linux/drivers/block/xen-blkback
Dongli Zhang 4a8c31a1c6 xen/blkback: rework connect_ring() to avoid inconsistent xenstore 'ring-page-order' set by malicious blkfront
The xenstore 'ring-page-order' is used globally for each blkback queue and
therefore should be read from xenstore only once. However, it is obtained
in read_per_ring_refs() which might be called multiple times during the
initialization of each blkback queue.

If the blkfront is malicious and the 'ring-page-order' is set in different
value by blkfront every time before blkback reads it, this may end up at
the "WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages));" in
xen_blkif_disconnect() when frontend is destroyed.

This patch reworks connect_ring() to read xenstore 'ring-page-order' only
once.

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2019-02-24 10:17:56 -05:00
..
Makefile
blkback.c xen/blkback: move persistent grants flags to bool 2018-08-27 12:12:04 -04:00
common.h xen/blkback: remove unused pers_gnts_lock from struct xen_blkif_ring 2018-08-27 12:12:04 -04:00
xenbus.c xen/blkback: rework connect_ring() to avoid inconsistent xenstore 'ring-page-order' set by malicious blkfront 2019-02-24 10:17:56 -05:00