4.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
commit 59a5e266c3f5c1567508888dd61a45b86daed0fa upstream.
My static checker complains that "devno" can be negative, meaning that
we read before the start of the loop. I've looked at the code, and I
think the warning is right. This come from /proc so it's root only or
it would be quite a quite a serious bug. The call tree looks like this:
proc_scsi_write() <- gets id and channel from simple_strtoul()
-> scsi_add_single_device() <- calls shost->transportt->user_scan()
-> ata_scsi_user_scan()
-> ata_find_dev()
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/ata/libata-scsi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3028,10 +3028,12 @@ static unsigned int atapi_xlat(struct at
static struct ata_device *ata_find_dev(struct ata_port *ap, int devno)
{
if (!sata_pmp_attached(ap)) {
- if (likely(devno < ata_link_max_devices(&ap->link)))
+ if (likely(devno >= 0 &&
+ devno < ata_link_max_devices(&ap->link)))
return &ap->link.device[devno];
} else {
- if (likely(devno < ap->nr_pmp_links))
+ if (likely(devno >= 0 &&
+ devno < ap->nr_pmp_links))
return &ap->pmp_link[devno].device[0];
}