From 9ac8b24194d4f6bc773b11c3d16a0d740e6a0736 Mon Sep 17 00:00:00 2001
From: HuangYi <huang@crypto.com>
Date: Fri, 1 Sep 2023 12:35:36 +0800
Subject: [PATCH] Problem: memiavl's root hash is not safe to retain in commit
 info

Solution:
- clone the byte slices when nesserary
---
 CHANGELOG.md              | 1 +
 memiavl/mem_node.go       | 4 ++++
 memiavl/node.go           | 3 +++
 memiavl/persisted_node.go | 4 ++++
 memiavl/tree.go           | 5 +++--
 5 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9513367c05..38079052be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -37,6 +37,7 @@
 - [#1123](https://github.com/crypto-org-chain/cronos/pull/1123) Fix memiavl snapshot switching
 - [#1125](https://github.com/crypto-org-chain/cronos/pull/1125) Fix genesis migrate for feeibc, evm, feemarket and gravity.
 - [#1130](https://github.com/crypto-org-chain/cronos/pull/1130) Fix lock issues when state-sync with memiavl.
+- [#]() Fix memiavl's unsafe retain of the root hashes.
 
 ### Features
 
diff --git a/memiavl/mem_node.go b/memiavl/mem_node.go
index 6f8eb375bf..f56e345aa6 100644
--- a/memiavl/mem_node.go
+++ b/memiavl/mem_node.go
@@ -70,6 +70,10 @@ func (node *MemNode) Mutate(version, cowVersion uint32) *MemNode {
 	return n
 }
 
+func (node *MemNode) SafeHash() []byte {
+	return node.Hash()
+}
+
 // Computes the hash of the node without computing its descendants. Must be
 // called on nodes which have descendant node hashes already computed.
 func (node *MemNode) Hash() []byte {
diff --git a/memiavl/node.go b/memiavl/node.go
index c756ecdbeb..6f659313c8 100644
--- a/memiavl/node.go
+++ b/memiavl/node.go
@@ -20,6 +20,9 @@ type Node interface {
 	Right() Node
 	Hash() []byte
 
+	// SafeHash returns byte slice that's safe to retain
+	SafeHash() []byte
+
 	// PersistedNode clone a new node, MemNode modify in place
 	Mutate(version, cowVersion uint32) *MemNode
 
diff --git a/memiavl/persisted_node.go b/memiavl/persisted_node.go
index 50579dd3b9..59f8c2ac98 100644
--- a/memiavl/persisted_node.go
+++ b/memiavl/persisted_node.go
@@ -131,6 +131,10 @@ func (node PersistedNode) Right() Node {
 	return PersistedNode{snapshot: node.snapshot, index: node.index - 1}
 }
 
+func (node PersistedNode) SafeHash() []byte {
+	return bytes.Clone(node.Hash())
+}
+
 func (node PersistedNode) Hash() []byte {
 	if node.isLeaf {
 		return node.leafNode().Hash()
diff --git a/memiavl/tree.go b/memiavl/tree.go
index 3d10a01e7f..79067f27ed 100644
--- a/memiavl/tree.go
+++ b/memiavl/tree.go
@@ -162,12 +162,13 @@ func (t *Tree) Version() int64 {
 	return int64(t.version)
 }
 
-// RootHash updates the hashes and return the current root hash
+// RootHash updates the hashes and return the current root hash,
+// it clones the persisted node's bytes, so the returned bytes is safe to retain.
 func (t *Tree) RootHash() []byte {
 	if t.root == nil {
 		return emptyHash
 	}
-	return t.root.Hash()
+	return t.root.SafeHash()
 }
 
 func (t *Tree) GetWithIndex(key []byte) (int64, []byte) {