Re: [PATCH v2 17/30] v4l: subdev: compat: Implement handling for VIDIOC_SUBDEV_[GS]_ROUTING

[Jacopo Mondi <jacopo@jmondi.org>]

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Hi Laurent, Sakari,

On Wed, Jan 16, 2019 at 01:53:03AM +0200, Laurent Pinchart wrote:
> Hi Niklas,
>
> Thank you for the patch.
>
> On Fri, Nov 02, 2018 at 12:31:31AM +0100, Niklas Söderlund wrote:
> > From: Sakari Ailus <sakari.ailus@linux.intel.com>
> >
> > Implement compat IOCTL handling for VIDIOC_SUBDEV_G_ROUTING and
> > VIDIOC_SUBDEV_S_ROUTING IOCTLs.
>
> Let's instead design the ioctl in a way that doesn't require compat
> handling.
>

Care to explain what makes this ioctl require a compat version? I
don't see assumptions on the word length on the implementation. What
am I missing?

Thanks
  j

> > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > ---
> >  drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 77 +++++++++++++++++++
> >  1 file changed, 77 insertions(+)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > index 6481212fda772c73..83af332763f41a6b 100644
> > --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> > @@ -1045,6 +1045,66 @@ static int put_v4l2_event32(struct v4l2_event __user *p64,
> >  	return 0;
> >  }
> >
> > +struct v4l2_subdev_routing32 {
> > +	compat_caddr_t routes;
> > +	__u32 num_routes;
> > +	__u32 reserved[5];
> > +};
> > +
> > +static int get_v4l2_subdev_routing(struct v4l2_subdev_routing __user *p64,
> > +				   struct v4l2_subdev_routing32 __user *p32)
> > +{
> > +	struct v4l2_subdev_route __user *routes;
> > +	compat_caddr_t p;
> > +	u32 num_routes;
> > +
> > +	if (!access_ok(VERIFY_READ, p32, sizeof(*p32)) ||
> > +	    get_user(p, &p32->routes) ||
> > +	    get_user(num_routes, &p32->num_routes) ||
> > +	    put_user(num_routes, &p64->num_routes) ||
> > +	    copy_in_user(&p64->reserved, &p32->reserved,
> > +			 sizeof(p64->reserved)) ||
> > +	    num_routes > U32_MAX / sizeof(*p64->routes))
> > +		return -EFAULT;
> > +
> > +	routes = compat_ptr(p);
> > +
> > +	if (!access_ok(VERIFY_READ, routes,
> > +		       num_routes * sizeof(*p64->routes)))
> > +		return -EFAULT;
> > +
> > +	if (put_user((__force struct v4l2_subdev_route *)routes,
> > +		     &p64->routes))
> > +		return -EFAULT;
> > +
> > +	return 0;
> > +}
> > +
> > +static int put_v4l2_subdev_routing(struct v4l2_subdev_routing __user *p64,
> > +				   struct v4l2_subdev_routing32 __user *p32)
> > +{
> > +	struct v4l2_subdev_route __user *routes;
> > +	compat_caddr_t p;
> > +	u32 num_routes;
> > +
> > +	if (!access_ok(VERIFY_WRITE, p32, sizeof(*p32)) ||
> > +	    get_user(p, &p32->routes) ||
> > +	    get_user(num_routes, &p64->num_routes) ||
> > +	    put_user(num_routes, &p32->num_routes) ||
> > +	    copy_in_user(&p32->reserved, &p64->reserved,
> > +			 sizeof(p64->reserved)) ||
> > +	    num_routes > U32_MAX / sizeof(*p64->routes))
> > +		return -EFAULT;
> > +
> > +	routes = compat_ptr(p);
> > +
> > +	if (!access_ok(VERIFY_WRITE, routes,
> > +		       num_routes * sizeof(*p64->routes)))
> > +		return -EFAULT;
> > +
> > +	return 0;
> > +}
> > +
> >  struct v4l2_edid32 {
> >  	__u32 pad;
> >  	__u32 start_block;
> > @@ -1117,6 +1177,8 @@ static int put_v4l2_edid32(struct v4l2_edid __user *p64,
> >  #define VIDIOC_STREAMOFF32	_IOW ('V', 19, s32)
> >  #define VIDIOC_G_INPUT32	_IOR ('V', 38, s32)
> >  #define VIDIOC_S_INPUT32	_IOWR('V', 39, s32)
> > +#define VIDIOC_SUBDEV_G_ROUTING32 _IOWR('V', 38, struct v4l2_subdev_routing32)
> > +#define VIDIOC_SUBDEV_S_ROUTING32 _IOWR('V', 39, struct v4l2_subdev_routing32)
> >  #define VIDIOC_G_OUTPUT32	_IOR ('V', 46, s32)
> >  #define VIDIOC_S_OUTPUT32	_IOWR('V', 47, s32)
> >
> > @@ -1195,6 +1257,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >  	case VIDIOC_STREAMOFF32: cmd = VIDIOC_STREAMOFF; break;
> >  	case VIDIOC_G_INPUT32: cmd = VIDIOC_G_INPUT; break;
> >  	case VIDIOC_S_INPUT32: cmd = VIDIOC_S_INPUT; break;
> > +	case VIDIOC_SUBDEV_G_ROUTING32: cmd = VIDIOC_SUBDEV_G_ROUTING; break;
> > +	case VIDIOC_SUBDEV_S_ROUTING32: cmd = VIDIOC_SUBDEV_S_ROUTING; break;
> >  	case VIDIOC_G_OUTPUT32: cmd = VIDIOC_G_OUTPUT; break;
> >  	case VIDIOC_S_OUTPUT32: cmd = VIDIOC_S_OUTPUT; break;
> >  	case VIDIOC_CREATE_BUFS32: cmd = VIDIOC_CREATE_BUFS; break;
> > @@ -1227,6 +1291,15 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >  		compatible_arg = 0;
> >  		break;
> >
> > +	case VIDIOC_SUBDEV_G_ROUTING:
> > +	case VIDIOC_SUBDEV_S_ROUTING:
> > +		err = alloc_userspace(sizeof(struct v4l2_subdev_routing),
> > +				      0, &new_p64);
> > +		if (!err)
> > +			err = get_v4l2_subdev_routing(new_p64, p32);
> > +		compatible_arg = 0;
> > +		break;
> > +
> >  	case VIDIOC_G_EDID:
> >  	case VIDIOC_S_EDID:
> >  		err = alloc_userspace(sizeof(struct v4l2_edid), 0, &new_p64);
> > @@ -1368,6 +1441,10 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
> >  		if (put_v4l2_edid32(new_p64, p32))
> >  			err = -EFAULT;
> >  		break;
> > +	case VIDIOC_SUBDEV_G_ROUTING:
> > +	case VIDIOC_SUBDEV_S_ROUTING:
> > +		err = put_v4l2_subdev_routing(new_p64, p32);
> > +		break;
> >  	}
> >  	if (err)
> >  		return err;
>
> --
> Regards,
>
> Laurent Pinchart

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