On Sat, Feb 17, 2024 at 03:18:59PM -0600, Alex Elder wrote:
> On 2/17/24 9:47 AM, Erick Archer wrote:
> > When a struct containing a flexible array is included in another struct,
> > and there is a member after the struct-with-flex-array, there is a
> > possibility of memory overlap. These cases must be audited [1]. See:
> >
> > struct inner {
> > ...
> > int flex[];
> > };
> >
> > struct outer {
> > ...
> > struct inner header;
> > int overlap;
> > ...
> > };
> >
> > This is the scenario for the "struct audio_apbridgea_hdr" structure
> > that is included in the following "struct audio_apbridgea_*_request"
> > structures:
>
> Yeah this was not a very good way to define these header
> structures, but I'm glad to hear the flexible array at the
> end was never used. I don't know why it was there; maybe
> it's an artifact from some other information that got removed.
>
> If the code compiles with your change, it ought to be fine.
> (It compiles for me.)
>
> It would be good for Vaibhav or Mark to comment though, maybe
> they can provide some context.
Sorry for the delay guys.
The way this was done comes from associated firmware that ran on the
APBridge. This goes back a while but I think the packet headers may have
been in flux at the time and this was a convenient way to change all of
the packets if & when it changed. Anyway, it doesn't seem so convenient
now. :)
So, yeah, getting rid of it sounds like a good thing to do to me.
> I'd like to hear from these others, but otherwise this change
> looks good to me.
>
> Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
> > diff --git a/drivers/staging/greybus/audio_apbridgea.h b/drivers/staging/greybus/audio_apbridgea.h
> > index efec0f815efd..ab707d310129 100644
> > --- a/drivers/staging/greybus/audio_apbridgea.h
> > +++ b/drivers/staging/greybus/audio_apbridgea.h
> > @@ -65,7 +65,6 @@
> > struct audio_apbridgea_hdr {
> > __u8 type;
> > __le16 i2s_port;
> > - __u8 data[];
> > } __packed;
> >
> > struct audio_apbridgea_set_config_request {
> > --
> > 2.25.1
Acked-by: Mark Greer <mgreer@xxxxxxxxxxxxxxx>
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