media: v4l2-ioctl: Fix check_ext_ctrls

commit 861f92cb91 upstream.

Drivers that do not use the ctrl-framework use this function instead.

Fix the following issues:

- Do not check for multiple classes when getting the DEF_VAL.
- Return -EINVAL for request_api calls
- Default value cannot be changed, return EINVAL as soon as possible.
- Return the right error_idx
[If an error is found when validating the list of controls passed with
VIDIOC_G_EXT_CTRLS, then error_idx shall be set to ctrls->count to
indicate to userspace that no actual hardware was touched.
It would have been much nicer of course if error_idx could point to the
control index that failed the validation, but sadly that's not how the
API was designed.]

Fixes v4l2-compliance:
Control ioctls (Input 0):
        warn: v4l2-test-controls.cpp(834): error_idx should be equal to count
        warn: v4l2-test-controls.cpp(855): error_idx should be equal to count
		fail: v4l2-test-controls.cpp(813): doioctl(node, VIDIOC_G_EXT_CTRLS, &ctrls)
	test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
Buffer ioctls (Input 0):
		fail: v4l2-test-buffers.cpp(1994): ret != EINVAL && ret != EBADR && ret != ENOTTY
	test Requests: FAIL

Cc: stable@vger.kernel.org
Fixes: 6fa6f831f0 ("media: v4l2-ctrls: add core request support")
Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -869,7 +869,7 @@ static void v4l_print_default(const void *arg, bool write_only)
 	pr_cont("driver-specific ioctl\n");
 }
 
-static int check_ext_ctrls(struct v4l2_ext_controls *c, int allow_priv)
+static bool check_ext_ctrls(struct v4l2_ext_controls *c, unsigned long ioctl)
 {
 	__u32 i;
 
@@ -878,23 +878,41 @@ static int check_ext_ctrls(struct v4l2_ext_controls *c, int allow_priv)
 	for (i = 0; i < c->count; i++)
 		c->controls[i].reserved2[0] = 0;
 
-	/* V4L2_CID_PRIVATE_BASE cannot be used as control class
-	   when using extended controls.
-	   Only when passed in through VIDIOC_G_CTRL and VIDIOC_S_CTRL
-	   is it allowed for backwards compatibility.
-	 */
-	if (!allow_priv && c->which == V4L2_CID_PRIVATE_BASE)
-		return 0;
-	if (!c->which)
-		return 1;
+	switch (c->which) {
+	case V4L2_CID_PRIVATE_BASE:
+		/*
+		 * V4L2_CID_PRIVATE_BASE cannot be used as control class
+		 * when using extended controls.
+		 * Only when passed in through VIDIOC_G_CTRL and VIDIOC_S_CTRL
+		 * is it allowed for backwards compatibility.
+		 */
+		if (ioctl == VIDIOC_G_CTRL || ioctl == VIDIOC_S_CTRL)
+			return false;
+		break;
+	case V4L2_CTRL_WHICH_DEF_VAL:
+		/* Default value cannot be changed */
+		if (ioctl == VIDIOC_S_EXT_CTRLS ||
+		    ioctl == VIDIOC_TRY_EXT_CTRLS) {
+			c->error_idx = c->count;
+			return false;
+		}
+		return true;
+	case V4L2_CTRL_WHICH_CUR_VAL:
+		return true;
+	case V4L2_CTRL_WHICH_REQUEST_VAL:
+		c->error_idx = c->count;
+		return false;
+	}
+
 	/* Check that all controls are from the same control class. */
 	for (i = 0; i < c->count; i++) {
 		if (V4L2_CTRL_ID2WHICH(c->controls[i].id) != c->which) {
-			c->error_idx = i;
-			return 0;
+			c->error_idx = ioctl == VIDIOC_TRY_EXT_CTRLS ? i :
+								      c->count;
+			return false;
 		}
 	}
-	return 1;
+	return true;
 }
 
 static int check_fmt(struct file *file, enum v4l2_buf_type type)
@@ -2187,7 +2205,7 @@ static int v4l_g_ctrl(const struct v4l2_ioctl_ops *ops,
 	ctrls.controls = &ctrl;
 	ctrl.id = p->id;
 	ctrl.value = p->value;
-	if (check_ext_ctrls(&ctrls, 1)) {
+	if (check_ext_ctrls(&ctrls, VIDIOC_G_CTRL)) {
 		int ret = ops->vidioc_g_ext_ctrls(file, fh, &ctrls);
 
 		if (ret == 0)
@@ -2221,7 +2239,7 @@ static int v4l_s_ctrl(const struct v4l2_ioctl_ops *ops,
 	ctrls.controls = &ctrl;
 	ctrl.id = p->id;
 	ctrl.value = p->value;
-	if (check_ext_ctrls(&ctrls, 1))
+	if (check_ext_ctrls(&ctrls, VIDIOC_S_CTRL))
 		return ops->vidioc_s_ext_ctrls(file, fh, &ctrls);
 	return -EINVAL;
 }
@@ -2243,8 +2261,8 @@ static int v4l_g_ext_ctrls(const struct v4l2_ioctl_ops *ops,
 					vfd, vfd->v4l2_dev->mdev, p);
 	if (ops->vidioc_g_ext_ctrls == NULL)
 		return -ENOTTY;
-	return check_ext_ctrls(p, 0) ? ops->vidioc_g_ext_ctrls(file, fh, p) :
-					-EINVAL;
+	return check_ext_ctrls(p, VIDIOC_G_EXT_CTRLS) ?
+				ops->vidioc_g_ext_ctrls(file, fh, p) : -EINVAL;
 }
 
 static int v4l_s_ext_ctrls(const struct v4l2_ioctl_ops *ops,
@@ -2264,8 +2282,8 @@ static int v4l_s_ext_ctrls(const struct v4l2_ioctl_ops *ops,
 					vfd, vfd->v4l2_dev->mdev, p);
 	if (ops->vidioc_s_ext_ctrls == NULL)
 		return -ENOTTY;
-	return check_ext_ctrls(p, 0) ? ops->vidioc_s_ext_ctrls(file, fh, p) :
-					-EINVAL;
+	return check_ext_ctrls(p, VIDIOC_S_EXT_CTRLS) ?
+				ops->vidioc_s_ext_ctrls(file, fh, p) : -EINVAL;
 }
 
 static int v4l_try_ext_ctrls(const struct v4l2_ioctl_ops *ops,
@@ -2285,8 +2303,8 @@ static int v4l_try_ext_ctrls(const struct v4l2_ioctl_ops *ops,
 					  vfd, vfd->v4l2_dev->mdev, p);
 	if (ops->vidioc_try_ext_ctrls == NULL)
 		return -ENOTTY;
-	return check_ext_ctrls(p, 0) ? ops->vidioc_try_ext_ctrls(file, fh, p) :
-					-EINVAL;
+	return check_ext_ctrls(p, VIDIOC_TRY_EXT_CTRLS) ?
+			ops->vidioc_try_ext_ctrls(file, fh, p) : -EINVAL;
 }
 
 /*