No, it's more than that. While that struct might be a generic overrun, the question is how you check bounds on filling buf. The paper is discussing that schemes

No, it's more than that. While that struct might be a generic overrun, the question is how you check bounds on filling buf. The paper is discussing that schemes to constrain buffer size using a global hardware or software address-based size constraints ("low-fat") as bounds checks are less safe than claimed.