From: "Serge E. Hallyn" <serge@hallyn.com>
To: Will Drewry <wad@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org, kees.cook@canonical.com,
eparis@redhat.com, agl@chromium.org, mingo@elte.hu,
jmorris@namei.org, Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Michal Marek <mmarek@suse.cz>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Jiri Slaby <jslaby@suse.cz>, David Howells <dhowells@redhat.com>
Subject: Re: [PATCH 3/7] seccomp_filter: Enable ftrace-based system call filtering
Date: Thu, 28 Apr 2011 11:20:15 -0500 [thread overview]
Message-ID: <20110428162015.GA1927@hallyn.com> (raw)
In-Reply-To: <BANLkTikrXHvLhFH0A2LbpZ7sGBi0iOH+gQ@mail.gmail.com>
Quoting Will Drewry (wad@chromium.org):
> >> void __secure_computing(int this_syscall)
> >> {
> >> - int mode = current->seccomp.mode;
> >> + int mode = -1;
> >> int * syscall;
> >> -
> >> + /* Do we need an RCU read lock to access current's state? */
> >
> > I'm actually confused to why you are using RCU. What are you protecting.
> > Currently, I see the state is always accessed from current->seccomp. But
> > current should not be fighting with itself.
> >
> > Maybe I'm missing something.
>
> I'm sure it's me that's missing something. I believe the seccomp
> pointer can be accessed from:
> - current
> - via /proc/<pid>/seccomp_filter (read-only)
>
> Given those cases, would it make sense to ditch the RCU interface for it?
ISTM you need them to protect the reader.
-serge
next prev parent reply other threads:[~2011-04-28 16:20 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-28 3:08 [PATCH 2/7] tracing: split out syscall_trace_enter construction Will Drewry
2011-04-28 3:08 ` [PATCH 3/7] seccomp_filter: Enable ftrace-based system call filtering Will Drewry
2011-04-28 13:50 ` Steven Rostedt
2011-04-28 15:30 ` Will Drewry
2011-04-28 16:20 ` Serge E. Hallyn [this message]
2011-04-28 16:56 ` Steven Rostedt
2011-04-28 18:02 ` Will Drewry
2011-04-28 14:29 ` Frederic Weisbecker
2011-04-28 15:15 ` Will Drewry
2011-04-28 15:57 ` Frederic Weisbecker
2011-04-28 16:05 ` Will Drewry
2011-04-28 15:12 ` Frederic Weisbecker
2011-04-28 15:20 ` Frederic Weisbecker
2011-04-28 15:29 ` Will Drewry
2011-04-28 16:13 ` Frederic Weisbecker
2011-04-28 16:48 ` Will Drewry
2011-04-28 17:36 ` Frederic Weisbecker
2011-04-28 18:21 ` Will Drewry
2011-04-28 16:28 ` Steven Rostedt
2011-04-28 16:53 ` Will Drewry
2011-04-28 16:55 ` Serge E. Hallyn
2011-04-28 17:16 ` Steven Rostedt
2011-04-28 17:39 ` Serge E. Hallyn
2011-04-28 18:01 ` Will Drewry
2011-04-28 18:21 ` Steven Rostedt
2011-04-28 18:34 ` Will Drewry
2011-04-28 18:54 ` Serge E. Hallyn
2011-04-28 19:07 ` Steven Rostedt
2011-04-28 19:06 ` Steven Rostedt
2011-04-28 18:51 ` Serge E. Hallyn
2011-05-03 8:39 ` Avi Kivity
2011-04-28 3:08 ` [PATCH 4/7] seccomp_filter: add process state reporting Will Drewry
2011-04-28 3:21 ` KOSAKI Motohiro
2011-04-28 3:24 ` Will Drewry
2011-04-28 3:40 ` Al Viro
2011-04-28 3:43 ` Will Drewry
2011-04-28 22:54 ` James Morris
2011-05-02 10:08 ` Will Drewry
2011-05-12 3:04 ` [PATCH 4/5] v2 " Will Drewry
2011-04-28 3:08 ` [PATCH 5/7] seccomp_filter: Document what seccomp_filter is and how it works Will Drewry
2011-04-28 7:06 ` Ingo Molnar
2011-04-28 14:56 ` Eric Paris
2011-04-28 18:37 ` Will Drewry
2011-04-29 13:18 ` Frederic Weisbecker
2011-04-29 16:13 ` Will Drewry
2011-05-03 1:29 ` Frederic Weisbecker
2011-05-03 1:47 ` Frederic Weisbecker
2011-05-04 9:15 ` Will Drewry
2011-05-04 9:29 ` Will Drewry
2011-05-04 17:52 ` Frederic Weisbecker
2011-05-04 18:23 ` Steven Rostedt
2011-05-04 18:30 ` Frederic Weisbecker
2011-05-04 18:46 ` Steven Rostedt
2011-05-05 9:21 ` Will Drewry
2011-05-05 13:14 ` Serge E. Hallyn
2011-05-12 3:20 ` Will Drewry
2011-05-06 11:53 ` Steven Rostedt
2011-05-06 13:35 ` Eric Paris
2011-05-07 1:58 ` Will Drewry
2011-05-12 3:04 ` [PATCH 5/5] v2 " Will Drewry
2011-05-06 16:30 ` [PATCH 5/7] " Eric Paris
2011-05-07 2:11 ` Will Drewry
2011-05-04 12:16 ` Steven Rostedt
2011-05-04 15:54 ` Eric Paris
2011-05-04 16:06 ` Steven Rostedt
2011-05-04 16:22 ` Eric Paris
2011-05-04 16:39 ` Steven Rostedt
2011-05-04 18:02 ` Eric Paris
2011-05-04 17:03 ` Frederic Weisbecker
2011-05-04 17:55 ` Eric Paris
2011-04-28 17:43 ` Serge E. Hallyn
2011-04-28 15:46 ` Randy Dunlap
2011-04-28 18:23 ` Will Drewry
2011-04-28 3:08 ` [PATCH 6/7] include/linux/syscalls.h: add __ layer of macros with return types Will Drewry
2011-04-28 3:08 ` [PATCH 7/7] arch/x86: hook int returning system calls Will Drewry
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