Date: Wed, 25 Jun 2014 20:07:05 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>,
        "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
        Alexei Starovoitov <ast@plumgrid.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Daniel Borkmann <dborkman@redhat.com>, Will Drewry <wad@chromium.org>,
        Julien Tinnes <jln@chromium.org>, David Drysdale <drysdale@google.com>,
        linux-api@vger.kernel.org, x86@kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org,
        linux-arch@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: Re: [PATCH v8 3/9] seccomp: introduce writer locking
Message-ID: <20140625180705.GB18185@redhat.com>
References: <1403642893-23107-1-git-send-email-keescook@chromium.org> <1403642893-23107-4-git-send-email-keescook@chromium.org>
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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(&current->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.

Oleg.

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