CVE-2022-49385 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
driver: base: fix UAF when driver_attach failed
When driver_attach(drv); failed, the driver_private will be freed. But it has been added to the bus, which caused a UAF.
To fix it, we need to delete it from the bus when failed.
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Analysis
by VulDB Data Team • 05/13/2025
The vulnerability described in CVE-2022-49385 represents a critical use-after-free condition within the Linux kernel's device driver subsystem. This flaw occurs in the driver attachment mechanism where the kernel fails to properly handle cleanup operations when driver attachment processes encounter failures. The issue manifests specifically within the driver base subsystem, which is fundamental to how the kernel manages device drivers and their interactions with hardware resources.
The technical implementation of this vulnerability stems from improper synchronization between the driver attachment process and the bus registration mechanism. When driver_attach() function fails during the attachment process, the kernel attempts to free the driver_private structure that was allocated to manage the driver's state. However, this structure had already been added to the bus's driver list, creating a scenario where freed memory is still referenced by the bus subsystem. This mismanagement results in a use-after-free condition that can be exploited to execute arbitrary code with kernel privileges, as the freed memory structure may be reallocated for other purposes while the bus continues to reference the old location.
The operational impact of this vulnerability extends beyond simple system instability, presenting a significant security risk that could be leveraged by malicious actors to escalate privileges and gain unauthorized access to kernel-level resources. The vulnerability affects the fundamental device driver management capabilities of the Linux kernel, potentially compromising the integrity of the entire system. Attackers could exploit this condition to execute code in kernel space, bypassing security mechanisms and potentially establishing persistent backdoors. The flaw particularly impacts systems that rely heavily on dynamic driver loading and device management, making it a serious concern for enterprise environments and security-critical applications.
This vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software systems, and demonstrates characteristics consistent with the attack patterns documented in the MITRE ATT&CK framework under the privilege escalation and defense evasion techniques. The fix implemented addresses the root cause by ensuring proper cleanup operations when driver attachment fails, specifically requiring that the driver_private structure be removed from the bus registration list before attempting to free it. This remediation approach follows established security best practices for memory management in kernel space and aligns with the principle of least privilege by preventing access to freed memory structures. The resolution demonstrates the critical importance of proper resource management in kernel-level code and underscores the necessity of thorough testing of error handling paths in security-critical systems.