From: Oleg Nesterov <oleg@redhat.com>
To: Tycho Andersen <tycho@tycho.ws>
Cc: Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@amacapital.net>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Serge E . Hallyn" <serge@hallyn.com>,
Christian Brauner <christian@brauner.io>,
Tyler Hicks <tyhicks@canonical.com>,
Akihiro Suda <suda.akihiro@lab.ntt.co.jp>,
Aleksa Sarai <asarai@suse.de>,
linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org, linux-api@vger.kernel.org
Subject: Re: [PATCH v8 1/2] seccomp: add a return code to trap to userspace
Date: Fri, 30 Nov 2018 11:17:51 +0100 [thread overview]
Message-ID: <20181130101751.GA23670@redhat.com> (raw)
In-Reply-To: <20181129230826.GB4676@cisco>
On 11/29, Tycho Andersen wrote:
>
> /*
> * These should never be seen by user programs. To return one of ERESTART*
> * codes, signal_pending() MUST be set. Note that ptrace can observe these
> * at syscall exit tracing, but they will never be left for the debugged user
> * process to see.
> */
> #define ERESTARTSYS 512
>
> So basically, if you respond with -ERESTARTSYS with no signal pending, you'll
> leak it to userspace.
Yes,
> It turns out this is already possible with
> SECCOMP_RET_TRAP (and probably ptrace alone,
Yes,
> The question is: do we care?
I think we do not care, debugger can do anything with the tracee.
Oleg.
next prev parent reply other threads:[~2018-11-30 10:17 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-29 22:40 [PATCH v8 0/2] seccomp trap to userspace Tycho Andersen
2018-10-29 22:40 ` [PATCH v8 1/2] seccomp: add a return code to " Tycho Andersen
2018-10-30 14:32 ` Oleg Nesterov
2018-10-30 15:32 ` Tycho Andersen
2018-11-01 14:48 ` Oleg Nesterov
2018-11-01 20:33 ` Tycho Andersen
2018-11-02 11:29 ` Oleg Nesterov
2018-11-02 13:50 ` Tycho Andersen
2018-10-30 15:02 ` Oleg Nesterov
2018-10-30 15:54 ` Tycho Andersen
2018-10-30 16:27 ` Oleg Nesterov
2018-10-30 16:39 ` Oleg Nesterov
2018-10-30 17:21 ` Tycho Andersen
2018-10-30 21:32 ` Kees Cook
2018-10-31 13:04 ` Oleg Nesterov
2018-10-30 21:38 ` Kees Cook
2018-10-30 21:49 ` Kees Cook
2018-10-30 21:54 ` Tycho Andersen
2018-10-30 22:00 ` Kees Cook
2018-10-30 22:32 ` Tycho Andersen
2018-10-30 22:34 ` Kees Cook
2018-10-31 0:29 ` Tycho Andersen
2018-10-31 1:29 ` Kees Cook
2018-11-01 13:40 ` Oleg Nesterov
2018-11-01 19:56 ` Tycho Andersen
2018-11-02 10:02 ` Oleg Nesterov
2018-11-02 13:38 ` Tycho Andersen
2018-11-01 13:56 ` Oleg Nesterov
2018-11-01 19:58 ` Tycho Andersen
2018-11-29 23:08 ` Tycho Andersen
2018-11-30 10:17 ` Oleg Nesterov [this message]
2018-10-29 22:40 ` [PATCH v8 2/2] samples: add an example of seccomp user trap Tycho Andersen
2018-10-29 23:31 ` Serge E. Hallyn
2018-10-30 2:05 ` Tycho Andersen
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