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vhost/scsi: potential memory corruption

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This code in vhost_scsi_make_tpg() is confusing because we limit "tpgt"
to UINT_MAX but the data type of "tpg->tport_tpgt" and that is a u16.

I looked at the context and it turns out that in
vhost_scsi_set_endpoint(), "tpg->tport_tpgt" is used as an offset into
the vs_tpg[] array which has VHOST_SCSI_MAX_TARGET (256) elements so
anything higher than 255 then it is invalid.  I have made that the limit
now.

In vhost_scsi_send_evt() we mask away values higher than 255, but now
that the limit has changed, we don't need the mask.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Dan Carpenter 2015-02-05 10:37:33 +03:00 committed by Nicholas Bellinger
parent 1a1ff8256a
commit 59c816c1f2
1 changed files with 3 additions and 3 deletions
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6
drivers/vhost/scsi.c
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@ -1249,7 +1249,7 @@ vhost_scsi_send_evt(struct vhost_scsi *vs,
* lun[4-7] need to be zero according to virtio-scsi spec.
*/
evt->event.lun[0] = 0x01;
evt->event.lun[1] = tpg->tport_tpgt & 0xFF;
evt->event.lun[1] = tpg->tport_tpgt;
if (lun->unpacked_lun >= 256)
evt->event.lun[2] = lun->unpacked_lun >> 8 | 0x40 ;
evt->event.lun[3] = lun->unpacked_lun & 0xFF;
@ -2120,12 +2120,12 @@ vhost_scsi_make_tpg(struct se_wwn *wwn,
struct vhost_scsi_tport, tport_wwn);
struct vhost_scsi_tpg *tpg;
unsigned long tpgt;
u16 tpgt;
int ret;
if (strstr(name, "tpgt_") != name)
return ERR_PTR(-EINVAL);
if (kstrtoul(name + 5, 10, &tpgt) || tpgt > UINT_MAX)
if (kstrtou16(name + 5, 10, &tpgt) || tpgt >= VHOST_SCSI_MAX_TARGET)
return ERR_PTR(-EINVAL);
tpg = kzalloc(sizeof(struct vhost_scsi_tpg), GFP_KERNEL);