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=-2.7 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, URIBL_BLOCKED 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 CD211C433ED for ; Thu, 1 Apr 2021 21:44:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A26B7610CE for ; Thu, 1 Apr 2021 21:44:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234867AbhDAVo2 (ORCPT ); Thu, 1 Apr 2021 17:44:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234502AbhDAVo2 (ORCPT ); Thu, 1 Apr 2021 17:44:28 -0400 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07A32C0613E6; Thu, 1 Apr 2021 14:44:28 -0700 (PDT) Received: by mail-lf1-x133.google.com with SMTP id b14so4904997lfv.8; Thu, 01 Apr 2021 14:44:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=p5UHqgEsaG4BovGbqPF81FuvYChe6c9272oCDYHdNkg=; b=eE8/j9uvnFhGf6BuQMC4WU7xwhoeyYJfwvaI7+4TNwgA8tl5PUc05hXZLGDMj5ftr2 Lr1atxW0tNcdBEtwONv02QzXVuPDR0wc1NEqgUwbK+fDrFqEkkyYLmv2HjqMz//doT7Q rmmiTEdCKSZctq5j0fXw2IvoUp5CTlUZNC3jXjEqgCyjbbmN/VdqT0JD4JSyFjSUcJ9i rK1rQBermHh/vGwx4Z+ntQbNcbR443P9bQpts2NLlvhGpq93WOiQeBaiwl10aTx90TwF 2Y+2nfUhL6AVYgsQc+lHuGINiUU0wvr2cQQ5lmaQ9l4UWYflto/TjTqokkzRmhA699jO lh2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=p5UHqgEsaG4BovGbqPF81FuvYChe6c9272oCDYHdNkg=; b=o7U1v85v1vFqZznqxXb6/kCtnF9GB4o8Es/SBo6HGBPpD1pyKmu4qUpdBBidUbe3ro lR/gUS3fXBDa/PXy9YWa0kj22bfFJrDGG1Xy9FZp9MrNho2sBoz3XpSGbBkGaB0zd/sm 1On57qt7vOLY1vEYh9GHyT0FR5D4Z3eE+3yyr96DWrUJ9BeQCB99IRiDfx/trWYDggFf lRhCESGJ1O3zCfocSAL0Y2cYh1zb85Y7aodEBSDhsNMJB+sN1QFu19ldKJO07svvTmPr uGAl0my+n2C9F/73QosTykRv7+5S6uknspIfVmwAysBy6NTWy6KUDi0gjLjFsR6YLim8 GC7w== X-Gm-Message-State: AOAM531LnfDp6cHW0PkgiEqIjdLRZqisCXImOljIbahi3Qnl0t6fjdq5 oWkEoUCTXlX3r2wXeQE8CGVRqljJaZjKO12aK9A= X-Google-Smtp-Source: ABdhPJx1Pvtv4tV9xeYq56fM/HgtZqpb5E1pcEg8D6OdsZRm+i/Yai4bpcat2Kb0U1ulEmUUcFpxE6U8EuGi3KJku9Q= X-Received: by 2002:a19:ed06:: with SMTP id y6mr6899997lfy.539.1617313466544; Thu, 01 Apr 2021 14:44:26 -0700 (PDT) MIME-Version: 1.0 References: <20210326160501.46234-1-lmb@cloudflare.com> In-Reply-To: From: Alexei Starovoitov Date: Thu, 1 Apr 2021 14:44:15 -0700 Message-ID: Subject: Re: [PATCH bpf v2 1/2] bpf: link: refuse non-O_RDWR flags in BPF_OBJ_GET To: Lorenz Bauer Cc: Alexei Starovoitov , Daniel Borkmann , kernel-team , Networking , bpf Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Mar 31, 2021 at 7:04 AM Lorenz Bauer wrote: > > On Fri, 26 Mar 2021 at 16:05, Lorenz Bauer wrote: > > > > Invoking BPF_OBJ_GET on a pinned bpf_link checks the path access > > permissions based on file_flags, but the returned fd ignores flags. > > This means that any user can acquire a "read-write" fd for a pinned > > link with mode 0664 by invoking BPF_OBJ_GET with BPF_F_RDONLY in > > file_flags. The fd can be used to invoke BPF_LINK_DETACH, etc. > > > > Fix this by refusing non-O_RDWR flags in BPF_OBJ_GET. This works > > because OBJ_GET by default returns a read write mapping and libbpf > > doesn't expose a way to override this behaviour for programs > > and links. > > Hi Alexei and Daniel, > > I think these two patches might have fallen through the cracks, could > you take a look? I'm not sure what the etiquette is around bumping a > set, so please let me know if you'd prefer me to send the patches with > acks included or something like that. Applied both. Thanks