Final answer:
To control which Amazon S3 buckets can call which AWS Lambda functions, use IAM and resource policies. Specify permissions in the Lambda function's resource policy and the S3 bucket's bucket policy. Use conditions to restrict access.
Step-by-step explanation:
In order to control which Amazon S3 buckets can call which AWS Lambda functions, you can make use of various IAM (Identity and Access Management) and resource policies. A common approach is to use the Lambda function's Resource-based policy and the S3 bucket's Bucket policy to define the permissions.
For example, you can explicitly allow the Lambda function to access specific S3 buckets by specifying the bucket ARN (Amazon Resource Name) in the Lambda function's resource policy. You can also specify the conditions under which the bucket can be accessed, such as the IP address range or other authentication methods.
By configuring these policies, you can ensure that only authorized S3 buckets can invoke your Lambda functions, providing better security and control.