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=-26.3 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_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 A4C4FC4361B for ; Tue, 23 Mar 2021 20:41:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D015619CB for ; Tue, 23 Mar 2021 20:41:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233581AbhCWUkr (ORCPT ); Tue, 23 Mar 2021 16:40:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44948 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233472AbhCWUj6 (ORCPT ); Tue, 23 Mar 2021 16:39:58 -0400 Received: from mail-qv1-xf49.google.com (mail-qv1-xf49.google.com [IPv6:2607:f8b0:4864:20::f49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 069E8C0613E2 for ; Tue, 23 Mar 2021 13:39:57 -0700 (PDT) Received: by mail-qv1-xf49.google.com with SMTP id h12so16964qvm.9 for ; Tue, 23 Mar 2021 13:39:56 -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=2eJKl2P+mphx8MXuY5eZ3j0r297zj+fSj+T5WKlAy0E=; b=F7DyYoTINGuplDxZdhovljaDSjsbsbsHDaccNJNpVFG1uHl0pH2Jb8ZGxI9pRViGzn P9bXGOaY4DL6wqzXTQkCjWG3FbAPFgW9yZwRM/QptFOt0nz84XtEbqR1NLBkEGidZJa3 CrJkw9qpHdhwZrMFRZHgVsRqmb2+bUfA3erzvVzdp42rL0vgo1/PfyIuO8eBVtII3M96 zF220AVy6U0HEFNIfOCZZan85P2t79rpIjJGqHqbbixIsFbkx3V9i1GVLeV4Nyw/Kyqe 1GNwZ/VIvbro/fYpjQY24QiS/HC8Qnb62x6xeycl0QxRVHSbtfzTj1X67bnIdj4QhdeH nwSw== 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=2eJKl2P+mphx8MXuY5eZ3j0r297zj+fSj+T5WKlAy0E=; b=Mo+VOWS4S6prg3B8vKAr17FdiK5SZvLW/VTe/C6L3t9dxCscnjTm/NqB0mFIuaATru B+cec8uVY/t49ZAcq+8tz5pAGpeYl30002hNYYPnCuhWXE2YJ89BZoibtXlJYaTzTKyN SbvP0N0+UPq5B8omypi4yIAekGh3sJgiHMdlmiapNaVf3pIoUHel9Nk2CRRFs8Ud45Cq shERhh9zmwN2YMDT9/vv88UefM3eDSu3040ZelVDUq5bsEtgTDTtEt/ygfkFzryEV9bi 5iOHM4ILqwzawU6priYfH7+CwkkR4QjlBRd19J9jmzLs21PvxiDA5cZ438sZhDFs8dni kCng== X-Gm-Message-State: AOAM5315lP59DYy1iThAAtHT1VGiY5Lr/Lgc8dziTjLI2lB5OVKr6rps bKxR47VlU+xvC08+0JFMUplDZmpr6u6uBQaGyyg= X-Google-Smtp-Source: ABdhPJxkrzfmdWRBTsfApsBgU0/vtdyh9mzsMw1+qzCVhW8+YL7dn0iZkK/RRt+cwJ1LZa5E4YW9O+Nm9AJq6lZMkTQ= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:e9a3:260d:763b:67dc]) (user=samitolvanen job=sendgmr) by 2002:a0c:ea4b:: with SMTP id u11mr129682qvp.43.1616531996172; Tue, 23 Mar 2021 13:39:56 -0700 (PDT) Date: Tue, 23 Mar 2021 13:39:33 -0700 In-Reply-To: <20210323203946.2159693-1-samitolvanen@google.com> Message-Id: <20210323203946.2159693-5-samitolvanen@google.com> Mime-Version: 1.0 References: <20210323203946.2159693-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog Subject: [PATCH v3 04/17] module: ensure __cfi_check alignment 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 , 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, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org CONFIG_CFI_CLANG_SHADOW assumes the __cfi_check() function is page aligned and at the beginning of the .text section. While Clang would normally align the function correctly, it fails to do so for modules with no executable code. This change ensures the correct __cfi_check() location and alignment. It also discards the .eh_frame section, which Clang can generate with certain sanitizers, such as CFI. Link: https://bugs.llvm.org/show_bug.cgi?id=46293 Signed-off-by: Sami Tolvanen --- scripts/module.lds.S | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 168cd27e6122..2ba9e5ce71df 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,10 +3,21 @@ * Archs are free to supply their own linker scripts. ld will * combine them automatically. */ +#include + +#ifdef CONFIG_CFI_CLANG +# define ALIGN_CFI ALIGN(PAGE_SIZE) +# define SANITIZER_DISCARDS *(.eh_frame) +#else +# define ALIGN_CFI +# define SANITIZER_DISCARDS +#endif + SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) + SANITIZER_DISCARDS } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -40,7 +51,14 @@ SECTIONS { *(.rodata..L*) } - .text : { *(.text .text.[0-9a-zA-Z_]*) } + /* + * With CONFIG_CFI_CLANG, we assume __cfi_check is at the beginning + * of the .text section, and is aligned to PAGE_SIZE. + */ + .text : ALIGN_CFI { + *(.text.__cfi_check) + *(.text .text.[0-9a-zA-Z_]* .text..L.cfi*) + } } /* bring in arch-specific sections */ -- 2.31.0.291.g576ba9dcdaf-goog