[PATCH] scsi: lpfc: don't dereference localport before it has been null checked

[PATCH] scsi: lpfc: don't dereference localport before it has been null checked

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

localport is being dereferenced to assign lport and then immediately
afterwards localport is being sanity checked to see if it is null.
Fix this by only dereferencing localport until after it has been
null checked.

Detected by CoverityScan, CID#1463038 ("Dereference before null check")

Fixes: 3a8cefbfc5ee ("scsi: lpfc: Beef up stat counters for debug")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/scsi/lpfc/lpfc_attr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index 797bb42a6306..986a3dc2efaf 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -277,13 +277,13 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr,
 	}
 
 	localport = vport->localport;
-	lport = (struct lpfc_nvme_lport *)localport->private;
 	if (!localport) {
 		len = snprintf(buf, PAGE_SIZE,
 				"NVME Initiator x%llx is not allocated\n",
 				wwn_to_u64(vport->fc_portname.u.wwn));
 		return len;
 	}
+	lport = (struct lpfc_nvme_lport *)localport->private;
 	len = snprintf(buf, PAGE_SIZE, "NVME Initiator Enabled\n");
 
 	spin_lock_irq(shost->host_lock);
-- 
2.14.1

Re: [PATCH] scsi: lpfc: don't dereference localport before it has been null checked

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

Re: [PATCH] scsi: lpfc: don't dereference localport before it has been null checked

[Martin K. Petersen]

Colin,

> localport is being dereferenced to assign lport and then immediately
> afterwards localport is being sanity checked to see if it is null.
> Fix this by only dereferencing localport until after it has been
> null checked.

Applied to 4.16/scsi-queue, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering