Filter State and Dynamic Metadata

Oct 13, 2025 by magicalceylontours.com 94 views

Introduction

In the realm of Golang filters, accessing filter state and dynamic metadata is a common practice. However, these mechanisms are not designed to store sensitive information, such as secrets. Moreover, passing secrets directly into plugin configurations can lead to security vulnerabilities, including the leakage of secrets when dumping configurations. In this article, we will explore a proposed solution to expose generic secrets to Golang HTTP filters in a secure and efficient manner.

Current Limitations

The current implementation of Golang filters has several limitations when it comes to handling secrets:

Filter State and Dynamic Metadata: These mechanisms are not intended for storing sensitive information, such as secrets. Using them for this purpose can lead to security risks and inconsistencies.
Passing Secrets Directly into Plugin Configurations: This approach can benefit from Envoy's SDS (Service Discovery and Secret Management) features, but it also introduces the risk of leaking secrets when dumping configurations.

Proposed Solution

To address these limitations, we propose the following solution:

Declare Secrets Accessible from Go Plugin in Go Plugin Configuration

The first step is to declare the secrets that are accessible from the Go plugin in the Go plugin configuration. This will enable the plugin to retrieve the necessary secrets without having to pass them directly into the configuration.

Introduce a SecretManager Interface in the GO Envoy SDK

To manage secrets securely, we introduce a SecretManager interface in the GO Envoy SDK. This interface will provide a standardized way for plugins to interact with secrets, ensuring consistency and security across the system.

Wire the Go SecretManager with C++ SecretManager, Filtering on Exposed Secrets

The final step is to wire the Go SecretManager with the C++ SecretManager, filtering on the exposed secrets. This will enable the Go plugin to access the secrets managed by the C++ SecretManager, while ensuring that only the necessary secrets are exposed.

Benefits of the Proposed Solution

The proposed solution offers several benefits:

Improved Security: By using a standardized SecretManager interface, we can ensure that secrets are handled securely and consistently across the system.
Increased Flexibility: The solution allows plugins to access secrets without having to pass them directly into the configuration, making it easier to manage complex configurations.
Better Consistency: The use of a SecretManager interface ensures that secrets are managed in a consistent manner, reducing the risk of errors and inconsistencies.

Implementation Details

To implement the proposed solution, we will need to make the following changes:

Declare Secrets Accessible from Go Plugin in Go Plugin Configuration

In the Go plugin configuration, we will add a new section to declare the secrets that are accessible from the plugin. This section will contain the necessary information to retrieve the secrets, such as the secret name and the SDS configuration.

Introduce a SecretManager Interface in the GO Envoy SDK

We will introduce a new interface, SecretManager, in the GO Envoy SDK. This interface will provide a standardized way for plugins to interact with secrets, including methods for retrieving and managing secrets.

Wire the Go SecretManager with C++ SecretManager, Filtering on Exposed Secrets

We will wire the Go SecretManager with the C++ SecretManager, filtering on the exposed secrets. This will enable the Go plugin to access the secrets managed by the C++ SecretManager, while ensuring that only the necessary secrets are exposed.

Example Use Case

To demonstrate the proposed solution, let's consider an example use case:

Suppose we have a Golang plugin that needs to access a secret for authentication purposes. We can declare the secret in the Go plugin configuration, using the SecretManager interface to retrieve the necessary secret.

// Declare the secret in the Go plugin configuration
secretConfig := &SecretConfig{
    SecretName: "my_secret",
    SDSConfig: &SDSConfig{
        // SDS configuration
    },
}

// Create a SecretManager instance
secretManager := NewSecretManager(secretConfig)

// Retrieve the secret using the SecretManager
secret, err := secretManager.GetSecret("my_secret")
if err != nil {
    // Handle error
}

// Use the retrieved secret for authentication purposes
authToken := secret.Value

Conclusion

Q: What is the main goal of exposing generic secrets to Golang HTTP filters?

A: The main goal is to provide a secure and efficient way to handle secrets in Golang HTTP filters, ensuring that sensitive information is not leaked or compromised.

Q: Why is it not recommended to pass secrets directly into plugin configurations?

A: Passing secrets directly into plugin configurations can lead to security vulnerabilities, including the leakage of secrets when dumping configurations. It also does not benefit from Envoy's SDS (Service Discovery and Secret Management) features.

Q: What is the role of the SecretManager interface in the GO Envoy SDK?

A: The SecretManager interface provides a standardized way for plugins to interact with secrets, including methods for retrieving and managing secrets.

Q: How does the proposed solution improve security?

A: The proposed solution improves security by using a standardized SecretManager interface, ensuring that secrets are handled securely and consistently across the system.

Q: What are the benefits of using a SecretManager interface?

A: The benefits of using a SecretManager interface include improved security, increased flexibility, and better consistency.

Q: How does the proposed solution increase flexibility?

A: The proposed solution increases flexibility by allowing plugins to access secrets without having to pass them directly into the configuration, making it easier to manage complex configurations.

Q: What is the role of the C++ SecretManager in the proposed solution?

A: The C++ SecretManager is used to manage secrets securely, and the Go SecretManager is wired with it, filtering on exposed secrets.

Q: How does the proposed solution ensure consistency?

A: The proposed solution ensures consistency by using a standardized SecretManager interface, which provides a consistent way for plugins to interact with secrets.

Q: What is the example use case provided in the article?

A: The example use case provided in the article demonstrates how to declare a secret in the Go plugin configuration, create a SecretManager instance, retrieve the secret using the SecretManager, and use the retrieved secret for authentication purposes.

Q: What are the key takeaways from the proposed solution?

A: The key takeaways from the proposed solution are:

Declare secrets accessible from the Go plugin in the Go plugin configuration.
Introduce a SecretManager interface in the GO Envoy SDK.
Wire the Go SecretManager with the C++ SecretManager, filtering on exposed secrets.

Q: What are the next steps for implementing the proposed solution?

A: The next steps for implementing the proposed solution include:

Declaring secrets accessible from the Go plugin in the Go plugin configuration.
Implementing the SecretManager interface in the GO Envoy SDK.
Wiring the Go SecretManager with the C++ SecretManager, filtering on exposed secrets.

Q: What are the potential challenges and limitations of the proposed solution?

A: The potential challenges and limitations of the proposed solution include:

Ensuring that the SecretManager interface is implemented correctly and consistently across the system.
Managing complex configurations and ensuring that secrets are handled securely.
Ensuring that the C++ SecretManager is properly integrated with the Go SecretManager.