token: Add close_authority and re-enable CloseAccount for non-native Accounts #314
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mvines
approved these changes
Aug 25, 2020
CriesofCarrots
changed the title
jackcmay
approved these changes
Aug 26, 2020
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There are cases when the SOL required for rent at the creation of an SPL token account will be subsidized by a 3rd party, opening the door for a financial attack where users request token accounts from the subsidizer only to immediately close them in order to drain SOL from the subsidizer.
Our previous solution to this attack was to disable CloseAccount for non-native accounts, locking that SOL forever.
This PR re-enables CloseAccount for non-native accounts, and adds an Account::close_authority, enabling a 3rd party as above to reclaim their SOL when an account has 0 token balance.
Also adds a couple clarifying comments to the mint section of process_set_authority
Closes #302
Reverts #127