[PATCH] scsi: csiostor: Fix a possible null-pointer dereference in csio_eh_lun_reset_handler()

[PATCH] scsi: csiostor: Fix a possible null-pointer dereference in csio_eh_lun_reset_handler()

[Tuo Li]

In this function, rn is checked by an if statement. If it is NULL,
execution transfers to the fail label. However, rn may still
be dereferenced later via the following macro:

  CSIO_INC_STATS(rn, n_lun_rst_fail);

To avoid a potential null-pointer dereference, return FAILED directly when
rn is NULL, rather than transferring control to the common fail label.

Signed-off-by: Tuo Li <islituo@gmail.com>
---
 drivers/scsi/csiostor/csio_scsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/csiostor/csio_scsi.c b/drivers/scsi/csiostor/csio_scsi.c
index 34bde6650fae..feb1a9a9390b 100644
--- a/drivers/scsi/csiostor/csio_scsi.c
+++ b/drivers/scsi/csiostor/csio_scsi.c
@@ -2074,7 +2074,7 @@ csio_eh_lun_reset_handler(struct scsi_cmnd *cmnd)
 	struct csio_scsi_level_data sld;
 
 	if (!rn)
-		goto fail;
+		return FAILED;
 
 	csio_dbg(hw, "Request to reset LUN:%llu (ssni:0x%x tgtid:%d)\n",
 		      cmnd->device->lun, rn->flowid, rn->scsi_id);
-- 
2.43.0

[PATCH] scsi: csiostor: Fix a possible null-pointer dereference in csio_eh_lun_reset_handler()

[Jia-Ju Bai]

In csio_eh_lun_reset_handler(), there is an if statement on line 2072 to
check whether rn is NULL:
    if (!rn)

When rn is NULL, it is used on line 2217:
    CSIO_INC_STATS(rn, n_lun_rst_fail);

Thus, a possible null-pointer dereference may occur.

To fix this bug, csio_eh_lun_reset_handler() directly returns FAILED
when rn is NULL.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/scsi/csiostor/csio_scsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/csiostor/csio_scsi.c b/drivers/scsi/csiostor/csio_scsi.c
index 469d0bc9f5fe..c81d743d3544 100644
--- a/drivers/scsi/csiostor/csio_scsi.c
+++ b/drivers/scsi/csiostor/csio_scsi.c
@@ -2070,7 +2070,7 @@ csio_eh_lun_reset_handler(struct scsi_cmnd *cmnd)
 	struct csio_scsi_level_data sld;
 
 	if (!rn)
-		goto fail;
+		return FAILED;
 
 	csio_dbg(hw, "Request to reset LUN:%llu (ssni:0x%x tgtid:%d)\n",
 		      cmnd->device->lun, rn->flowid, rn->scsi_id);
-- 
2.17.0