Fix reader locking when changing the sub buffer order
CVE-2024-50207
What is CVE-2024-50207?
In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Fix reader locking when changing the sub buffer order
The function ring_buffer_subbuf_order_set() updates each ring_buffer_per_cpu and installs new sub buffers that match the requested page order. This operation may be invoked concurrently with readers that rely on some of the modified data, such as the head bit (RB_PAGE_HEAD), or the ring_buffer_per_cpu.pages and reader_page pointers. However, no exclusive access is acquired by ring_buffer_subbuf_order_set(). Modifying the mentioned data while a reader also operates on them can then result in incorrect memory access and various crashes.
Fix the problem by taking the reader_lock when updating a specific ring_buffer_per_cpu in ring_buffer_subbuf_order_set().
Affected Version(s)
Linux 8e7b58c27b3c567316a51079b375b846f9223bba
Linux 8e7b58c27b3c567316a51079b375b846f9223bba < 09661f75e75cb6c1d2d8326a70c311d46729235f
Linux 6.8