* [PATCH] libata: array underflow in ata_find_dev()
@ 2017-07-19 10:06 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2017-07-19 10:06 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-ide, kernel-janitors
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@oracle.com>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index d462c5a3a7ef..44ba292f2cd7 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3030,10 +3030,12 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
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];
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] libata: array underflow in ata_find_dev()
@ 2017-07-19 10:06 ` Dan Carpenter
0 siblings, 0 replies; 4+ messages in thread
From: Dan Carpenter @ 2017-07-19 10:06 UTC (permalink / raw)
To: Tejun Heo; +Cc: linux-ide, kernel-janitors
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@oracle.com>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index d462c5a3a7ef..44ba292f2cd7 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3030,10 +3030,12 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
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];
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] libata: array underflow in ata_find_dev()
2017-07-19 10:06 ` Dan Carpenter
@ 2017-07-19 14:34 ` Tejun Heo
-1 siblings, 0 replies; 4+ messages in thread
From: Tejun Heo @ 2017-07-19 14:34 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-ide, kernel-janitors
Hello,
On Wed, Jul 19, 2017 at 01:06:41PM +0300, Dan Carpenter wrote:
> 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@oracle.com>
I'm impressed that the static checker caught this. Thanks a lot for
the fix, and lol at the code. :) Applied to libata/for-4.13-fixes w/
stable cc'd.
Thanks!
--
tejun
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] libata: array underflow in ata_find_dev()
@ 2017-07-19 14:34 ` Tejun Heo
0 siblings, 0 replies; 4+ messages in thread
From: Tejun Heo @ 2017-07-19 14:34 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-ide, kernel-janitors
Hello,
On Wed, Jul 19, 2017 at 01:06:41PM +0300, Dan Carpenter wrote:
> 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@oracle.com>
I'm impressed that the static checker caught this. Thanks a lot for
the fix, and lol at the code. :) Applied to libata/for-4.13-fixes w/
stable cc'd.
Thanks!
--
tejun
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-07-19 14:34 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-07-19 10:06 [PATCH] libata: array underflow in ata_find_dev() Dan Carpenter
2017-07-19 10:06 ` Dan Carpenter
2017-07-19 14:34 ` Tejun Heo
2017-07-19 14:34 ` Tejun Heo
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