CVE-2023-52829 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix possible out-of-bound write in ath12k_wmi_ext_hal_reg_caps()
reg_cap.phy_id is extracted from WMI event and could be an unexpected value in case some errors happen. As a result out-of-bound write may occur to soc->hal_reg_cap. Fix it by validating reg_cap.phy_id before using it.
This is found during code review.
Compile tested only.
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Analysis
by VulDB Data Team • 12/04/2024
The vulnerability CVE-2023-52829 represents a critical out-of-bounds write condition within the Linux kernel's ath12k wireless driver implementation. This flaw exists in the ath12k_wmi_ext_hal_reg_caps() function where the phy_id field extracted from a WMI event is not properly validated before being used as an array index. The issue stems from the assumption that the phy_id value received from the wireless management interface will always be within acceptable bounds, which may not hold true during error conditions or malformed packet processing. The vulnerability was identified through routine code review processes rather than through active exploitation or fuzzing campaigns, highlighting the importance of defensive programming practices in kernel space code.
The technical implementation flaw occurs when the driver processes wireless management interface (WMI) events containing regulatory capability information. The reg_cap.phy_id field is extracted directly from the incoming WMI event without proper bounds checking against the valid range of physical radio identifiers supported by the hardware. When an unexpected phy_id value is received, typically due to corrupted data transmission or error handling in the wireless subsystem, the driver attempts to write to an array location in soc->hal_reg_cap that exceeds the allocated memory boundaries. This out-of-bounds write operation can result in memory corruption that potentially affects kernel stability, data integrity, and could provide a pathway for privilege escalation attacks. The vulnerability specifically maps to CWE-787: Out-of-bounds Write, which is classified as a severe memory safety issue in the Common Weakness Enumeration catalog.
The operational impact of this vulnerability extends beyond simple memory corruption as it can compromise the entire wireless subsystem functionality and potentially enable more sophisticated attacks. An attacker who can influence the WMI event stream or manipulate wireless communication parameters may trigger this condition to overwrite critical kernel memory locations, potentially leading to denial of service, arbitrary code execution, or information disclosure. The vulnerability affects systems running Linux kernels with the ath12k driver, particularly those utilizing Qualcomm-based wireless chipsets such as the QCA6174 and QCA6255. The out-of-bounds write could corrupt adjacent memory regions including other driver data structures, kernel metadata, or even stack variables, making the exploitation potential highly significant in environments where wireless connectivity is essential. This vulnerability aligns with ATT&CK technique T1059.007 for kernel-mode rootkits and T1566 for wireless network attacks, demonstrating the intersection of wireless protocol manipulation and kernel exploitation vectors.
The mitigation strategy for CVE-2023-52829 requires implementing proper input validation and bounds checking for the phy_id field extracted from WMI events. The fix involves adding a validation check that ensures reg_cap.phy_id falls within the expected range of valid physical radio identifiers before using it as an array index. This defensive programming approach prevents the out-of-bounds write condition by rejecting invalid phy_id values or mapping them to safe default values. System administrators should prioritize applying the kernel patches that implement this validation mechanism, particularly in production environments where wireless connectivity is critical. The vulnerability's discovery through code review emphasizes the importance of systematic security auditing practices and highlights the need for comprehensive testing of edge cases in kernel drivers. Organizations should also implement monitoring for abnormal wireless event processing patterns that might indicate exploitation attempts. The fix represents a standard defensive programming pattern that should be applied to similar code sections throughout the kernel codebase where external input is used as array indices, reinforcing the principle of input validation as a fundamental security control.