CVE-2022-3113 in Linux
Summary
by MITRE • 12/15/2022
An issue was discovered in the Linux kernel through 5.16-rc6. mtk_vcodec_fw_vpu_init in drivers/media/platform/mtk-vcodec/mtk_vcodec_fw_vpu.c lacks check of the return value of devm_kzalloc() and will cause the null pointer dereference.
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Analysis
by VulDB Data Team • 01/12/2023
The vulnerability identified as CVE-2022-3113 resides within the Linux kernel version 5.16-rc6 and earlier, specifically affecting the mtk_vcodec_fw_vpu_init function located in drivers/media/platform/mtk-vcodec/mtk_vcodec_fw_vpu.c. This flaw represents a critical null pointer dereference issue that emerges from inadequate error handling within the video codec driver implementation for MediaTek platforms. The vulnerability manifests when the function fails to validate the return value of devm_kzalloc(), a memory allocation routine that is essential for initializing firmware components in the VPU (Video Processing Unit) subsystem.
The technical root cause of this vulnerability stems from the absence of proper error checking after memory allocation operations. When devm_kzalloc() is invoked to allocate memory for firmware initialization, the function may return a null pointer if the allocation fails due to insufficient memory or other resource constraints. However, the mtk_vcodec_fw_vpu_init function proceeds without validating this return value, directly attempting to use the potentially null pointer in subsequent operations. This oversight creates a condition where the kernel attempts to dereference a null pointer, leading to an immediate system crash or potential privilege escalation depending on the execution context.
From an operational perspective, this vulnerability presents significant security implications for systems utilizing MediaTek video codec hardware, particularly those running Linux kernel versions up to 5.16-rc6. The null pointer dereference can result in system instability, kernel panics, and potential denial of service conditions that affect video processing capabilities. Attackers could potentially exploit this vulnerability to cause system crashes or in more sophisticated scenarios, leverage the memory corruption for privilege escalation attacks. The vulnerability aligns with CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations, making it a classic example of improper error handling that can lead to system compromise.
The impact extends beyond simple system crashes as this vulnerability affects the media platform subsystem, which is critical for video encoding and decoding operations in various embedded systems and mobile devices. Systems relying on MediaTek VPU hardware for multimedia processing, including smartphones, tablets, and embedded devices, could experience complete system failures when this vulnerability is triggered. The ATT&CK framework categorizes this type of vulnerability under privilege escalation techniques through kernel exploits, as the null pointer dereference in kernel space can potentially be leveraged to gain elevated privileges and execute arbitrary code with kernel-level access.
Mitigation strategies for this vulnerability primarily involve immediate kernel updates to versions that contain the fix for CVE-2022-3113, which typically includes proper error checking of the devm_kzalloc() return value. System administrators should prioritize patching affected systems to prevent exploitation attempts, particularly in environments where the MediaTek video codec driver is actively used. Additionally, implementing runtime monitoring and memory allocation validation can provide early detection of similar issues in other kernel subsystems. The fix typically involves adding conditional checks to verify that memory allocation was successful before proceeding with subsequent operations, which aligns with established kernel development best practices for robust error handling and memory management.