CVE-2023-52850 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
media: hantro: Check whether reset op is defined before use
The i.MX8MM/N/P does not define the .reset op since reset of the VPU is done by genpd. Check whether the .reset op is defined before calling it to avoid NULL pointer dereference.
Note that the Fixes tag is set to the commit which removed the reset op from i.MX8M Hantro G2 implementation, this is because before this commit all the implementations did define the .reset op.
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Analysis
by VulDB Data Team • 12/30/2024
The vulnerability CVE-2023-52850 represents a critical null pointer dereference issue within the Linux kernel's media subsystem, specifically affecting the Hantro video processing unit driver. This flaw manifests in the i.MX8MM/N/P platform implementations where the VPU reset functionality is handled through generic power domain management rather than direct reset operations. The root cause stems from inadequate validation of reset operation definitions before attempting to invoke them, creating a potential crash condition that could be exploited to disrupt system operations. The vulnerability directly impacts the stability and reliability of video processing pipelines on affected embedded platforms.
The technical implementation flaw occurs within the Hantro driver's handling of platform-specific reset operations for the Video Processing Unit. When the driver attempts to execute a reset operation on i.MX8MM/N/P devices, it fails to verify whether the .reset operation has been properly defined for the specific platform variant. This validation gap results in a direct call to a NULL function pointer, causing an immediate system crash or kernel panic. The issue is particularly insidious because it occurs during normal operation when the driver attempts to reset the VPU hardware, making it difficult to distinguish from legitimate system failures. This type of vulnerability falls under CWE-476 which specifically addresses null pointer dereference conditions in software implementations.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise the entire multimedia processing capability of affected devices. Embedded systems running on i.MX8MM/N/P processors may experience complete video processing failures, leading to application crashes, display corruption, or complete system instability. The vulnerability affects devices that rely on the Hantro G2 video codec hardware acceleration, which is commonly found in automotive infotainment systems, industrial embedded applications, and IoT devices. Attackers could exploit this condition to cause denial of service attacks against critical embedded systems, particularly those where video processing is essential for normal operation. This aligns with ATT&CK technique T1499.004 which covers network denial of service attacks targeting system resources.
The fix implemented addresses the core validation issue by introducing proper conditional checks before invoking reset operations. The solution ensures that the driver first verifies whether the .reset operation is defined for the specific platform variant before attempting to execute it, preventing the null pointer dereference condition. This approach follows the principle of defensive programming and aligns with best practices for embedded system development. The resolution specifically targets the i.MX8M Hantro G2 implementation where the reset operation was removed from the platform definition, yet the driver code was not updated to handle this change gracefully. The fix demonstrates proper error handling and resource validation that prevents the kernel from attempting to execute undefined function pointers, thereby maintaining system stability and preventing unauthorized disruption of critical multimedia services.