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From: Stephen Boyd <swboyd@chromium.org>
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Date: Sun, 17 Dec 2023 01:08:16 +0000
Message-ID: <CAE-0n52nK6fs_K8s1pfwGw0K_6HCzAMPfjNruxkVmWZfbEUTDA@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] drm/bridge: ti-sn65dsi86: Never store more than
 msg->size bytes in AUX xfer
To: Douglas Anderson <dianders@chromium.org>, dri-devel@lists.freedesktop.org
Cc: Guenter Roeck <groeck@chromium.org>, Andrzej Hajda <andrzej.hajda@intel.com>, 
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@gmail.com>, 
	Jernej Skrabec <jernej.skrabec@gmail.com>, Jonas Karlman <jonas@kwiboo.se>, 
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>, 
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, 
	Neil Armstrong <neil.armstrong@linaro.org>, Robert Foss <rfoss@kernel.org>, 
	Sam Ravnborg <sam@ravnborg.org>, Thomas Zimmermann <tzimmermann@suse.de>, linux-kernel@vger.kernel.org
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Quoting Douglas Anderson (2023-12-14 12:37:52)
> For aux reads, the value `msg->size` indicates the size of the buffer
> provided by `msg->buffer`. We should never in any circumstances write
> more bytes to the buffer since it may overflow the buffer.
>
> In the ti-sn65dsi86 driver there is one code path that reads the
> transfer length from hardware. Even though it's never been seen to be
> a problem, we should make extra sure that the hardware isn't
> increasing the length since doing so would cause us to overrun the
> buffer.
>
> Fixes: 982f589bde7a ("drm/bridge: ti-sn65dsi86: Update reply on aux failures")
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>