From patchwork Thu Mar 18 17:10:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12148841 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=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 005EAC4360C for ; Thu, 18 Mar 2021 17:12:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D699F64F30 for ; Thu, 18 Mar 2021 17:12:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232286AbhCRRLi (ORCPT ); Thu, 18 Mar 2021 13:11:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232298AbhCRRLZ (ORCPT ); Thu, 18 Mar 2021 13:11:25 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84F23C061761 for ; Thu, 18 Mar 2021 10:11:25 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id t1so2184941ybq.1 for ; Thu, 18 Mar 2021 10:11:25 -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=D5aIIw6ZgnQjO2LtKhTG0SnhlhRc7naBZb5HRsoPMYM=; b=DJs3PpKGZT5abgDxmLr20bRHSgWSXko38GVppWq5gA7qETnUgw0bw1lS6eKo3WFfko eAOZfq1smTFvIJOqfLkfTgwT4IQsV0telQvn0vGMyfw2yLTgzy8zulsGkDko+Wr94eVd R9bvyDRw0x6920hAolwlIsKRpDU4dsmS/kGGsKqFSuew1E2FLbM4OYgfHXGESRlJlvO0 nm2nTQhXGxw/QP5qx+9mb8RX37C7kICUl3sUZfQnPG/LnLB/Yv5y6sC+sDSXnH4r5rMW v9Q1TPupu6griqvZD2j2qc0nAa5fRI/yinH70Q08aajflrVhE6iYA50ugnXHLsPdr6HX Sn+Q== 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=D5aIIw6ZgnQjO2LtKhTG0SnhlhRc7naBZb5HRsoPMYM=; b=eMTrimvR5C9yr+d305SeKV41UlyxZDtTqslCOT1EcvT7tbu6U348OmwssLZSS6tDOW ZzBIqPZd2RRFVUbybKkHrKIN1n3jfYIWTZvn5BtOOLqW7VadOmUBFf//xmvsN5k4/wGC wHAspPB4uZJIbXqnrNzOP3RVm1nafmlXXbFelaxzB5/b5K60YNMXiwk/7gr6S7cky/0X yTdLNBM6We5EK76KrwAzvZx7DWuwNrxze6vq+y3egPPfkn0JbrTzg1suJJ6zX4BQ0R8C ROeb10oQ9EkZmKvwYAb1mj10zyf1in3Aiwb/n83BqLTywuki0DFhlhf7rpCe5+lmJQPS uJDA== X-Gm-Message-State: AOAM533wdDtaQeugUSXbdVKcxV+WumoUeoRHasz6vj9RlYBYJJ/N8x74 lhOh18fX6PEvntCH5GOQM0VR18P/DusCzrPh/OM= X-Google-Smtp-Source: ABdhPJyPBt6MH4faEqf0AYmhZmuTW6b6F0vtOC0nIFwVJkoD535hPrMSE+Vii/iaUNCDzOi8rgltoGh+k3M7Eul0cOI= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:c0d7:a7ba:fb41:a35a]) (user=samitolvanen job=sendgmr) by 2002:a25:804e:: with SMTP id a14mr496516ybn.206.1616087484769; Thu, 18 Mar 2021 10:11:24 -0700 (PDT) Date: Thu, 18 Mar 2021 10:10:58 -0700 In-Reply-To: <20210318171111.706303-1-samitolvanen@google.com> Message-Id: <20210318171111.706303-5-samitolvanen@google.com> Mime-Version: 1.0 References: <20210318171111.706303-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog Subject: [PATCH v2 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 , 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-kbuild@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 | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 168cd27e6122..93518579cf5d 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -3,10 +3,19 @@ * 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) +#else +# define ALIGN_CFI +#endif + SECTIONS { /DISCARD/ : { *(.discard) *(.discard.*) + *(.eh_frame) } __ksymtab 0 : { *(SORT(___ksymtab+*)) } @@ -40,7 +49,14 @@ 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 */