policy

A session policy for your user so that you can use the same Identity and Access Management (IAM) role across multiple users. This policy scopes down a user's access to portions of their Amazon S3 bucket. Variables that you can use inside this policy include ${Transfer:UserName}, ${Transfer:HomeDirectory}, and ${Transfer:HomeBucket}.

This policy applies only when the domain of ServerId is Amazon S3. Amazon EFS does not use session policies.

For session policies, Transfer Family stores the policy as a JSON blob, instead of the Amazon Resource Name (ARN) of the policy. You save the policy as a JSON blob and pass it in the Policy argument.

For an example of a session policy, see Example session policy.

For more information, see AssumeRole in the Amazon Web Services Security Token Service API Reference.