linux-kernel - [PATCH v2 1/1] scsi: fc: check for rport presence in fc_block_scsi

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Message-Id: <20170926065809.7980-1-jthumshirn@suse.de>
Date:   Tue, 26 Sep 2017 08:58:09 +0200
From:   Johannes Thumshirn <jthumshirn@...e.de>
To:     "Martin K . Petersen" <martin.petersen@...cle.com>
Cc:     Linux SCSI Mailinglist <linux-scsi@...r.kernel.org>,
        Linux Kernel Mailinglist <linux-kernel@...r.kernel.org>,
        Hannes Reinecke <hare@...e.de>,
        Bart Van Assche <Bart.VanAssche@...disk.com>,
        Christoph Hellwig <hch@....de>,
        Johannes Thumshirn <jthumshirn@...e.de>
Subject: [PATCH v2 1/1] scsi: fc: check for rport presence in fc_block_scsi_eh

Coverity-scan recently found a possible NULL pointer dereference in
fc_block_scsi_eh() as starget_to_rport() either returns the rport for
the startget or NULL.

While it is rather unlikely to have fc_block_scsi_eh() called without
an rport associated it's a good idea to catch potential misuses of the
API gracefully.

Signed-off-by: Johannes Thumshirn <jthumshirn@...e.de>
Reviewed-by: Bart Van Assche <bart.vanassche@....com>
---

Changes since v1:
- s/WARN_ON/WARN_ON_ONCE/ (Bart)

---
 drivers/scsi/scsi_transport_fc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index ba9d70f8a6a1..38abff7b5dbc 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -3328,6 +3328,9 @@ int fc_block_scsi_eh(struct scsi_cmnd *cmnd)
 {
 	struct fc_rport *rport = starget_to_rport(scsi_target(cmnd->device));
 
+	if (WARN_ON_ONCE(!rport))
+		return 0;
+
 	return fc_block_rport(rport);
 }
 EXPORT_SYMBOL(fc_block_scsi_eh);
-- 
2.13.5