| Message ID | 20220920144213.10536-1-duoming@zju.edu.cn |
|---|---|
| State | New |
| Headers | show |
| Series | scsi: libsas: fix use-after-free bug in smp_execute_task_sg | expand |
On 2022/9/20 22:42, Duoming Zhou wrote: > When executing SMP task failed, the smp_execute_task_sg() > calls del_timer() to delete the "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 the UAF bug 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. > > Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > --- > drivers/scsi/libsas/sas_expander.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index fa2209080cc..5ce25183010 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -67,7 +67,7 @@ static int smp_execute_task_sg(struct domain_device *dev, > res = i->dft->lldd_execute_task(task, GFP_KERNEL); > > if (res) { > - del_timer(&task->slow_task->timer); > + del_timer_sync(&task->slow_task->timer); > pr_notice("executing SMP task failed:%d\n", res); > break; > } > The timer should be triggered 10 seconds later. I am curious why we stay this long before del_timer(). However this change looks good to me. Reviewed-by: Jason Yan <yanaijie@huawei.com>
Hello, On Thu, 22 Sep 2022 22:06:30 +0800 Jason Yan wrote: > On 2022/9/20 22:42, Duoming Zhou wrote: > > When executing SMP task failed, the smp_execute_task_sg() > > calls del_timer() to delete the "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 the UAF bug 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. > > > > Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") > > Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> > > --- > > drivers/scsi/libsas/sas_expander.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > > index fa2209080cc..5ce25183010 100644 > > --- a/drivers/scsi/libsas/sas_expander.c > > +++ b/drivers/scsi/libsas/sas_expander.c > > @@ -67,7 +67,7 @@ static int smp_execute_task_sg(struct domain_device *dev, > > res = i->dft->lldd_execute_task(task, GFP_KERNEL); > > > > if (res) { > > - del_timer(&task->slow_task->timer); > > + del_timer_sync(&task->slow_task->timer); > > pr_notice("executing SMP task failed:%d\n", res); > > break; > > } > > > > The timer should be triggered 10 seconds later. I am curious why we stay > this long before del_timer(). I think the hacker may create a large number of hardware interrupts to increase the delayed time. > However this change looks good to me. > Reviewed-by: Jason Yan <yanaijie@huawei.com> Thank you! Best regards, Duoming Zhou
Duoming, > When executing SMP task failed, the smp_execute_task_sg() calls > del_timer() to delete the "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 the UAF bug will happen. Applied to 6.1/scsi-staging, thanks!
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index fa2209080cc..5ce25183010 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -67,7 +67,7 @@ static int smp_execute_task_sg(struct domain_device *dev, res = i->dft->lldd_execute_task(task, GFP_KERNEL); if (res) { - del_timer(&task->slow_task->timer); + del_timer_sync(&task->slow_task->timer); pr_notice("executing SMP task failed:%d\n", res); break; }
When executing SMP task failed, the smp_execute_task_sg() calls del_timer() to delete the "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 the UAF bug 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. Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> --- drivers/scsi/libsas/sas_expander.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)