From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754983Ab2B0TrY (ORCPT ); Mon, 27 Feb 2012 14:47:24 -0500 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:64965 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753965Ab2B0TrW convert rfc822-to-8bit (ORCPT ); Mon, 27 Feb 2012 14:47:22 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of wad@chromium.org designates 10.112.25.8 as permitted sender) smtp.mail=wad@chromium.org; dkim=pass header.i=wad@chromium.org MIME-Version: 1.0 In-Reply-To: <20120227175407.GD10608@redhat.com> References: <1330140111-17201-1-git-send-email-wad@chromium.org> <1330140111-17201-10-git-send-email-wad@chromium.org> <20120227175407.GD10608@redhat.com> Date: Mon, 27 Feb 2012 13:47:17 -0600 Message-ID: Subject: Re: [PATCH v11 10/12] ptrace,seccomp: Add PTRACE_SECCOMP support From: Will Drewry To: Oleg Nesterov Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com, netdev@vger.kernel.org, x86@kernel.org, arnd@arndb.de, davem@davemloft.net, hpa@zytor.com, mingo@redhat.com, peterz@infradead.org, rdunlap@xenotime.net, mcgrathr@chromium.org, tglx@linutronix.de, luto@mit.edu, eparis@redhat.com, serge.hallyn@canonical.com, djm@mindrot.org, scarybeasts@gmail.com, indan@nul.nu, pmoore@redhat.com, akpm@linux-foundation.org, corbet@lwn.net, eric.dumazet@gmail.com, markus@chromium.org, coreyb@linux.vnet.ibm.com, keescook@chromium.org, Denys Vlasenko Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 27, 2012 at 11:54 AM, Oleg Nesterov wrote: > On 02/24, Will Drewry wrote: >> >>  arch/Kconfig              |    1 + >>  include/linux/ptrace.h    |    7 +++++-- >>  include/linux/seccomp.h   |    4 +++- >>  include/linux/tracehook.h |    6 ++++++ >>  kernel/ptrace.c           |    4 ++++ >>  kernel/seccomp.c          |   18 ++++++++++++++++++ > > FYI, this conflicts with the changes -mm tree. > > The changes in ptrace.* confict with Denys's > "ptrace: simplify PTRACE_foo constants and PTRACE_SETOPTIONS code" > > The change in tracehook.h conflicts with > "ptrace: the killed tracee should not enter the syscall" What's the best way to reconcile this in this day and age? I don't see these in kernel-next yet and I can't tell if there is a public -mm anywhere anymore. I can use the patches from the mailing list with Denys's changes if that'd be good enough. His cleanup will make this code even smaller! >> --- a/kernel/seccomp.c >> +++ b/kernel/seccomp.c >> @@ -354,6 +354,24 @@ int __secure_computing_int(int this_syscall) >>                       seccomp_send_sigsys(this_syscall, reason_code); >>                       return -1; >>               } >> +             case SECCOMP_RET_TRACE: { >> +                     int ret; >> +                     struct pt_regs *regs = task_pt_regs(current); >> +                     if (!(test_tsk_thread_flag(current, TIF_SYSCALL_TRACE)) || >> +                         !(current->ptrace & PT_TRACE_SECCOMP)) >> +                             return -1; >> +                     /* >> +                      * PT_TRACE_SECCOMP and seccomp.trace indicate whether >> +                      * tracehook_report_syscall_entry needs to signal the >> +                      * tracer.  This avoids race conditions in hand off and >> +                      * the requirement for TIF_SYSCALL_TRACE ensures that >> +                      * we are in the syscall slow path. >> +                      */ >> +                     current->seccomp.trace = 1; >> +                     ret = tracehook_report_syscall_entry(regs); >> +                     current->seccomp.trace = 0; >> +                     return ret; > > To be honest, this interface looks a bit strange to me... > > Once again, sorry if this was already discussed. But perhaps it would > be better to introduce PTRACE_EVENT_SECCOMP/PTRACE_O_SECCOMP instead? > > SECCOMP_RET_TRACE: could simply do ptrace_event(PTRACE_EVENT_SECCOMP) > unconditionaly. The tracer can set the option and do PTRACE_CONT if it > doesn't want the system call notifications. Works for me - this also gets rid of the extra int for brief state tracking. I'll switch over to that in the next rev. (More follow-ups to your reviews incoming too :). Thanks! will