From patchwork Fri Mar 12 00:49:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12133425 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, URIBL_BLOCKED,USER_AGENT_GIT,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 DA88AC432C3 for ; Fri, 12 Mar 2021 00:50:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFA0C64F9E for ; Fri, 12 Mar 2021 00:50:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231542AbhCLAtq (ORCPT ); Thu, 11 Mar 2021 19:49:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231278AbhCLAt3 (ORCPT ); Thu, 11 Mar 2021 19:49:29 -0500 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC997C061763 for ; Thu, 11 Mar 2021 16:49:28 -0800 (PST) Received: by mail-qv1-xf4a.google.com with SMTP id t18so16438620qva.6 for ; Thu, 11 Mar 2021 16:49:28 -0800 (PST) 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=H7rLHacy3F07lJtMDfRAgErCQuUrrLGxI+6W0d6WNpU=; b=sUvmGnJ+rhgNMV6BMGfzMD6FhlSVemJZuz19BUK84N0z28Eoya5RelUNEB4bGszQ8g h59RKb80ZeuYZloMlKF0xAboydHMpXu92lVUTi82QMs81W8kTnYA1ZDNiNx3x+misJXL GM0Xkdrdn0O8zTvSRuEj345cHir/Ug/LUWrHGzcxiWWeQYb101FpAB0rLvX5F/W4gV7o YylaNmKIJoPpazOXW8XD4FPKiXg1EBF1QXOtdCNVG3JMSbC9vt6JCxYbBgz4DChIKPWL wQv7/tmAQxWr5y+X5O61j8AOyrVenfu0Qfcg0+4/OzYM99F4RhaIvLi87Qy1DQXYuiSQ dkFg== 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=H7rLHacy3F07lJtMDfRAgErCQuUrrLGxI+6W0d6WNpU=; b=ZRgjLP3nsJBQi5vHa22gbF/pnHJBkuv0H+DyYz0N5bjoxg3tKi3I8knBydfJxQGauI ShH5HZzNz4krTbwOVsjvCJwl0/yajoOqyYIMW56qe5m7QHSxatiM6fZ0OhGRL/wiOAd0 QeQZDPS3OQN02Ng4zfld3fUHrsJTB2kylkV8jKZ2izIVxPJ9Xc+5eWFyq89Ra/IEUgfP 2MSZ/2kmHg+Z4NYTb7vOMCjMP8lHR6Gbl7tmalvJAeKNYRS9jqkchDL/KT2LxdY9LYlo KMaHtCeW8nlU1aG4Wrr0xuNdSDEobjSaPDDAdz4RbU2F/plDkZs5ktAjDtg09mFM5Bu8 WnxA== X-Gm-Message-State: AOAM531HB1fwmPdRGG7sTxsnrqV65tV8IwqBIOGc12ZQZEcjgJQjcJjx 0Ri5Jq/Gf3qVHN0qBv204Lme8zOkuUixcNHvO84= X-Google-Smtp-Source: ABdhPJzcwYBUkwwPBHNvKt/g3QgQMzip9UKPQANWzW+ZzALJcGM1EFSFPH1hDnIaEovkHR0Pipxp3EXxwVLjJY4HWJw= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:c86b:8269:af92:55a]) (user=samitolvanen job=sendgmr) by 2002:a0c:f541:: with SMTP id p1mr10332251qvm.14.1615510168097; Thu, 11 Mar 2021 16:49:28 -0800 (PST) Date: Thu, 11 Mar 2021 16:49:06 -0800 In-Reply-To: <20210312004919.669614-1-samitolvanen@google.com> Message-Id: <20210312004919.669614-5-samitolvanen@google.com> Mime-Version: 1.0 References: <20210312004919.669614-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog Subject: [PATCH 04/17] module: cfi: 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 , 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 Precedence: bulk List-ID: X-Mailing-List: linux-pci@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 | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 168cd27e6122..552ddb084f76 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,10 +3,13 @@ * Archs are free to supply their own linker scripts. ld will * combine them automatically. */ +#include + SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) + *(.eh_frame) } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -40,7 +43,16 @@ SECTIONS { *(.rodata..L*) } - .text : { *(.text .text.[0-9a-zA-Z_]*) } +#ifdef CONFIG_CFI_CLANG + /* + * With CFI_CLANG, ensure __cfi_check is at the beginning of the + * .text section, and that the section is aligned to page size. + */ + .text : ALIGN(PAGE_SIZE) { + *(.text.__cfi_check) + *(.text .text.[0-9a-zA-Z_]* .text..L.cfi*) + } +#endif } /* bring in arch-specific sections */