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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 EF242C54E8F for ; Tue, 12 May 2020 00:12:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD9F620714 for ; Tue, 12 May 2020 00:12:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WTnl9KRJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728366AbgELAMR (ORCPT ); Mon, 11 May 2020 20:12:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1728357AbgELAMO (ORCPT ); Mon, 11 May 2020 20:12:14 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6FA7EC061A0E for ; Mon, 11 May 2020 17:12:13 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id o11so4360233qve.21 for ; Mon, 11 May 2020 17:12:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eMaf4xc8D2BTATY0do2dFv+4nFGdf/qS8KpJ23BpHA0=; b=WTnl9KRJI4BwzNnZvPbjEij1Gyw+15IRSe+l0FJ4S+5s+XJIWK78bOeswKixQoY+ns O6wXSLSIxB78mJmAfk7OuyqntA8WQVWnDj2DUWd5wKLRjvEbSVGmOvrSrjFYiE/BV1uk voa+EQAClkeYRlTT4viM5mPtGg7uU8SpXdrpmHxRrveN0lCyXXwqN23t+tHOQWl+cXeE DYAXRSmZSGzklhJAM997GHYslerGdc0Pv1dSqQbuXqXnlHN4OY+p65gusAJKVS8R+ugv nJNKo1ZA3/w/p5z2H1P6Z3Ip8+dzTSaCYdym+DAsT0gpcZNkn0m+c5/NqCFVLlZeQztC ac5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eMaf4xc8D2BTATY0do2dFv+4nFGdf/qS8KpJ23BpHA0=; b=TWitJHzCPyRwY7y/sCqmy5EhlwEAWo+D72BQjxXpKwAxwTSDt+EbaYZDQBlWRv8wIq QcUqvjzv9KYSky3fOisqvw12mI42Zjo8Apz5BFoqLjghrGoIIcryYCTko0x9eriHtx14 hrnXQp9q4XgOdTidZ0t3LZFiQSiErO8NneZh6L3fOVwkMZXl/6fDMrMSd1Q2CnKpDidb dSSbekmYAQ1QXGwouWBS2XSb3N69+3lRhFHBAx7HE70IgR1Q8ijH3Ue3GgyKOMfx484E v9fA1t3sENcOfhJvlF5G6vYmJcPv6DaGNiQk0T3zobx6jsGfuazYePcs1yyhpF4RPeCi fwnQ== X-Gm-Message-State: AGi0PuY1Eh0FCh5jJMj8x4jHLbQnDDf5rAKbCTgetSg0OvclDRFJx6Bn 3FBjexCuV4myHoUmr/cYAOEFAOc= X-Google-Smtp-Source: APiQypIOM3v0IvzYlBLoCseN6fNtA0BGMXPAe7n/8UDiFV3tUxZn65Tq/kITIfPvNITpZRmCY34ZI/U= X-Received: by 2002:ad4:42c7:: with SMTP id f7mr18867291qvr.127.1589242332555; Mon, 11 May 2020 17:12:12 -0700 (PDT) Date: Mon, 11 May 2020 17:12:10 -0700 In-Reply-To: <20200508215340.41921-3-alexei.starovoitov@gmail.com> Message-Id: <20200512001210.GA235661@google.com> Mime-Version: 1.0 References: <20200508215340.41921-1-alexei.starovoitov@gmail.com> <20200508215340.41921-3-alexei.starovoitov@gmail.com> Subject: Re: [PATCH v5 bpf-next 2/3] bpf: implement CAP_BPF From: sdf@google.com To: Alexei Starovoitov Cc: davem@davemloft.net, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com, linux-security-module@vger.kernel.org, acme@redhat.com, jamorris@linux.microsoft.com, jannh@google.com, kpsingh@google.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 05/08, Alexei Starovoitov wrote: > From: Alexei Starovoitov [..] > @@ -3932,7 +3977,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr > __user *, uattr, unsigned int, siz > union bpf_attr attr; > int err; > - if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN)) > + if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) > return -EPERM; This is awesome, thanks for reviving the effort! One question I have about this particular snippet: Does it make sense to drop bpf_capable checks for the operations that work on a provided fd? The use-case I have in mind is as follows: * privileged (CAP_BPF) process loads the programs/maps and pins them at some known location * unprivileged process opens up those pins and does the following: * prepares the maps (and will later on read them) * does SO_ATTACH_BPF/SO_ATTACH_REUSEPORT_EBPF which afaik don't require any capabilities This essentially pushes some of the permission checks into a fs layer. So whoever has a file descriptor (via unix sock or open) can do BPF operations on the object that represents it. Thoughts? Am I missing something important?