CVE-2024-50069 in Linux
Summary
by MITRE • 10/29/2024
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: apple: check devm_kasprintf() returned value
devm_kasprintf() can return a NULL pointer on failure but this returned value is not checked. Fix this lack and check the returned value.
Found by code review.
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Analysis
by VulDB Data Team • 10/02/2025
The vulnerability identified as CVE-2024-50069 represents a critical NULL pointer dereference issue within the Linux kernel's pinctrl subsystem, specifically affecting Apple-based hardware platforms. This flaw resides in the device tree pin control driver implementation where the kernel fails to properly validate the return value from the devm_kasprintf() function. The pinctrl subsystem is responsible for managing pin configuration and multiplexing operations on embedded systems, making it a fundamental component in device driver functionality. When the kernel attempts to allocate memory for string formatting operations through devm_kasprintf(), the function may return NULL upon memory allocation failure, but the existing code does not check for this condition, creating a potential crash scenario.
The technical implementation flaw stems from the absence of proper error handling in the Apple pinctrl driver where devm_kasprintf() is called without validating its return value. This function serves as a memory management helper that combines the functionality of kasprintf with device memory management, automatically freeing the allocated memory when the device is removed. However, when memory allocation fails, devm_kasprintf() returns NULL, and subsequent code execution attempts to use this NULL pointer as a valid string reference. This pattern violates standard kernel coding practices and creates a direct path for kernel crashes or undefined behavior, as the system attempts to process a NULL pointer reference in memory operations.
The operational impact of this vulnerability extends beyond simple system instability, potentially allowing for denial of service conditions that could affect device functionality on Apple hardware platforms. When the kernel encounters a memory allocation failure during pin control operations, the lack of NULL pointer validation causes the system to crash or become unresponsive, effectively rendering the affected hardware unusable until a reboot occurs. This vulnerability particularly affects devices running Linux kernels that implement Apple's pinctrl driver, including various mobile and embedded systems where pin configuration is critical for proper hardware operation. The issue is particularly concerning in embedded environments where system reliability is paramount, as such crashes could lead to complete system failure and potential data loss.
The fix for CVE-2024-50069 involves implementing proper error checking after the devm_kasprintf() call, ensuring that the returned pointer is validated before any further operations are performed. This remediation aligns with established kernel security practices and follows the principle of defensive programming where all function calls that may fail are checked for proper return values. The solution requires adding a simple NULL check immediately after the devm_kasprintf() invocation, returning an appropriate error code if the allocation fails, and ensuring that subsequent code paths properly handle this error condition. This approach follows the CWE-476 principle of null pointer dereference prevention and aligns with ATT&CK technique T1499.004 for system disruption through resource exhaustion. The fix demonstrates the importance of proper memory management in kernel space operations and reinforces the need for comprehensive error handling in device driver implementations. This vulnerability serves as a reminder of the critical importance of validating all kernel function return values, particularly in memory allocation operations that are fundamental to system stability and security.