libnvdimm: Out of bounds read in __nd_ioctl()

libnvdimm: Out of bounds read in __nd_ioctl()

[ Upstream commit aaa6448d1985a0d432036721261bd5cae6aaea4e ]

The "cmd" comes from the user and it can be up to 255.  It it's more
than the number of bits in long, it results out of bounds read when we
check test_bit(cmd, &cmd_mask).  The highest valid value for "cmd" is
ND_CMD_CALL (10) so I added a compare against that.

Fixes: 430ef3231e6d ("libnvdimm: control (ioctl) messages for nvdimm_bus and nvdimm devices")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20200225162055.amtosfy7m35aivxg@kili.mountain
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>