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使用 IAM 进行身份验证

概述

使用 IAM 身份验证，您可以在缓存配置为使用 Redis 版本 7 或更高版本时，使用 Amazon IAM 身份对与 ElastiCache for Redis 的连接进行身份验证。这使您可以增强安全模型并简化许多管理安全任务。您还可以使用 IAM 身份验证，遵循最低权限原则，为每个单独的 ElastiCache 缓存和 ElastiCache 用户配置精细的访问控制。ElastiCache for Redis 的 IAM 身份验证的工作原理是在 Redis AUTH 或 HELLO 命令中提供有效期很短的 IAM 身份验证令牌，而不是有效期很长的 ElastiCache 用户密码。有关 IAM 身份验证令牌的更多信息，请参阅《Amazon 一般参考指南》中的 Signature Version 4 签名流程和下面的代码示例。

您可以使用 IAM 身份及其关联策略进一步限制 Redis 访问权限。您还可以直接从联合身份提供商向用户授予对 Redis 缓存的访问权限。

要将 Amazon IAM 与 ElastiCache for Redis 一起使用，您首先需要创建身份验证模式设置为 IAM 的 ElastiCache 用户，然后创建或重用 IAM 身份。IAM 身份需要关联策略来向 ElastiCache 缓存和 ElastiCache 用户授予 elasticache:Connect 操作权限。配置完成后，您可以使用 IAM 用户或角色的 Amazon 凭证创建 IAM 身份验证令牌。最后，在连接到 Redis 缓存时，您需要在 Redis 客户端中提供有效期较短的 IAM 身份验证令牌作为密码。支持凭证提供程序的 Redis 客户端可以为每个新连接自动生成临时凭证。ElastiCache for Redis 将对启用 IAM 的 ElastiCache 用户的连接请求执行 IAM 身份验证，并将通过 IAM 验证连接请求。

限制

使用 IAM 身份验证时，以下限制适用：

设置

要设置 IAM 身份验证，请执行以下操作：

连接

使用令牌作为密码进行连接

您首先需要使用 Amazon SigV4 预签名请求生成有效期较短的 IAM 身份验证令牌。之后，您需要在连接到 Redis 缓存时提供 IAM 身份验证令牌作为密码，如下例所示。

String userId = "insert user id";
String cacheName = "insert cache name";
boolean isServerless = true;
String region = "insert region";

// Create a default AWS Credentials provider.
// This will look for AWS credentials defined in environment variables or system properties.
AWSCredentialsProvider awsCredentialsProvider = new DefaultAWSCredentialsProviderChain();

// Create an IAM authentication token request and signed it using the AWS credentials.
// The pre-signed request URL is used as an IAM authentication token for ElastiCache Redis.
IAMAuthTokenRequest iamAuthTokenRequest = new IAMAuthTokenRequest(userId, cacheName, region, isServerless);
String iamAuthToken = iamAuthTokenRequest.toSignedRequestUri(awsCredentialsProvider.getCredentials());

// Construct Redis URL with IAM Auth credentials provider
RedisURI redisURI = RedisURI.builder()
    .withHost(host)
    .withPort(port)
    .withSsl(ssl)
    .withAuthentication(userId, iamAuthToken)
    .build();

// Create a new Lettuce Redis client
RedisClient client = RedisClient.create(redisURI);
client.connect();

以下为 IAMAuthTokenRequest 的定义。

public class IAMAuthTokenRequest {
    private static final HttpMethodName REQUEST_METHOD = HttpMethodName.GET;
    private static final String REQUEST_PROTOCOL = "http://";
    private static final String PARAM_ACTION = "Action";
    private static final String PARAM_USER = "User";
    private static final String PARAM_RESOURCE_TYPE = "ResourceType";
    private static final String RESOURCE_TYPE_SERVERLESS_CACHE = "ServerlessCache";
    private static final String ACTION_NAME = "connect";
    private static final String SERVICE_NAME = "elasticache";
    private static final long TOKEN_EXPIRY_SECONDS = 900;

    private final String userId;
    private final String cacheName;
    private final String region;
    private final boolean isServerless;

    public IAMAuthTokenRequest(String userId, String cacheName, String region, boolean isServerless) {
        this.userId = userId;
        this.cacheName = cacheName;
        this.region = region;
        this.isServerless = isServerless;
    }

    public String toSignedRequestUri(AWSCredentials credentials) throws URISyntaxException {
        Request<Void> request = getSignableRequest();
        sign(request, credentials);
        return new URIBuilder(request.getEndpoint())
            .addParameters(toNamedValuePair(request.getParameters()))
            .build()
            .toString()
            .replace(REQUEST_PROTOCOL, "");
    }

    private <T> Request<T> getSignableRequest() {
        Request<T> request  = new DefaultRequest<>(SERVICE_NAME);
        request.setHttpMethod(REQUEST_METHOD);
        request.setEndpoint(getRequestUri());
        request.addParameters(PARAM_ACTION, Collections.singletonList(ACTION_NAME));
        request.addParameters(PARAM_USER, Collections.singletonList(userId));
        if (isServerless) {
            request.addParameters(PARAM_RESOURCE_TYPE, Collections.singletonList(RESOURCE_TYPE_SERVERLESS_CACHE));
        }
        return request;
    }

    private URI getRequestUri() {
        return URI.create(String.format("%s%s/", REQUEST_PROTOCOL, cacheName));
    }

    private <T> void sign(SignableRequest<T> request, AWSCredentials credentials) {
        AWS4Signer signer = new AWS4Signer();
        signer.setRegionName(region);
        signer.setServiceName(SERVICE_NAME);

        DateTime dateTime = DateTime.now();
        dateTime = dateTime.plus(Duration.standardSeconds(TOKEN_EXPIRY_SECONDS));

        signer.presignRequest(request, credentials, dateTime.toDate());
    }

    private static List<NameValuePair> toNamedValuePair(Map<String, List<String>> in) {
        return in.entrySet().stream()
            .map(e -> new BasicNameValuePair(e.getKey(), e.getValue().get(0)))
            .collect(Collectors.toList());
    }
}

使用凭证提供程序进行连接

以下代码显示了如何使用 IAM 身份验证凭证提供程序通过 ElastiCache for Redis 进行身份验证。

String userId = "insert user id";
String cacheName = "insert cache name";
boolean isServerless = true;
String region = "insert region";

// Create a default AWS Credentials provider.
// This will look for AWS credentials defined in environment variables or system properties.
AWSCredentialsProvider awsCredentialsProvider = new DefaultAWSCredentialsProviderChain();

// Create an IAM authentication token request. Once this request is signed it can be used as an
// IAM authentication token for ElastiCache Redis.
IAMAuthTokenRequest iamAuthTokenRequest = new IAMAuthTokenRequest(userId, cacheName, region, isServerless);

// Create a Redis credentials provider using IAM credentials.
RedisCredentialsProvider redisCredentialsProvider = new RedisIAMAuthCredentialsProvider(
    userId, iamAuthTokenRequest, awsCredentialsProvider);
    
// Construct Redis URL with IAM Auth credentials provider
RedisURI redisURI = RedisURI.builder()
    .withHost(host)
    .withPort(port)
    .withSsl(ssl)
    .withAuthentication(redisCredentialsProvider)
    .build();

// Create a new Lettuce Redis client
RedisClient client = RedisClient.create(redisURI);
client.connect();

以下是 Lettuce Redis 客户端的示例，该客户端将 IAMAuthTokenRequest 封装在凭证提供程序中，以便在需要时自动生成临时凭证。

public class RedisIAMAuthCredentialsProvider implements RedisCredentialsProvider {
    private static final long TOKEN_EXPIRY_SECONDS = 900;

    private final AWSCredentialsProvider awsCredentialsProvider;
    private final String userId;
    private final IAMAuthTokenRequest iamAuthTokenRequest;
    private final Supplier<String> iamAuthTokenSupplier;

    public RedisIAMAuthCredentialsProvider(String userId,
        IAMAuthTokenRequest iamAuthTokenRequest,
        AWSCredentialsProvider awsCredentialsProvider) {
        this.userName = userName;
        this.awsCredentialsProvider = awsCredentialsProvider;
        this.iamAuthTokenRequest = iamAuthTokenRequest;      
        this.iamAuthTokenSupplier = Suppliers.memoizeWithExpiration(this::getIamAuthToken, TOKEN_EXPIRY_SECONDS, TimeUnit.SECONDS);
    }

    @Override
    public Mono<RedisCredentials> resolveCredentials() {
        return Mono.just(RedisCredentials.just(userId, iamAuthTokenSupplier.get()));
    }

    private String getIamAuthToken() {
        return iamAuthTokenRequest.toSignedRequestUri(awsCredentialsProvider.getCredentials());
    }
}