Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752103AbaF0R1U (ORCPT ); Fri, 27 Jun 2014 13:27:20 -0400 Received: from mail-ob0-f177.google.com ([209.85.214.177]:43482 "EHLO mail-ob0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751953AbaF0R1G (ORCPT ); Fri, 27 Jun 2014 13:27:06 -0400 MIME-Version: 1.0 In-Reply-To: <20140625180705.GB18185@redhat.com> References: <1403642893-23107-1-git-send-email-keescook@chromium.org> <1403642893-23107-4-git-send-email-keescook@chromium.org> <20140625180705.GB18185@redhat.com> Date: Fri, 27 Jun 2014 10:27:05 -0700 X-Google-Sender-Auth: 1BbBV6EEfSsvkxRb2BCJ4_fZvH4 Message-ID: Subject: Re: [PATCH v8 3/9] seccomp: introduce writer locking From: Kees Cook To: Oleg Nesterov Cc: LKML , Andy Lutomirski , "Michael Kerrisk (man-pages)" , Alexei Starovoitov , Andrew Morton , Daniel Borkmann , Will Drewry , Julien Tinnes , David Drysdale , Linux API , "x86@kernel.org" , "linux-arm-kernel@lists.infradead.org" , linux-mips@linux-mips.org, linux-arch , linux-security-module Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 25, 2014 at 11:07 AM, Oleg Nesterov wrote: > On 06/24, Kees Cook wrote: >> >> +static void copy_seccomp(struct task_struct *p) >> +{ >> +#ifdef CONFIG_SECCOMP >> + /* >> + * Must be called with sighand->lock held, which is common to >> + * all threads in the group. Regardless, nothing special is >> + * needed for the child since it is not yet in the tasklist. >> + */ >> + BUG_ON(!spin_is_locked(¤t->sighand->siglock)); >> + >> + get_seccomp_filter(current); >> + p->seccomp = current->seccomp; >> + >> + if (p->seccomp.mode != SECCOMP_MODE_DISABLED) >> + set_tsk_thread_flag(p, TIF_SECCOMP); >> +#endif >> +} > > Wait. But what about no_new_privs? We should copy it as well... > > Perhaps this helper should be updated a bit and moved into seccomp.c so > that seccomp_sync_threads() could use it too. Ah! Yes. I had been thinking it had been copied during the task_struct duplication, but that would have been before holding sighand->lock, so it needs explicit recopying. Thanks! -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/