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[PATCH 2/7] drm/msm: fix memory corruption with too many bridges

Johan Hovold posted 7 patches 3 years, 6 months ago
There is a newer version of this series
[PATCH 2/7] drm/msm: fix memory corruption with too many bridges
Posted by Johan Hovold 3 years, 6 months ago 
Add the missing sanity checks on the bridge counter to avoid corrupting
data beyond the fixed-sized bridge array in case there are ever more
than eight bridges.

a3376e3ec81c ("drm/msm: convert to drm_bridge")
ab5b0107ccf3 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
a689554ba6ed ("drm/msm: Initial add DSI connector support")
Fixes: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
Cc: stable@vger.kernel.org	# 3.12
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 6 ++++++
 drivers/gpu/drm/msm/dsi/dsi.c       | 6 ++++++
 drivers/gpu/drm/msm/hdmi/hdmi.c     | 5 +++++
 3 files changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 3e284fed8d30..fbe950edaefe 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1604,6 +1604,12 @@ int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
 		return -EINVAL;
 
 	priv = dev->dev_private;
+
+	if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
+		DRM_DEV_ERROR(dev->dev, "too many bridges\n");
+		return -ENOSPC;
+	}
+
 	dp_display->drm_dev = dev;
 
 	dp_priv = container_of(dp_display, struct dp_display_private, dp_display);
diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
index 39bbabb5daf6..8a95c744972a 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.c
+++ b/drivers/gpu/drm/msm/dsi/dsi.c
@@ -218,6 +218,12 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
 		return -EINVAL;
 
 	priv = dev->dev_private;
+
+	if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
+		DRM_DEV_ERROR(dev->dev, "too many bridges\n");
+		return -ENOSPC;
+	}
+
 	msm_dsi->dev = dev;
 
 	ret = msm_dsi_host_modeset_init(msm_dsi->host, dev);
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
Re: [PATCH 2/7] drm/msm: fix memory corruption with too many bridges
Posted by Dmitry Baryshkov 3 years, 6 months ago 
On 12/09/2022 18:40, Johan Hovold wrote:
> Add the missing sanity checks on the bridge counter to avoid corrupting
> data beyond the fixed-sized bridge array in case there are ever more
> than eight bridges.
> 
> a3376e3ec81c ("drm/msm: convert to drm_bridge")
> ab5b0107ccf3 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
> a689554ba6ed ("drm/msm: Initial add DSI connector support")

Most probably you've missed the Fixes: here.

> Fixes: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
> Cc: stable@vger.kernel.org	# 3.12
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>   drivers/gpu/drm/msm/dp/dp_display.c | 6 ++++++
>   drivers/gpu/drm/msm/dsi/dsi.c       | 6 ++++++
>   drivers/gpu/drm/msm/hdmi/hdmi.c     | 5 +++++

Could you please split this into respective dp/dsi/hdmi patches. This 
will assist both the review and the stable team.

Otherwise LGTM.

>   3 files changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 3e284fed8d30..fbe950edaefe 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -1604,6 +1604,12 @@ int msm_dp_modeset_init(struct msm_dp *dp_display, struct drm_device *dev,
>   		return -EINVAL;
>   
>   	priv = dev->dev_private;
> +
> +	if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
> +		DRM_DEV_ERROR(dev->dev, "too many bridges\n");
> +		return -ENOSPC;
> +	}
> +
>   	dp_display->drm_dev = dev;
>   
>   	dp_priv = container_of(dp_display, struct dp_display_private, dp_display);
> diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c
> index 39bbabb5daf6..8a95c744972a 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi.c
> @@ -218,6 +218,12 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
>   		return -EINVAL;
>   
>   	priv = dev->dev_private;
> +
> +	if (priv->num_bridges == ARRAY_SIZE(priv->bridges)) {
> +		DRM_DEV_ERROR(dev->dev, "too many bridges\n");
> +		return -ENOSPC;
> +	}
> +
>   	msm_dsi->dev = dev;
>   
>   	ret = msm_dsi_host_modeset_init(msm_dsi->host, dev);
> 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;
>   

-- 
With best wishes
Dmitry
Re: [PATCH 2/7] drm/msm: fix memory corruption with too many bridges
Posted by Johan Hovold 3 years, 6 months ago 
On Mon, Sep 12, 2022 at 08:55:55PM +0300, Dmitry Baryshkov wrote:
> On 12/09/2022 18:40, Johan Hovold wrote:
> > Add the missing sanity checks on the bridge counter to avoid corrupting
> > data beyond the fixed-sized bridge array in case there are ever more
> > than eight bridges.
> > 
> > a3376e3ec81c ("drm/msm: convert to drm_bridge")
> > ab5b0107ccf3 ("drm/msm: Initial add eDP support in msm drm driver (v5)")
> > a689554ba6ed ("drm/msm: Initial add DSI connector support")
> 
> Most probably you've missed the Fixes: here.

Indeed, thanks for catching that.

> > Fixes: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
> > Cc: stable@vger.kernel.org	# 3.12
> > Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> > ---
> >   drivers/gpu/drm/msm/dp/dp_display.c | 6 ++++++
> >   drivers/gpu/drm/msm/dsi/dsi.c       | 6 ++++++
> >   drivers/gpu/drm/msm/hdmi/hdmi.c     | 5 +++++
> 
> Could you please split this into respective dp/dsi/hdmi patches. This 
> will assist both the review and the stable team.

Yeah, you're right, that should help the stable team if nothing else.

> Otherwise LGTM.

Johan

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