ACPI: NFIT: Fix input validation of bus-family

commit 9a7e3d7f056831a6193d6d737fb7a26dfdceb04b upstream.

Dan reports that smatch thinks userspace can craft an out-of-bound bus
family number. However, nd_cmd_clear_to_send() blocks all non-zero
values of bus-family since only the kernel can initiate these commands.
However, in the speculation path, family is a user controlled array
index value so mask it for speculation safety. Also, since the
nd_cmd_clear_to_send() safety is non-obvious and possibly may change in
the future include input validation as if userspace could get past the
nd_cmd_clear_to_send() gatekeeper.

Link: http://lore.kernel.org/r/20201111113000.GA1237157@mwanda
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 6450ddbd5d8e ("ACPI: NFIT: Define runtime firmware activation commands")
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions