CVE-2023-52457 in Linux
Summary
by MITRE • 02/23/2024
In the Linux kernel, the following vulnerability has been resolved:
serial: 8250: omap: Don't skip resource freeing if pm_runtime_resume_and_get() failed
Returning an error code from .remove() makes the driver core emit the little helpful error message:
remove callback returned a non-zero value. This will be ignored.
and then remove the device anyhow. So all resources that were not freed are leaked in this case. Skipping serial8250_unregister_port() has the potential to keep enough of the UART around to trigger a use-after-free.
So replace the error return (and with it the little helpful error message) by a more useful error message and continue to cleanup.
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Analysis
by VulDB Data Team • 06/26/2024
The vulnerability described in CVE-2023-52457 resides within the Linux kernel's serial driver implementation, specifically affecting the 8250 serial driver for omap platforms. This issue represents a resource management failure that occurs during device removal operations, creating potential for memory corruption and system instability. The flaw manifests in the driver's handling of power management runtime resume operations, where improper error code propagation leads to incomplete resource cleanup. The vulnerability is classified under CWE-459 as incomplete cleanup, which directly relates to the failure to properly release system resources during device removal. The problem affects the serial8250_unregister_port() function which is responsible for cleaning up UART resources when a device is removed from the system.
The technical flaw occurs when pm_runtime_resume_and_get() fails during the device removal process, causing the driver to return an error code from its .remove() callback method. This error return triggers the driver core to emit a misleading error message stating that the remove callback returned a non-zero value, which is subsequently ignored. However, this approach leaves critical resources in an inconsistent state, as the driver skips the serial8250_unregister_port() cleanup function. The failure to properly free resources creates a scenario where portions of the UART hardware context remain allocated, potentially leading to use-after-free conditions when the system attempts to access previously freed memory locations. This particular pattern of resource leak is particularly dangerous because it can persist across multiple device operations and potentially allow for memory corruption that could be exploited.
The operational impact of this vulnerability extends beyond simple resource leaks to potentially compromise system stability and security. When the driver fails to properly clean up UART resources, it leaves the system in a state where memory corruption can occur, particularly in environments where serial communication is heavily utilized. The use-after-free condition that can result from this vulnerability provides an attack surface that aligns with ATT&CK technique T1068, which involves exploiting local privilege escalation opportunities through system resource manipulation. The vulnerability affects systems using omap serial drivers, which are common in embedded devices and mobile platforms, making it particularly concerning for IoT devices and mobile computing environments where such hardware is prevalent. The potential for memory corruption in kernel space creates risks that could be leveraged by malicious actors to escalate privileges or cause system crashes.
Mitigation strategies for CVE-2023-52457 focus on ensuring proper error handling and resource cleanup during device removal operations. The fix implemented in the kernel modifies the driver to replace the error return with a more informative error message while continuing with the cleanup process. This approach prevents the driver core from ignoring the error and instead ensures that all resources are properly freed even when pm_runtime_resume_and_get() fails. System administrators should ensure their kernels are updated to versions containing the patched driver code, which addresses the improper error handling in the serial8250 driver. The fix also emphasizes proper error propagation mechanisms that maintain system stability while providing meaningful diagnostic information for developers and system administrators. Organizations running embedded systems or mobile platforms utilizing omap serial hardware should prioritize this update to prevent potential memory corruption issues that could lead to system compromise or denial of service conditions.