Commit 50cf0bd2 authored by Dan Carpenter's avatar Dan Carpenter Committed by Kamal Mostafa

vhost/scsi: potential memory corruption

commit 59c816c1 upstream.

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: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Reference: CVE-2015-4036
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
parent 72139bf0
......@@ -1115,7 +1115,7 @@ tcm_vhost_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;
......@@ -1985,12 +1985,12 @@ tcm_vhost_make_tpg(struct se_wwn *wwn,
struct tcm_vhost_tport, tport_wwn);
struct tcm_vhost_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 tcm_vhost_tpg), GFP_KERNEL);
......
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