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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 B581AC433ED for ; Tue, 11 May 2021 02:04:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88E0261622 for ; Tue, 11 May 2021 02:04:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230369AbhEKCFg (ORCPT ); Mon, 10 May 2021 22:05:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230362AbhEKCFf (ORCPT ); Mon, 10 May 2021 22:05:35 -0400 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67689C061574; Mon, 10 May 2021 19:04:30 -0700 (PDT) Received: by mail-pl1-x635.google.com with SMTP id b21so10096734plz.0; Mon, 10 May 2021 19:04:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=FAkiD+F8EGFEXXB2wgPC00kKeAj+LDr86VTrzLzFEYM=; b=p7LuOMJl2G+UZBBm+HhjKOVm76lvDOdsIWSW/cYMWu0z6PHY0hc3Aa7YV8IeMB5QLt H63sUljAjiHlcpDSs5mRDgommAXeT0/EcWhJBiNPYUtB5OG/K41MoIQo9mc2Z4/Iy42L xP173fp5Kwp68chlsCq8U50/RDPkbtyVPHUdWRaf2yyappL41w1hu6uNYoqHCihrjWQC ctxh9pNr8miGwCBJU6RNexFkka16l8R5Y21VYgT5GbL819/WAhXu4qnlAuSuOe2OIlsq JpVxj0e6Y9WOqfLUpIFlr/vCwMT20gIHL+9fUZdwCOXqszRdAqun2d01KhHCy8Htk0Im ognQ== 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; bh=FAkiD+F8EGFEXXB2wgPC00kKeAj+LDr86VTrzLzFEYM=; b=tBKhI/PXXPBfolI0ZqsOGBZdtWe8++KV8R0HM7Nc/9n/bYg9/zFURaw4xccBrqzr7O HWHbevxlZmXzTG8g44p4B93vWl11Kba49ZiHwOOtwMVz0AKI18CmYDdWpYEeR2e/JGlA iS0Qg3xUDzUZKKinWpQiFDBv1ESKXzukTwJMRF8U9hPHVNnERYiaFKKJmhwVKoPKwTL7 blDBo/upX9koXTFtd5kLUm2JuXE7N9w/grJJBT65dT4F311QLtKRfg+XGsigL2F96VcS /aVRAlDGpLZhVmvUR5e7D+C9wk9NxbXO6yF37f8m4hrnOo943xpF0H2rZ/z7IPMLCdk5 hSww== X-Gm-Message-State: AOAM530BzMsbqcSxzyjdQ2zLBsMVPgWirqrKpDuvVU4N+q0qlSyUKW7j Y3Ywt4CfbxvrxZYmXqjL9Rg= X-Google-Smtp-Source: ABdhPJzw0a/aGm3KCJqbO5MTeJ4kjEBU3TYGUedRrBJzPTq1fVBie3ydBnx4UvkFYdAMJIPNP49puA== X-Received: by 2002:a17:90b:2393:: with SMTP id mr19mr2284042pjb.24.1620698669870; Mon, 10 May 2021 19:04:29 -0700 (PDT) Received: from ast-mbp.dhcp.thefacebook.com ([2620:10d:c090:400::5:bba4]) by smtp.gmail.com with ESMTPSA id a18sm12541979pgg.51.2021.05.10.19.04.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 May 2021 19:04:29 -0700 (PDT) Date: Mon, 10 May 2021 19:04:25 -0700 From: Alexei Starovoitov To: YiFei Zhu Cc: containers@lists.linux.dev, bpf@vger.kernel.org, YiFei Zhu , linux-security-module@vger.kernel.org, Alexei Starovoitov , Andrea Arcangeli , Andy Lutomirski , Austin Kuo , Claudio Canella , Daniel Borkmann , Daniel Gruss , Dimitrios Skarlatos , Giuseppe Scrivano , Hubertus Franke , Jann Horn , Jinghao Jia , Josep Torrellas , Kees Cook , Sargun Dhillon , Tianyin Xu , Tobin Feldman-Fitzthum , Tom Hromatka , Will Drewry Subject: Re: [RFC PATCH bpf-next seccomp 10/12] seccomp-ebpf: Add ability to read user memory Message-ID: <20210511020425.54nygajvrpxqnfsh@ast-mbp.dhcp.thefacebook.com> References: <53db70ed544928d227df7e3f3a1f8c53e3665c65.1620499942.git.yifeifz2@illinois.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53db70ed544928d227df7e3f3a1f8c53e3665c65.1620499942.git.yifeifz2@illinois.edu> Precedence: bulk List-ID: On Mon, May 10, 2021 at 12:22:47PM -0500, YiFei Zhu wrote: > > +BPF_CALL_3(bpf_probe_read_user_dumpable, void *, dst, u32, size, > + const void __user *, unsafe_ptr) > +{ > + int ret = -EPERM; > + > + if (get_dumpable(current->mm)) > + ret = copy_from_user_nofault(dst, unsafe_ptr, size); Could you explain a bit more how dumpable flag makes it safe for unpriv? The unpriv prog is attached to the children tasks only, right? and dumpable gets cleared if euid changes?