On Thu, Feb 13, 2025 at 02:25:27PM -0800, Alison Schofield wrote:
> On Thu, Feb 13, 2025 at 03:29:12PM +1030, Gustavo A. R. Silva wrote:
> > -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> > getting ready to enable it, globally.
> >
> > So, in order to avoid ending up with flexible-array members in the
> > middle of other structs, we use the `__struct_group()` helper to
> > separate the flexible array from the rest of the members in the
> > flexible structure. We then use the newly created tagged `struct
> > nd_cmd_pkg_hdr` to replace the type of the objects causing trouble
> > (`pkg`) in multiple structs.
> >
> > So, with these changes, fix the following warnings:
> >
> > drivers/acpi/nfit/intel.c:692:35: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
>
> One sample warning is good.
>
> How about adding a comment on why the usage of __struct_group() here
> means this doesn't break userspace.
>
> snip
>
> > diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h
> > index 73516e263627..34c11644d5d7 100644
> > --- a/include/uapi/linux/ndctl.h
> > +++ b/include/uapi/linux/ndctl.h
>
> FWIW: In a patch like this where reviewers likely want to see
> the header file change first, put it first in the diff.
> (git diff.orderfile)
TIL about diff.orderfile! :) Just for my own education, what do you have
as the contents for your orderfile? Is it just simply:
*.h
?
>
>
> > @@ -227,12 +227,15 @@ enum ars_masks {
> > */
> >
> > struct nd_cmd_pkg {
> > - __u64 nd_family; /* family of commands */
> > - __u64 nd_command;
> > - __u32 nd_size_in; /* INPUT: size of input args */
> > - __u32 nd_size_out; /* INPUT: size of payload */
> > - __u32 nd_reserved2[9]; /* reserved must be zero */
> > - __u32 nd_fw_size; /* OUTPUT: size fw wants to return */
> > + /* New members MUST be added within the __struct_group() macro below. */
> > + __struct_group(nd_cmd_pkg_hdr, __hdr, /* no attrs */,
> > + __u64 nd_family; /* family of commands */
> > + __u64 nd_command;
> > + __u32 nd_size_in; /* INPUT: size of input args */
> > + __u32 nd_size_out; /* INPUT: size of payload */
> > + __u32 nd_reserved2[9]; /* reserved must be zero */
> > + __u32 nd_fw_size; /* OUTPUT: size fw wants to return */
> > + );
> > unsigned char nd_payload[]; /* Contents of call */
> > };
Gustavo, any updates on this patch? I'm skimming through patchwork to
check on stalled patches...
--
Kees Cook
