linux/drivers/s390/cio
Peter Oberparleiter 0e501fd0f3 s390/cio: fix out-of-bounds access on cio_ignore free
[ Upstream commit 1b60741127 ]

The channel-subsystem-driver scans for newly available devices whenever
device-IDs are removed from the cio_ignore list using a command such as:

  echo free >/proc/cio_ignore

Since an I/O device scan might interfer with running I/Os, commit
172da89ed0 ("s390/cio: avoid excessive path-verification requests")
introduced an optimization to exclude online devices from the scan.

The newly added check for online devices incorrectly assumes that
an I/O-subchannel's drvdata points to a struct io_subchannel_private.
For devices that are bound to a non-default I/O subchannel driver, such
as the vfio_ccw driver, this results in an out-of-bounds read access
during each scan.

Fix this by changing the scan logic to rely on a driver-independent
online indication. For this we can use struct subchannel->config.ena,
which is the driver's requested subchannel-enabled state. Since I/Os
can only be started on enabled subchannels, this matches the intent
of the original optimization of not scanning devices where I/O might
be running.

Fixes: 172da89ed0 ("s390/cio: avoid excessive path-verification requests")
Fixes: 0c3812c347 ("s390/cio: derive cdev information only for IO-subchannels")
Cc: <stable@vger.kernel.org> # v5.15
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-10 18:15:33 +01:00
..
Makefile
airq.c
blacklist.c
blacklist.h
ccwgroup.c s390/qeth: fix deadlock during failing recovery 2021-09-21 20:02:24 -07:00
ccwreq.c
chp.c
chp.h
chsc.c
chsc.h
chsc_sch.c
chsc_sch.h
cio.c
cio.h
cio_debug.h
cio_debugfs.c s390/cio: introduce CIO debugfs directory 2021-03-22 11:36:04 +01:00
cio_inject.c
cio_inject.h
cmf.c
crw.c
css.c
css.h s390/cio: avoid excessive path-verification requests 2021-09-27 13:54:38 +02:00
device.c
device.h
device_fsm.c
device_id.c
device_ops.c
device_pgid.c s390/cio: add basic protected virtualization support 2019-06-15 12:25:00 +02:00
device_status.c
eadm_sch.c
eadm_sch.h
fcx.c
idset.c
idset.h
io_sch.h
ioasm.c
ioasm.h s390: assume diag308 set always works 2018-04-10 07:38:59 +02:00
isc.c
itcw.c
orb.h
qdio.h
qdio_debug.c
qdio_debug.h
qdio_main.c s390/qdio: remove unused support for SLIB parameters 2021-08-18 10:01:28 +02:00
qdio_setup.c
qdio_thinint.c
scm.c
trace.c
trace.h s390: use struct tpi_info in lowcore.h 2021-06-07 17:07:01 +02:00
vfio_ccw_async.c
vfio_ccw_chp.c
vfio_ccw_cp.c
vfio_ccw_cp.h
vfio_ccw_drv.c
vfio_ccw_fsm.c
vfio_ccw_ops.c
vfio_ccw_private.h
vfio_ccw_trace.c
vfio_ccw_trace.h