From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 21A2D158008 for ; Thu, 15 Jun 2023 13:06:41 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 7AABAE08F5; Thu, 15 Jun 2023 13:06:37 +0000 (UTC) Received: from smtp.gentoo.org (dev.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 41F1DE08E8 for ; Thu, 15 Jun 2023 13:06:37 +0000 (UTC) Message-ID: Date: Thu, 15 Jun 2023 15:06:33 +0200 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [gentoo-dev] [PATCH 1/2 v2] kernel-build.eclass: add IUSE="+strip modules-sign", install generated keys Content-Language: en-US, nl-NL To: gentoo-dev@lists.gentoo.org References: From: Andrew Ammerlaan Organization: Gentoo Linux In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Archives-Salt: 0b953280-42c7-47c4-b380-3f6a7f43334d X-Archives-Hash: f65d54acc96c8853cecb6693631ebd9e Version 2 moves all of the logic into the eclass, reducing code duplication at the cost of potentially having to adjust the CONFIG_MODULE_SIG_* logic at some later stage if this changes upstream. We now also unset KBUILD_SIGN_PIN, as is done in linux-mod-r1.eclass as well. From b0e42a34469c3799b2c2c636d794a95040549133 Mon Sep 17 00:00:00 2001 From: Andrew Ammerlaan Date: Thu, 15 Jun 2023 11:50:10 +0200 Subject: [PATCH] kernel-build.eclass: add IUSE="+strip modules-sign", install generated keys - Let the kernel build system handle stripping of the modules. This is necessary for successfully signing and compressing modules. Inspired by linux-mod-r1.eclass. - If the build system has generated keys or certificates, install them. This is required to successfully sign external kernel modules. - Enable module signing configure options if requested by the user. - Define the user variables MODULES_SIGN_HASH and MODULES_SIGN_KEY. For controlling the used hashing algorithm and allowing the use of external keys. These variables are the same as in linux-mod-r1.eclass - Warn the user if we are letting the kernel build system generate the signing key. This key will end up binary packages. Plus external modules will have to be resigned if gentoo-kernel is re-emerged (i.e. a new key was generated). Closes: https://bugs.gentoo.org/814344 Closes: https://bugs.gentoo.org/881651 Signed-off-by: Andrew Ammerlaan --- eclass/kernel-build.eclass | 115 +++++++++++++++++++++++++++++++++++-- 1 file changed, 111 insertions(+), 4 deletions(-) diff --git a/eclass/kernel-build.eclass b/eclass/kernel-build.eclass index da215a055a467..7634a4445350f 100644 --- a/eclass/kernel-build.eclass +++ b/eclass/kernel-build.eclass @@ -1,4 +1,4 @@ -# Copyright 2020-2022 Gentoo Authors +# Copyright 2020-2023 Gentoo Authors # Distributed under the terms of the GNU General Public License v2 # @ECLASS: kernel-build.eclass @@ -41,6 +41,50 @@ BDEPEND=" app-alternatives/yacc " +IUSE="+strip" + +# @ECLASS_VARIABLE: ALLOW_MODULES_SIGN +# @PRE_INHERIT +# @DEFAULT_UNSET +# @DESCRIPTION: +# If set to a non-null value, adds IUSE=modules-sign and required +# logic to manipulate the kernel config while respecting the +# MODULES_SIGN_HASH and MODULES_SIGN_KEY user variables. + +# @ECLASS_VARIABLE: MODULES_SIGN_HASH +# @USER_VARIABLE +# @DEFAULT_UNSET +# @DESCRIPTION: +# Used with USE=modules-sign. Can be set to hash algorithm to use +# during signature generation (CONFIG_MODULE_SIG_SHA256). +# +# Valid values: sha512,sha384,sha256,sha224,sha1 +# +# Default if unset: sha512 + +# @ECLASS_VARIABLE: MODULES_SIGN_KEY +# @USER_VARIABLE +# @DEFAULT_UNSET +# @DESCRIPTION: +# Used with USE=modules-sign. Can be set to the path of the private +# key in PEM format to use, or a PKCS#11 URI (CONFIG_MODULE_SIG_KEY). +# +# If path is relative (e.g. "certs/name.pem"), it is assumed to be +# relative to the kernel build directory being used. +# +# If the key requires a passphrase or PIN, the used kernel sign-file +# utility recognizes the KBUILD_SIGN_PIN environment variable. Be +# warned that the package manager may store this value in binary +# packages, database files, temporary files, and possibly logs. This +# eclass unsets the variable after use to mitigate the issue (notably +# for shared binary packages), but use this with care. +# +# Default if unset: certs/signing_key.pem + +if [[ -n "${ALLOW_MODULES_SIGN}" ]]; then + IUSE+=" modules-sign" +fi + # @FUNCTION: kernel-build_src_configure # @DESCRIPTION: # Prepare the toolchain for building the kernel, get the default .config @@ -83,7 +127,7 @@ kernel-build_src_configure() { LD="${LD}" AR="$(tc-getAR)" NM="$(tc-getNM)" - STRIP=":" + STRIP="$(tc-getSTRIP)" OBJCOPY="$(tc-getOBJCOPY)" OBJDUMP="$(tc-getOBJDUMP)" @@ -176,8 +220,18 @@ kernel-build_src_install() { targets+=( dtbs_install ) fi + # Use the kernel build system to strip, this ensures the modules + # are stripped *before* they are signed or compressed. + local strip_args + if use strip; then + strip_args="--strip-unneeded" + fi + # Modules were already stripped by the kernel build system + dostrip -x /lib/modules + emake O="${WORKDIR}"/build "${MAKEARGS[@]}" \ - INSTALL_MOD_PATH="${ED}" INSTALL_PATH="${ED}/boot" "${targets[@]}" + INSTALL_MOD_PATH="${ED}" INSTALL_MOD_STRIP="${strip_args}" \ + INSTALL_PATH="${ED}/boot" "${targets[@]}" # note: we're using mv rather than doins to save space and time # install main and arch-specific headers first, and scripts @@ -217,6 +271,14 @@ kernel-build_src_install() { local image_path=$(dist-kernel_get_image_path) cp -p "build/${image_path}" "${ED}${kernel_dir}/${image_path}" || die + # If a key was generated, copy it so external modules can be signed + local suffix + for suffix in pem x509; do + if [[ -f "build/certs/signing_key.${suffix}" ]]; then + cp -p "build/certs/signing_key.${suffix}" "${ED}${kernel_dir}/certs" || die + fi + done + # building modules fails with 'vmlinux has no symtab?' if stripped use ppc64 && dostrip -x "${kernel_dir}/${image_path}" @@ -239,6 +301,9 @@ kernel-build_src_install() { dosym "../../../${kernel_dir}" "/lib/modules/${module_ver}/build" dosym "../../../${kernel_dir}" "/lib/modules/${module_ver}/source" + # unset to at least be out of the environment file in, e.g. shared binpkgs + unset KBUILD_SIGN_PIN + save_config build/.config } @@ -248,6 +313,25 @@ kernel-build_src_install() { kernel-build_pkg_postinst() { kernel-install_pkg_postinst savedconfig_pkg_postinst + if [[ -n "${ALLOW_MODULES_SIGN}" ]]; then + if use modules-sign && [[ -z "${MODULES_SIGN_KEY}" ]]; then + ewarn + ewarn "MODULES_SIGN_KEY was not set, this means the kernel build system" + ewarn "automatically generated the signing key. This key was installed" + ewarn "in ${EROOT}/usr/src/linux-${PV}${KV_LOCALVERSION}/certs" + ewarn "and will also be included in any binary packages." + ewarn "Please take appropriate action to protect the key!" + ewarn + ewarn "Recompiling this package causes a new key to be generated. As" + ewarn "a result any external kernel modules will need to be resigned." + ewarn "Use emerge @module-rebuild, or manually sign the modules as" + ewarn "described on the wiki [1]" + ewarn + ewarn "Consider using the MODULES_SIGN_KEY variable to use an external key." + ewarn + ewarn "[1]: https://wiki.gentoo.org/wiki/Signed_kernel_module_support" + fi + fi } # @FUNCTION: kernel-build_merge_configs @@ -270,16 +354,39 @@ kernel-build_merge_configs() { local user_configs=( "${BROOT}"/etc/kernel/config.d/*.config ) shopt -u nullglob + local merge_configs=( "${@}" ) + + if [[ -n "${ALLOW_MODULES_SIGN}" ]]; then + if use modules-sign; then + : "${MODULES_SIGN_HASH:=sha512}" + cat <<-EOF > "${WORKDIR}/modules-sign.config" || die + ## Enable module signing + CONFIG_MODULE_SIG=y + CONFIG_MODULE_SIG_ALL=y + CONFIG_MODULE_SIG_FORCE=y + CONFIG_MODULE_SIG_${MODULES_SIGN_HASH^^}=y + EOF + if [[ -e "${MODULES_SIGN_KEY}" ]]; then + echo "CONFIG_MODULE_SIG_KEY=\"${MODULES_SIGN_KEY}\"" \ + >> "${WORKDIR}/modules-sign.config" + elif [[ -n "${MODULES_SIGN_KEY}" ]]; then + die "MODULES_SIGN_KEY=${MODULES_SIGN_KEY} not found!" + fi + merge_configs+=( "${WORKDIR}/modules-sign.config" ) + fi + fi + if [[ ${#user_configs[@]} -gt 0 ]]; then elog "User config files are being applied:" local x for x in "${user_configs[@]}"; do elog "- ${x}" done + merge_configs+=( "${user_configs[@]}" ) fi ./scripts/kconfig/merge_config.sh -m -r \ - .config "${@}" "${user_configs[@]}" || die + .config "${merge_configs[@]}" || die } fi