scsi: libsas: Fix use-after-free bug in smp_execute_task_sg()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: scsi: libsas: Fix use-after-free bug in smp_execute_task_sg() When executing SMP task failed, the smp_execute_task_sg() calls del_timer() to delete "slow_task->timer". However, if the timer handler sas_task_internal_timedout() is running, the del_timer() in smp_execute_task_sg() will not stop it and a UAF will happen. The process is shown below: (thread 1) | (thread 2) smp_execute_task_sg() | sas_task_internal_timedout() ... | del_timer() | ... | ... sas_free_task(task) | kfree(task->slow_task) //FREE| | task->slow_task->... //USE Fix by calling del_timer_sync() in smp_execute_task_sg(), which makes sure the timer handler have finished before the "task->slow_task" is deallocated.

References

• https://git.kernel.org/stable/c/117331a2a5227fb4369c2a1f321d3e3e2e2ef8fe
• https://git.kernel.org/stable/c/a9e5176ead6de64f572ad5c87a72825d9d3c82ae
• https://git.kernel.org/stable/c/e45a1516d2933703a4823d9db71e17c3abeba24f
• https://git.kernel.org/stable/c/f7a785177611ffc97d645fcbc196e6de6ad2421d
• https://git.kernel.org/stable/c/2e12ce270f0d926085c1209cc90397e307deef97
• https://git.kernel.org/stable/c/46ba53c30666717cb06c2b3c5d896301cd00d0c0