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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: 81993e81a9 ("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>
This commit is contained in:
Daniel Mentz 2017-08-02 23:42:17 -04:00 committed by Mauro Carvalho Chehab
parent 025a26fa14
commit 9c7ba1d763
1 changed files with 2 additions and 1 deletions
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3
drivers/media/v4l2-core/v4l2-compat-ioctl32.c
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@ -799,7 +799,8 @@ static int put_v4l2_event32(struct v4l2_event *kp, struct v4l2_event32 __user *u
copy_to_user(&up->u, &kp->u, sizeof(kp->u)) ||
put_user(kp->pending, &up->pending) ||
put_user(kp->sequence, &up->sequence) ||
compat_put_timespec(&kp->timestamp, &up->timestamp) ||
put_user(kp->timestamp.tv_sec, &up->timestamp.tv_sec) ||
put_user(kp->timestamp.tv_nsec, &up->timestamp.tv_nsec) ||
put_user(kp->id, &up->id) ||
copy_to_user(up->reserved, kp->reserved, 8 * sizeof(__u32)))
return -EFAULT;