Limit number of accounts that a transaction can lock (#22201)

sdk/src/feature_set.rs

@@ -287,6 +287,10 @@ pub mod cap_accounts_data_len {
     solana_sdk::declare_id!("capRxUrBjNkkCpjrJxPGfPaWijB7q3JoDfsWXAnt46r");
 }
 
+pub mod max_tx_account_locks {
+    solana_sdk::declare_id!("CBkDroRDqm8HwHe6ak9cguPjUomrASEkfmxEaZ5CNNxz");
+}
+
 lazy_static! {
     /// Map of feature identifiers to user-visible description
     pub static ref FEATURE_NAMES: HashMap<Pubkey, &'static str> = [
@@ -353,6 +357,7 @@ lazy_static! {
         (allow_votes_to_directly_update_vote_state::id(), "enable direct vote state update"),
         (reject_all_elf_rw::id(), "reject all read-write data in program elfs"),
         (cap_accounts_data_len::id(), "cap the accounts data len"),
+        (max_tx_account_locks::id(), "enforce max number of locked accounts per transaction"),
         /*************** ADD NEW FEATURES HERE ***************/
     ]
     .iter()

sdk/src/transaction/error.rs

@@ -105,6 +105,10 @@ pub enum TransactionError {
     /// Transaction would exceed max account data limit within the block
     #[error("Transaction would exceed max account data limit within the block")]
     WouldExceedMaxAccountDataCostLimit,
+
+    /// Transaction locked too many accounts
+    #[error("Transaction locked too many accounts")]
+    TooManyAccountLocks,
 }
 
 impl From<SanitizeError> for TransactionError {
@@ -114,12 +118,7 @@ impl From<SanitizeError> for TransactionError {
 }
 
 impl From<SanitizeMessageError> for TransactionError {
-    fn from(err: SanitizeMessageError) -> Self {
-        match err {
-            SanitizeMessageError::IndexOutOfBounds
-            | SanitizeMessageError::ValueOutOfBounds
-            | SanitizeMessageError::InvalidValue => Self::SanitizeFailure,
-            SanitizeMessageError::DuplicateAccountKey => Self::AccountLoadedTwice,
-        }
+    fn from(_err: SanitizeMessageError) -> Self {
+        Self::SanitizeFailure
     }
 }

sdk/src/transaction/sanitized.rs

@@ -20,6 +20,11 @@ use {
     std::sync::Arc,
 };
 
+/// Maximum number of accounts that a transaction may lock.
+/// 64 was chosen because it is roughly twice the previous
+/// number of account keys that could fit in a legacy tx.
+pub const MAX_TX_ACCOUNT_LOCKS: usize = 64;
+
 /// Sanitized transaction and the hash of its message
 #[derive(Debug, Clone)]
 pub struct SanitizedTransaction {
@@ -59,10 +64,6 @@ impl SanitizedTransaction {
             }),
         };
 
-        if message.has_duplicates() {
-            return Err(TransactionError::AccountLoadedTwice);
-        }
-
         let is_simple_vote_tx = is_simple_vote_tx.unwrap_or_else(|| {
             let mut ix_iter = message.program_instructions_iter();
             ix_iter.next().map(|(program_id, _ix)| program_id) == Some(&crate::vote::program::id())
@@ -79,10 +80,6 @@ impl SanitizedTransaction {
     pub fn try_from_legacy_transaction(tx: Transaction) -> Result<Self> {
         tx.sanitize()?;
 
-        if tx.message.has_duplicates() {
-            return Err(TransactionError::AccountLoadedTwice);
-        }
-
         Ok(Self {
             message_hash: tx.message.hash(),
             message: SanitizedMessage::Legacy(tx.message),
@@ -143,8 +140,24 @@ impl SanitizedTransaction {
         }
     }
 
+    /// Validate and return the account keys locked by this transaction
+    pub fn get_account_locks(
+        &self,
+        feature_set: &feature_set::FeatureSet,
+    ) -> Result<TransactionAccountLocks> {
+        if self.message.has_duplicates() {
+            Err(TransactionError::AccountLoadedTwice)
+        } else if feature_set.is_active(&feature_set::max_tx_account_locks::id())
+            && self.message.account_keys_len() > MAX_TX_ACCOUNT_LOCKS
+        {
+            Err(TransactionError::TooManyAccountLocks)
+        } else {
+            Ok(self.get_account_locks_unchecked())
+        }
+    }
+
     /// Return the list of accounts that must be locked during processing this transaction.
-    pub fn get_account_locks(&self) -> TransactionAccountLocks {
+    pub fn get_account_locks_unchecked(&self) -> TransactionAccountLocks {
         let message = &self.message;
         let num_readonly_accounts = message.num_readonly_accounts();
         let num_writable_accounts = message