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Commit 0812542d authored by Dan Carpenter's avatar Dan Carpenter Committed by Sasha Levin
Browse files

vhost/scsi: potential memory corruption 



[ Upstream commit 59c816c1f24df0204e01851431d3bab3eb76719c ]

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>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
parent 52e98050

drivers/vhost/scsi.c

+3 −3
Original line number Diff line number Diff line
@@ -1251,7 +1251,7 @@ 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;
@@ -2122,12 +2122,12 @@ 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);