Re: [PATCH][next] hostap: Add __counted_by for struct prism2_download_data and use struct_size()

From: Kees Cook
Date: Tue Oct 10 2023 - 18:50:41 EST


On Mon, Oct 09, 2023 at 01:41:18PM -0600, Gustavo A. R. Silva wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> While there, use struct_size() helper, instead of the open-coded
> version, to calculate the size for the allocation of the whole
> flexible structure, including of course, the flexible-array member.
>
> This code was found with the help of Coccinelle, and audited and
> fixed manually.
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

I realize I didn't actually send my R-b for this thread, so here it is:

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

:)

--
Kees Cook