CVE-2023-52503

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> tee: amdtee: fix use-after-free vulnerability in amdtee_close_session<br /> <br /> There is a potential race condition in amdtee_close_session that may<br /> cause use-after-free in amdtee_open_session. For instance, if a session<br /> has refcount == 1, and one thread tries to free this session via:<br /> <br /> kref_put(&amp;sess-&gt;refcount, destroy_session);<br /> <br /> the reference count will get decremented, and the next step would be to<br /> call destroy_session(). However, if in another thread,<br /> amdtee_open_session() is called before destroy_session() has completed<br /> execution, alloc_session() may return &amp;#39;sess&amp;#39; that will be freed up<br /> later in destroy_session() leading to use-after-free in<br /> amdtee_open_session.<br /> <br /> To fix this issue, treat decrement of sess-&gt;refcount and removal of<br /> &amp;#39;sess&amp;#39; from session list in destroy_session() as a critical section, so<br /> that it is executed atomically.