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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 A45D4C433DF for ; Mon, 29 Jun 2020 20:40:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84A9E20672 for ; Mon, 29 Jun 2020 20:40:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="eIyxYRft" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731705AbgF2Ukb (ORCPT ); Mon, 29 Jun 2020 16:40:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731674AbgF2TOL (ORCPT ); Mon, 29 Jun 2020 15:14:11 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1CA5CC08EB0D for ; Sun, 28 Jun 2020 23:18:53 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id y18so6689069plr.4 for ; Sun, 28 Jun 2020 23:18:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=UIGzgreIfTFOxxrVnfdOtVBSBIsQ6xr6g7mQ/APcJYs=; b=eIyxYRftnOui04V4XDgcCKRZPnSL1iLVTOLK21hciuVaKMrlO/me6I6zabNcmW51hm sEP0n59JEFsgLPSQ4aRAQ2lJpdfBlUFjFZ+BQZG9PBaB8aynL14Bhv8xALE7JNi7Dg0C QWW2xnjqIifsayeGW/Ay6Sbs+HR/6nZ4+JWWg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=UIGzgreIfTFOxxrVnfdOtVBSBIsQ6xr6g7mQ/APcJYs=; b=klpXxSDTe9h/mFHbG4tQSBMJQJuIu1lRjcpokrNroeIFJ6hOHDvRQmLyeiUsR3VW11 Jo6Et9lMcguhMAItlzsInJueQrq++KJRLzHufOfenawsY298p9YVCD8w0DkBkQKeNtdt Sp8ixaO7LrTowqjRJ24h8I1687dEOjripmvRfVFKSfHUErjHln+ziz+bhxfCWObe+4RD HXx6GxyT4YoPte3sy69wlmIyN85iho8hqA8tHdozrjzF06cH2wt01HZr7GTa+ZzaJv8u prHEsmVoLtDOhnRugEAAuRiJsFzSxQbVlvm6QCDrU+6Ia0LUiUODAAQf5LrPV0loZQbN u8nA== X-Gm-Message-State: AOAM531w0h3d1oyUI1o9ICInBhS+XlOOo1033T4kodGYYwhaINzZL3v3 NQ9lQkrHLNOFvL3W2GfxvYheYw== X-Google-Smtp-Source: ABdhPJzz69mu7O4q6VbFBjTvIO71CEyN6mZuFliZ3G3JlPVzh4yITRE6mx9hV24nwgpSONTnA4Ny3g== X-Received: by 2002:a17:90a:1781:: with SMTP id q1mr15164767pja.24.1593411532684; Sun, 28 Jun 2020 23:18:52 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id d18sm7737172pjv.25.2020.06.28.23.18.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Jun 2020 23:18:48 -0700 (PDT) From: Kees Cook To: Will Deacon Cc: Kees Cook , Catalin Marinas , Mark Rutland , Ard Biesheuvel , Peter Collingbourne , James Morse , Borislav Petkov , Thomas Gleixner , Ingo Molnar , Russell King , Masahiro Yamada , Arvind Sankar , Nick Desaulniers , Nathan Chancellor , Arnd Bergmann , x86@kernel.org, clang-built-linux@googlegroups.com, linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 11/17] arm64/build: Warn on orphan section placement Date: Sun, 28 Jun 2020 23:18:34 -0700 Message-Id: <20200629061840.4065483-12-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629061840.4065483-1-keescook@chromium.org> References: <20200629061840.4065483-1-keescook@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We don't want to depend on the linker's orphan section placement heuristics as these can vary between linkers, and may change between versions. All sections need to be explicitly named in the linker script. Remove .eh_frame, since there are none left. Add .plt, .data.rel.ro, .igot.*, and .iplt to discards as they are not actually used. While .got.plt is also not used, it must be included otherwise ld.bfd will fail to link with the error: aarch64-linux-gnu-ld: discarded output section: `.got.plt' However, as it'd be better to validate that it stays effectively empty, add an assert, as suggested by Ard Biesheuvel. Explicitly include debug sections when they're present. Finally, enable orphan section warnings. Acked-by: Will Deacon Signed-off-by: Kees Cook --- arch/arm64/Makefile | 4 ++++ arch/arm64/kernel/vmlinux.lds.S | 11 ++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 895486606f74..fb3aa2d7de4d 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -29,6 +29,10 @@ LDFLAGS_vmlinux += --fix-cortex-a53-843419 endif endif +# We never want expected sections to be placed heuristically by the +# linker. All sections should be explicitly named in the linker script. +LDFLAGS_vmlinux += --orphan-handling=warn + ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y) ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y) $(warning LSE atomics not supported by binutils) diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index b5a94ec1eada..320ba5ec2adc 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -94,7 +94,8 @@ SECTIONS /DISCARD/ : { *(.interp .dynamic) *(.dynsym .dynstr .hash .gnu.hash) - *(.eh_frame) + *(.plt) *(.data.rel.ro) + *(.igot.*) *(.iplt) } . = KIMAGE_VADDR + TEXT_OFFSET; @@ -244,9 +245,17 @@ SECTIONS _end = .; STABS_DEBUG + DWARF_DEBUG ELF_DETAILS HEAD_SYMBOLS + + /* + * Make sure that the .got.plt is either completely empty or it + * contains only the lazy dispatch entries. + */ + .got.plt (INFO) : { *(.got.plt) } + ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, ".got.plt not empty") } #include "image-vars.h" -- 2.25.1 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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 4F3DFC433E0 for ; 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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id d18sm7737172pjv.25.2020.06.28.23.18.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 28 Jun 2020 23:18:48 -0700 (PDT) From: Kees Cook To: Will Deacon Subject: [PATCH v4 11/17] arm64/build: Warn on orphan section placement Date: Sun, 28 Jun 2020 23:18:34 -0700 Message-Id: <20200629061840.4065483-12-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200629061840.4065483-1-keescook@chromium.org> References: <20200629061840.4065483-1-keescook@chromium.org> MIME-Version: 1.0 X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, Kees Cook , Arnd Bergmann , Catalin Marinas , Masahiro Yamada , x86@kernel.org, Nick Desaulniers , Russell King , linux-kernel@vger.kernel.org, Nathan Chancellor , clang-built-linux@googlegroups.com, Arvind Sankar , Ingo Molnar , James Morse , Thomas Gleixner , Borislav Petkov , Peter Collingbourne , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org 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 We don't want to depend on the linker's orphan section placement heuristics as these can vary between linkers, and may change between versions. All sections need to be explicitly named in the linker script. Remove .eh_frame, since there are none left. Add .plt, .data.rel.ro, .igot.*, and .iplt to discards as they are not actually used. While .got.plt is also not used, it must be included otherwise ld.bfd will fail to link with the error: aarch64-linux-gnu-ld: discarded output section: `.got.plt' However, as it'd be better to validate that it stays effectively empty, add an assert, as suggested by Ard Biesheuvel. Explicitly include debug sections when they're present. Finally, enable orphan section warnings. Acked-by: Will Deacon Signed-off-by: Kees Cook --- arch/arm64/Makefile | 4 ++++ arch/arm64/kernel/vmlinux.lds.S | 11 ++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 895486606f74..fb3aa2d7de4d 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -29,6 +29,10 @@ LDFLAGS_vmlinux += --fix-cortex-a53-843419 endif endif +# We never want expected sections to be placed heuristically by the +# linker. All sections should be explicitly named in the linker script. +LDFLAGS_vmlinux += --orphan-handling=warn + ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y) ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y) $(warning LSE atomics not supported by binutils) diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index b5a94ec1eada..320ba5ec2adc 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -94,7 +94,8 @@ SECTIONS /DISCARD/ : { *(.interp .dynamic) *(.dynsym .dynstr .hash .gnu.hash) - *(.eh_frame) + *(.plt) *(.data.rel.ro) + *(.igot.*) *(.iplt) } . = KIMAGE_VADDR + TEXT_OFFSET; @@ -244,9 +245,17 @@ SECTIONS _end = .; STABS_DEBUG + DWARF_DEBUG ELF_DETAILS HEAD_SYMBOLS + + /* + * Make sure that the .got.plt is either completely empty or it + * contains only the lazy dispatch entries. + */ + .got.plt (INFO) : { *(.got.plt) } + ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, ".got.plt not empty") } #include "image-vars.h" -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel