CVE-2022-48708 in Linux
Summary
by MITRE • 05/21/2024
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: single: fix potential NULL dereference
Added checking of pointer "function" in pcs_set_mux(). pinmux_generic_get_function() can return NULL and the pointer "function" was dereferenced without checking against NULL.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2022-48708 represents a critical NULL pointer dereference flaw within the Linux kernel's pin control subsystem, specifically affecting the single pin controller implementation. This issue resides in the pinctrl framework which manages the configuration of hardware pins for various system functions including GPIO, serial communication, and peripheral interfaces. The vulnerability was discovered through systematic kernel verification processes conducted by the Linux Verification Center, utilizing the SVACE static analysis tool that specializes in identifying potential runtime errors in kernel code.
The technical flaw manifests in the pcs_set_mux() function where the code fails to validate the return value from pinmux_generic_get_function() before attempting to dereference the resulting pointer. When pinmux_generic_get_function() returns NULL, typically due to invalid pin configuration requests or resource allocation failures, the subsequent dereference operation causes an immediate system crash or potential privilege escalation. This pattern of NULL pointer dereference constitutes a fundamental violation of memory safety principles and represents a classic software error pattern categorized under CWE-476. The flaw specifically affects the single pin controller driver implementation within the pinctrl subsystem, which is responsible for managing pin configurations for systems with limited pin control capabilities.
The operational impact of this vulnerability extends beyond simple system crashes, as it creates potential attack vectors for malicious actors seeking to exploit kernel memory management weaknesses. In embedded systems or devices where the kernel handles critical hardware interfaces, such a vulnerability could lead to system instability, denial of service conditions, or potentially enable privilege escalation attacks that compromise the integrity of the entire system. The vulnerability affects systems using the single pin controller implementation, which is commonly found in embedded platforms, IoT devices, and specialized hardware configurations where pin multiplexing is required but implemented through simplified controller architectures.
Mitigation strategies for CVE-2022-48708 should prioritize immediate kernel updates from vendors that include the patched version of the pinctrl subsystem. The fix involves implementing proper NULL pointer validation in the pcs_set_mux() function before any dereference operations occur, ensuring that the code gracefully handles cases where pinmux_generic_get_function() returns NULL. Organizations should also consider implementing runtime monitoring and system hardening measures that can detect and prevent exploitation attempts targeting kernel memory corruption vulnerabilities. This vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and represents a clear example of how kernel-level memory safety issues can be exploited to gain unauthorized system access. System administrators should perform thorough vulnerability assessments to identify systems running affected kernel versions and apply patches promptly to prevent potential exploitation by adversaries who may target this specific NULL pointer dereference pattern.