From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 769CEC43382 for ; Thu, 27 Sep 2018 22:50:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28E8321722 for ; Thu, 27 Sep 2018 22:50:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=tycho-ws.20150623.gappssmtp.com header.i=@tycho-ws.20150623.gappssmtp.com header.b="d1ySdirD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 28E8321722 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=tycho.ws Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728554AbeI1FKi (ORCPT ); Fri, 28 Sep 2018 01:10:38 -0400 Received: from mail-ot1-f67.google.com ([209.85.210.67]:35860 "EHLO mail-ot1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726337AbeI1FKh (ORCPT ); Fri, 28 Sep 2018 01:10:37 -0400 Received: by mail-ot1-f67.google.com with SMTP id c18-v6so4234673otm.3 for ; Thu, 27 Sep 2018 15:50:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tycho-ws.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=/zJfM9GE6AKjvgquwPQ/0ceLGlSpIPHhNQftyRiruSY=; b=d1ySdirD0UIEDejUae0JedohfvjFTLcWz8PSf3ojtmutnqL9V1sZztbn8EbIEmlx0g TsP1CCbs6QVe8F4JjHZtKfuQEWo9JlaMd/kGimTU2a7AVBCMUzBSqX19u3wWx5XKtoaw rGBH7DsDgEB9apYDtygmMcSOSxifcz0X9QXZdBaCxsM9dBoIVUSODMmXg25bLEaOGgVq Sn1R5KOdDyqQgWYswnsDTkjLLyJ3eyUnpE6CxiMXMmKqfQkNdSVxkfxHJnGI1fCmw6kf 6i4EXzQvlBQnH1uq8OMkra7KJeYg59Luf+IMaSQsWNpXW4ZvKhAqzHr6nOsKXgGfF9lK VtNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=/zJfM9GE6AKjvgquwPQ/0ceLGlSpIPHhNQftyRiruSY=; b=rs4sDw1SfH0/8pITfoBY2Kn9ZGgKsgKwa3B8KWEnX9kNPCM8q65ksKXHThOzv1gQFS +5i1427PCqhqoKJTo4qXXCSACCLbhaGjX5uiHrROSmpFcX6b/GAj2RF53fNIz41i83Ju X2FQRZ7SwEpoinZP+MC/HBTSjSMsFlSuQyJ+3OzH8R1VyfVX84ShbB/M5zSJw21g+k/G opZEg2sgwJIEIzBEh8oxRuZBWyx2fWQ+T2aggiED9D4A39YdwxOspTbjRtIHo/jjeD4L MFcbOf+Qz98FE9k3P+GlttSVecMEE1HxFaBXR3CeWd/4qYg8P5N+2eNkcL12RvNmfPA5 VPQA== X-Gm-Message-State: ABuFfoj24iKpnZ6BdE2tcAw85fIFqeQiNMxti5BXydmWwMyty/kkkz3f 5I+/tttwMsAr+teeD1F6BQat0g== X-Google-Smtp-Source: ACcGV61Z7eqb3DXrF4G4fdurBLXNnoik4YijAh5Yh+Fjy2/KCM3zNsRZ/5rK6VHnCmsTfNKQWQr50Q== X-Received: by 2002:a9d:7:: with SMTP id 7-v6mr7825517ota.312.1538088600311; Thu, 27 Sep 2018 15:50:00 -0700 (PDT) Received: from cisco.cisco.com ([128.107.241.175]) by smtp.gmail.com with ESMTPSA id n2-v6sm1064743otl.15.2018.09.27.15.49.57 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 27 Sep 2018 15:49:59 -0700 (PDT) Date: Thu, 27 Sep 2018 16:49:51 -0600 From: Tycho Andersen To: Jann Horn Cc: Kees Cook , kernel list , containers@lists.linux-foundation.org, Linux API , Andy Lutomirski , Oleg Nesterov , "Eric W. Biederman" , "Serge E. Hallyn" , Christian Brauner , Tyler Hicks , suda.akihiro@lab.ntt.co.jp, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v7 5/6] seccomp: add a way to pass FDs via a notification fd Message-ID: <20180927224951.GG15491@cisco.cisco.com> References: <20180927151119.9989-1-tycho@tycho.ws> <20180927151119.9989-6-tycho@tycho.ws> <20180927221408.GD15491@cisco.cisco.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 28, 2018 at 12:17:07AM +0200, Jann Horn wrote: > On Fri, Sep 28, 2018 at 12:14 AM Tycho Andersen wrote: > > On Thu, Sep 27, 2018 at 09:28:07PM +0200, Jann Horn wrote: > > > On Thu, Sep 27, 2018 at 5:11 PM Tycho Andersen wrote: > > > > This patch adds a way to insert FDs into the tracee's process (also > > > > close/overwrite fds for the tracee). This functionality is necessary to > > > > mock things like socketpair() or dup2() or similar, but since it depends on > > > > external (vfs) patches, I've left it as a separate patch as before so the > > > > core functionality can still be merged while we argue about this. Except > > > > this time it doesn't add any ugliness to the API :) > > > [...] > > > > +static long seccomp_notify_put_fd(struct seccomp_filter *filter, > > > > + unsigned long arg) > > > > +{ > > > > + struct seccomp_notif_put_fd req; > > > > + void __user *buf = (void __user *)arg; > > > > + struct seccomp_knotif *knotif = NULL; > > > > + long ret; > > > > + > > > > + if (copy_from_user(&req, buf, sizeof(req))) > > > > + return -EFAULT; > > > > + > > > > + if (req.fd < 0 && req.to_replace < 0) > > > > + return -EINVAL; > > > > + > > > > + ret = mutex_lock_interruptible(&filter->notify_lock); > > > > + if (ret < 0) > > > > + return ret; > > > > + > > > > + ret = -ENOENT; > > > > + list_for_each_entry(knotif, &filter->notif->notifications, list) { > > > > + struct file *file = NULL; > > > > + > > > > + if (knotif->id != req.id) > > > > + continue; > > > > > > Are you intentionally permitting non-SENT states here? It shouldn't > > > make a big difference, but I think it'd be nice to at least block the > > > use of notifications in SECCOMP_NOTIFY_REPLIED state. > > > > Agreed, I'll block everything besides REPLIED. > > Do you mean SENT? In REPLIED state, seccomp_notify_put_fd() > is racy because the target task is in the process of waking up, right? Yes, sorry, I mean SENT. Tycho