diff options
author | V3n3RiX <venerix@redcorelinux.org> | 2017-10-09 18:53:29 +0100 |
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committer | V3n3RiX <venerix@redcorelinux.org> | 2017-10-09 18:53:29 +0100 |
commit | 4f2d7949f03e1c198bc888f2d05f421d35c57e21 (patch) | |
tree | ba5f07bf3f9d22d82e54a462313f5d244036c768 /eclass/pax-utils.eclass |
reinit the tree, so we can have metadata
Diffstat (limited to 'eclass/pax-utils.eclass')
-rw-r--r-- | eclass/pax-utils.eclass | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/eclass/pax-utils.eclass b/eclass/pax-utils.eclass new file mode 100644 index 000000000000..ca8f15d9c919 --- /dev/null +++ b/eclass/pax-utils.eclass @@ -0,0 +1,190 @@ +# Copyright 1999-2016 Gentoo Foundation +# Distributed under the terms of the GNU General Public License v2 + +# @ECLASS: pax-utils.eclass +# @MAINTAINER: +# The Gentoo Linux Hardened Team <hardened@gentoo.org> +# @AUTHOR: +# Author: Kevin F. Quinn <kevquinn@gentoo.org> +# Author: Anthony G. Basile <blueness@gentoo.org> +# @BLURB: functions to provide PaX markings for hardened kernels +# @DESCRIPTION: +# +# This eclass provides support for manipulating PaX markings on ELF binaries, +# whether the system is using legacy PT_PAX markings or the newer XATTR_PAX. +# The eclass wraps the use of paxctl-ng, paxctl, set/getattr and scanelf utilities, +# deciding which to use depending on what's installed on the build host, and +# whether we're working with PT_PAX, XATTR_PAX or both. +# +# To control what markings are made, set PAX_MARKINGS in /etc/portage/make.conf +# to contain either "PT", "XT" or "none". The default is to attempt both +# PT_PAX and XATTR_PAX. + +if [[ -z ${_PAX_UTILS_ECLASS} ]]; then +_PAX_UTILS_ECLASS=1 + +# @ECLASS-VARIABLE: PAX_MARKINGS +# @DESCRIPTION: +# Control which markings are made: +# PT = PT_PAX markings, XT = XATTR_PAX markings +# Default to PT markings. +PAX_MARKINGS=${PAX_MARKINGS:="PT XT"} + +# @FUNCTION: pax-mark +# @USAGE: <flags> <ELF files> +# @RETURN: Shell true if we succeed, shell false otherwise +# @DESCRIPTION: +# Marks <ELF files> with provided PaX <flags> +# +# Flags are passed directly to the utilities unchanged. +# +# @CODE +# p: disable PAGEEXEC P: enable PAGEEXEC +# e: disable EMUTRAMP E: enable EMUTRAMP +# m: disable MPROTECT M: enable MPROTECT +# r: disable RANDMMAP R: enable RANDMMAP +# s: disable SEGMEXEC S: enable SEGMEXEC +# @CODE +# +# Default flags are 'PeMRS', which are the most restrictive settings. Refer +# to http://pax.grsecurity.net/ for details on what these flags are all about. +# +# Please confirm any relaxation of restrictions with the Gentoo Hardened team. +# Either ask on the gentoo-hardened mailing list, or CC/assign hardened@g.o on +# the bug report. +pax-mark() { + local f # loop over paxables + local flags # pax flags + local ret=0 # overall return code of this function + + # Only the actual PaX flags and z are accepted + # 1. The leading '-' is optional + # 2. -C -c only make sense for paxctl, but are unnecessary + # because we progressively do -q -qc -qC + # 3. z is allowed for the default + + flags="${1//[!zPpEeMmRrSs]}" + [[ "${flags}" ]] || return 0 + shift + + # z = default. For XATTR_PAX, the default is no xattr field at all + local dodefault="" + [[ "${flags//[!z]}" ]] && dodefault="yes" + + if has PT ${PAX_MARKINGS}; then + # Uncomment to list all files to be marked + # _pax_list_files einfo "$@" + for f in "$@"; do + + # First try paxctl + if type -p paxctl >/dev/null; then + einfo "PT_PAX marking -${flags} ${f} with paxctl" + # We try modifying the existing PT_PAX_FLAGS header. + paxctl -q${flags} "${f}" >/dev/null 2>&1 && continue + # We no longer try to create/convert a PT_PAX_FLAGS header, bug #590422 + # paxctl -qC${flags} "${f}" >/dev/null 2>&1 && continue + # paxctl -qc${flags} "${f}" >/dev/null 2>&1 && continue + fi + + # Next try paxctl-ng -> this will not create/convert any program headers. + if type -p paxctl-ng >/dev/null && paxctl-ng -L ; then + einfo "PT_PAX marking -${flags} ${f} with paxctl-ng" + flags="${flags//z}" + [[ ${dodefault} == "yes" ]] && paxctl-ng -L -z "${f}" >/dev/null 2>&1 + [[ "${flags}" ]] || continue + paxctl-ng -L -${flags} "${f}" >/dev/null 2>&1 && continue + fi + + # Finally fall back on scanelf. + if type -p scanelf >/dev/null && [[ ${PAX_MARKINGS} != "none" ]]; then + einfo "PT_PAX marking -${flags} ${f} with scanelf" + scanelf -Xxz ${flags} "$f" >/dev/null 2>&1 + # We failed to set PT_PAX flags. + elif [[ ${PAX_MARKINGS} != "none" ]]; then + elog "Failed to set PT_PAX markings -${flags} ${f}." + ret=1 + fi + done + fi + + if has XT ${PAX_MARKINGS}; then + # Uncomment to list all files to be marked + # _pax_list_files einfo "$@" + flags="${flags//z}" + for f in "$@"; do + + # First try paxctl-ng. + if type -p paxctl-ng >/dev/null && paxctl-ng -l ; then + einfo "XATTR_PAX marking -${flags} ${f} with paxctl-ng" + [[ ${dodefault} == "yes" ]] && paxctl-ng -d "${f}" >/dev/null 2>&1 + [[ "${flags}" ]] || continue + paxctl-ng -l -${flags} "${f}" >/dev/null 2>&1 && continue + fi + + # Next try setfattr. + if type -p setfattr >/dev/null; then + [[ "${flags//[!Ee]}" ]] || flags+="e" # bug 447150 + einfo "XATTR_PAX marking -${flags} ${f} with setfattr" + [[ ${dodefault} == "yes" ]] && setfattr -x "user.pax.flags" "${f}" >/dev/null 2>&1 + setfattr -n "user.pax.flags" -v "${flags}" "${f}" >/dev/null 2>&1 && continue + fi + + # We failed to set XATTR_PAX flags. + if [[ ${PAX_MARKINGS} != "none" ]]; then + elog "Failed to set XATTR_PAX markings -${flags} ${f}." + ret=1 + fi + done + fi + + # [[ ${ret} == 1 ]] && elog "Executables may be killed by PaX kernels." + + return ${ret} +} + +# @FUNCTION: list-paxables +# @USAGE: <files> +# @RETURN: Subset of <files> which are ELF executables or shared objects +# @DESCRIPTION: +# Print to stdout all of the <files> that are suitable to have PaX flag +# markings, i.e., filter out the ELF executables or shared objects from a list +# of files. This is useful for passing wild-card lists to pax-mark, although +# in general it is preferable for ebuilds to list precisely which ELFS are to +# be marked. Often not all the ELF installed by a package need remarking. +# @EXAMPLE: +# pax-mark -m $(list-paxables ${S}/{,usr/}bin/*) +list-paxables() { + file "$@" 2> /dev/null | grep -E 'ELF.*(executable|shared object)' | sed -e 's/: .*$//' +} + +# @FUNCTION: host-is-pax +# @RETURN: Shell true if the build process is PaX enabled, shell false otherwise +# @DESCRIPTION: +# This is intended for use where the build process must be modified conditionally +# depending on whether the host is PaX enabled or not. It is not indented to +# determine whether the final binaries need PaX markings. Note: if procfs is +# not mounted on /proc, this returns shell false (e.g. Gentoo/FreeBSD). +host-is-pax() { + grep -qs ^PaX: /proc/self/status +} + + +# INTERNAL FUNCTIONS +# ------------------ +# +# These functions are for use internally by the eclass - do not use +# them elsewhere as they are not supported (i.e. they may be removed +# or their function may change arbitrarily). + +# Display a list of things, one per line, indented a bit, using the +# display command in $1. +_pax_list_files() { + local f cmd + cmd=$1 + shift + for f in "$@"; do + ${cmd} " ${f}" + done +} + +fi |