Re: [PATCH v22 08/12] landlock: Add syscall implementations

[Jann Horn]

On Thu, Oct 29, 2020 at 12:30 PM Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
> On 29/10/2020 02:06, Jann Horn wrote:
> > On Tue, Oct 27, 2020 at 9:04 PM Mickaël Salaün <mic@xxxxxxxxxxx> wrote:
> >> These 3 system calls are designed to be used by unprivileged processes
> >> to sandbox themselves:
[...]
> >> +       /*
> >> +        * Similar checks as for seccomp(2), except that an -EPERM may be
> >> +        * returned.
> >> +        */
> >> +       if (!task_no_new_privs(current)) {
> >> +               err = security_capable(current_cred(), current_user_ns(),
> >> +                               CAP_SYS_ADMIN, CAP_OPT_NOAUDIT);
> >
> > I think this should be ns_capable_noaudit(current_user_ns(), CAP_SYS_ADMIN)?
>
> Right. The main difference is that ns_capable*() set PF_SUPERPRIV in
> current->flags. I guess seccomp should use ns_capable_noaudit() as well?

Yeah. That seccomp code is from commit e2cfabdfd0756, with commit date
in April 2012, while ns_capable_noaudit() was introduced in commit
98f368e9e263, with commit date in June 2016; the seccomp code predates
the availability of that API.

Do you want to send a patch to Kees for that, or should I?