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

[Laurent Pinchart]

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() ?

> ---
>  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