From fa6065661a86656a29e89ed1a3529cb7103f5394 Mon Sep 17 00:00:00 2001
From: MarcoFalke <falke.marco@gmail.com>
Date: Fri, 11 Feb 2022 17:26:40 +0100
Subject: [PATCH] refactor: Avoid unsigned integer overflow in core_write

---
 src/core_write.cpp                | 2 +-
 test/sanitizer_suppressions/ubsan | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/core_write.cpp b/src/core_write.cpp
index 5ea62cf3eda56..c4b6b8d27e526 100644
--- a/src/core_write.cpp
+++ b/src/core_write.cpp
@@ -65,7 +65,7 @@ std::string FormatScript(const CScript& script)
         ret += strprintf("0x%x ", HexStr(std::vector<uint8_t>(it2, script.end())));
         break;
     }
-    return ret.substr(0, ret.size() - 1);
+    return ret.substr(0, ret.empty() ? ret.npos : ret.size() - 1);
 }
 
 const std::map<unsigned char, std::string> mapSigHashTypes = {
diff --git a/test/sanitizer_suppressions/ubsan b/test/sanitizer_suppressions/ubsan
index 2084e02b8ae09..bdaee5d1912a7 100644
--- a/test/sanitizer_suppressions/ubsan
+++ b/test/sanitizer_suppressions/ubsan
@@ -47,7 +47,6 @@ unsigned-integer-overflow:arith_uint256.h
 unsigned-integer-overflow:common/bloom.cpp
 unsigned-integer-overflow:coins.cpp
 unsigned-integer-overflow:compressor.cpp
-unsigned-integer-overflow:core_write.cpp
 unsigned-integer-overflow:crypto/
 unsigned-integer-overflow:hash.cpp
 unsigned-integer-overflow:policy/fees.cpp