CVE-2022-49445 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: renesas: core: Fix possible null-ptr-deref in sh_pfc_map_resources()
It will cause null-ptr-deref when using 'res', if platform_get_resource() returns NULL, so move using 'res' after devm_ioremap_resource() that will check it to avoid null-ptr-deref. And use devm_platform_get_and_ioremap_resource() to simplify code.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/28/2025
The vulnerability CVE-2022-49445 represents a critical null pointer dereference issue within the Linux kernel's pinctrl subsystem, specifically affecting the Renesas SoC platform support. This flaw exists in the sh_pfc_map_resources() function which handles pin configuration resources for Renesas processors. The vulnerability stems from improper handling of resource allocation and memory mapping operations that can lead to system crashes and potential security implications. The issue occurs when platform_get_resource() returns a NULL pointer, but the code continues to reference this null resource pointer before proper validation occurs.
The technical implementation flaw manifests in the sequence of operations within the pinctrl driver where platform_get_resource() is called to retrieve hardware resource information, but the subsequent devm_ioremap_resource() operation which validates the resource pointer is not properly positioned in the execution flow. This creates a window where a null pointer dereference can occur when the code attempts to access resource fields before the validation occurs. The vulnerability directly maps to CWE-476 which describes null pointer dereference conditions in software implementations. The improper resource handling violates standard kernel programming practices where resource validation must occur before pointer dereference operations.
The operational impact of this vulnerability extends beyond simple system crashes to potentially enable privilege escalation or denial of service attacks in embedded systems and automotive applications that rely on Renesas SoC platforms. When exploited, the null pointer dereference causes immediate kernel panics and system instability, affecting devices such as automotive infotainment systems, industrial control units, and embedded networking equipment. The vulnerability affects systems running Linux kernel versions prior to the fix, particularly those implementing the Renesas pin control framework for peripheral configuration management. Attackers could leverage this vulnerability to cause system unavailability or potentially gain unauthorized access to system resources.
Mitigation strategies for this vulnerability include updating to kernel versions that contain the patched implementation where the code sequence has been restructured to use devm_platform_get_and_ioremap_resource() function. This standardized approach consolidates the resource retrieval and mapping operations into a single validated call that properly handles null pointer conditions. System administrators should prioritize kernel updates across all affected Renesas platform deployments, particularly in mission-critical environments where system stability is paramount. The fix aligns with ATT&CK technique T1068 which describes privilege escalation through kernel vulnerabilities, making it essential for security teams to address this issue promptly. Organizations should also implement continuous monitoring for similar resource handling patterns in custom kernel modules and driver implementations to prevent analogous vulnerabilities from emerging in their own codebases.