Add the missing sanity check on the bridge counter to avoid corrupting
data beyond the fixed-sized bridge array in case there are ever more
than eight bridges.

Fixes: a3376e3ec81c ("drm/msm: convert to drm_bridge")
Cc: stable@vger.kernel.org	# 3.12
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/gpu/drm/msm/hdmi/hdmi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c
index 93fe61b86967..a0ed6aa8e4e1 100644
--- a/drivers/gpu/drm/msm/hdmi/hdmi.c
+++ b/drivers/gpu/drm/msm/hdmi/hdmi.c
@@ -300,6 +300,11 @@ int msm_hdmi_modeset_init(struct hdmi *hdmi,
 	struct platform_device *pdev = hdmi->pdev;
 	int ret;
 
+	if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
+		DRM_DEV_ERROR(dev->dev, "too many bridges\n");
+		return -ENOSPC;
+	}
+
 	hdmi->dev = dev;
 	hdmi->encoder = encoder;
 
-- 
2.35.1

On 13/09/2022 11:53, Johan Hovold wrote:
> Add the missing sanity check on the bridge counter to avoid corrupting
> data beyond the fixed-sized bridge array in case there are ever more
> than eight bridges.
> 
> Fixes: a3376e3ec81c ("drm/msm: convert to drm_bridge")
> Cc: stable@vger.kernel.org	# 3.12
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>   drivers/gpu/drm/msm/hdmi/hdmi.c | 5 +++++
>   1 file changed, 5 insertions(+)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

-- 
With best wishes
Dmitry

On 9/13/2022 1:53 AM, Johan Hovold wrote:
> Add the missing sanity check on the bridge counter to avoid corrupting
> data beyond the fixed-sized bridge array in case there are ever more
> than eight bridges.
>
> Fixes: a3376e3ec81c ("drm/msm: convert to drm_bridge")
> Cc: stable@vger.kernel.org	# 3.12
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> ---
>   drivers/gpu/drm/msm/hdmi/hdmi.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdmi.c
> index 93fe61b86967..a0ed6aa8e4e1 100644
> --- a/drivers/gpu/drm/msm/hdmi/hdmi.c
> +++ b/drivers/gpu/drm/msm/hdmi/hdmi.c
> @@ -300,6 +300,11 @@ int msm_hdmi_modeset_init(struct hdmi *hdmi,
>   	struct platform_device *pdev = hdmi->pdev;
>   	int ret;
>   
> +	if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
> +		DRM_DEV_ERROR(dev->dev, "too many bridges\n");
> +		return -ENOSPC;
> +	}
> +
>   	hdmi->dev = dev;
>   	hdmi->encoder = encoder;
>