From d18e02ef444b48b1f48cd57ef3bd2c57b1f42038 Mon Sep 17 00:00:00 2001
From: Jack May <jack@solana.com>
Date: Fri, 18 Jun 2021 11:37:39 -0700
Subject: [PATCH] fix loader instruction checker (#18047)

---
 sdk/program/src/bpf_loader_upgradeable.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sdk/program/src/bpf_loader_upgradeable.rs b/sdk/program/src/bpf_loader_upgradeable.rs
index 25a4878ee7..2ff747ba76 100644
--- a/sdk/program/src/bpf_loader_upgradeable.rs
+++ b/sdk/program/src/bpf_loader_upgradeable.rs
@@ -189,11 +189,11 @@ pub fn upgrade(
 }
 
 pub fn is_upgrade_instruction(instruction_data: &[u8]) -> bool {
-    3 == instruction_data[0]
+    !instruction_data.is_empty() && 3 == instruction_data[0]
 }
 
 pub fn is_set_authority_instruction(instruction_data: &[u8]) -> bool {
-    4 == instruction_data[0]
+    !instruction_data.is_empty() && 4 == instruction_data[0]
 }
 
 /// Returns the instructions required to set a buffers's authority.
@@ -331,6 +331,7 @@ mod tests {
 
     #[test]
     fn test_is_set_authority_instruction() {
+        assert!(!is_set_authority_instruction(&[]));
         assert_is_instruction(
             is_set_authority_instruction,
             UpgradeableLoaderInstruction::SetAuthority {},
@@ -339,6 +340,7 @@ mod tests {
 
     #[test]
     fn test_is_upgrade_instruction() {
+        assert!(!is_upgrade_instruction(&[]));
         assert_is_instruction(
             is_upgrade_instruction,
             UpgradeableLoaderInstruction::Upgrade {},