From 99f9ee0f63627462e4daa3e785ec23086aa3a0b5 Mon Sep 17 00:00:00 2001
From: William Banfield <4561443+williambanfield@users.noreply.github.com>
Date: Fri, 1 Apr 2022 17:44:38 -0400
Subject: [PATCH] abci++: correct max-size check to only operate on added and
 unmodified (#8242)

---
 types/tx.go      | 14 ++++++++------
 types/tx_test.go | 19 +++++++++++++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/types/tx.go b/types/tx.go
index b81114452..0c354a941 100644
--- a/types/tx.go
+++ b/types/tx.go
@@ -188,13 +188,7 @@ func (t TxRecordSet) Validate(maxSizeBytes int64, otxs Txs) error {
 	// Only the slices are copied, the transaction contents are shared.
 	allCopy := sortedCopy(t.all)
 
-	var size int64
 	for i, cur := range allCopy {
-		size += int64(len(cur))
-		if size > maxSizeBytes {
-			return fmt.Errorf("transaction data size %d exceeds maximum %d", size, maxSizeBytes)
-		}
-
 		// allCopy is sorted, so any duplicated data will be adjacent.
 		if i+1 < len(allCopy) && bytes.Equal(cur, allCopy[i+1]) {
 			return fmt.Errorf("found duplicate transaction with hash: %x", cur.Hash())
@@ -207,6 +201,14 @@ func (t TxRecordSet) Validate(maxSizeBytes int64, otxs Txs) error {
 	removedCopy := sortedCopy(t.removed)
 	unmodifiedCopy := sortedCopy(t.unmodified)
 
+	var size int64
+	for _, cur := range append(unmodifiedCopy, addedCopy...) {
+		size += int64(len(cur))
+		if size > maxSizeBytes {
+			return fmt.Errorf("transaction data size %d exceeds maximum %d", size, maxSizeBytes)
+		}
+	}
+
 	// make a defensive copy of otxs so that the order of
 	// the caller's data is not altered.
 	otxsCopy := sortedCopy(otxs)
diff --git a/types/tx_test.go b/types/tx_test.go
index d8737e9f0..77afa1b23 100644
--- a/types/tx_test.go
+++ b/types/tx_test.go
@@ -64,6 +64,25 @@ func TestValidateTxRecordSet(t *testing.T) {
 		err := txrSet.Validate(9, []Tx{})
 		require.Error(t, err)
 	})
+	t.Run("should not error on removed transaction size exceeding max data size", func(t *testing.T) {
+		trs := []*abci.TxRecord{
+			{
+				Action: abci.TxRecord_ADDED,
+				Tx:     Tx([]byte{1, 2, 3, 4, 5}),
+			},
+			{
+				Action: abci.TxRecord_ADDED,
+				Tx:     Tx([]byte{6, 7, 8, 9}),
+			},
+			{
+				Action: abci.TxRecord_REMOVED,
+				Tx:     Tx([]byte{10}),
+			},
+		}
+		txrSet := NewTxRecordSet(trs)
+		err := txrSet.Validate(9, []Tx{[]byte{10}})
+		require.NoError(t, err)
+	})
 	t.Run("should error on duplicate transactions with the same action", func(t *testing.T) {
 		trs := []*abci.TxRecord{
 			{