Re: [PATCH v3 0/4] Add seccomp notifier ioctl that enables adding fds

Sargun Dhillon
2020-06-03T23:57:40Z

On Wed, Jun 3, 2020 at 4:42 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Tue, Jun 02, 2020 at 06:10:40PM -0700, Sargun Dhillon wrote:
> > Sargun Dhillon (4):
> > fs, net: Standardize on file_receive helper to move fds across
> > processes
> > pid: Use file_receive helper to copy FDs
>
> The fixes (that should add open-coded cgroups stuff) should be separate
> patches so they can be backported.
Patch 1/4, and 2/4 are separated so they can be backported. Patch 1 should
go into long term, and patch 2 should land in stable.

Do you see anything in 1/4, and 2/4 that shouldn't be there?

>
> The helper doesn't take the __user pointer I thought we'd agreed it
> should to avoid changing any SCM_RIGHTS behaviors?
>
It doesn't change the SCM_RIGHTS behaviour because it continues
to have the logic which allocates the file descriptor outside of the
helper.
1. Allocate FD (this happens in scm.c)
2. Copy FD # to userspace (this happens in scm.c)
3. Receive FD (this happens in the new helper)

> > seccomp: Introduce addfd ioctl to seccomp user notifier
> > selftests/seccomp: Test SECCOMP_IOCTL_NOTIF_ADDFD
>
> Otherwise, yeah, this should be good.
>
> --
> Kees Cook