drm/msm/hdmi: fix memory corruption with too many bridges

stable inclusion
from stable-v5.10.153
commit 08c7375fa27a8ceee028868e03ffb3a0db919d44
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64YCA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=08c7375fa27a8ceee028868e03ffb3a0db919d44

--------------------------------

commit 4c1294da upstream.

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: a3376e3e ("drm/msm: convert to drm_bridge")
Cc: stable@vger.kernel.org	# 3.12
Signed-off-by: NJohan Hovold <johan+linaro@kernel.org>
Tested-by: NKuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: NKuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: NDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/502670/
Link: https://lore.kernel.org/r/20220913085320.8577-5-johan+linaro@kernel.orgSigned-off-by: NAbhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLipeng Sang <sanglipeng1@jd.com>

drivers/gpu/drm/msm/hdmi/hdmi.c

@@ -293,6 +293,11 @@ 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;