From patchwork Tue Oct 25 14:12:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evgeniy Baskov X-Patchwork-Id: 13019323 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35EF4FA3745 for ; Tue, 25 Oct 2022 14:13:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232968AbiJYONX (ORCPT ); Tue, 25 Oct 2022 10:13:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232946AbiJYONV (ORCPT ); Tue, 25 Oct 2022 10:13:21 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 707129C7E4; Tue, 25 Oct 2022 07:13:19 -0700 (PDT) Received: from localhost.localdomain (unknown [83.149.199.65]) by mail.ispras.ru (Postfix) with ESMTPSA id 1B37A419E9C9; Tue, 25 Oct 2022 14:13:16 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 1B37A419E9C9 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1666707196; bh=fViJDAK7Jhjm7j67wCahWTDXOcbmMv5WuCSXc1GBvn0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s6QaZrGXcpcaJ2A5BEn7J5H8f5rZe/kj/BDwztW6nCUOKyZiYaXL+L1C41mgnciH+ OCZ6RVKxFamOFgCJT6ZcjxcTwWQFExvZZNWbziGVBbbI5+96pcciQ47rxKSyFLzhU3 28Slr0PxWap659fbgOrgpLGhApAkdLpywUfoh9TI= From: Evgeniy Baskov To: Ard Biesheuvel Cc: Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , lvc-project@linuxtesting.org, x86@kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v2 02/23] x86/build: Remove RWX sections and align on 4KB Date: Tue, 25 Oct 2022 17:12:40 +0300 Message-Id: <953b10b58f87a5a218091062fa24c284eb9b5252.1666705333.git.baskov@ispras.ru> X-Mailer: git-send-email 2.37.4 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Avoid creating sections simultaneously writable and readable to prepare for W^X implementation. Align sections on page size (4KB) to allow protecting them in the page tables. Split init code form ".init" segment into separate R_X ".inittext" segment and make ".init" segment non-executable. Also add these segments to x86_32 architecture for consistency. Currently paging is disabled in x86_32 in compressed kernel, so protection is not applied anyways, but .init code was incorrectly placed in non-executable ".data" segment. This should not change anything meaningful in memory layout now, but might be required in case memory protection will also be implemented in compressed kernel for x86_32. Signed-off-by: Evgeniy Baskov --- arch/x86/kernel/vmlinux.lds.S | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 15f29053cec4..6587e0201b50 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -102,12 +102,11 @@ jiffies = jiffies_64; PHDRS { text PT_LOAD FLAGS(5); /* R_E */ data PT_LOAD FLAGS(6); /* RW_ */ -#ifdef CONFIG_X86_64 -#ifdef CONFIG_SMP +#if defined(CONFIG_X86_64) && defined(CONFIG_SMP) percpu PT_LOAD FLAGS(6); /* RW_ */ #endif - init PT_LOAD FLAGS(7); /* RWE */ -#endif + inittext PT_LOAD FLAGS(5); /* R_E */ + init PT_LOAD FLAGS(6); /* RW_ */ note PT_NOTE FLAGS(0); /* ___ */ } @@ -226,9 +225,10 @@ SECTIONS #endif INIT_TEXT_SECTION(PAGE_SIZE) -#ifdef CONFIG_X86_64 - :init -#endif + :inittext + + . = ALIGN(PAGE_SIZE); + /* * Section for code used exclusively before alternatives are run. All @@ -240,6 +240,7 @@ SECTIONS .altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) { *(.altinstr_aux) } + :init INIT_DATA_SECTION(16)