From 1363675adb162050bcf67a43a02d3eb349e305f5 Mon Sep 17 00:00:00 2001
From: thiolliere <gui.thiolliere@gmail.com>
Date: Tue, 31 Mar 2020 18:41:55 +0200
Subject: [PATCH] safe slice operation (#5471)

---
 substrate/frame/support/src/hash.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/substrate/frame/support/src/hash.rs b/substrate/frame/support/src/hash.rs
index f8d6409060..693e929a30 100644
--- a/substrate/frame/support/src/hash.rs
+++ b/substrate/frame/support/src/hash.rs
@@ -92,6 +92,10 @@ impl StorageHasher for Twox64Concat {
 }
 impl ReversibleStorageHasher for Twox64Concat {
 	fn reverse(x: &[u8]) -> &[u8] {
+		if x.len() < 8 {
+			crate::debug::error!("Invalid reverse: hash length too short");
+			return &[]
+		}
 		&x[8..]
 	}
 }
@@ -110,6 +114,10 @@ impl StorageHasher for Blake2_128Concat {
 }
 impl ReversibleStorageHasher for Blake2_128Concat {
 	fn reverse(x: &[u8]) -> &[u8] {
+		if x.len() < 16 {
+			crate::debug::error!("Invalid reverse: hash length too short");
+			return &[]
+		}
 		&x[16..]
 	}
 }