From patchwork Wed Feb 5 22:39:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kristen Carlson Accardi X-Patchwork-Id: 11367279 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 035B713A4 for ; Wed, 5 Feb 2020 22:40:44 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 6B0D8214AF for ; Wed, 5 Feb 2020 22:40:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B0D8214AF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-17676-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 9984 invoked by uid 550); 5 Feb 2020 22:39:56 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 9931 invoked from network); 5 Feb 2020 22:39:54 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,407,1574150400"; d="scan'208";a="225092452" From: Kristen Carlson Accardi To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, arjan@linux.intel.com, keescook@chromium.org Cc: rick.p.edgecombe@intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Kristen Carlson Accardi Subject: [RFC PATCH 06/11] x86: make sure _etext includes function sections Date: Wed, 5 Feb 2020 14:39:45 -0800 Message-Id: <20200205223950.1212394-7-kristen@linux.intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200205223950.1212394-1-kristen@linux.intel.com> References: <20200205223950.1212394-1-kristen@linux.intel.com> MIME-Version: 1.0 We will be using -ffunction-sections to place each function in it's own text section so it can be randomized at load time. The linker considers these .text.* sections "orphaned sections", and will place them after the first similar section (.text). However, we need to move _etext so that it is after both .text and .text.* We also need to calculate text size to include .text AND .text.* Signed-off-by: Kristen Carlson Accardi --- arch/x86/kernel/vmlinux.lds.S | 18 +++++++++++++++++- include/asm-generic/vmlinux.lds.h | 2 +- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 3a1a819da137..e54e9ac5b429 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -146,8 +146,24 @@ SECTIONS #endif } :text =0xcccc - /* End of text section, which should occupy whole number of pages */ +#ifdef CONFIG_FG_KASLR + /* + * -ffunction-sections creates .text.* sections, which are considered + * "orphan sections" and added after the first similar section (.text). + * Adding this ALIGN statement causes the address of _etext + * to be below that of all the .text.* orphaned sections + */ + . = ALIGN(PAGE_SIZE); +#endif _etext = .; + + /* + * the size of the .text section is used to calculate the address + * range for orc lookups. If we just use SIZEOF(.text), we will + * miss all the .text.* sections. Calculate the size using _etext + * and _stext and save the value for later. + */ + text_size = _etext - _stext; . = ALIGN(PAGE_SIZE); X86_ALIGN_RODATA_BEGIN diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index e00f41aa8ec4..edf19f4296e2 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -798,7 +798,7 @@ . = ALIGN(4); \ .orc_lookup : AT(ADDR(.orc_lookup) - LOAD_OFFSET) { \ orc_lookup = .; \ - . += (((SIZEOF(.text) + LOOKUP_BLOCK_SIZE - 1) / \ + . += (((text_size + LOOKUP_BLOCK_SIZE - 1) / \ LOOKUP_BLOCK_SIZE) + 1) * 4; \ orc_lookup_end = .; \ }