3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans Verkuil <hans.verk...@cisco.com>

commit b8c601e8af2d08f733d74defa8465303391bb930 upstream.

ctrl_is_pointer just hardcoded two known string controls, but that
caused problems when using e.g. custom controls that use a pointer
for the payload.

Reimplement this function: it now finds the v4l2_ctrl (if the driver
uses the control framework) or it calls vidioc_query_ext_ctrl (if the
driver implements that directly).

In both cases it can now check if the control is a pointer control
or not.

Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
Acked-by: Sakari Ailus <sakari.ai...@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mche...@s-opensource.com>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c |   59 +++++++++++++++++---------
 1 file changed, 39 insertions(+), 20 deletions(-)

--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -18,6 +18,8 @@
 #include <linux/videodev2.h>
 #include <linux/v4l2-subdev.h>
 #include <media/v4l2-dev.h>
+#include <media/v4l2-fh.h>
+#include <media/v4l2-ctrls.h>
 #include <media/v4l2-ioctl.h>
 
 static long native_ioctl(struct file *file, unsigned int cmd, unsigned long 
arg)
@@ -575,24 +577,39 @@ struct v4l2_ext_control32 {
        };
 } __attribute__ ((packed));
 
-/* The following function really belong in v4l2-common, but that causes
-   a circular dependency between modules. We need to think about this, but
-   for now this will do. */
-
-/* Return non-zero if this control is a pointer type. Currently only
-   type STRING is a pointer type. */
-static inline int ctrl_is_pointer(u32 id)
-{
-       switch (id) {
-       case V4L2_CID_RDS_TX_PS_NAME:
-       case V4L2_CID_RDS_TX_RADIO_TEXT:
-               return 1;
-       default:
-               return 0;
+/* Return true if this control is a pointer type. */
+static inline bool ctrl_is_pointer(struct file *file, u32 id)
+{
+       struct video_device *vdev = video_devdata(file);
+       struct v4l2_fh *fh = NULL;
+       struct v4l2_ctrl_handler *hdl = NULL;
+       struct v4l2_query_ext_ctrl qec = { id };
+       const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
+
+       if (test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))
+               fh = file->private_data;
+
+       if (fh && fh->ctrl_handler)
+               hdl = fh->ctrl_handler;
+       else if (vdev->ctrl_handler)
+               hdl = vdev->ctrl_handler;
+
+       if (hdl) {
+               struct v4l2_ctrl *ctrl = v4l2_ctrl_find(hdl, id);
+
+               return ctrl && ctrl->is_ptr;
        }
+
+       if (!ops->vidioc_query_ext_ctrl)
+               return false;
+
+       return !ops->vidioc_query_ext_ctrl(file, fh, &qec) &&
+               (qec.flags & V4L2_CTRL_FLAG_HAS_PAYLOAD);
 }
 
-static int get_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct 
v4l2_ext_controls32 __user *up)
+static int get_v4l2_ext_controls32(struct file *file,
+                                  struct v4l2_ext_controls *kp,
+                                  struct v4l2_ext_controls32 __user *up)
 {
        struct v4l2_ext_control32 __user *ucontrols;
        struct v4l2_ext_control __user *kcontrols;
@@ -624,7 +641,7 @@ static int get_v4l2_ext_controls32(struc
                        return -EFAULT;
                if (get_user(id, &kcontrols->id))
                        return -EFAULT;
-               if (ctrl_is_pointer(id)) {
+               if (ctrl_is_pointer(file, id)) {
                        void __user *s;
 
                        if (get_user(p, &ucontrols->string))
@@ -639,7 +656,9 @@ static int get_v4l2_ext_controls32(struc
        return 0;
 }
 
-static int put_v4l2_ext_controls32(struct v4l2_ext_controls *kp, struct 
v4l2_ext_controls32 __user *up)
+static int put_v4l2_ext_controls32(struct file *file,
+                                  struct v4l2_ext_controls *kp,
+                                  struct v4l2_ext_controls32 __user *up)
 {
        struct v4l2_ext_control32 __user *ucontrols;
        struct v4l2_ext_control __user *kcontrols =
@@ -671,7 +690,7 @@ static int put_v4l2_ext_controls32(struc
                /* Do not modify the pointer when copying a pointer control.
                   The contents of the pointer was changed, not the pointer
                   itself. */
-               if (ctrl_is_pointer(id))
+               if (ctrl_is_pointer(file, id))
                        size -= sizeof(ucontrols->value64);
                if (copy_in_user(ucontrols, kcontrols, size))
                        return -EFAULT;
@@ -884,7 +903,7 @@ static long do_video_ioctl(struct file *
        case VIDIOC_G_EXT_CTRLS:
        case VIDIOC_S_EXT_CTRLS:
        case VIDIOC_TRY_EXT_CTRLS:
-               err = get_v4l2_ext_controls32(&karg.v2ecs, up);
+               err = get_v4l2_ext_controls32(file, &karg.v2ecs, up);
                compatible_arg = 0;
                break;
        case VIDIOC_DQEVENT:
@@ -911,7 +930,7 @@ static long do_video_ioctl(struct file *
        case VIDIOC_G_EXT_CTRLS:
        case VIDIOC_S_EXT_CTRLS:
        case VIDIOC_TRY_EXT_CTRLS:
-               if (put_v4l2_ext_controls32(&karg.v2ecs, up))
+               if (put_v4l2_ext_controls32(file, &karg.v2ecs, up))
                        err = -EFAULT;
                break;
        }


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