Re: [PATCH] fscrypt: Replace 1-element array with flexible array

From: Eric Biggers
Date: Mon May 22 2023 - 22:50:14 EST


On Mon, May 22, 2023 at 06:23:06PM -0700, Kees Cook wrote:
> On May 22, 2023 4:02:06 PM PDT, Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> >On Mon, May 22, 2023 at 02:39:28PM -0700, Kees Cook wrote:
> >> In the future, we can add annotations for the flexible array member
> >> "encrypted_path" to have a size determined by the "len" member.
> >
> >That seems unlikely, as 'struct fscrypt_symlink_data' is an on-disk data
> >structure. The "len" field does not necessarily use CPU endianness, and before
> >being validated it might be greater than the size of the allocated space.
>
> Oh yes, good point.
>
> >I agree that it should use a flex array (and thanks for catching this one that I
> >had forgotten about...), but the above explanation seems wrong.
>
> Shall I spin a v2?

Yes, please go ahead.

- Eric