CVE-2023-35829 in Linux
Summary
by MITRE • 06/19/2023
An issue was discovered in the Linux kernel before 6.3.2. A use-after-free was found in rkvdec_remove in drivers/staging/media/rkvdec/rkvdec.c.
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Analysis
by VulDB Data Team • 07/15/2023
The vulnerability identified as CVE-2023-35829 represents a critical use-after-free condition within the Linux kernel's staging media driver for Rockchip VPU hardware acceleration. This flaw exists in the rkvdec_remove function located in drivers/staging/media/rkvdec/rkvdec.c and affects kernel versions prior to 6.3.2. The issue arises from improper memory management during device removal operations, creating a scenario where freed memory locations may still be accessed by subsequent operations. Such vulnerabilities are particularly dangerous in kernel space contexts as they can lead to arbitrary code execution or system instability when exploited by malicious actors. The rkvdec driver specifically handles Rockchip VPU decoding operations, making this vulnerability relevant to systems utilizing Rockchip SoCs for multimedia processing.
The technical implementation of this use-after-free vulnerability stems from the device removal handler not properly managing reference counts or memory pointers during the cleanup process. When the rkvdec_remove function executes, it likely frees memory structures associated with the device context while other kernel threads or interrupt handlers may still be referencing these locations. This creates a window where memory corruption can occur, potentially allowing attackers to manipulate kernel memory layout or inject malicious code. The vulnerability falls under CWE-416 which specifically addresses use-after-free conditions, and represents a classic example of improper resource management in kernel drivers. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1547.001 for registry run keys for persistence, as successful exploitation could enable privilege escalation.
The operational impact of this vulnerability extends beyond simple system crashes or hangs, as it provides potential attack vectors for privilege escalation and system compromise. Attackers with local access or those able to trigger the device removal process could exploit this condition to execute arbitrary code with kernel privileges. Systems utilizing Rockchip-based hardware for video decoding, including embedded devices, media centers, and automotive infotainment systems, would be particularly at risk. The vulnerability's exploitation potential is heightened by the fact that it occurs during normal device removal operations, making detection more difficult as such operations are routine. Organizations running affected kernel versions should prioritize patching to prevent potential exploitation, as the window for exploitation exists during device lifecycle management operations.
Mitigation strategies for CVE-2023-35829 primarily focus on immediate kernel version updates to 6.3.2 or later, which contain the necessary patches to address the use-after-free condition. System administrators should also implement monitoring for device removal events and unusual kernel behavior that might indicate exploitation attempts. Additional defensive measures include disabling unnecessary staging drivers when not required, implementing proper kernel lockdown configurations, and maintaining comprehensive system logging for kernel-level activities. The patch for this vulnerability typically involves proper reference counting mechanisms and ensuring all pointers are cleared after memory deallocation. Organizations should also conduct vulnerability assessments to identify systems running affected kernel versions and prioritize remediation efforts based on risk exposure and system criticality.