media: v4l2-compat-ioctl32: Fix timespec conversion
authorDaniel Mentz <danielmentz@google.com>
Thu, 3 Aug 2017 03:42:17 +0000 (23:42 -0400)
committerMauro Carvalho Chehab <mchehab@s-opensource.com>
Wed, 9 Aug 2017 14:36:44 +0000 (10:36 -0400)
commit9c7ba1d7634cef490b85bc64c4091ff004821bfd
tree6e467b252bf0553fec5f951552233a4b5478f803
parent025a26fa14f8fd55d50ab284a30c016a5be953d0
media: v4l2-compat-ioctl32: Fix timespec conversion

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: stable@vger.kernel.org
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>
drivers/media/v4l2-core/v4l2-compat-ioctl32.c