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: [email protected]
Cc: H. Peter Anvin <[email protected]>
Cc: Laurent Pinchart <[email protected]>
Cc: Tiffany Lin <[email protected]>
Cc: Ricardo Ribalda Delgado <[email protected]>
Cc: Sakari Ailus <[email protected]>
Signed-off-by: Daniel Mentz <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 84ad195562c74b4f4c4678c7ec7dbfd1192806ba..af8b4c5b0efa71660275155e21656aa98bd947c5 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -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;