From 117331a2a5227fb4369c2a1f321d3e3e2e2ef8fe Mon Sep 17 00:00:00 2001 From: Duoming Zhou Date: Tue, 20 Sep 2022 22:42:13 +0800 Subject: [PATCH] scsi: libsas: Fix use-after-free bug in smp_execute_task_sg() [ Upstream commit 46ba53c30666717cb06c2b3c5d896301cd00d0c0 ] 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. Link: https://lore.kernel.org/r/20220920144213.10536-1-duoming@zju.edu.cn Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") Reviewed-by: Jason Yan Signed-off-by: Duoming Zhou Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- 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 9fdb9c9fbda4..173f91ae38f0 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -85,7 +85,7 @@ 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; }