In the Linux kernel, the CVE-2024-46713 vulnerability has been resolved. The AUX buffer is strictly a sub-buffer, serialize using aux_mutex to avoid complications.  (16Sep 2024)

Preface: A mutex is a mutual exclusion lock. Only one thread can hold the lock. Mutexes are used to protect data or other resources from concurrent access. A mutex has attributes, which specify the characteristics of the mutex.

Background: During the boot process, the console provides a lot of important information about the initial phase of the system startup. To avoid loss of the early messages the kernel utilizes what is called a ring buffer. This buffer stores all messages, including boot messages, generated by the printk() function within the kernel code. The messages from the kernel ring buffer are then read and stored in log files on permanent storage, for example, by the syslog service. The buffer mentioned above is a cyclic data structure which has a fixed size, and is hard-coded into the kernel.

Vulnerability details: In the Linux kernel, the following vulnerability has been resolved: perf/aux: Fix AUX buffer serialization Ole reported that event->mmap_mutex is strictly insufficient to serialize the AUX buffer, add a per RB mutex to fully serialize it. Note that in the lock order comment the perf_event::mmap_mutex order was already wrong, that is, it nesting under mmap_lock is not new with this patch.

Official announcement: Please refer to the vendor announcement for details – https://nvd.nist.gov/vuln/detail/CVE-2024-46713

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