جزئیات آسیب‌پذیری

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free by using call_rcu() for oplock_info ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfo_get() and proc_show_files(). Since there is no RCU grace period delay between nullifying the pointer and freeing the memory, a reader can still access oplock_info structure after it has been freed. This can leads to a use-after-free especially in opinfo_get() where atomic_inc_not_zero() is called on already freed memory. Fix this by switching to deferred freeing using call_rcu().

• https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a
• https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c
• https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e
• https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde
• https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294