[libcamera-devel] [PATCH 02/15] v4l2: v4l2_camera_proxy: Check for null arg values in ioctl handlers

[Jacopo Mondi]

Hi Paul, Laurent

On Wed, Jun 17, 2020 at 04:06:07AM +0300, Laurent Pinchart wrote:
> Hi Paul,
>
> Thank you for the patch.
>
> On Tue, Jun 16, 2020 at 10:12:31PM +0900, Paul Elder wrote:
> > The ioctl handlers currently don't check if arg is null, so if it ever
> > is, it will cause a segfault. Check that arg is null and return -EFAULT
> > in all vidioc ioctl handlers.
> >
> > Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
> Can't you check that in V4L2CameraProxy::ioctl() ?
>

And maybe use !arg  for the check ?

Thanks
  j

> > ---
> >  src/v4l2/v4l2_camera_proxy.cpp | 33 +++++++++++++++++++++++++++++++--
> >  1 file changed, 31 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
> > index 594dd13..5b74b53 100644
> > --- a/src/v4l2/v4l2_camera_proxy.cpp
> > +++ b/src/v4l2/v4l2_camera_proxy.cpp
> > @@ -238,6 +238,9 @@ int V4L2CameraProxy::vidioc_querycap(struct v4l2_capability *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_querycap";
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	*arg = capabilities_;
> >
> >  	return 0;
> > @@ -247,6 +250,8 @@ int V4L2CameraProxy::vidioc_enum_fmt(int fd, struct v4l2_fmtdesc *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_enum_fmt fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> >
> >  	if (!validateBufferType(arg->type) ||
> >  	    arg->index >= streamConfig_.formats().pixelformats().size())
> > @@ -264,6 +269,8 @@ int V4L2CameraProxy::vidioc_g_fmt(int fd, struct v4l2_format *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_g_fmt fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> >
> >  	if (!validateBufferType(arg->type))
> >  		return -EINVAL;
> > @@ -303,6 +310,9 @@ int V4L2CameraProxy::vidioc_s_fmt(int fd, struct v4l2_format *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_s_fmt fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> >  		return ret;
> > @@ -334,6 +344,9 @@ int V4L2CameraProxy::vidioc_try_fmt(int fd, struct v4l2_format *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_try_fmt fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	if (!validateBufferType(arg->type))
> >  		return -EINVAL;
> >
> > @@ -361,6 +374,8 @@ int V4L2CameraProxy::vidioc_reqbufs(int fd, struct v4l2_requestbuffers *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_reqbufs fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> >
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> > @@ -444,6 +459,9 @@ int V4L2CameraProxy::vidioc_querybuf(int fd, struct v4l2_buffer *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_querybuf fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> >  		return ret;
> > @@ -461,8 +479,10 @@ int V4L2CameraProxy::vidioc_querybuf(int fd, struct v4l2_buffer *arg)
> >
> >  int V4L2CameraProxy::vidioc_qbuf(int fd, struct v4l2_buffer *arg)
> >  {
> > -	LOG(V4L2Compat, Debug) << "Servicing vidioc_qbuf, index = "
> > -			       << arg->index << " fd = " << fd;
> > +	LOG(V4L2Compat, Debug) << "Servicing vidioc_qbuf fd = " << fd;
> > +
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> >
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> > @@ -487,6 +507,9 @@ int V4L2CameraProxy::vidioc_dqbuf(int fd, struct v4l2_buffer *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_dqbuf fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> >  		return ret;
> > @@ -522,6 +545,9 @@ int V4L2CameraProxy::vidioc_streamon(int fd, int *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_streamon fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> >  		return ret;
> > @@ -538,6 +564,9 @@ int V4L2CameraProxy::vidioc_streamoff(int fd, int *arg)
> >  {
> >  	LOG(V4L2Compat, Debug) << "Servicing vidioc_streamoff fd = " << fd;
> >
> > +	if (arg == nullptr)
> > +		return -EFAULT;
> > +
> >  	int ret = lock(fd);
> >  	if (ret < 0)
> >  		return ret;
>
> --
> Regards,
>
> Laurent Pinchart
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