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=-26.2 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, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 4EDC8C433B4 for ; Thu, 8 Apr 2021 18:29:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29F2561131 for ; Thu, 8 Apr 2021 18:29:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232871AbhDHS3U (ORCPT ); Thu, 8 Apr 2021 14:29:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232870AbhDHS3F (ORCPT ); Thu, 8 Apr 2021 14:29:05 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EDE5C0613D8 for ; Thu, 8 Apr 2021 11:28:52 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id i6so2882910ybk.2 for ; Thu, 08 Apr 2021 11:28:52 -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=sqe+SRM2tt54QgMNprHB5Ltl/JmQ4l0M9EfeayUX7cA=; b=prCsiu3tjKJFc4pP0/+ujOO/HtNJYS943pILJiCXrDbIUQY4DwftcDzmjbqU8Znqzs ReSZn865iFbsu11kWjfPBjM/AAiEJpAQQHUMwHxVVAeHXhQN1OHlhomroaYK7Vaim+wi us6bUks8K563fMiSGiRf7cDSFVVRsSPVT9Kp3Y6HKLvXNYAASpNp0uCsZPUmsVI2RO78 7etrNqjlHs2AhheD8vpQrc/1+H0Q9t7QljuufEgx8rL0gFyVyX8i17OaiFy0DvugM8k8 kC3kVB6YoMV5Pfl80tgCca3MJ2B4VTCYyxzgyxEgHMcv4rScjHAd8A0N7P1fnaJc+bQt ykzg== 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=sqe+SRM2tt54QgMNprHB5Ltl/JmQ4l0M9EfeayUX7cA=; b=U8f1KulAu5elSx39OpLcM6ub8UEAfslfeGdUn9tafu3XqLorSDQj8oPcFt3B0H7vQK 3KgXaiILQPd5N6ivex30n+9kAg2F0gn1v514MqTrgO/TDTGq+XtQZ8zGSy02CjTtm7Rx WDO5IfT7Q1bAfbIgRNSWTjI7Prl78FWlmTkFljMbUrwWnfUECCAwILXViSXVDKlm8O3b INyaQZH0aI6GxLN0w3jHBEK7bg1DXxFwFaSr0QkjiSTPkxIvn5fd9uJfWEv6YkuVkH8c y1tsf2bQWkmJdNI8drTa0sJp6e+QzizOlG431lulS4wL/rRT82VxhtgtRIBPFse1I8OX q6Ng== X-Gm-Message-State: AOAM531915ftmT9rCuceVfP/esWxITdDchJEdyjRa65AX/E41toDJe6+ FX9BUvYWxwDZAnoRlkRvurZHmAdwsSkt80UekjE= X-Google-Smtp-Source: ABdhPJxYVjdCzFadep6CzUxo/2ynBssueHSOvDokbrGpmosVElcDFd+DnNsM/GYXnls1d0LLyuI1Tzej1BjrPfvz2Cw= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:3560:8505:40a2:e021]) (user=samitolvanen job=sendgmr) by 2002:a25:ae03:: with SMTP id a3mr14172639ybj.118.1617906531475; Thu, 08 Apr 2021 11:28:51 -0700 (PDT) Date: Thu, 8 Apr 2021 11:28:28 -0700 In-Reply-To: <20210408182843.1754385-1-samitolvanen@google.com> Message-Id: <20210408182843.1754385-4-samitolvanen@google.com> Mime-Version: 1.0 References: <20210408182843.1754385-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog Subject: [PATCH v6 03/18] mm: add generic function_nocfi macro From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , Peter Zijlstra , Sedat Dilek , Mark Rutland , Catalin Marinas , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With CONFIG_CFI_CLANG, the compiler replaces function addresses in instrumented C code with jump table addresses. This means that __pa_symbol(function) returns the physical address of the jump table entry instead of the actual function, which may not work as the jump table code will immediately jump to a virtual address that may not be mapped. To avoid this address space confusion, this change adds a generic definition for function_nocfi(), which architectures that support CFI can override. The typical implementation of would use inline assembly to take the function address, which avoids compiler instrumentation. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Acked-by: Mark Rutland Tested-by: Nathan Chancellor --- include/linux/mm.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8ba434287387..22cce9c7dd05 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -124,6 +124,16 @@ extern int mmap_rnd_compat_bits __read_mostly; #define lm_alias(x) __va(__pa_symbol(x)) #endif +/* + * With CONFIG_CFI_CLANG, the compiler replaces function addresses in + * instrumented C code with jump table addresses. Architectures that + * support CFI can define this macro to return the actual function address + * when needed. + */ +#ifndef function_nocfi +#define function_nocfi(x) (x) +#endif + /* * To prevent common memory management code establishing * a zero page mapping on a read fault. -- 2.31.1.295.g9ea45b61b8-goog 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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 E30DCC433ED for ; Thu, 8 Apr 2021 18:31:51 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7126860C3E for ; 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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=sqe+SRM2tt54QgMNprHB5Ltl/JmQ4l0M9EfeayUX7cA=; b=UVjO3Gg7UKvCoySoUN332fqfx/y1RMneR3eeQ7KmRJmqYdbIjIOfs5LKGMfVOyRsuQ agloz8+QFhT3Jyksuhs0YULl+RBW6YOgouCzZUOr3m2agRb/KDNytEmXNgzj74j8KPsY D4szlK+CZbu6QS73DjBMmK9laGaeAQVuAcEwPJ2KbMCw7TsIffDQNW9Yy1xB5UMhE2Ji x+OK16kw7rshem3LehDQBF7svnHiGv/CKh5zHcGGMNB81rX1srKaGnkwGPySE/SaUEEd hndeG4fIIDRSrNfpOj4gJO1qNu0cfVVr335okXRENdij6/IrqmPACOs7kVt/myuat9nO DldQ== X-Gm-Message-State: AOAM532Pt8gniGfUOlfoWs+HlD+zAFmjqfE0EDf8iYlQheb34CIf5RJ1 +WE0yyJ4mzQV9KqzQ+WyVVgFrMzWv3WfqAMv4eE= X-Google-Smtp-Source: ABdhPJxYVjdCzFadep6CzUxo/2ynBssueHSOvDokbrGpmosVElcDFd+DnNsM/GYXnls1d0LLyuI1Tzej1BjrPfvz2Cw= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:3560:8505:40a2:e021]) (user=samitolvanen job=sendgmr) by 2002:a25:ae03:: with SMTP id a3mr14172639ybj.118.1617906531475; Thu, 08 Apr 2021 11:28:51 -0700 (PDT) Date: Thu, 8 Apr 2021 11:28:28 -0700 In-Reply-To: <20210408182843.1754385-1-samitolvanen@google.com> Message-Id: <20210408182843.1754385-4-samitolvanen@google.com> Mime-Version: 1.0 References: <20210408182843.1754385-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog Subject: [PATCH v6 03/18] mm: add generic function_nocfi macro From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , Peter Zijlstra , Sedat Dilek , Mark Rutland , Catalin Marinas , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210408_192853_125406_2BC75FA6 X-CRM114-Status: GOOD ( 15.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org With CONFIG_CFI_CLANG, the compiler replaces function addresses in instrumented C code with jump table addresses. This means that __pa_symbol(function) returns the physical address of the jump table entry instead of the actual function, which may not work as the jump table code will immediately jump to a virtual address that may not be mapped. To avoid this address space confusion, this change adds a generic definition for function_nocfi(), which architectures that support CFI can override. The typical implementation of would use inline assembly to take the function address, which avoids compiler instrumentation. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Acked-by: Mark Rutland Tested-by: Nathan Chancellor --- include/linux/mm.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8ba434287387..22cce9c7dd05 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -124,6 +124,16 @@ extern int mmap_rnd_compat_bits __read_mostly; #define lm_alias(x) __va(__pa_symbol(x)) #endif +/* + * With CONFIG_CFI_CLANG, the compiler replaces function addresses in + * instrumented C code with jump table addresses. Architectures that + * support CFI can define this macro to return the actual function address + * when needed. + */ +#ifndef function_nocfi +#define function_nocfi(x) (x) +#endif + /* * To prevent common memory management code establishing * a zero page mapping on a read fault. -- 2.31.1.295.g9ea45b61b8-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel