Re: [Freedreno] [PATCH v2 04/10] drm/msm/hdmi: fix memory corruption with too many bridges

[Kuogee Hsieh]

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: sta...@vger.kernel.org      # 3.12
Signed-off-by: Johan Hovold <johan+lin...@kernel.org>

Tested-by: Kuogee Hsieh <quic_khs...@quicinc.com>
Reviewed-by: Kuogee Hsieh <quic_khs...@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;