[PATCH AUTOSEL 4.14 009/127] scsi: fnic: fix use after free

Sasha Levin
2020-09-18T02:37:57Z

From: Pan Bian <bianpan2016@163.com>

[ Upstream commit ec990306f77fd4c58c3b27cc3b3c53032d6e6670 ]

The memory chunk io_req is released by mempool_free. Accessing
io_req->start_time will result in a use after free bug. The variable
start_time is a backup of the timestamp. So, use start_time here to
avoid use after free.

Link: https://lore.kernel.org/r/1572881182-37664-1-git-send-email-bianpan2016@163.com
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/fnic/fnic_scsi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/fnic/fnic_scsi.c b/drivers/scsi/fnic/fnic_scsi.c
index d79ac0b24f5af..04c25ca2be45f 100644
--- a/drivers/scsi/fnic/fnic_scsi.c
+++ b/drivers/scsi/fnic/fnic_scsi.c
@@ -1034,7 +1034,8 @@ static void fnic_fcpio_icmnd_cmpl_handler(struct fnic *fnic,
atomic64_inc(&fnic_stats->io_stats.io_completions);

- io_duration_time = jiffies_to_msecs(jiffies) - jiffies_to_msecs(io_req->start_time);
+ io_duration_time = jiffies_to_msecs(jiffies) -
+ jiffies_to_msecs(start_time);

if(io_duration_time <= 10)
atomic64_inc(&fnic_stats->io_stats.io_btw_0_to_10_msec);
--
2.25.1