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=-15.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,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 067E9C3A5A2 for ; Sun, 22 Sep 2019 18:51:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CAF9821D7E for ; Sun, 22 Sep 2019 18:51:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569178296; bh=dPMBz+h3etmnxoqEa7dwetX9+Br6b4R4IuSCrpEqtQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZT9bRgjo+v+XlxgVEHOQuYWASbn8Dy05277uru0/7Nn02hc5obCESbMqWTsHRRPOT 1bPQ7bQkcvcbuxgpxUS1r7hMvYH16mmlmV9rNwlYITk5iDL7YfpcWS7rlxV2F4jXTS ChTAJ240CQt/VtEsARxq/yKF9mkTMrLg6X2e4h4U= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405743AbfIVSvf (ORCPT ); Sun, 22 Sep 2019 14:51:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:49264 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405182AbfIVSv1 (ORCPT ); Sun, 22 Sep 2019 14:51:27 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 352DB208C2; Sun, 22 Sep 2019 18:51:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569178285; bh=dPMBz+h3etmnxoqEa7dwetX9+Br6b4R4IuSCrpEqtQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PtJasEcWzdbI9VUoMApYxLFtdMx2o3jisvBrzoLxEZg++0vIKdxjZ265q2JTZlVWL 4Wo5/ITptEywsPMkEAgqsjlHx165GWmP9GbSHZLtMWp2cbb1uxvgSsovezGW74eZUC gfL6Qal4BhIXo8VS0vRpM1sL87hFhagIiuPLPJ4M= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kees Cook , Ard Biesheuvel , Will Deacon , Sasha Levin Subject: [PATCH AUTOSEL 5.2 065/185] arm64/efi: Move variable assignments after SECTIONS Date: Sun, 22 Sep 2019 14:47:23 -0400 Message-Id: <20190922184924.32534-65-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190922184924.32534-1-sashal@kernel.org> References: <20190922184924.32534-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kees Cook [ Upstream commit 90776dd1c427cbb4d381aa4b13338f1fb1d20f5e ] It seems that LLVM's linker does not correctly handle variable assignments involving section positions that are updated during the SECTIONS parsing. Commit aa69fb62bea1 ("arm64/efi: Mark __efistub_stext_offset as an absolute symbol explicitly") ran into this too, but found a different workaround. However, this was not enough, as other variables were also miscalculated which manifested as boot failures under UEFI where __efistub__end was not taking the correct _end value (they should be the same): $ ld.lld -EL -maarch64elf --no-undefined -X -shared \ -Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \ -o vmlinux.lld -T poc.lds --whole-archive vmlinux.o && \ readelf -Ws vmlinux.lld | egrep '\b(__efistub_|)_end\b' 368272: ffff000002218000 0 NOTYPE LOCAL HIDDEN 38 __efistub__end 368322: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 38 _end $ aarch64-linux-gnu-ld.bfd -EL -maarch64elf --no-undefined -X -shared \ -Bsymbolic -z notext -z norelro --no-apply-dynamic-relocs \ -o vmlinux.bfd -T poc.lds --whole-archive vmlinux.o && \ readelf -Ws vmlinux.bfd | egrep '\b(__efistub_|)_end\b' 338124: ffff000012318000 0 NOTYPE LOCAL DEFAULT ABS __efistub__end 383812: ffff000012318000 0 NOTYPE GLOBAL DEFAULT 15325 _end To work around this, all of the __efistub_-prefixed variable assignments need to be moved after the linker script's SECTIONS entry. As it turns out, this also solves the problem fixed in commit aa69fb62bea1, so those changes are reverted here. Link: https://github.com/ClangBuiltLinux/linux/issues/634 Link: https://bugs.llvm.org/show_bug.cgi?id=42990 Acked-by: Ard Biesheuvel Signed-off-by: Kees Cook Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- arch/arm64/kernel/image-vars.h | 51 +++++++++++++++++++++++++++++++++ arch/arm64/kernel/image.h | 42 --------------------------- arch/arm64/kernel/vmlinux.lds.S | 2 ++ 3 files changed, 53 insertions(+), 42 deletions(-) create mode 100644 arch/arm64/kernel/image-vars.h diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h new file mode 100644 index 0000000000000..25a2a9b479c2f --- /dev/null +++ b/arch/arm64/kernel/image-vars.h @@ -0,0 +1,51 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Linker script variables to be set after section resolution, as + * ld.lld does not like variables assigned before SECTIONS is processed. + */ +#ifndef __ARM64_KERNEL_IMAGE_VARS_H +#define __ARM64_KERNEL_IMAGE_VARS_H + +#ifndef LINKER_SCRIPT +#error This file should only be included in vmlinux.lds.S +#endif + +#ifdef CONFIG_EFI + +__efistub_stext_offset = stext - _text; + +/* + * The EFI stub has its own symbol namespace prefixed by __efistub_, to + * isolate it from the kernel proper. The following symbols are legally + * accessed by the stub, so provide some aliases to make them accessible. + * Only include data symbols here, or text symbols of functions that are + * guaranteed to be safe when executed at another offset than they were + * linked at. The routines below are all implemented in assembler in a + * position independent manner + */ +__efistub_memcmp = __pi_memcmp; +__efistub_memchr = __pi_memchr; +__efistub_memcpy = __pi_memcpy; +__efistub_memmove = __pi_memmove; +__efistub_memset = __pi_memset; +__efistub_strlen = __pi_strlen; +__efistub_strnlen = __pi_strnlen; +__efistub_strcmp = __pi_strcmp; +__efistub_strncmp = __pi_strncmp; +__efistub_strrchr = __pi_strrchr; +__efistub___flush_dcache_area = __pi___flush_dcache_area; + +#ifdef CONFIG_KASAN +__efistub___memcpy = __pi_memcpy; +__efistub___memmove = __pi_memmove; +__efistub___memset = __pi_memset; +#endif + +__efistub__text = _text; +__efistub__end = _end; +__efistub__edata = _edata; +__efistub_screen_info = screen_info; + +#endif + +#endif /* __ARM64_KERNEL_IMAGE_VARS_H */ diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h index 2b85c0d6fa3d1..c7d38c660372c 100644 --- a/arch/arm64/kernel/image.h +++ b/arch/arm64/kernel/image.h @@ -65,46 +65,4 @@ DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET); \ DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS); -#ifdef CONFIG_EFI - -/* - * Use ABSOLUTE() to avoid ld.lld treating this as a relative symbol: - * https://github.com/ClangBuiltLinux/linux/issues/561 - */ -__efistub_stext_offset = ABSOLUTE(stext - _text); - -/* - * The EFI stub has its own symbol namespace prefixed by __efistub_, to - * isolate it from the kernel proper. The following symbols are legally - * accessed by the stub, so provide some aliases to make them accessible. - * Only include data symbols here, or text symbols of functions that are - * guaranteed to be safe when executed at another offset than they were - * linked at. The routines below are all implemented in assembler in a - * position independent manner - */ -__efistub_memcmp = __pi_memcmp; -__efistub_memchr = __pi_memchr; -__efistub_memcpy = __pi_memcpy; -__efistub_memmove = __pi_memmove; -__efistub_memset = __pi_memset; -__efistub_strlen = __pi_strlen; -__efistub_strnlen = __pi_strnlen; -__efistub_strcmp = __pi_strcmp; -__efistub_strncmp = __pi_strncmp; -__efistub_strrchr = __pi_strrchr; -__efistub___flush_dcache_area = __pi___flush_dcache_area; - -#ifdef CONFIG_KASAN -__efistub___memcpy = __pi_memcpy; -__efistub___memmove = __pi_memmove; -__efistub___memset = __pi_memset; -#endif - -__efistub__text = _text; -__efistub__end = _end; -__efistub__edata = _edata; -__efistub_screen_info = screen_info; - -#endif - #endif /* __ARM64_KERNEL_IMAGE_H */ diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 7fa0083749078..803b24d2464ae 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -245,6 +245,8 @@ SECTIONS HEAD_SYMBOLS } +#include "image-vars.h" + /* * The HYP init code and ID map text can't be longer than a page each, * and should not cross a page boundary. -- 2.20.1