[PATCH v2 02/10] drm/msm/dp: fix memory corruption with too many bridges

Johan Hovold
2022-09-13T08:58:39Z

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: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
Cc: stable@vger.kernel.org # 5.17
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
drivers/gpu/drm/msm/dp/dp_display.c | 6 ++++++
1 file changed, 6 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);
--
2.35.1