Commit ee929d5a authored by Ricardo Ribalda's avatar Ricardo Ribalda Committed by Mauro Carvalho Chehab
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media: uvcvideo: Check controls flags before accessing them 



We can figure out if reading/writing a set of controls can fail without
accessing them by checking their flags.

This way we can honor the API closer:

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.

Fixes v4l2-compliance:
Control ioctls (Input 0):
		warn: v4l2-test-controls.cpp(765): g_ext_ctrls(0) invalid error_idx 0
                fail: v4l2-test-controls.cpp(645): invalid error index write only control
        test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL

Reviewed-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarRicardo Ribalda <ribalda@chromium.org>
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 70fa906d

drivers/media/usb/uvc/uvc_ctrl.c

+22 −0
Original line number Diff line number Diff line
@@ -1042,6 +1042,28 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id, 
	return 0;

}



int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,

			   bool read)

{

	struct uvc_control_mapping *mapping;

	struct uvc_control *ctrl;



	if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0)

		return -EACCES;



	ctrl = uvc_find_control(chain, v4l2_id, &mapping);

	if (!ctrl)

		return -EINVAL;



	if (!(ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR) && read)

		return -EACCES;



	if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read)

		return -EACCES;



	return 0;

}



static const char *uvc_map_get_name(const struct uvc_control_mapping *map)

{

	const char *name;

drivers/media/usb/uvc/uvc_v4l2.c

+34 −5
Original line number Diff line number Diff line
@@ -1003,6 +1003,26 @@ static int uvc_ioctl_query_ext_ctrl(struct file *file, void *fh, 
	return 0;

}



static int uvc_ctrl_check_access(struct uvc_video_chain *chain,

				 struct v4l2_ext_controls *ctrls,

				 unsigned long ioctl)

{

	struct v4l2_ext_control *ctrl = ctrls->controls;

	unsigned int i;

	int ret = 0;



	for (i = 0; i < ctrls->count; ++ctrl, ++i) {

		ret = uvc_ctrl_is_accessible(chain, ctrl->id,

					    ioctl == VIDIOC_G_EXT_CTRLS);

		if (ret)

			break;

	}



	ctrls->error_idx = ioctl == VIDIOC_TRY_EXT_CTRLS ? i : ctrls->count;



	return ret;

}



static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh,

				 struct v4l2_ext_controls *ctrls)

{
@@ -1012,6 +1032,10 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh, 
	unsigned int i;

	int ret;



	ret = uvc_ctrl_check_access(chain, ctrls, VIDIOC_G_EXT_CTRLS);

	if (ret < 0)

		return ret;



	if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {

		for (i = 0; i < ctrls->count; ++ctrl, ++i) {

			struct v4l2_queryctrl qc = { .id = ctrl->id };
@@ -1048,13 +1072,17 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh, 


static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,

				     struct v4l2_ext_controls *ctrls,

				     bool commit)

				     unsigned long ioctl)

{

	struct v4l2_ext_control *ctrl = ctrls->controls;

	struct uvc_video_chain *chain = handle->chain;

	unsigned int i;

	int ret;



	ret = uvc_ctrl_check_access(chain, ctrls, ioctl);

	if (ret < 0)

		return ret;



	ret = uvc_ctrl_begin(chain);

	if (ret < 0)

		return ret;
@@ -1063,14 +1091,15 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle, 
		ret = uvc_ctrl_set(handle, ctrl);

		if (ret < 0) {

			uvc_ctrl_rollback(handle);

			ctrls->error_idx = commit ? ctrls->count : i;

			ctrls->error_idx = ioctl == VIDIOC_S_EXT_CTRLS ?

						    ctrls->count : i;

			return ret;

		}

	}



	ctrls->error_idx = 0;



	if (commit)

	if (ioctl == VIDIOC_S_EXT_CTRLS)

		return uvc_ctrl_commit(handle, ctrls->controls, ctrls->count);

	else

		return uvc_ctrl_rollback(handle);
@@ -1081,7 +1110,7 @@ static int uvc_ioctl_s_ext_ctrls(struct file *file, void *fh, 
{

	struct uvc_fh *handle = fh;



	return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, true);

	return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, VIDIOC_S_EXT_CTRLS);

}



static int uvc_ioctl_try_ext_ctrls(struct file *file, void *fh,
@@ -1089,7 +1118,7 @@ static int uvc_ioctl_try_ext_ctrls(struct file *file, void *fh, 
{

	struct uvc_fh *handle = fh;



	return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, false);

	return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, VIDIOC_TRY_EXT_CTRLS);

}



static int uvc_ioctl_querymenu(struct file *file, void *fh,

drivers/media/usb/uvc/uvcvideo.h

+2 −0
Original line number Diff line number Diff line
@@ -901,6 +901,8 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle) 


int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl);

int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl);

int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,

			   bool read);



int uvc_xu_ctrl_query(struct uvc_video_chain *chain,

		      struct uvc_xu_control_query *xqry);