Race Condition in Linux Kernel tty Subsystem

Executive Summary

This vulnerability in the Linux kernel involves a race condition in the tty subsystem. The function vcc_cleanup() clears the tty pointer without holding the necessary port lock, which can lead to a use-after-free scenario. Specifically, vcc_event() callbacks may read the tty pointer under the port lock and then attempt to use the tty's port after vcc_cleanup() has already destroyed and freed it.

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Detection Guidance

This vulnerability is specific to the Linux kernel's tty subsystem and requires kernel-level detection. There are no direct network or system commands to detect it as it involves a race condition in the vcc_cleanup() function. Monitoring kernel logs for tty-related crashes or use-after-free errors may indicate exploitation. Check for kernel oops messages or crashes in /var/log/kern.log or dmesg output.

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Impact Analysis

This vulnerability could lead to system instability or crashes due to use-after-free errors. Attackers might exploit it to execute arbitrary code, escalate privileges, or cause denial-of-service conditions on affected systems running vulnerable Linux kernel versions.

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Compliance Impact

This vulnerability is a use-after-free issue in the Linux kernel's tty subsystem, specifically in the vcc_cleanup function. It does not directly relate to data protection or privacy compliance standards like GDPR or HIPAA, as it involves kernel memory management rather than data handling or access control.

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Mitigation Strategies

Apply the Linux kernel patch that resolves this issue. Ensure the fix for tty: vcc: hold port lock when clearing tty pointer in vcc_cleanup is installed on affected systems.

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