Re: [PATCH v3 1/4] fs, net: Standardize on file_receive helper to move fds across processes

Kees Cook
2020-06-11T03:02:58Z

On Wed, Jun 10, 2020 at 08:48:45AM +0000, David Laight wrote:
> From: Sargun Dhillon
> > Sent: 10 June 2020 09:13
> In essence the 'copy_to_user' is done by the wrapper code.
> The code filling in the CMSG buffer can be considered to be
> writing a kernel buffer.
>
> IIRC other kernels (eg NetBSD) do the copies for ioctl() requests
> in the ioctl syscall wrapper.
> The IOW/IOR/IOWR flags have to be right.

Yeah, this seems like it'd make a lot more sense (and would have easily
caught the IOR/IOW issue pointed out later in the thread). I wonder how
insane it would be to try to fix that globally in the kernel...

--
Kees Cook