Re: [PATCH v5] hfsplus: fix uninit-value by validating catalog record size

[Charalampos Mitrodimas <charmitro@posteo.net>]

Deepanshu Kartikey <kartikey406@gmail.com> writes:

> On Tue, Feb 24, 2026 at 12:28 AM Viacheslav Dubeyko
> <Slava.Dubeyko@ibm.com> wrote:
>>
>
>> > +     case HFSPLUS_FILE_THREAD:
>> > +             /* Ensure we have at least the fixed fields before reading nodeName.length */
>> > +             if (fd->entrylength < offsetof(struct hfsplus_cat_thread, nodeName) +
>> > +                 offsetof(struct hfsplus_unistr, unicode)) {
>> > +                     pr_err("thread record too short (got %u)\n", fd->entrylength);
>> > +                     return -EIO;
>> > +             }
>
> The check is in the HFSPLUS_FOLDER_THREAD/HFSPLUS_FILE_THREAD case in
> hfsplus_brec_read_cat() function (fs/hfsplus/bfind.c):
>
> This validates that we have at least the minimum bytes needed before
> calling hfsplus_cat_thread_size() which reads nodeName.length.

Hi,

So... yes, while this is essentially what I recommended, just checking
entrylength against HFSPLUS_MIN_THREAD_SZ will yield the same results,
because:

HFSPLUS_MIN_THREAD_SZ is already defined 10, the same value as the
offsetof chain. hfsplus_readdir() already uses it for the same
guard. It's shorter, consistent with other places and the intent is
immediately clear (easier to read).

Cheers,
C. Mitrodimas