[PATCH AUTOSEL 5.10 19/27] scsi: pm8001: Fix use-after-free for aborted SSP/STP sas_task

Sasha Levin
2022-02-09T18:44:42Z

From: John Garry <john.garry@huawei.com>

[ Upstream commit df7abcaa1246e2537ab4016077b5443bb3c09378 ]

Currently a use-after-free may occur if a sas_task is aborted by the upper
layer before we handle the I/O completion in mpi_ssp_completion() or
mpi_sata_completion().

In this case, the following are the two steps in handling those I/O
completions:

- Call complete() to inform the upper layer handler of completion of
the I/O.

- Release driver resources associated with the sas_task in
pm8001_ccb_task_free() call.

When complete() is called, the upper layer may free the sas_task. As such,
we should not touch the associated sas_task afterwards, but we do so in the
pm8001_ccb_task_free() call.

Fix by swapping the complete() and pm8001_ccb_task_free() calls ordering.

Link: https://lore.kernel.org/r/1643289172-165636-4-git-send-email-john.garry@huawei.com
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/pm8001/pm80xx_hwi.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c b/drivers/scsi/pm8001/pm80xx_hwi.c
index a203a4fc2674a..b08e285e7fff6 100644
--- a/drivers/scsi/pm8001/pm80xx_hwi.c
+++ b/drivers/scsi/pm8001/pm80xx_hwi.c
@@ -2133,9 +2133,9 @@ mpi_ssp_completion(struct pm8001_hba_info *pm8001_ha , void *piomb)
pm8001_dbg(pm8001_ha, FAIL,
"task 0x%p done with io_status 0x%x resp 0x%x stat 0x%x but aborted by upper layer!\n",
t, status, ts->resp, ts->stat);
+ pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
if (t->slow_task)
complete(&t->slow_task->completion);
- pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
} else {
spin_unlock_irqrestore(&t->task_state_lock, flags);
pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
@@ -2726,9 +2726,9 @@ mpi_sata_completion(struct pm8001_hba_info *pm8001_ha, void *piomb)
pm8001_dbg(pm8001_ha, FAIL,
"task 0x%p done with io_status 0x%x resp 0x%x stat 0x%x but aborted by upper layer!\n",
t, status, ts->resp, ts->stat);
+ pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
if (t->slow_task)
complete(&t->slow_task->completion);
- pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
} else {
spin_unlock_irqrestore(&t->task_state_lock, flags);
pm8001_ccb_task_free_done(pm8001_ha, t, ccb, tag);
--
2.34.1