From: Mike Rapoport <rppt@linux.ibm.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>, Jann Horn <jannh@google.com>,
Daniel Colascione <dancol@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Nick Kralevich <nnk@google.com>, Nosh Minwalla <nosh@google.com>,
Tim Murray <timmurray@google.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Linux API <linux-api@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/7] Add a UFFD_SECURE flag to the userfaultfd API.
Date: Fri, 25 Oct 2019 23:12:43 +0300 [thread overview]
Message-ID: <20191025201242.GA8710@linux.ibm.com> (raw)
In-Reply-To: <20191024151054.GJ9902@redhat.com>
Hi,
On Thu, Oct 24, 2019 at 11:10:54AM -0400, Andrea Arcangeli wrote:
> Hello,
>
> On Thu, Oct 24, 2019 at 12:02:59PM +0300, Mike Rapoport wrote:
> > That's no the reason that UFFD_FEATURE_EVENT_FORK does not show up in
> > Debian code search, CRIU simply is not there. Debian packages CRIU only in
> > experimental and I believe that's not indexed by the code search.
> >
> > As for the limitations, the races were fixed, I just forgot to update the
> > wiki. As for the supported memory types and COW pages, these only affect
> > efficiency of post-copy, but not the correctness.
>
> That's what I was hoping for. If the wiki information is stale and
> there are no races it is totally plausible that it's being actively
> used in production so we need to fix the kernel bug. I was just
> checking because I wasn't sure anymore of the status after I read the
> wiki.
>
> If the CRIU initialization code that issues the uffd syscall runs as
> global root the ABI breaking permission check from Andy sounds the
> simplest for a short term fix, because it will be unnoticed by any
> production usage with CIRU --lazy-pages.
In general, criu can run as non-root, but such use of criu has limitations,
so allowing criu --lazy-pages only for root sounds reasonable as a short
term solution.
> Then later we could add a UFFD_FEATURE_EVENT_FORK2 that will not
> require root permission.
Agree.
> Thanks,
> Andrea
>
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2019-10-25 20:12 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-12 19:15 [PATCH 0/7] Harden userfaultfd Daniel Colascione
2019-10-12 19:15 ` [PATCH 1/7] Add a new flags-accepting interface for anonymous inodes Daniel Colascione
2019-10-14 4:26 ` kbuild test robot
2019-10-14 4:26 ` kbuild test robot
2019-10-14 4:26 ` kbuild test robot
2019-10-14 15:38 ` Jann Horn
2019-10-14 18:15 ` Daniel Colascione
2019-10-14 18:30 ` Jann Horn
2019-10-15 8:08 ` Christoph Hellwig
2019-10-12 19:15 ` [PATCH 2/7] Add a concept of a "secure" anonymous file Daniel Colascione
2019-10-14 3:01 ` kbuild test robot
2019-10-14 3:01 ` kbuild test robot
2019-10-14 3:01 ` kbuild test robot
2019-10-15 8:08 ` Christoph Hellwig
2019-10-12 19:15 ` [PATCH 3/7] Add a UFFD_SECURE flag to the userfaultfd API Daniel Colascione
2019-10-12 23:10 ` Andy Lutomirski
2019-10-13 0:51 ` Daniel Colascione
2019-10-13 1:14 ` Andy Lutomirski
2019-10-13 1:38 ` Daniel Colascione
2019-10-14 16:04 ` Jann Horn
2019-10-23 19:09 ` Andrea Arcangeli
2019-10-23 19:21 ` Andy Lutomirski
2019-10-23 21:16 ` Andrea Arcangeli
2019-10-23 21:25 ` Andy Lutomirski
2019-10-23 22:41 ` Andrea Arcangeli
2019-10-23 23:01 ` Andy Lutomirski
2019-10-23 23:27 ` Andrea Arcangeli
2019-10-23 20:05 ` Daniel Colascione
2019-10-24 0:23 ` Andrea Arcangeli
2019-10-23 20:15 ` Linus Torvalds
2019-10-24 9:02 ` Mike Rapoport
2019-10-24 15:10 ` Andrea Arcangeli
2019-10-25 20:12 ` Mike Rapoport [this message]
2019-10-22 21:27 ` Daniel Colascione
2019-10-23 4:11 ` Andy Lutomirski
2019-10-23 7:29 ` Cyrill Gorcunov
2019-10-23 12:43 ` Mike Rapoport
2019-10-23 17:13 ` Andy Lutomirski
2019-10-12 19:15 ` [PATCH 4/7] Teach SELinux about a new userfaultfd class Daniel Colascione
2019-10-12 23:08 ` Andy Lutomirski
2019-10-13 0:11 ` Daniel Colascione
2019-10-13 0:46 ` Andy Lutomirski
2019-10-12 19:16 ` [PATCH 5/7] Let userfaultfd opt out of handling kernel-mode faults Daniel Colascione
2019-10-12 19:16 ` [PATCH 6/7] Allow users to require UFFD_SECURE Daniel Colascione
2019-10-12 23:12 ` Andy Lutomirski
2019-10-12 19:16 ` [PATCH 7/7] Add a new sysctl for limiting userfaultfd to user mode faults Daniel Colascione
2019-10-16 0:02 ` [PATCH 0/7] Harden userfaultfd James Morris
2019-11-15 15:09 ` Stephen Smalley
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