CVE-2022-49459 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
thermal/drivers/broadcom: Fix potential NULL dereference in sr_thermal_probe
platform_get_resource() may return NULL, add proper check to avoid potential NULL dereferencing.
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Analysis
by VulDB Data Team • 02/26/2025
The vulnerability identified as CVE-2022-49459 represents a critical null pointer dereference flaw within the Linux kernel's thermal subsystem, specifically affecting the Broadcom platform driver implementation. This issue resides in the sr_thermal_probe function where the platform_get_resource() API call is invoked without proper validation of its return value. The kernel's thermal management framework is responsible for monitoring and controlling temperature levels across various hardware components, making this vulnerability particularly concerning for system stability and reliability.
The technical root cause of this vulnerability stems from inadequate input validation within the kernel's device driver initialization process. When platform_get_resource() fails to locate or retrieve the requested hardware resource information, it returns a NULL pointer value to the calling function. The sr_thermal_probe function in the broadcom thermal driver does not perform a NULL check before proceeding with operations that assume the resource pointer is valid. This oversight creates a potential crash scenario where the kernel attempts to dereference a NULL pointer, leading to immediate system instability and potential denial of service conditions.
From an operational impact perspective, this vulnerability affects systems running Linux kernels that incorporate the affected Broadcom thermal driver code. The null pointer dereference can result in immediate system crashes or panics, particularly during system boot processes or when thermal management subsystems are initialized. Attackers could potentially exploit this vulnerability to cause system downtime, especially in embedded systems or servers where continuous operation is critical. The vulnerability is classified under CWE-476 as a NULL Pointer Dereference, which represents a common and dangerous class of software defects that can lead to system instability and potential privilege escalation scenarios.
The exploitation of this vulnerability typically occurs during normal system operation when the thermal subsystem attempts to initialize hardware resources for temperature monitoring. The attack vector is relatively straightforward since it requires only normal system operation to trigger the faulty code path. Systems utilizing Broadcom-based hardware platforms, particularly those with integrated thermal management controllers, are most susceptible to this issue. The vulnerability demonstrates a fundamental flaw in kernel driver development practices, where proper error handling and input validation are not consistently applied during resource acquisition operations.
Mitigation strategies for CVE-2022-49459 involve applying the official kernel patch that introduces proper NULL pointer checks before resource dereferencing operations. System administrators should prioritize updating their kernel versions to include the fix, particularly in production environments where system stability is paramount. The recommended approach includes verifying that platform_get_resource() returns a valid pointer before proceeding with any operations that depend on that resource. Additionally, organizations should implement comprehensive monitoring systems to detect potential system crashes or instability patterns that might indicate exploitation attempts. This vulnerability aligns with ATT&CK technique T1499.001 for system shutdown/reboot attacks, as the null pointer dereference can cause system instability and denial of service conditions. Regular kernel updates and security assessments should be conducted to prevent similar issues in other kernel subsystems and drivers. The fix demonstrates the importance of proper error handling in kernel space code and serves as a reminder of the critical need for robust input validation in low-level system components that directly interface with hardware resources.