Merge bitcoin#24319: refactor: Avoid unsigned integer overflow in cor…

…e_write

fa60656 refactor: Avoid unsigned integer overflow in core_write (MarcoFalke)

Pull request description:

  Also, I find the new code a bit easier to understand.

ACKs for top commit:
  shaavan:
    Code Review ACK fa60656

Tree-SHA512: cd751e3b4dc97ef525eb8be8d0a49e9629389cb114df18d59a06e05388822af2939078e937f01494e6b317d601743b1a433ba47aa40c4dc602372d1f0fd0dc11

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 = {

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