[SCSI] scsi_transport_fc: Protect against overflow in dev_loss_tmo

The rport structure defines dev_loss_tmo as u32, which is
later multiplied with HZ to get the actual timeout value.
This might overflow for large dev_loss_tmo values. So we
should be better using u64 as intermediate variables here
to protect against overflow.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 6cfffc88022..55fe730a860 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -834,7 +834,7 @@ static ssize_t
 store_fc_rport_dev_loss_tmo(struct device *dev, struct device_attribute *attr,
                             const char *buf, size_t count)
 {
-        int val;
+        unsigned long val;
         struct fc_rport *rport = transport_class_to_rport(dev);
         struct Scsi_Host *shost = rport_to_shost(rport);
         struct fc_internal *i = to_fc_internal(shost->transportt);
@@ -848,6 +848,12 @@ store_fc_rport_dev_loss_tmo(struct device *dev, struct device_attribute *attr,
                 return -EINVAL;
 
         /*
+         * Check for overflow; dev_loss_tmo is u32
+         */
+        if (val > UINT_MAX)
+                return -EINVAL;
+
+        /*
          * If fast_io_fail is off we have to cap
          * dev_loss_tmo at SCSI_DEVICE_BLOCK_MAX_TIMEOUT
          */
@@ -2865,7 +2871,7 @@ void
 fc_remote_port_delete(struct fc_rport  *rport)
 {
         struct Scsi_Host *shost = rport_to_shost(rport);
-        int timeout = rport->dev_loss_tmo;
+        unsigned long timeout = rport->dev_loss_tmo;
         unsigned long flags;
 
         /*