fix: prevent undelegation of closed delegated accounts

src/error.rs

@@ -87,6 +87,8 @@ pub enum DlpError {
     InvalidDiscriminator = 39,
     #[error("Invalid delegation record deserialization")]
     InvalidDelegationRecordData = 40,
+    #[error("Delegated account is already closed")]
+    DelegateAccountClosed = 41,
     #[error("An infallible error is encountered possibly due to logic error")]
     InfallibleError = 100,
 }

src/processor/fast/undelegate.rs

@@ -68,6 +68,7 @@ use super::{
 ///
 /// - Close the delegation metadata
 /// - Close the delegation record
+/// - If delegated account is closed then stop the process
 /// - If delegated account has no data, assign to prev owner (and stop here)
 /// - If there's data, create an "undelegate_buffer" and store the data in it
 /// - Close the original delegated account
@@ -87,6 +88,12 @@ pub fn process_undelegate(
         return Err(ProgramError::NotEnoughAccountKeys);
     };
 
+    // Reject undelegation of closed account
+    if delegated_account.lamports() == 0 && delegated_account.data_is_empty() {
+        log!("Delegated account is already closed");
+        return Err(DlpError::DelegateAccountClosed.into());
+    }
+
     // Check accounts
     require_signer(validator, "validator")?;
     require_owned_pda(delegated_account, &crate::fast::ID, "delegated account")?;

tests/test_undelegate_close_account.rs

@@ -0,0 +1,137 @@
+use dlp::pda::{
+    delegation_metadata_pda_from_delegated_account, delegation_record_pda_from_delegated_account,
+    fees_vault_pda, validator_fees_vault_pda_from_validator,
+};
+use solana_program::{hash::Hash, native_token::LAMPORTS_PER_SOL, rent::Rent, system_program};
+use solana_program_test::{read_file, BanksClient, ProgramTest};
+use solana_sdk::{
+    account::Account,
+    signature::{Keypair, Signer},
+    transaction::Transaction,
+};
+
+use crate::fixtures::{
+    get_delegation_metadata_data, get_delegation_record_data, DELEGATED_PDA_ID,
+    DELEGATED_PDA_OWNER_ID, TEST_AUTHORITY,
+};
+
+mod fixtures;
+
+#[tokio::test]
+async fn test_undelegate_close_account() {
+    // Setup
+    let (banks, _, authority, blockhash) = setup_program_test_env().await;
+
+    // Create the undelegate tx
+    let ix_undelegate = dlp::instruction_builder::undelegate(
+        authority.pubkey(),
+        DELEGATED_PDA_ID,
+        DELEGATED_PDA_OWNER_ID,
+        authority.pubkey(),
+    );
+
+    // Submit the transaction
+    let tx = Transaction::new_signed_with_payer(
+        &[ix_undelegate],
+        Some(&authority.pubkey()),
+        &[&authority],
+        blockhash,
+    );
+    let res = banks.process_transaction(tx).await;
+    assert!(res.is_err(), "Delegate account is already closed");
+}
+
+async fn setup_program_test_env() -> (BanksClient, Keypair, Keypair, Hash) {
+    let mut program_test = ProgramTest::new("dlp", dlp::ID, None);
+    program_test.prefer_bpf(true);
+    let authority = Keypair::from_bytes(&TEST_AUTHORITY).unwrap();
+
+    program_test.add_account(
+        authority.pubkey(),
+        Account {
+            lamports: LAMPORTS_PER_SOL,
+            data: vec![],
+            owner: system_program::id(),
+            executable: false,
+            rent_epoch: 0,
+        },
+    );
+
+    // Setup a Closed delegated PDA
+    program_test.add_account(
+        DELEGATED_PDA_ID,
+        Account {
+            lamports: 0,
+            data: vec![],
+            owner: dlp::id(),
+            executable: false,
+            rent_epoch: 0,
+        },
+    );
+
+    // Setup the delegated record PDA
+    let delegation_record_data = get_delegation_record_data(authority.pubkey(), None);
+    program_test.add_account(
+        delegation_record_pda_from_delegated_account(&DELEGATED_PDA_ID),
+        Account {
+            lamports: Rent::default().minimum_balance(delegation_record_data.len()),
+            data: delegation_record_data,
+            owner: dlp::id(),
+            executable: false,
+            rent_epoch: 0,
+        },
+    );
+
+    // Setup the delegated metadata PDA
+    let delegation_metadata_data = get_delegation_metadata_data(authority.pubkey(), Some(true));
+    program_test.add_account(
+        delegation_metadata_pda_from_delegated_account(&DELEGATED_PDA_ID),
+        Account {
+            lamports: Rent::default().minimum_balance(delegation_metadata_data.len()),
+            data: delegation_metadata_data,
+            owner: dlp::id(),
+            executable: false,
+            rent_epoch: 0,
+        },
+    );
+
+    // Setup program to test undelegation
+    let data = read_file("tests/buffers/test_delegation.so");
+    program_test.add_account(
+        DELEGATED_PDA_OWNER_ID,
+        Account {
+            lamports: Rent::default().minimum_balance(data.len()),
+            data,
+            owner: solana_sdk::bpf_loader::id(),
+            executable: true,
+            rent_epoch: 0,
+        },
+    );
+
+    // Setup the protocol fees vault
+    program_test.add_account(
+        fees_vault_pda(),
+        Account {
+            lamports: Rent::default().minimum_balance(0),
+            data: vec![],
+            owner: dlp::id(),
+            executable: false,
+            rent_epoch: 0,
+        },
+    );
+
+    // Setup the validator fees vault
+    program_test.add_account(
+        validator_fees_vault_pda_from_validator(&authority.pubkey()),
+        Account {
+            lamports: LAMPORTS_PER_SOL,
+            data: vec![],
+            owner: dlp::id(),
+            executable: false,
+            rent_epoch: 0,
+        },
+    );
+
+    let (banks, payer, blockhash) = program_test.start().await;
+    (banks, payer, authority, blockhash)
+}