HexEditor: find_and_highlight: Limit search to remaining buffer size

Author: https://github.com/bcoles
Commit: https://github.com/SerenityOS/serenity/commit/3bbae6c18bd
Pull-request: https://github.com/SerenityOS/serenity/pull/7311

Userland/Applications/HexEditor/HexEditor.cpp

@@ -563,7 +563,7 @@ int HexEditor::find_and_highlight(ByteBuffer& needle, int start)
     if (m_buffer.is_empty())
         return -1;
 
-    auto raw_offset = memmem(m_buffer.data() + start, m_buffer.size(), needle.data(), needle.size());
+    auto raw_offset = memmem(m_buffer.data() + start, m_buffer.size() - start, needle.data(), needle.size());
     if (raw_offset == NULL)
         return -1;