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=-9.1 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_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 C0364C282D9 for ; Thu, 31 Jan 2019 19:29:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 906BA20B1F for ; Thu, 31 Jan 2019 19:29:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="Co3V1O2w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729369AbfAaT27 (ORCPT ); Thu, 31 Jan 2019 14:28:59 -0500 Received: from mail-pf1-f193.google.com ([209.85.210.193]:37653 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729317AbfAaT24 (ORCPT ); Thu, 31 Jan 2019 14:28:56 -0500 Received: by mail-pf1-f193.google.com with SMTP id y126so1938510pfb.4 for ; Thu, 31 Jan 2019 11:28:55 -0800 (PST) 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=s01BexUIwWPAOZc8ULyS2OIx258H75BSpCIC9WlFXeA=; b=Co3V1O2wLJokDkFdLVsjREI0nao2Jg7jlHpj2lNY+2lrpHZRzNneoqScxkhcIpLze5 8S7D+RePNeJ29sqQDnQbf7k4atEUy6m58s/U+MttCo8N5HwI4Wir5FMsTfYD8Q4YcON4 JPocWAj6c1SizKDGsVfD4L5MMLc91rT/EnQkQ= 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=s01BexUIwWPAOZc8ULyS2OIx258H75BSpCIC9WlFXeA=; b=LEoH4Mq/GnB40C+eLyFNao5gaukLI+jDKT0Rx1SIqryCD0wWI56JsGZv+pLPVz7PFv RAUdE/uvahH9A5WBxUirFlYhSDI/xjQAXKMFZ9hf2nGn5kWpyP9vVCt8T4h9CRRHNIVq Zv4LqkACKZG9CYB/nGtXnHLMjV+XtiTfDu5y/Rn+/yiiReEweOGHtdTASCVxw/r9EWNS dD4p9x2AN/E6UQPTPN270JUBgOcHG5NyQasJoQR1ur/SZhC4c+AQZrptNxGoUkdBnhbv awDPVirivvmZtwd6VYvM0nzo0SIxuqUyodVK3l+ZT0K23LrEFrS7ukOsxaBTa71WEdsX aTOA== X-Gm-Message-State: AJcUukec+Ek9/4CKCcf73q9Hkem8VpfgwyTc2YWDvuDTu3J5G2x1Cmey iunz4PcJ3tPITC4gpSIYmVD5yQ== X-Google-Smtp-Source: ALg8bN6cmIR/qbhV/Uq/U9H2S0j+DXRELuumBvMvyw891Bchw+ZY/JtGEi73minvNQOLad44JyJxUA== X-Received: by 2002:a62:7042:: with SMTP id l63mr37555534pfc.89.1548962935607; Thu, 31 Jan 2019 11:28:55 -0800 (PST) Received: from skynet.sea.corp.google.com ([2620:15c:17:4:29de:3bb1:1270:e679]) by smtp.gmail.com with ESMTPSA id s130sm11164399pgc.60.2019.01.31.11.28.54 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Jan 2019 11:28:55 -0800 (PST) From: Thomas Garnier To: kernel-hardening@lists.openwall.com Cc: kristen@linux.intel.com, Thomas Garnier , Masahiro Yamada , "Peter Zijlstra (Intel)" , Ingo Molnar , Andrew Morton , Kees Cook , Mathieu Desnoyers , Thomas Garnier , Nicholas Piggin , Sam Ravnborg , Palmer Dabbelt , Michael Forney , Cao jin , linux-kernel@vger.kernel.org Subject: [PATCH v6 16/27] compiler: Option to add PROVIDE_HIDDEN replacement for weak symbols Date: Thu, 31 Jan 2019 11:24:23 -0800 Message-Id: <20190131192533.34130-17-thgarnie@chromium.org> X-Mailer: git-send-email 2.20.1.495.gaa96b0ce6b-goog In-Reply-To: <20190131192533.34130-1-thgarnie@chromium.org> References: <20190131192533.34130-1-thgarnie@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 Provide an option to have a PROVIDE_HIDDEN (linker script) entry for each weak symbol. This option solves an error in x86_64 where the linker optimizes PIE generated code to be non-PIE because --emit-relocs was used instead of -pie (to reduce dynamic relocations). Signed-off-by: Thomas Garnier --- init/Kconfig | 7 +++++++ scripts/link-vmlinux.sh | 14 ++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/init/Kconfig b/init/Kconfig index 116e0de4817f..2261c9891631 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2104,6 +2104,13 @@ config ASN1 inform it as to what tags are to be expected in a stream and what functions to call on what tags. +config WEAK_PROVIDE_HIDDEN + bool + help + Generate linker script PROVIDE_HIDDEN entries for all weak symbols. It + allows to prevent non-PIE code being replaced by the linker if the + emit-relocs option is used instead of PIE (useful for x86_64 PIE). + source "kernel/Kconfig.locks" config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index bc7f1fc1f55b..abf44a804c79 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -119,6 +119,17 @@ kallsyms() ${CC} ${aflags} -c -o ${2} ${afile} } +gen_weak_provide_hidden() +{ + if [ -n "${CONFIG_WEAK_PROVIDE_HIDDEN}" ]; then + local pattern="s/^\s\+ w \(\w\+\)$/PROVIDE_HIDDEN(\1 = .);/gp" + echo -e "SECTIONS {\n. = _end;" > .tmp_vmlinux_hiddenld + ${NM} ${1} | sed -n "${pattern}" >> .tmp_vmlinux_hiddenld + echo "}" >> .tmp_vmlinux_hiddenld + LDFLAGS_vmlinux="${LDFLAGS_vmlinux} -T .tmp_vmlinux_hiddenld" + fi +} + # Create map file with all symbols from ${1} # See mksymap for additional details mksysmap() @@ -200,6 +211,9 @@ modpost_link vmlinux.o # modpost vmlinux.o to check for section mismatches ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o +# Generate weak linker script +gen_weak_provide_hidden vmlinux.o + kallsymso="" kallsyms_vmlinux="" if [ -n "${CONFIG_KALLSYMS}" ]; then -- 2.20.1.495.gaa96b0ce6b-goog