Do not permit token accounts to be closed when the withheld amount is non-zero

Author: mvines

token/program-2022/src/extension/confidential_transfer/mod.rs

@@ -108,6 +108,7 @@ impl ConfidentialTransferAccount {
     pub fn closable(&self) -> ProgramResult {
         if self.pending_balance == pod::ElGamalCiphertext::zeroed()
             && self.available_balance == pod::ElGamalCiphertext::zeroed()
+            && self.withheld_amount == pod::ElGamalCiphertext::zeroed()
         {
             Ok(())
         } else {

token/program-2022/src/extension/confidential_transfer/processor.rs

@@ -236,6 +236,11 @@ fn process_empty_account(
     }
 
     ct_token_account.available_balance = pod::ElGamalCiphertext::zeroed();
+
+    if ct_token_account.withheld_amount != pod::ElGamalCiphertext::zeroed() {
+        msg!("Withheld amount is not zero");
+        return Err(ProgramError::InvalidAccountData);
+    }
     ct_token_account.closable()?;
 
     Ok(())