Re: [PATCH][next] media: usb: siano: Fix undefined behavior bug in struct smsusb_urb_t

[Kees Cook]

On Fri, Sep 29, 2023 at 05:42:11PM +0200, Gustavo A. R. Silva wrote:
> `struct urb` is a flexible structure, which means that it contains a
> flexible-array member at the bottom. This could potentially lead to an
> overwrite of the object `wq` at run-time with the contents of `urb`.
> 
> Fix this by placing object `urb` at the end of `struct smsusb_urb_t`.
> 
> Fixes: dd47fbd40e6e ("[media] smsusb: don't sleep while atomic")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

As Jann pointed out, it's unlikely there is a function bug here, but I
still think it's right to make sure this is robust and clears the way
for -Wflex-array-member-not-at-end.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook