Re: [PATCH] ARM: ixp4xx: Replace 0-length arrays with flexible arrays

[Linus Walleij]

On Thu, Jan 12, 2023 at 11:54 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> On Sun, Jan 08, 2023 at 12:58:37AM +0100, Linus Walleij wrote:
> > On Thu, Jan 5, 2023 at 10:57 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> >
> > > Zero-length arrays are deprecated[1]. Replace npe_load_firmware's
> > > union of 0-length arrays with flexible arrays. Detected with GCC 13,
> > > using -fstrict-flex-arrays=3:
> > >
> > > drivers/soc/ixp4xx/ixp4xx-npe.c: In function 'npe_load_firmware':
> > > drivers/soc/ixp4xx/ixp4xx-npe.c:570:60: warning: array subscript i is outside array bounds of 'u32[0]' {aka 'unsigned int[]'} [-Warray-bounds=]
> > >   570 |                         image->data[i] = swab32(image->data[i]);
> > > include/uapi/linux/swab.h:115:54: note: in definition of macro '__swab32'
> > >   115 | #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
> > >       |                                                      ^
> > > drivers/soc/ixp4xx/ixp4xx-npe.c:570:42: note: in expansion of macro 'swab32'
> > >   570 |                         image->data[i] = swab32(image->data[i]);
> > >       |                                          ^~~~~~
> > > drivers/soc/ixp4xx/ixp4xx-npe.c:522:29: note: while referencing 'data'
> > >   522 |                         u32 data[0];
> > >       |                             ^~~~
> > >
> > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays
> > >
> > > Cc: Krzysztof Halasa <khalasa@xxxxxxx>
> > > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > > Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
> > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> >
> > Looks good to me:
> > Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
>
> Thanks!
>
> > Do you need me to funnel this to the SoC tree or do you have
> > some quickpath for fixes like this?
>
> I'll take it via my tree if unless you'd rather it go through yours.
> Most maintainers take these directly, but some don't want to. I'm
> flexible! :)

Just pick it into your tree, the IXP4xx is low activity and I do not
submit new material every merge window, so this is easiest.

Thanks!
Linus Walleij