Messages in this thread | | | Date | Sat, 30 May 2020 09:09:29 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 2/3] seccomp: Introduce addfd ioctl to seccomp user notifier |
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On Sat, May 30, 2020 at 03:58:27PM +0200, Christian Brauner wrote: > On Sat, May 30, 2020 at 05:17:24AM +0200, Jann Horn wrote: > > On Sat, May 30, 2020 at 4:43 AM Kees Cook <keescook@chromium.org> wrote: > > > I mean, yes, that's certainly better, but it just seems a shame that > > > everyone has to do the get_unused/put_unused dance just because of how > > > SCM_RIGHTS does this weird put_user() in the middle. > > > > > > Can anyone clarify the expected failure mode from SCM_RIGHTS? Can we > > > move the put_user() after instead? > > > > Honestly, I think trying to remove file descriptors and such after > > -EFAULT is a waste of time. If userspace runs into -EFAULT, userspace > [...] > > There's really no point in trying to save a broken scm message imho.
Right -- my concern is about stuffing a fd into a process without it knowing (this is likely an overly paranoid concern, given that if the process is getting EFAULT at the end of a list of fds, all the prior ones will be installed too..)
-- Kees Cook
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