media: v4l2-compat-ioctl32: Fix timespec conversion
authorDaniel Mentz <danielmentz@google.com>
Thu, 3 Aug 2017 03:42:17 +0000 (23:42 -0400)
committerRaspbian kernel package updater <root@raspbian.org>
Sun, 8 Oct 2017 01:09:27 +0000 (01:09 +0000)
commit4982e7a7732664a8d5d62ad22ce11123ee6ab516
treedb668d92ae5ffbe8af9443bb7cfa72d581638e8a
parent5c76e040b28f15ab6d1d518673caa9147d59c4fc
media: v4l2-compat-ioctl32: Fix timespec conversion

commit 9c7ba1d7634cef490b85bc64c4091ff004821bfd upstream.

Certain syscalls like recvmmsg support 64 bit timespec values for the
X32 ABI. The helper function compat_put_timespec converts a timespec
value to a 32 bit or 64 bit value depending on what ABI is used. The
v4l2 compat layer, however, is not designed to support 64 bit timespec
values and always uses 32 bit values. Hence, compat_put_timespec must
not be used.

Without this patch, user space will be provided with bad timestamp
values from the VIDIOC_DQEVENT ioctl. Also, fields of the struct
v4l2_event32 that come immediately after timestamp get overwritten,
namely the field named id.

Fixes: 81993e81a994 ("compat: Get rid of (get|put)_compat_time(val|spec)")
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Tiffany Lin <tiffany.lin@mediatek.com>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Daniel Mentz <danielmentz@google.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/media/v4l2-core/v4l2-compat-ioctl32.c