From a5a4144ef0ac7f42d24ac0d5620db0950c5685f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Drwi=C4=99ga?= <tomusdrw@users.noreply.github.com>
Date: Tue, 14 Aug 2018 13:13:19 +0200
Subject: [PATCH] Reject too large transactions (#558)

* Fix is_valid condition when removing transactions from the pool.

* Less verbosity.

* Reject too large transctions from the pool.

* Bring back the warning level.

* Fix link.
---
 polkadot/consensus/src/lib.rs          |  6 ------
 polkadot/transaction-pool/src/error.rs |  5 +++++
 polkadot/transaction-pool/src/lib.rs   | 13 +++++++++++--
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/polkadot/consensus/src/lib.rs b/polkadot/consensus/src/lib.rs
index be926d1da1..244fdeb55d 100644
--- a/polkadot/consensus/src/lib.rs
+++ b/polkadot/consensus/src/lib.rs
@@ -770,12 +770,6 @@ impl<C> CreateProposal<C> where C: PolkadotApi {
 			let result = self.transaction_pool.cull_and_get_pending(BlockId::hash(self.parent_hash), |pending_iterator| {
 				let mut pending_size = 0;
 				for pending in pending_iterator {
-					// skip and cull transactions which are too large.
-					if pending.encoded_size() > MAX_TRANSACTIONS_SIZE {
-						unqueue_invalid.push(pending.hash().clone());
-						continue
-					}
-
 					if pending_size + pending.encoded_size() >= MAX_TRANSACTIONS_SIZE { break }
 
 					match block_builder.push_extrinsic(pending.primitive_extrinsic()) {
diff --git a/polkadot/transaction-pool/src/error.rs b/polkadot/transaction-pool/src/error.rs
index ef6cdf6b41..99281e8d78 100644
--- a/polkadot/transaction-pool/src/error.rs
+++ b/polkadot/transaction-pool/src/error.rs
@@ -55,6 +55,11 @@ error_chain! {
 			description("Unrecognised address in extrinsic"),
 			display("Unrecognised address in extrinsic: {}", who),
 		}
+		/// Extrinsic too large
+		TooLarge(got: usize, max: usize) {
+			description("Extrinsic too large"),
+			display("Extrinsic is too large ({} > {})", got, max),
+		}
 	}
 }
 
diff --git a/polkadot/transaction-pool/src/lib.rs b/polkadot/transaction-pool/src/lib.rs
index d76eae57cb..676b0d9773 100644
--- a/polkadot/transaction-pool/src/lib.rs
+++ b/polkadot/transaction-pool/src/lib.rs
@@ -59,6 +59,11 @@ use substrate_runtime_primitives::traits::{Bounded, Checkable, Hash as HashT, Bl
 pub use extrinsic_pool::txpool::{Options, Status, LightStatus, VerifiedTransaction as VerifiedTransactionOps};
 pub use error::{Error, ErrorKind, Result};
 
+/// Maximal size of a single encoded extrinsic.
+///
+/// See also polkadot-consensus::MAX_TRANSACTIONS_SIZE
+const MAX_TRANSACTION_SIZE: usize = 4 * 1024 * 1024;
+
 /// Type alias for convenience.
 pub type CheckedExtrinsic = <UncheckedExtrinsic as Checkable<fn(Address) -> std::result::Result<AccountId, &'static str>>>::Checked;
 
@@ -279,14 +284,18 @@ impl<'a, A> txpool::Verifier<UncheckedExtrinsic> for Verifier<'a, A> where
 	type Error = Error;
 
 	fn verify_transaction(&self, uxt: UncheckedExtrinsic) -> Result<Self::VerifiedTransaction> {
-
 		if !uxt.is_signed() {
 			bail!(ErrorKind::IsInherent(uxt))
 		}
 
 		let encoded = uxt.encode();
-		let (encoded_size, hash) = (encoded.len(), BlakeTwo256::hash(&encoded));
+		let encoded_size = encoded.len();
 
+		if encoded_size > MAX_TRANSACTION_SIZE {
+			bail!(ErrorKind::TooLarge(encoded_size, MAX_TRANSACTION_SIZE));
+		}
+
+		let hash = BlakeTwo256::hash(&encoded);
 		debug!(target: "transaction-pool", "Transaction submitted: {}", ::substrate_primitives::hexdisplay::HexDisplay::from(&encoded));
 
 		let inner = match uxt.clone().check_with(|a| self.lookup(a)) {