pax-utils.eclass: updated eclass to handle PT_PAX and XT_PAXXT_PAX

1 files changed, 198 insertions, 0 deletions

diff --git a/profiles/eclass/pax-utils.eclass b/profiles/eclass/pax-utils.eclass
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+++ b/profiles/eclass/pax-utils.eclass
@@ -0,0 +1,198 @@
+# Copyright 1999-2011 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: /var/cvsroot/gentoo-x86/eclass/pax-utils.eclass,v 1.18 2012/04/06 18:03:54 blueness Exp $
+
+# @ECLASS: pax-utils.eclass
+# @MAINTAINER:
+# The Gentoo Linux Hardened Team <hardened@gentoo.org>
+# @AUTHOR:
+# Original Author: Kevin F. Quinn <kevquinn@gentoo.org>
+# Modifications for bug #365825, @ ECLASS markup: Anthony G. Basile <blueness@gentoo.org>
+# Modifications for bug #431092: Anthony G. Basile <blueness@gentoo.org>
+# @BLURB: functions to provide pax markings
+# @DESCRIPTION:
+# This eclass provides support for manipulating PaX markings on ELF binaries,
+# wrapping the use of the paxctl and scanelf utilities.  It decides which to
+# use depending on what is installed on the build host, preferring paxctl to
+# scanelf.  If paxctl is not installed, we fall back to scanelf since it is
+# always present.  However, currently scanelf doesn't do all that paxctl can.
+#
+# To control what markings are made, set PAX_MARKINGS in /etc/portage/make.conf
+# to contain either "PT", "XT" or "none".  If PAX_MARKINGS contains "PT", and
+# the necessary utility is installed, then PT_PAX_FLAGS markings will be made.
+# Similarly, if  PAX_MARKINGS contains "XT", then xattr markings will be made.
+# If PAX_MARKINGS is set to "none", no markings will be made.
+
+if [[ ${___ECLASS_ONCE_PAX_UTILS} != "recur -_+^+_- spank" ]] ; then
+___ECLASS_ONCE_PAX_UTILS="recur -_+^+_- spank"
+
+# Default to PT markings.
+PAX_MARKINGS=${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.  Possible flags at the
+# time of writing, taken from /sbin/paxctl, are:
+#
+#	p: disable PAGEEXEC		P: enable PAGEEXEC
+#	e: disable EMUTRMAP		E: enable EMUTRMAP
+#	m: disable MPROTECT		M: enable MPROTECT
+#	r: disable RANDMMAP		R: enable RANDMMAP
+#	s: disable SEGMEXEC		S: enable SEGMEXEC
+#
+# 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.
+# Do not use the obsolete flag 'x'/'X' which has been deprecated.
+#
+# 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 pt_fail=0 pt_failures=""		# record PT_PAX failures
+	local xt_fail=0 xt_failures=""		# record xattr PAX marking failures
+	local ret=0							# overal return code of this function
+
+	# You can call pax-mark with/out leading '-' on flags
+	flags=${1//-}
+	shift
+
+	if has PT ${PAX_MARKINGS}; then
+
+		#First try paxctl-ng
+	 	if type -p paxctl-ng > /dev/null; then
+			einfo "PT PaX marking -${flags}"
+			_pax_list_files einfo "$@"
+			for f in "$@"; do
+				paxctl-ng -L -${flags} "${f}" && continue
+				pt_fail=1
+				pt_failures="${pt_failures} ${f}"
+			done
+
+		#Next try paxctl
+		elif type -p paxctl > /dev/null; then
+			einfo "PT PaX marking -${flags}"
+			_pax_list_files einfo "$@"
+			for f in "$@"; do
+				# First, try modifying the existing PAX_FLAGS header
+				paxctl -q${flags} "${f}" && continue
+				# Second, try stealing the (unused under PaX) PT_GNU_STACK header
+				paxctl -qc${flags} "${f}" && continue
+				# Third, creating a PT_PAX header (works on ET_EXEC)
+				paxctl -qC${flags} "${f}" && continue
+				pt_fail=1
+				pt_failures="${pt_failures} ${f}"
+			done
+
+		#Finally fall back on scanelf
+		elif type -p scanelf > /dev/null && [[ ${PAX_MARKINGS} != "none" ]]; then
+			einfo "Fallback PaX marking -${flags}"
+			_pax_list_files einfo "$@"
+			scanelf -Xxz ${flags} "$@"
+
+		#We failed to set PT_PAX flags
+		elif [[ ${PAX_MARKINGS} != "none" ]]; then
+			pt_failures="$*"
+			pt_fail=1
+		fi
+
+		if [[ ${pt_fail} == 1 ]]; then
+			ewarn "Failed to set XT_PAX markings -${flags} for:"
+			_pax_list_files ewarn ${pt_failures}
+			ret=1
+		fi
+	fi
+
+	if has XT ${PAX_MARKINGS}; then
+
+		#First try paxctl-ng
+	 	if type -p paxctl-ng > /dev/null; then
+			einfo "XT PaX marking -${flags}"
+			_pax_list_files einfo "$@"
+			for f in "$@"; do
+				paxctl-ng -l -${flags} "${f}" && continue
+				xt_fail=1
+				xt_failures="${tx_failures} ${f}"
+			done
+
+		#Next try set/get 
+		elif type -p setfattr > /dev/null; then
+			einfo "XT PaX marking -${flags}"
+			_pax_list_files einfo "$@"
+			for f in "$@"; do
+				setfattr -n "user.pax.flags" -v "${flags}" "${f}" && continue
+				xt_fail=1
+				xt_failures="${tx_failures} ${f}"
+			done
+
+		#We failed to set PT_PAX flags
+		elif [[ ${PAX_MARKINGS} != "none" ]]; then
+			pt_failures="$*"
+			pt_fail=1
+		fi
+
+		if [[ ${xt_fail} == 1 ]]; then
+			ewarn "Failed to set XT_PAX markings -${flags} for:"
+			_pax_list_files ewarn ${xt_failures}
+			ret=1
+		fi
+	fi
+
+	[[ ${ret} == 1 ]] && ewarn "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 intedened to
+# determine whether the final binaries need PaX markings.  Note: if procfs is
+# not mounted on /proc, this returns shell false (e.g. Gentoo/FBSD).
+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 arbitratily).
+
+# 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