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From: Oleg Nesterov <oleg@redhat.com>
To: Will Drewry <wad@chromium.org>
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 <dvlasenk@redhat.com>
Subject: Re: [PATCH v11 10/12] ptrace,seccomp: Add PTRACE_SECCOMP support
Date: Wed, 29 Feb 2012 17:14:37 +0100	[thread overview]
Message-ID: <20120229161437.GA3078@redhat.com> (raw)
In-Reply-To: <CABqD9hZ3apFGi+BmX5UNgz=NJUbTigj6acDKG=wu9rrL0wN1Ww@mail.gmail.com>

On 02/28, Will Drewry wrote:
>
> On Tue, Feb 28, 2012 at 11:04 AM, Will Drewry <wad@chromium.org> wrote:
> > On Tue, Feb 28, 2012 at 10:43 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> >>
> >> Great. In this case this patch becomes really trivial. Just 2 defines
> >> in ptrace.h and the unconditional ptrace_event() under SECCOMP_RET_TRACE.
>
> hrm the only snag is that I can't then rely on TIF_SYSCALL_TRACE to
> ensure seccomp is in the slow-path.  Right now, on x86, seccomp is
> slow-path, but it doesn't have to be to have the syscall and args.
> However, for ptrace to behavior properly, I believed it did need to be
> in the slow path.  If SECCOMP_RET_TRACE doesn't rely on
> PTRACE_SYSCALL, then it introduces a need for seccomp to always be in
> the slow path or to flag (somehow) when it needs slow path.

My understanding of this magic is very limited, and I'm afraid
I misunderstood... So please correct me.

But what is the problem? system_call checks _TIF_WORK_SYSCALL_ENTRY
which includes _TIF_SECCOMP | _TIF_SYSCALL_TRACE, and jumps to
tracesys which does SAVE_REST.

Anyway. secure_computing() is called by syscall_trace_enter() which
also calls tracehook_report_syscall_entry(). If SECCOMP_RET_TRACE
can't do ptrace_event() then why tracehook_report_syscall_entry() is
fine?

Oleg.


  reply	other threads:[~2012-02-29 16:23 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-25  3:21 [PATCH v11 01/12] sk_run_filter: add support for custom load_pointer Will Drewry
2012-02-25  3:21 ` [PATCH v11 02/12] net/compat.c,linux/filter.h: share compat_sock_fprog Will Drewry
2012-02-25  3:21 ` [PATCH v11 03/12] seccomp: kill the seccomp_t typedef Will Drewry
2012-02-25  3:21 ` [PATCH v11 04/12] asm/syscall.h: add syscall_get_arch Will Drewry
2012-02-25  3:21 ` [PATCH v11 05/12] arch/x86: add syscall_get_arch to syscall.h Will Drewry
2012-02-25  3:21 ` [PATCH v11 06/12] seccomp: add system call filtering using BPF Will Drewry
2012-02-26 20:28   ` Kees Cook
2012-02-27 16:23     ` Will Drewry
2012-02-27 16:49       ` Eric Paris
2012-02-27 18:55         ` Kees Cook
2012-02-27 19:25           ` Eric Paris
2012-02-27 20:00             ` Kees Cook
2012-02-27 20:34               ` Eric Paris
2012-02-27 20:49                 ` Kees Cook
2012-02-27 17:09   ` Oleg Nesterov
2012-02-27 19:54     ` Will Drewry
2012-02-27 20:15       ` Kees Cook
2012-02-28 15:13       ` Oleg Nesterov
2012-02-28 17:18         ` Will Drewry
2012-02-28  6:51   ` Indan Zupancic
2012-02-28  7:52     ` Kees Cook
2012-02-28 17:17     ` Will Drewry
2012-02-28 17:47       ` Markus Gutschke
2012-02-25  3:21 ` [PATCH v11 07/12] seccomp: add SECCOMP_RET_ERRNO Will Drewry
2012-02-25 20:20   ` Kees Cook
2012-02-27 16:22     ` Will Drewry
2012-02-27 17:11   ` Oleg Nesterov
2012-02-27 18:09     ` Kees Cook
2012-02-27 18:14       ` Oleg Nesterov
2012-02-27 18:35         ` Andrew Lutomirski
2012-02-27 19:14           ` Kees Cook
2012-02-27 19:54             ` Will Drewry
2012-02-25  3:21 ` [PATCH v11 08/12] signal, x86: add SIGSYS info and make it synchronous Will Drewry
2012-02-27 17:22   ` Oleg Nesterov
2012-02-27 17:34     ` Roland McGrath
2012-02-27 18:08       ` Oleg Nesterov
2012-02-27 20:24     ` Will Drewry
2012-02-28 16:02       ` Oleg Nesterov
2012-02-28 17:06         ` Will Drewry
2012-02-25  3:21 ` [PATCH v11 09/12] seccomp: Add SECCOMP_RET_TRAP Will Drewry
2012-02-25  3:21 ` [PATCH v11 10/12] ptrace,seccomp: Add PTRACE_SECCOMP support Will Drewry
2012-02-27 17:54   ` Oleg Nesterov
2012-02-27 19:47     ` Will Drewry
2012-02-28 16:43       ` Oleg Nesterov
2012-02-28 17:04         ` Will Drewry
2012-02-28 18:34           ` Will Drewry
2012-02-29 16:14             ` Oleg Nesterov [this message]
2012-02-29 16:33               ` Will Drewry
2012-02-29 17:09                 ` Oleg Nesterov
2012-02-29 17:41                   ` Roland McGrath
2012-02-29 17:51                     ` Will Drewry
2012-02-25  3:21 ` [PATCH v11 11/12] x86: Enable HAVE_ARCH_SECCOMP_FILTER Will Drewry
2012-02-25  3:21 ` [PATCH v11 12/12] Documentation: prctl/seccomp_filter Will Drewry

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