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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 B5743C433EF for ; Tue, 14 Sep 2021 19:39:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 982C46109E for ; Tue, 14 Sep 2021 19:39:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232575AbhINTkb (ORCPT ); Tue, 14 Sep 2021 15:40:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232552AbhINTkb (ORCPT ); Tue, 14 Sep 2021 15:40:31 -0400 Received: from mail-lj1-x22a.google.com (mail-lj1-x22a.google.com [IPv6:2a00:1450:4864:20::22a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31B59C061762 for ; Tue, 14 Sep 2021 12:39:13 -0700 (PDT) Received: by mail-lj1-x22a.google.com with SMTP id o11so660853ljp.8 for ; Tue, 14 Sep 2021 12:39:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=aeXwmIgch5WdkpveenJmPeY14PQ1LoSRtKhoZ8R2ZN4=; b=E2QZm15xPjr/oWMY3iwMNj1tCXmIb5gTlQ3a8w0mki3WM83ocnAaFZO2cE8qkxJwLR aobGFaVqRefIPy2/h78IdfM6qFH+tofHv3K1o0MBA2koB09YYdlzJg9NMwDdGYibx9r+ N8vo2nAu3SG55qHrSsV1OfPWwYV/u5LP6H0G435Wty9+v9DiDUFC29jPJmJ6wffF4GQ4 YFw/Sjx5guzRdwJ6tolYpZlyO3DRIeP73/BId7Wc105H+AeVLhIzqSMMO1W6UNpUEun2 h+2kPvrJ2cXqC9g8iQNqKvWmmy7z1nj1L9AHi3Crme67QTXVqvLcBI4U5TTGj9XdPNOd r1cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=aeXwmIgch5WdkpveenJmPeY14PQ1LoSRtKhoZ8R2ZN4=; b=WL7oYu8ZrJDWQaxCz9coUG1fH/GulJIJvssoP4IEiMg8yjJeN8WMCmNFZFk89MPChf SE12dFxW3TzFNIHjXnxWj/ul0WUFqikkhBud0bC5vP/X+sJseYBqWud5noKgUaLt1XYi yMxYTBKkSlLwquHVjTGxnHlmaEnUWdDXuzRkNJGOWlaB5CaNfkvePlNp5/mj+szn9DdA GT8UDuflU42hNOcS8OjnSTPfBO4mlXGBhjY05iOGm9ppe3iDbnEhrHDc+skYF82LPigk veLKzHqmKkRgWdecWLfA4mRRzQl1wGBq+s3v7sIHiqAAfJio/oA5k3yhJg6ayTwcMgv0 7Raw== X-Gm-Message-State: AOAM53393wfuENkFal2Gc4PBirPU97xjl84cXM4vEMob3HxGMZqu7CQ3 EO2p61goaFVQnOCwZeTi55UsbeaoH+oxc5j3eCVarQ== X-Google-Smtp-Source: ABdhPJxgAXKpry1tlDJug10xY3s3IbKLhBYYOOOqRKPqGpSgDAtG9tD969ZapfyKNyp/uNRFVYGOG2GTwBTdYez5RS0= X-Received: by 2002:a05:651c:1305:: with SMTP id u5mr16539923lja.198.1631648351403; Tue, 14 Sep 2021 12:39:11 -0700 (PDT) MIME-Version: 1.0 References: <20210914191045.2234020-1-samitolvanen@google.com> <20210914191045.2234020-6-samitolvanen@google.com> In-Reply-To: <20210914191045.2234020-6-samitolvanen@google.com> From: Nick Desaulniers Date: Tue, 14 Sep 2021 12:39:00 -0700 Message-ID: Subject: Re: [PATCH v3 05/16] tracepoint: Exclude tp_stub_func from CFI checking To: Sami Tolvanen Cc: x86@kernel.org, Kees Cook , Josh Poimboeuf , Peter Zijlstra , Nathan Chancellor , Sedat Dilek , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Tue, Sep 14, 2021 at 12:11 PM Sami Tolvanen wrote: > > If allocate_probes fails, func_remove replaces the old function > with a pointer to tp_stub_func, which is called using a mismatching > function pointer that's will always trip indirect call checks with > CONFIG_CFI_CLANG. Use DEFINE_CFI_IMMEDATE_RETURN_STUB to define > tp_stub_func to allow it to pass CFI checking. > > Signed-off-by: Sami Tolvanen Reviewed-by: Nick Desaulniers > --- > kernel/tracepoint.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c > index 64ea283f2f86..58acc7d86c3f 100644 > --- a/kernel/tracepoint.c > +++ b/kernel/tracepoint.c > @@ -99,10 +99,7 @@ struct tp_probes { > }; > > /* Called in removal of a func but failed to allocate a new tp_funcs */ > -static void tp_stub_func(void) > -{ > - return; > -} > +static DEFINE_CFI_IMMEDIATE_RETURN_STUB(tp_stub_func); > > static inline void *allocate_probes(int count) > { > -- > 2.33.0.309.g3052b89438-goog > -- Thanks, ~Nick Desaulniers