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=-19.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,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 E4A0CC433ED for ; Thu, 8 Apr 2021 17:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B395C61108 for ; Thu, 8 Apr 2021 17:59:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231716AbhDHR7u (ORCPT ); Thu, 8 Apr 2021 13:59:50 -0400 Received: from mail-oi1-f180.google.com ([209.85.167.180]:37567 "EHLO mail-oi1-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231676AbhDHR7t (ORCPT ); Thu, 8 Apr 2021 13:59:49 -0400 Received: by mail-oi1-f180.google.com with SMTP id k25so3086249oic.4; Thu, 08 Apr 2021 10:59:38 -0700 (PDT) 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=ax3ABmQpuWlTEUM4I+bnWh/ue2r9VyNMX16GZ55B25k=; b=opAZ6TLrYpnSvSawO7UNq0D0i6tGu9WTxQJ0CZ6u89/FnUmfRgiEAXYoGkA5yubn4s yXH4BNH2Jj5YBZ6gTHmVWGyfngBHbvb0nunb1ikIq7imMQicyL1Xkgm4ymf5VygwyRSm +zur+LH7jAdOxBQ6tA8QTUfQhjjY8mM7UIRAwglEaRhND4TYOE/eJdATKvFe5mRFN4zn 8/CyaubdfRqYRgW+5fxfVOwHVhKgwMilF8VVI1k5VivLrYqVnlJJEwA9lMVYW1umyM8w aDwKoC7B48iEs0JuafplxSxF1UoCQ1mg/W5Sar9bBBlZEiCz1fPMjiJJ5jB40OL7HVBE muXw== X-Gm-Message-State: AOAM5301mJKmDPjARF00deVw+viS1Kumh5WUEGX2MA88LHiURydmZnD/ OrNAb78wtR9yHzVwx6KeE7OsSRCrzIZcvLB8pX8= X-Google-Smtp-Source: ABdhPJwUtkkrpSPv+VoY0saC9mw4IuWibMv4PWM7IxUrA5g3CzTGF3ir/gABhN80eWU6JzFakFJnNLNDUf/+cZPpohk= X-Received: by 2002:aca:5fc3:: with SMTP id t186mr6880729oib.69.1617904778140; Thu, 08 Apr 2021 10:59:38 -0700 (PDT) MIME-Version: 1.0 References: <20210407213048.940498-1-nathan@kernel.org> In-Reply-To: <20210407213048.940498-1-nathan@kernel.org> From: "Rafael J. Wysocki" Date: Thu, 8 Apr 2021 19:59:27 +0200 Message-ID: Subject: Re: [PATCH] ACPI / CPPC: Replace cppc_attr with kobj_attribute To: Nathan Chancellor Cc: "Rafael J. Wysocki" , Len Brown , Kees Cook , Sami Tolvanen , ACPI Devel Maling List , Linux Kernel Mailing List , clang-built-linux@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Wed, Apr 7, 2021 at 11:32 PM Nathan Chancellor wrote: > > All of the CPPC sysfs show functions are called via indirect call in > kobj_attr_show(), where they should be of type > > ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr, char *buf); > > because that is the type of the ->show() member in > 'struct kobj_attribute' but they are actually of type > > ssize_t (*show)(struct kobject *kobj, struct attribute *attr, char *buf); > > because of the ->show() member in 'struct cppc_attr', resulting in a > Control Flow Integrity violation [1]. > > $ cat /sys/devices/system/cpu/cpu0/acpi_cppc/highest_perf > 3400 > > $ dmesg | grep "CFI failure" > [ 175.970559] CFI failure (target: show_highest_perf+0x0/0x8): > > As far as I can tell, the only different between 'struct cppc_attr' and > 'struct kobj_attribute' aside from the type of the attr parameter is the > type of the count parameter in the ->store() member (ssize_t vs. > size_t), which does not actually matter because all of these nodes are > read-only. > > Eliminate 'struct cppc_attr' in favor of 'struct kobj_attribute' to fix > the violation. > > [1]: https://lore.kernel.org/r/20210401233216.2540591-1-samitolvanen@google.com/ > > Fixes: 158c998ea44b ("ACPI / CPPC: add sysfs support to compute delivered performance") > Link: https://github.com/ClangBuiltLinux/linux/issues/1343 > Signed-off-by: Nathan Chancellor > --- > drivers/acpi/cppc_acpi.c | 14 +++----------- > 1 file changed, 3 insertions(+), 11 deletions(-) > > diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c > index 69057fcd2c04..a5e6fd0bafa1 100644 > --- a/drivers/acpi/cppc_acpi.c > +++ b/drivers/acpi/cppc_acpi.c > @@ -119,23 +119,15 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr); > */ > #define NUM_RETRIES 500ULL > > -struct cppc_attr { > - struct attribute attr; > - ssize_t (*show)(struct kobject *kobj, > - struct attribute *attr, char *buf); > - ssize_t (*store)(struct kobject *kobj, > - struct attribute *attr, const char *c, ssize_t count); > -}; > - > #define define_one_cppc_ro(_name) \ > -static struct cppc_attr _name = \ > +static struct kobj_attribute _name = \ > __ATTR(_name, 0444, show_##_name, NULL) > > #define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj) > > #define show_cppc_data(access_fn, struct_name, member_name) \ > static ssize_t show_##member_name(struct kobject *kobj, \ > - struct attribute *attr, char *buf) \ > + struct kobj_attribute *attr, char *buf) \ > { \ > struct cpc_desc *cpc_ptr = to_cpc_desc(kobj); \ > struct struct_name st_name = {0}; \ > @@ -161,7 +153,7 @@ show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf); > show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time); > > static ssize_t show_feedback_ctrs(struct kobject *kobj, > - struct attribute *attr, char *buf) > + struct kobj_attribute *attr, char *buf) > { > struct cpc_desc *cpc_ptr = to_cpc_desc(kobj); > struct cppc_perf_fb_ctrs fb_ctrs = {0}; > > base-commit: 454859c552da78b0f587205d308401922b56863e > -- Applied as 5.13 material, thanks!