From patchwork Wed Sep 23 17:38:58 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: 11795349 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 A3795618 for ; Wed, 23 Sep 2020 17:40:36 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 02F852067B for ; Wed, 23 Sep 2020 17:40:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02F852067B 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-19975-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 5699 invoked by uid 550); 23 Sep 2020 17:40:24 -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 5633 invoked from network); 23 Sep 2020 17:40:23 -0000 IronPort-SDR: uHVEBkXT3v1vA87jw7rwRT+jVBo/hvRuy36EUjKg3R0QgRwoucuFmd7YBzVr8PyasdqHgoCqu9 5ZMLZmaNnuuQ== X-IronPort-AV: E=McAfee;i="6000,8403,9753"; a="222548979" X-IronPort-AV: E=Sophos;i="5.77,293,1596524400"; d="scan'208";a="222548979" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False IronPort-SDR: HF6l80Vl4GPB6WBckXE/1zi6edCdb0E0SoZ0b2AIqsy1uPUzAKQS8Xx8vNJW5nsqHkQEO/idC8 xMkCI9K6Mq7w== X-IronPort-AV: E=Sophos;i="5.77,293,1596524400"; d="scan'208";a="309993016" From: Kristen Carlson Accardi To: keescook@chromium.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann Cc: arjan@linux.intel.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com, Kristen Carlson Accardi , Tony Luck , linux-arch@vger.kernel.org Subject: [PATCH v5 04/10] x86: Make sure _etext includes function sections Date: Wed, 23 Sep 2020 10:38:58 -0700 Message-Id: <20200923173905.11219-5-kristen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200923173905.11219-1-kristen@linux.intel.com> References: <20200923173905.11219-1-kristen@linux.intel.com> MIME-Version: 1.0 When 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). In order to accurately represent the end of the text section and the orphaned sections, _etext must be moved so that it is after both .text and .text.* The text size must also be calculated to include .text AND .text.* Signed-off-by: Kristen Carlson Accardi Reviewed-by: Tony Luck Tested-by: Tony Luck Reviewed-by: Kees Cook --- arch/x86/kernel/vmlinux.lds.S | 17 +++++++++++++++-- include/asm-generic/vmlinux.lds.h | 2 +- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 9a03e5b23135..b0718eef283f 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -146,9 +146,22 @@ SECTIONS #endif } :text =0xcccc - /* End of text section, which should occupy whole number of pages */ - _etext = .; + /* + * -ffunction-sections creates .text.* sections, which are considered + * "orphan sections" and added after the first similar section (.text). + * Placing this ALIGN statement before _etext causes the address of + * _etext to be below that of all the .text.* orphaned sections + */ . = ALIGN(PAGE_SIZE); + _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; X86_ALIGN_RODATA_BEGIN RO_DATA(PAGE_SIZE) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index afd5cdf79a3a..6f7239e033e8 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -863,7 +863,7 @@ . = 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 = .; \ }