linux-kernel - Re: [char-misc-next] Revert "mei: hdcp: Replace one-element array with flexible-array member"

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Date:   Tue, 28 Jul 2020 16:56:47 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Tomas Winkler <tomas.winkler@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-kernel@...r.kernel.org,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>
Subject: Re: [char-misc-next] Revert "mei: hdcp: Replace one-element array
 with flexible-array member"

Hi Tomas,

On 7/28/20 16:41, Tomas Winkler wrote:
> Greg please revert, this commit it changes size of
> struct wired_cmd_repeater_auth_stream_req_in, this is
> not what firmware is expecting.

Could you elaborate on what's the firmware expecting, exactly?

Thanks
--
Gustavo

> I really do not appreciate that the code is bypassing
> driver maintaner review, I think this is a minimum
> we can ask for, this is not for a first time.
> 
> This reverts commit c56967d674e361ebe716e66992e3c5332b25ac1f.
> 
> Cc: Gustavo A. R. Silva <gustavoars@...nel.org>
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> ---
>  drivers/misc/mei/hdcp/mei_hdcp.c | 2 +-
>  drivers/misc/mei/hdcp/mei_hdcp.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c b/drivers/misc/mei/hdcp/mei_hdcp.c
> index d1d3e025ca0e..e6c3dc595617 100644
> --- a/drivers/misc/mei/hdcp/mei_hdcp.c
> +++ b/drivers/misc/mei/hdcp/mei_hdcp.c
> @@ -572,7 +572,7 @@ static int mei_hdcp_verify_mprime(struct device *dev,
>  	       HDCP_2_2_MPRIME_LEN);
>  	drm_hdcp_cpu_to_be24(verify_mprime_in.seq_num_m, data->seq_num_m);
>  	memcpy(verify_mprime_in.streams, data->streams,
> -	       array_size(data->k, sizeof(*data->streams)));
> +	       (data->k * sizeof(struct hdcp2_streamid_type)));
>  
>  	verify_mprime_in.k = cpu_to_be16(data->k);
>  
> diff --git a/drivers/misc/mei/hdcp/mei_hdcp.h b/drivers/misc/mei/hdcp/mei_hdcp.h
> index 834757f5e072..18ffc773fa18 100644
> --- a/drivers/misc/mei/hdcp/mei_hdcp.h
> +++ b/drivers/misc/mei/hdcp/mei_hdcp.h
> @@ -358,7 +358,7 @@ struct wired_cmd_repeater_auth_stream_req_in {
>  	u8				seq_num_m[HDCP_2_2_SEQ_NUM_LEN];
>  	u8				m_prime[HDCP_2_2_MPRIME_LEN];
>  	__be16				k;
> -	struct hdcp2_streamid_type	streams[];
> +	struct hdcp2_streamid_type	streams[1];
>  } __packed;
>  
>  struct wired_cmd_repeater_auth_stream_req_out {
>