When we buy something on iTunes, not ours, we only have the right to use it. The right product is therefore limited and not pass it on to someone else is likely to be accepted by Apple or Amazon.
Unless otherwise noted, you can not sublicense or assign the rights to the digital content or part thereof to a third party.
Allowing third parties to have the details of our account is a violation of security under the contract. Although not a direct violation of contract terms, Apple or Amazon may consider that it is and end the privileges we have in the account.