CVE-2022-49608 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: ralink: Check for null return of devm_kcalloc
Because of the possible failure of the allocation, data->domains might be NULL pointer and will cause the dereference of the NULL pointer later. Therefore, it might be better to check it and directly return -ENOMEM without releasing data manually if fails, because the comment of the devm_kmalloc() says "Memory allocated with this function is automatically freed on driver detach.".
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 03/12/2025
This vulnerability exists within the Linux kernel's pinctrl subsystem, specifically in the Ralink driver implementation that manages pin configuration controls for various SoC platforms. The issue stems from inadequate error handling during memory allocation operations that can lead to critical system instability and potential security implications. The vulnerability affects the device tree pin control framework where the driver attempts to allocate memory for domain structures but fails to properly validate the allocation result before proceeding with subsequent operations. When devm_kcalloc fails to allocate the required memory, it returns a NULL pointer which subsequently gets assigned to data->domains, creating a dangerous condition where the code attempts to dereference this NULL pointer in later operations.
The technical flaw manifests as a classic null pointer dereference vulnerability that violates fundamental memory safety principles. The driver's implementation does not adequately check the return value of the memory allocation function, specifically devm_kcalloc, which is designed to allocate and manage memory with automatic cleanup on driver detachment. This particular allocation failure creates a scenario where the data->domains pointer remains uninitialized and contains a NULL value, leading to immediate system crashes or undefined behavior when the code attempts to access memory through this null reference. The vulnerability operates at the kernel level where such errors can result in complete system termination or provide attackers with potential privilege escalation pathways through controlled memory corruption.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable more sophisticated attack vectors within kernel space. When the driver encounters memory allocation failure during device initialization, the system may experience unexpected termination or reboot cycles that can disrupt critical services. The automatic memory management feature of devm_kcalloc is designed to prevent memory leaks by ensuring cleanup on driver detach, but this protection mechanism becomes ineffective when the allocation fails and the code path does not properly handle the error condition. This creates a scenario where the kernel's memory management subsystem may be left in an inconsistent state, potentially exposing other kernel components to memory corruption or unauthorized access.
Mitigation strategies for this vulnerability should focus on implementing proper error handling and validation mechanisms within the driver's initialization sequence. The recommended approach involves adding explicit null pointer checks immediately after memory allocation operations, ensuring that the driver returns appropriate error codes such as -ENOMEM when allocation failures occur. This follows established security best practices and aligns with the Linux kernel's documented error handling patterns where drivers must validate all memory allocation results before proceeding with operations that depend on the allocated memory. The solution directly addresses the root cause by ensuring that memory allocation failures are handled gracefully without attempting to dereference null pointers, thereby preventing both immediate system crashes and potential exploitation opportunities. Security frameworks such as CWE-476 and ATT&CK techniques related to kernel memory corruption should be considered when implementing these fixes, as they represent the specific categories of vulnerabilities that this issue falls into and the potential attack vectors that could be exploited through improper error handling.