CVE-2023-52798 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath11k: fix dfs radar event locking
The ath11k active pdevs are protected by RCU but the DFS radar event handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a read-side critical section.
Mark the code in question as an RCU read-side critical section to avoid any potential use-after-free issues.
Compile tested only.
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Analysis
by VulDB Data Team • 11/14/2024
The vulnerability CVE-2023-52798 resides within the Linux kernel's wireless networking subsystem, specifically affecting the ath11k driver that manages Qualcomm's Wi-Fi 6E chipsets. This issue represents a classic race condition scenario where the driver's handling of Dynamic Frequency Selection (DFS) radar events contains a critical flaw in memory management and synchronization. The ath11k driver operates with multiple physical device (pdev) instances that are protected by Read-Copy-Update (RCU) mechanisms to ensure safe concurrent access. However, the DFS radar event processing code path failed to properly acknowledge its dependency on RCU protection, creating a potential use-after-free condition when active pdevs are accessed during radar event handling operations.
The technical flaw manifests in the specific function call ath11k_mac_get_ar_by_pdev_id() which retrieves active pdev information during DFS radar event processing. This function operates within a context that should be explicitly marked as an RCU read-side critical section, yet the code did not include proper RCU annotation. The absence of this marking means that the kernel's RCU subsystem cannot guarantee that the pdev structures remain valid throughout the execution of this critical code path. When the DFS radar event handling code executes, it may attempt to access pdev structures that have already been freed or modified by concurrent operations, leading to memory corruption and potential system instability.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling arbitrary code execution or system crashes when DFS radar events occur during normal wireless operation. This is particularly concerning in enterprise or infrastructure environments where Wi-Fi access points continuously monitor for radar events to comply with regulatory requirements. The vulnerability affects systems running Linux kernels with the ath11k driver, especially those utilizing Qualcomm's Wi-Fi 6E chipsets in environments where DFS functionality is actively used. The use-after-free condition could be exploited by malicious actors to gain elevated privileges or cause denial of service attacks, making it a significant security concern for wireless infrastructure deployments.
The mitigation strategy involves properly marking the affected code section as an RCU read-side critical section, ensuring that the kernel's RCU subsystem correctly handles the synchronization requirements for accessing active pdev structures. This fix aligns with CWE-416, which addresses use-after-free vulnerabilities, and follows ATT&CK technique T1059.007 for privilege escalation through kernel exploitation. The solution requires updating the kernel source code to include proper RCU read-side critical section annotations around the ath11k_mac_get_ar_by_pdev_id() function call, ensuring that all access to RCU-protected data structures occurs within appropriate synchronization contexts. This remediation addresses the root cause by ensuring that the kernel's memory management subsystem correctly maintains data integrity during concurrent access scenarios. The fix has been compile-tested and represents a minimal but critical change that resolves the race condition while maintaining the driver's functionality and performance characteristics.