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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 288F9C433DF for ; Wed, 19 Aug 2020 20:16:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07D6C207DE for ; Wed, 19 Aug 2020 20:16:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="f9ikmvVO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726603AbgHSUQA (ORCPT ); Wed, 19 Aug 2020 16:16:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47676 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725275AbgHSUQA (ORCPT ); Wed, 19 Aug 2020 16:16:00 -0400 Received: from mail-lf1-x142.google.com (mail-lf1-x142.google.com [IPv6:2a00:1450:4864:20::142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9AA4C061757; Wed, 19 Aug 2020 13:15:59 -0700 (PDT) Received: by mail-lf1-x142.google.com with SMTP id c15so12750412lfi.3; Wed, 19 Aug 2020 13:15:59 -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=xePC5tWQFk10rZ9I7pPcAR7hQMEhWEsraYFUVXFyhu4=; b=f9ikmvVOpDDy6zvzvci9P1KduZsWvp5SQZU6lu4xAojkBwg4XwDyGWrqzA5ygBa+En hZDDcmOC/LrvQrWGch0ibhfkMjJScoAaTfi2ZyfppYRCfmJnl1hktmms/dyVh9lVeufT UOcuwbEPHVv5WlPzeojYTmSwrzCqSTEJCZOwgrhATF9MFk9e52VKWQfO1aRlfL4wFycq f0XPA4/zR3VC0vcCvK/kAyhPw9HyZ5kXsKDEoX9wDhzZKRhAA6KDk4zVPGnmh0pVQ/26 w61NpmiCtMFSnTJgbQUkZ47km6yiA6/POVmA40977jEowNMy2LpPVva6SFvOLGHbZ+5r K9yw== 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=xePC5tWQFk10rZ9I7pPcAR7hQMEhWEsraYFUVXFyhu4=; b=svFnxpUOoEJ2vABh6tLMljJCjt7s3q5gQxx0clLlIrseAh3w0fybIkw8Zf1s/aaiOz sttk0aZ/XODapcbH7QK8RtNU2VlsZlDwaztAgnhE7GagvG2/HKNNy9zg2gzY343oaXML I+78H2RaxxjjxD6KjuhchLSNJhadYLHwdHLJRio25OCKy5osf49HhJ3JdK3wXFZfnYJr CK57lyI9YhsXpXHYSJyvSDnu/O7PHsvclwKWTEoBpWqOMJwAYYSAMN4bYaDuIJVmanU8 mWHt7E9j/wKgt4m25dZMbRLvIIMIkPpx2pWxA0GKM6J+yndfqKQFcpEu68vi9rH9WHkY iaqQ== X-Gm-Message-State: AOAM532wGp0rYLaOeLsRprFyRTih3mZXmWrgjHmz7JfhJkwBU3mrWr9U cMDWpaJLDOMmhKcPyTbghOCU1O/+NT9g51lH38rP00fP X-Google-Smtp-Source: ABdhPJxrJ74g+H/Tpf8BvpHfeai1Eh4nBaXGsdu1qcZ601EkPlV6Vf3/j3Fs/mJG7DAZ634mtwyr1f8xJNvrAufkn3w= X-Received: by 2002:a05:6512:3610:: with SMTP id f16mr12837009lfs.8.1597868158219; Wed, 19 Aug 2020 13:15:58 -0700 (PDT) MIME-Version: 1.0 References: <20200818213356.2629020-1-andriin@fb.com> <20200818213356.2629020-5-andriin@fb.com> In-Reply-To: From: Alexei Starovoitov Date: Wed, 19 Aug 2020 13:15:46 -0700 Message-ID: Subject: Re: [PATCH bpf-next 4/7] libbpf: sanitize BPF program code for bpf_probe_read_{kernel,user}[_str] To: Andrii Nakryiko Cc: Yonghong Song , Andrii Nakryiko , bpf , Networking , Alexei Starovoitov , Daniel Borkmann , Kernel Team Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Aug 19, 2020 at 1:13 PM Andrii Nakryiko wrote: > > On Tue, Aug 18, 2020 at 6:42 PM Yonghong Song wrote: > > > > > > > > On 8/18/20 2:33 PM, Andrii Nakryiko wrote: > > > Add BPF program code sanitization pass, replacing calls to BPF > > > bpf_probe_read_{kernel,user}[_str]() helpers with bpf_probe_read[_str](), if > > > libbpf detects that kernel doesn't support new variants. > > > > I know this has been merged. The whole patch set looks good to me. > > A few nit or questions below. > > > > > > > > Signed-off-by: Andrii Nakryiko > > > --- > > > tools/lib/bpf/libbpf.c | 80 ++++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 80 insertions(+) > > > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > > > index ab0c3a409eea..bdc08f89a5c0 100644 > > > --- a/tools/lib/bpf/libbpf.c > > > +++ b/tools/lib/bpf/libbpf.c > > > @@ -180,6 +180,8 @@ enum kern_feature_id { > > > FEAT_ARRAY_MMAP, > > > /* kernel support for expected_attach_type in BPF_PROG_LOAD */ > > > FEAT_EXP_ATTACH_TYPE, > > > + /* bpf_probe_read_{kernel,user}[_str] helpers */ > > > + FEAT_PROBE_READ_KERN, > > > __FEAT_CNT, > > > }; > > > > > > @@ -3591,6 +3593,27 @@ static int probe_kern_exp_attach_type(void) > > > return probe_fd(bpf_load_program_xattr(&attr, NULL, 0)); > > > } > > > > > [...] > > > > > > +static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id) > > > +{ > > > + __u8 class = BPF_CLASS(insn->code); > > > + > > > + if ((class == BPF_JMP || class == BPF_JMP32) && > > > > Do we support BPF_JMP32 + BPF_CALL ... as a helper call? > > I am not aware of this. > > Verifier seems to support both. Check do_check in > kernel/bpf/verifier.c, around line 9000. So I decided to also support > it, even if Clang doesn't emit it (yet?). please check few lines below 9000 ;) jmp32 | call is rejected. I would remove that from libbpf as well.