From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: David Howells <dhowells@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Miklos Szeredi <mszeredi@suse.cz>,
syzkaller <syzkaller@googlegroups.com>,
Kostya Serebryany <kcc@google.com>,
Alexander Potapenko <glider@google.com>,
Eric Dumazet <edumazet@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
Robert Swiecki <swiecki@google.com>,
Kees Cook <keescook@google.com>
Subject: Re: fs: sandboxed process brings host down
Date: Fri, 22 Jan 2016 21:21:57 +0000 [thread overview]
Message-ID: <20160122212157.GG17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CACT4Y+aRgUi9CxMOi7GO3eU3aDZhOkpY9gbO1Qmt6=bAjLXTXQ@mail.gmail.com>
On Fri, Jan 22, 2016 at 10:06:14PM +0100, Dmitry Vyukov wrote:
> Hello,
>
> While running syzkaller fuzzer I hit the following problem. Supervisor
> process sandboxes worker processes that do random activities with
> CLONE_NEWUSER | CLONE_NEWNS | CLONE_NEWPID | CLONE_NEWUTS |
> CLONE_NEWNET | CLONE_NEWIPC | CLONE_IO, setrlimit, chroot, etc.
> Because of that worker process gains ability to bring whole machine
> down (does not happen without the sandbox).
AFAICS, what you are doing is essentially mount --rbind / / in infinite
loop in luserns. Which ends up eating all memory. There's any number
of ways to do the same. We can play whack-a-mole with them until the
kernel is completely ossified with accounting code of different sorts.
Or one can disable userns and be done with that.
next prev parent reply other threads:[~2016-01-22 21:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 21:06 fs: sandboxed process brings host down Dmitry Vyukov
2016-01-22 21:21 ` Al Viro [this message]
2016-01-22 21:38 ` Dmitry Vyukov
2016-01-22 21:55 ` Al Viro
2016-01-22 22:32 ` Robert Święcki
2016-01-22 21:46 ` Kees Cook
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