Vulnerability in drm/msm/mdp5 Package: Return Error Code in mdp5_mixer_release when Deadlock is Detected

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Background

The drm/msm/mdp5 package is a component of the Linux Kernel that provides support for display controllers on Qualcomm Snapdragon SoCs. It is responsible for managing the display pipeline and handling various operations related to graphics rendering and output. The mdp5_mixer_release function within this package is used to release a mixer resource, but it lacks proper error handling when a deadlock is detected. This vulnerability can potentially lead to resource leaks and system instability.

Vulnerability Detail

The vulnerability arises from the absence of error code return in the mdp5_mixer_release function when a deadlock is detected. This can result in resource leaks and potential system instability. An attacker could potentially trigger this vulnerability by repeatedly acquiring and releasing mixer resources, causing a deadlock condition. The impact of this vulnerability may vary depending on the specific use case and system configuration.

Workaround

As a workaround, users can apply the patch provided in the commit 22d8424913b1348c6324916745fadaeea5273f0e manually to their existing kernel version. The patch modifies the mdp5_mixer_release function to properly return an error code when a deadlock is detected. Here is the code snippet for the patch:

diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
index 5a6a3f3..c1a7f2e 100644
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c
@@ -1237,6 +1237,9 @@ void mdp5_mixer_release(struct mdp5_kms *mdp5_kms, struct mdp5_pipeline *pipeline
 		return;
 	}
 
+	if (mutex_is_locked(&mdp5_kms->lock))
+		return -EBUSY;
+
 	mutex_lock(&mdp5_kms->lock);
 
 	WARN_ON(!mdp5_kms->enabled);

Conclusion

In conclusion, the vulnerability in the drm/msm/mdp5 package allows for resource leaks and potential system instability due to the lack of error code return in the mdp5_mixer_release function when a deadlock is detected. It is recommended to update the Linux Kernel to version v5.4.198 or later to fix this vulnerability. Users can also apply the provided patch as a workaround. For further support on vulnerability remediation, please contact DevNack.com.

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