/[gentoo-x86]/eclass/pax-utils.eclass
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1# Copyright 1999-2006 Gentoo Foundation 1# Copyright 1999-2006 Gentoo Foundation
2# Distributed under the terms of the GNU General Public License v2 2# Distributed under the terms of the GNU General Public License v2
3# $Header: /var/cvsroot/gentoo-x86/eclass/pax-utils.eclass,v 1.2 2006/11/15 22:14:25 kevquinn Exp $ 3# $Header: /var/cvsroot/gentoo-x86/eclass/pax-utils.eclass,v 1.4 2006/12/02 11:33:04 kevquinn Exp $
4 4
5# Author: 5# Author:
6# Kevin F. Quinn <kevquinn@gentoo.org> 6# Kevin F. Quinn <kevquinn@gentoo.org>
7# 7#
8# This eclass provides support for manipulating PaX markings on ELF 8# This eclass provides support for manipulating PaX markings on ELF
9# binaries, wrapping the use of the chpax and paxctl utilities. 9# binaries, wrapping the use of the chpaxi, paxctl and scanelf utilities.
10# Currently it decides which to use depending on what is installed on the
11# build host; this may change in the future to use a control variable
12# (which would also mean modifying DEPEND to bring in sys-apps/paxctl etc).
13#
14#
15# CONTROL
16# -------
17#
18# To control what markings are set, assign PAX_MARKINGS in
19# /etc/make.conf to contain the strings "EI" and/or "PT".
20# If EI is present in PAX_MARKINGS (and the chpax utility
21# is present), the legacy 'chpax' style markings will be
22# set. If PT is present in PAX_MARKINGS (and the paxctl
23# utility is present), the 'paxctl' markings will be set.
24# Default is to try to do both. Set it to "NONE" to prevent
25# any markings being made.
26#
27#
28# PROVIDED FUNCTIONS
29# ------------------
30#
31#### pax-mark <flags> {<ELF files>}
32# Marks files <files> with provided PaX flags <flags>
33#
34# Please confirm any relaxation of restrictions with the
35# Gentoo Hardened team; either ask on the gentoo-hardened
36# mailing list, or CC/assign hardened@g.o on a bug.
37#
38# Flags are passed directly to the utilities unchanged. Possible
39# flags at the time of writing, taken from /sbin/paxctl, are:
40#
41# p: disable PAGEEXEC P: enable PAGEEXEC
42# e: disable EMUTRMAP E: enable EMUTRMAP
43# m: disable MPROTECT M: enable MPROTECT
44# r: disable RANDMMAP R: enable RANDMMAP
45# s: disable SEGMEXEC S: enable SEGMEXEC
46#
47# Default flags are 'PeMRS', which are the most restrictive
48# settings. Refer to http://pax.grsecurity.net/ for details
49# on what these flags are all about. There is an obsolete
50# flag 'x'/'X' which has been removed from PaX.
51#
52# If chpax is not installed, the legacy EI flags (which are
53# not strip-safe, and strictly speaking violate the ELF spec)
54# will not be set. If paxctl is not installed, it falls back
55# to scanelf. scanelf is always present, but currently doesn't
56# quite do all that paxctl can do.
57# Returns fail if one or more files could not be marked.
58#
59#
60#### list-paxables {<files>}
61# Prints to stdout all of <files> that are suitable to having PaX
62# flags (i.e. filter to just ELF files). Useful for passing wild-card
63# lists of files to pax-mark, although in general it is preferable
64# for ebuilds to list precisely which executables are to be marked.
65# Use like:
66# pax-mark -m $(list-paxables ${S}/{,usr/}bin/*)
67#
68#
69#### host-is-pax
70# Returns true if the host has a PaX-enabled kernel, false otherwise.
71# Intended for use where the build process must be modified conditionally
72# in order to satisfy PaX. Note; it is _not_ intended to indicate
73# whether the final executables should satisfy PaX - executables should
74# always be marked appropriately even if they're only going to be
75# installed on a non-PaX system.
10 76
11inherit eutils 77inherit eutils
12 78
13##### pax-mark #### 79# Default to both EI and PT markings.
14# Mark a file for PaX, with the provided flags, and log it into 80PAX_MARKINGS=${PAX_MARKINGS:="EI PT"}
15# a PaX database. Returns non-zero if flag marking failed.
16#
17# If paxctl is installed, but not chpax, then the legacy
18# EI flags (which are not strip-safe) will not be set.
19# If neither are installed, falls back to scanelf (which
20# is always present, but currently doesn't quite do all
21# that paxctl can do).
22 81
82# pax-mark <flags> {<ELF files>}
23pax-mark() { 83pax-mark() {
24 local flags fail=0 84 local f flags fail=0 failures=""
85 # Ignore '-' characters - in particular so that it doesn't matter if
86 # the caller prefixes with -
25 flags=$1 87 flags=${1//-}
26 shift 88 shift
27 if [[ -x /sbin/chpax ]]; then 89 # Try chpax, for (deprecated) EI legacy marking.
90 if type -p chpax > /dev/null && hasq EI ${PAX_MARKINGS}; then
28 einfo "Legacy EI PaX marking $* with ${flags}" 91 einfo "Legacy EI PaX marking -${flags}"
29 /sbin/chpax -${flags} $* || fail=1 92 _pax_list_files echo "$@"
93 for f in "$@"; do
94 /sbin/chpax -${flags} "${f}" && continue
95 fail=1
96 failures="${failures} ${f}"
97 done
30 fi 98 fi
31 if [[ -x /sbin/paxctl ]]; then 99 # Try paxctl, then scanelf - paxctl takes precedence
100 # over scanelf.
101 if type -p paxctl > /dev/null && hasq PT ${PAX_MARKINGS}; then
102 # Try paxctl, the upstream supported tool.
32 einfo "PT PaX marking $* with ${flags}" 103 einfo "PT PaX marking -${flags}"
33 /sbin/paxctl -${flags} $* || 104 _pax_list_files echo "$@"
34 /sbin/paxctl -c${flags} $* || 105 for f in "$@"; do
35 /sbin/paxctl -C${flags} $* || fail=1 106 /sbin/paxctl -q${flags} "${f}" && continue
36 elif [[ -x /usr/bin/scanelf ]]; then 107 /sbin/paxctl -qc${flags} "${f}" && continue
108 /sbin/paxctl -qC${flags} "${f}" && continue
109 fail=1
110 failures="${failures} ${f}"
111 done
112 elif type -p scanelf > /dev/null && [[ -n ${PAX_MARKINGS} ]]; then
113 # Try scanelf, Gentoo's swiss-army knife ELF utility
114 # Currently this sets EI and PT if it can, no option to
115 # control what it does.
37 einfo "Fallback PaX marking $* with ${flags}" 116 einfo "Fallback PaX marking -${flags}"
117 _pax_list_files echo "$@"
38 /usr/bin/scanelf -Xxz ${flags} $* 118 /usr/bin/scanelf -Xxz ${flags} "$@"
39 else 119 else
40 ewarn "Failed to set PaX markings ${flags} for files $*. Executables may be killed by PaX kernels." 120 # Out of options!
121 failures="$*"
41 fail=1 122 fail=1
123 fi
124 if [[ ${fail} == 1 ]]; then
125 ewarn "Failed to set PaX markings -${flags} for:"
126 _pax_list_files ewarn ${failures}
127 ewarn "Executables may be killed by PaX kernels."
42 fi 128 fi
43 return ${fail} 129 return ${fail}
44} 130}
45 131
132# list-paxables {<files>}
133list-paxables() {
134 file "$@" 2> /dev/null | grep ELF | sed -e 's/: .*$//'
135}
136
46##### host-is-pax 137# host-is-pax
47# Indicates whether the build machine has PaX or not; intended for use 138# Note: if procfs is not on /proc, this returns False (e.g. Gentoo/FBSD).
48# where the build process must be modified conditionally in order to satisfy PaX.
49host-is-pax() { 139host-is-pax() {
50 # We need procfs to work this out. PaX is only available on Linux,
51 # so result is always false on non-linux machines (e.g. Gentoo/*BSD)
52 [[ -e /proc/self/status ]] || return 1
53 grep ^PaX: /proc/self/status > /dev/null 140 grep -qs ^PaX: /proc/self/status
54 return $?
55} 141}
142
143
144# INTERNAL FUNCTIONS
145# ------------------
146#
147# These functions are for use internally by the eclass - do not use
148# them elsewhere as they are not supported (i.e. they may be removed
149# or their function may change arbitratily).
150
151# Display a list of things, one per line, indented a bit, using the
152# display command in $1.
153_pax_list_files() {
154 local f cmd
155 cmd=$1
156 shift
157 for f in "$@"; do
158 ${cmd} " ${f}"
159 done
160}
161

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