Re: [PATCH] ath6kl: Use struct_group() to avoid size-mismatched casting

[Kalle Valo]

Kees Cook <keescook@xxxxxxxxxxxx> wrote:

> In builds with -Warray-bounds, casts from smaller objects to larger
> objects will produce warnings. These can be overly conservative, but since
> -Warray-bounds has been finding legitimate bugs, it is desirable to turn
> it on globally. Instead of casting a u32 to a larger object, redefine
> the u32 portion of the header to a separate struct that can be used for
> both u32 operations and the distinct header fields. Silences this warning:
> 
> drivers/net/wireless/ath/ath6kl/htc_mbox.c: In function 'htc_wait_for_ctrl_msg':
> drivers/net/wireless/ath/ath6kl/htc_mbox.c:2275:20: error: array subscript 'struct htc_frame_hdr[0]' is partly outside array bounds of 'u32[1]' {aka 'unsigned int[1]'} [-Werror=array-bounds]
>  2275 |         if (htc_hdr->eid != ENDPOINT_0)
>       |                    ^~
> drivers/net/wireless/ath/ath6kl/htc_mbox.c:2264:13: note: while referencing 'look_ahead'
>  2264 |         u32 look_ahead;
>       |             ^~~~~~~~~~
> 
> This change results in no executable instruction differences.
> 
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx>

Patch applied to ath-next branch of ath.git, thanks.

e3128a9d482c ath6kl: Use struct_group() to avoid size-mismatched casting

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20211207063538.2767954-1-keescook@xxxxxxxxxxxx/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches