "Resource": [
        "arn:aws:s3:::my-policy-bucket/*",
        "arn:aws:s3:::my-policy-bucket"
      ]
    }
  ]
}
POLICY
}

    Where:

    • access_key: Static access key ID.
    • secret_key: Secret access key value.
    • bucket: Bucket name. This is a required setting.
    • policy: Policy name. This is a required setting.

    Policy settings:

    • Version: Version of the bucket policy description. This is an optional parameter.
    • Statement: Bucket policy rules:

      • Effect: Deny or allow the requested action. The possible values are Allow and Deny.

      • Principal: Requested permission subject ID. You can request permissions for a user, service account, or user group. Possible values: * and <subject_ID>. This is an optional parameter.

        You can get the IDs in the following ways:

      • Action: Action to allow when the policy is triggered. The possible values are s3:GetObject, s3:PutObject, and * (if you need to apply the policy to all actions).

      • Resource: Resource to apply the rule to.

      • Condition: Condition to check. This is an optional parameter.

        You can set multiple conditions for a rule and specify multiple keys for each condition. These conditions and their keys will be checked using the logical AND, i.e., the request must meet all the specified criteria at once.

        You can set multiple values for each condition key at the same time. These values will be checked using the logical OR, i.e., the request must match any of the specified condition key values.

    For more information about the resources you can create with Terraform, see this provider reference.

  2. Make sure the configuration files are correct.

    1. In the command line, navigate to the directory where you created the configuration file.

    2. Run a check using this command:

      terraform plan

    If you described the configuration correctly, the terminal will display a list of the resources being created and their settings. If the configuration contains any errors, Terraform will point them out.

  3. Deploy the cloud resources.

    1. If the configuration does not contain any errors, run this command:

      terraform apply

    2. Confirm creating the resources.

    This will create all resources you need in the specified folder. You can check the new resources and their settings using the management console.

To manage a bucket policy, use the update REST API method for the Bucket resource, the BucketService/Update gRPC API call, or the PutBucketPolicy S3 API method. If the bucket already had a bucket policy configured, it will be completely overwritten once you apply the new policy.

Note

If a bucket policy with no rules is applied to the bucket, access is denied to all users. To disable request verification for a bucket policy, delete it.

Viewing a policy

The minimum role required to view a bucket policy is storage.configViewer. For more information, see the role description.

To view the bucket policy applied to a bucket:

  1. In the management console, select Object Storage from the list of services.
  2. Select the bucket from the list.
  3. In the left-hand menu, select Security and go to the Access policy tab.

Run this command:

aws --endpoint https://storage.yandexcloud.net s3api get-bucket-policy \
  --bucket <bucket_name> \
  --output text

Result:

{
  "Policy": "{\"Version\":\"2012-10-17\",\"Statement\":{\"Effect\":\"Allow\",\"Principal\":\"*\",\"Action\":\"s3:GetObject\",\"Resource\":\"arn:aws:s3:::<bucket_name>/*\",\"Condition\":{\"Bool\":{\"aws:SecureTransport\":\"true\"}}}}"
}

For more information about parameters, see the data schema description.

Use the GetBucketPolicy S3 API method.

Deleting a policy

The minimum role required to delete a bucket policy is storage.configurer. For more information, see the role description.

To delete a bucket policy:

  1. In the management console, select Object Storage from the list of services.
  2. Select the bucket from the list.
  3. In the left-hand menu, select Security and go to the Access policy tab.
  4. Click and select Delete access policy.
  5. Click Delete.

Run the following command:

aws --endpoint https://storage.yandexcloud.net s3api delete-bucket-policy \
  --bucket <bucket_name>

If you do not have Terraform yet, install it and configure its Yandex Cloud provider.

If you applied a bucket policy using Terraform, you can delete it by following these steps:

  1. Find the parameters of the previously created bucket policy to delete in the configuration file:

    resource "yandex_storage_bucket" "b" {
  bucket = "my-policy-bucket"
  policy = <<POLICY
 {
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": "*",
      "Action": "s3:*",
      "Resource": [
        "arn:aws:s3:::my-policy-bucket/*",
        "arn:aws:s3:::my-policy-bucket"
      ]
    },
    {
      "Effect": "Deny",
      "Principal": "*",
      "Action": "s3:PutObject",
      "Resource": [
        "arn:aws:s3:::my-policy-bucket/*",
        "arn:aws:s3:::my-policy-bucket"
      ]
    }
  ]
}
POLICY
}

  2. Delete the policy field describing the bucket policy settings from the configuration file.

  3. Make sure the configuration files are correct.

    1. In the command line, navigate to the directory where you edited the configuration file.

    2. Run a check using this command:

      terraform plan

    If the configuration is correct, the terminal will display a list of the resources to create and their parameters, without the description of the bucket policy you are deleting. If the configuration contains any errors, Terraform will point them out.

  4. Delete the bucket policy.

    1. If the configuration does not contain any errors, run this command:

      terraform apply

    2. Type yes and press Enter.

    This will delete the bucket policy from the specified folder. You can check the bucket policy deletion using the management console.

Use the DeleteBucketPolicy S3 API method.

See also

Previous
Editing a bucket's ACL
Next
Configuring public access to a bucket