CVE-2022-49495 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/hdmi: check return value after calling platform_get_resource_byname()
It will cause null-ptr-deref if platform_get_resource_byname() returns NULL, we need check the return value.
Patchwork: https://patchwork.freedesktop.org/patch/482992/
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Analysis
by VulDB Data Team • 04/17/2025
The vulnerability identified as CVE-2022-49495 resides within the Linux kernel's display subsystem, specifically in the msm hdmi driver component. This issue represents a classic null pointer dereference scenario that can lead to system instability and potential security implications. The vulnerability manifests in the drm/msm/hdmi subsystem where the platform_get_resource_byname() function is invoked without proper validation of its return value. This function is responsible for retrieving resource information from the device tree or platform data structure, and when it fails to locate the requested resource, it returns NULL instead of a valid resource pointer. The absence of proper error checking in the calling code creates a dangerous condition where subsequent operations attempt to dereference this NULL pointer, leading to immediate system crashes or potential exploitation scenarios.
The technical flaw stems from inadequate input validation within the driver's resource acquisition logic. When platform_get_resource_byname() fails to find a named resource, it returns NULL to indicate the absence of the requested resource. However, the msm hdmi driver fails to check this return value before proceeding with operations that assume the resource pointer is valid. This pattern violates fundamental defensive programming practices and creates a direct pathway for null pointer dereference conditions. The vulnerability is classified as a software error that can be exploited through careful manipulation of the system's hardware resource configuration or by triggering the specific code path that invokes the problematic function. This type of vulnerability falls under the CWE-476 category of NULL Pointer Dereference, which is a well-documented weakness in software systems where null values are not properly validated before use.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling privilege escalation or denial of service conditions within the graphics subsystem. When the null pointer dereference occurs, it typically results in a kernel oops or system panic, causing the affected display driver to become unavailable and potentially bringing the entire system to a halt. In environments where the hdmi driver is critical for display output, this can result in complete system unresponsiveness. The vulnerability is particularly concerning in embedded systems or devices where display functionality is essential for user interaction or system monitoring. Attackers could potentially leverage this vulnerability to cause persistent denial of service conditions or in more sophisticated scenarios, exploit the kernel memory corruption to gain elevated privileges or execute arbitrary code within kernel space. The ATT&CK framework would classify this as a kernel-level vulnerability that could be used for privilege escalation and system compromise through the exploitation of memory corruption flaws.
Mitigation strategies for CVE-2022-49495 involve implementing proper error checking and validation of function return values within the affected driver code. The recommended approach is to always validate the return value from platform_get_resource_byname() before attempting to use the returned pointer. This includes adding explicit NULL checks and appropriate error handling mechanisms that either gracefully handle the resource acquisition failure or prevent the system from proceeding with invalid resource pointers. The patch referenced in the vulnerability description addresses this issue by ensuring that the return value is properly checked before subsequent operations are performed. System administrators should ensure that all kernel updates containing this fix are applied promptly, particularly in production environments where display stability is critical. Additionally, monitoring for kernel oops or system crash reports that may indicate this vulnerability's exploitation can serve as an early warning system for potential security incidents. The fix aligns with security best practices for kernel development and demonstrates the importance of defensive programming techniques in kernel-space code to prevent common memory corruption vulnerabilities that could be exploited by malicious actors.