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Revision 1.22 - (show annotations) (download)
Fri Jul 11 08:21:58 2014 UTC (2 months, 3 weeks ago) by ulm
Branch: MAIN
Changes since 1.21: +4 -4 lines
Avoid reserved names for functions and variables, bug 516092.

1 # Copyright 1999-2014 Gentoo Foundation
2 # Distributed under the terms of the GNU General Public License v2
3 # $Header: /var/cvsroot/gentoo-x86/eclass/pax-utils.eclass,v 1.21 2013/05/18 13:43:20 zorry Exp $
4
5 # @ECLASS: pax-utils.eclass
6 # @MAINTAINER:
7 # The Gentoo Linux Hardened Team <hardened@gentoo.org>
8 # @AUTHOR:
9 # Original Author: Kevin F. Quinn <kevquinn@gentoo.org>
10 # Modifications for bug #365825, @ ECLASS markup: Anthony G. Basile <blueness@gentoo.org>
11 # Modifications for bug #431092: Anthony G. Basile <blueness@gentoo.org>
12 # @BLURB: functions to provide pax markings
13 # @DESCRIPTION:
14 #
15 # This eclass provides support for manipulating PaX markings on ELF binaries,
16 # whether the system is using legacy PT_PAX markings or the newer XATTR_PAX.
17 # The eclass wraps the use of paxctl-ng, paxctl, set/getattr and scanelf utilities,
18 # deciding which to use depending on what's installed on the build host, and
19 # whether we're working with PT_PAX, XATTR_PAX or both.
20 #
21 # To control what markings are made, set PAX_MARKINGS in /etc/portage/make.conf
22 # to contain either "PT", "XT" or "none". The default is to attempt both
23 # PT_PAX and XATTR_PAX.
24
25 if [[ -z ${_PAX_UTILS_ECLASS} ]]; then
26 _PAX_UTILS_ECLASS=1
27
28 # @ECLASS-VARIABLE: PAX_MARKINGS
29 # @DESCRIPTION:
30 # Control which markings are made:
31 # PT = PT_PAX markings, XT = XATTR_PAX markings
32 # Default to PT markings.
33 PAX_MARKINGS=${PAX_MARKINGS:="PT"}
34
35 # @FUNCTION: pax-mark
36 # @USAGE: <flags> {<ELF files>}
37 # @RETURN: Shell true if we succeed, shell false otherwise
38 # @DESCRIPTION:
39 # Marks <ELF files> with provided PaX <flags>
40 #
41 # Flags are passed directly to the utilities unchanged
42 #
43 # p: disable PAGEEXEC P: enable PAGEEXEC
44 # e: disable EMUTRAMP E: enable EMUTRAMP
45 # m: disable MPROTECT M: enable MPROTECT
46 # r: disable RANDMMAP R: enable RANDMMAP
47 # s: disable SEGMEXEC S: enable SEGMEXEC
48 #
49 # Default flags are 'PeMRS', which are the most restrictive settings. Refer
50 # to http://pax.grsecurity.net/ for details on what these flags are all about.
51 #
52 # Please confirm any relaxation of restrictions with the Gentoo Hardened team.
53 # Either ask on the gentoo-hardened mailing list, or CC/assign hardened@g.o on
54 # the bug report.
55 pax-mark() {
56
57 local f # loop over paxables
58 local flags # pax flags
59 local pt_fail=0 pt_failures="" # record PT_PAX failures
60 local xt_fail=0 xt_failures="" # record xattr PAX marking failures
61 local ret=0 # overal return code of this function
62
63 # Only the actual PaX flags and z are accepted
64 # 1. The leading '-' is optional
65 # 2. -C -c only make sense for paxctl, but are unnecessary
66 # because we progressively do -q -qc -qC
67 # 3. z is allowed for the default
68
69 flags="${1//[!zPpEeMmRrSs]}"
70 [[ "${flags}" ]] || return 0
71 shift
72
73 # z = default. For XATTR_PAX, the default is no xattr field at all
74 local dodefault=""
75 [[ "${flags//[!z]}" ]] && dodefault="yes"
76
77 if has PT ${PAX_MARKINGS}; then
78
79 #First try paxctl -> this might try to create/convert program headers
80 if type -p paxctl > /dev/null; then
81 einfo "PT PaX marking -${flags} with paxctl"
82 _pax_list_files einfo "$@"
83 for f in "$@"; do
84 # First, try modifying the existing PAX_FLAGS header
85 paxctl -q${flags} "${f}" && continue
86 # Second, try creating a PT_PAX header (works on ET_EXEC)
87 # Even though this is less safe, most exes need it, eg bug #463170
88 paxctl -qC${flags} "${f}" && continue
89 # Third, try stealing the (unused under PaX) PT_GNU_STACK header
90 paxctl -qc${flags} "${f}" && continue
91 pt_fail=1
92 pt_failures="${pt_failures} ${f}"
93 done
94
95 #Next try paxctl-ng -> this will not create/convert any program headers
96 elif type -p paxctl-ng > /dev/null && paxctl-ng -L ; then
97 einfo "PT PaX marking -${flags} with paxctl-ng"
98 flags="${flags//z}"
99 _pax_list_files einfo "$@"
100 for f in "$@"; do
101 [[ ${dodefault} == "yes" ]] && paxctl-ng -L -z "${f}"
102 [[ "${flags}" ]] || continue
103 paxctl-ng -L -${flags} "${f}" && continue
104 pt_fail=1
105 pt_failures="${pt_failures} ${f}"
106 done
107
108 #Finally fall back on scanelf
109 elif type -p scanelf > /dev/null && [[ ${PAX_MARKINGS} != "none" ]]; then
110 einfo "Fallback PaX marking -${flags} with scanelf"
111 _pax_list_files einfo "$@"
112 scanelf -Xxz ${flags} "$@"
113
114 #We failed to set PT_PAX flags
115 elif [[ ${PAX_MARKINGS} != "none" ]]; then
116 pt_failures="$*"
117 pt_fail=1
118 fi
119
120 if [[ ${pt_fail} == 1 ]]; then
121 elog "Failed to set PT_PAX markings -${flags} for:"
122 _pax_list_files elog ${pt_failures}
123 ret=1
124 fi
125 fi
126
127 if has XT ${PAX_MARKINGS}; then
128
129 flags="${flags//z}"
130
131 #First try paxctl-ng
132 if type -p paxctl-ng > /dev/null && paxctl-ng -l ; then
133 einfo "XT PaX marking -${flags} with paxctl-ng"
134 _pax_list_files einfo "$@"
135 for f in "$@"; do
136 [[ ${dodefault} == "yes" ]] && paxctl-ng -d "${f}"
137 [[ "${flags}" ]] || continue
138 paxctl-ng -l -${flags} "${f}" && continue
139 xt_fail=1
140 xt_failures="${tx_failures} ${f}"
141 done
142
143 #Next try setfattr
144 elif type -p setfattr > /dev/null; then
145 [[ "${flags//[!Ee]}" ]] || flags+="e" # bug 447150
146 einfo "XT PaX marking -${flags} with setfattr"
147 _pax_list_files einfo "$@"
148 for f in "$@"; do
149 [[ ${dodefault} == "yes" ]] && setfattr -x "user.pax.flags" "${f}"
150 setfattr -n "user.pax.flags" -v "${flags}" "${f}" && continue
151 xt_fail=1
152 xt_failures="${tx_failures} ${f}"
153 done
154
155 #We failed to set XATTR_PAX flags
156 elif [[ ${PAX_MARKINGS} != "none" ]]; then
157 xt_failures="$*"
158 xt_fail=1
159 fi
160
161 if [[ ${xt_fail} == 1 ]]; then
162 elog "Failed to set XATTR_PAX markings -${flags} for:"
163 _pax_list_files elog ${xt_failures}
164 ret=1
165 fi
166 fi
167
168 # [[ ${ret} == 1 ]] && elog "Executables may be killed by PaX kernels."
169
170 return ${ret}
171 }
172
173 # @FUNCTION: list-paxables
174 # @USAGE: {<files>}
175 # @RETURN: Subset of {<files>} which are ELF executables or shared objects
176 # @DESCRIPTION:
177 # Print to stdout all of the <files> that are suitable to have PaX flag
178 # markings, i.e., filter out the ELF executables or shared objects from a list
179 # of files. This is useful for passing wild-card lists to pax-mark, although
180 # in general it is preferable for ebuilds to list precisely which ELFS are to
181 # be marked. Often not all the ELF installed by a package need remarking.
182 # @EXAMPLE:
183 # pax-mark -m $(list-paxables ${S}/{,usr/}bin/*)
184 list-paxables() {
185 file "$@" 2> /dev/null | grep -E 'ELF.*(executable|shared object)' | sed -e 's/: .*$//'
186 }
187
188 # @FUNCTION: host-is-pax
189 # @RETURN: Shell true if the build process is PaX enabled, shell false otherwise
190 # @DESCRIPTION:
191 # This is intended for use where the build process must be modified conditionally
192 # depending on whether the host is PaX enabled or not. It is not intedened to
193 # determine whether the final binaries need PaX markings. Note: if procfs is
194 # not mounted on /proc, this returns shell false (e.g. Gentoo/FBSD).
195 host-is-pax() {
196 grep -qs ^PaX: /proc/self/status
197 }
198
199
200 # INTERNAL FUNCTIONS
201 # ------------------
202 #
203 # These functions are for use internally by the eclass - do not use
204 # them elsewhere as they are not supported (i.e. they may be removed
205 # or their function may change arbitratily).
206
207 # Display a list of things, one per line, indented a bit, using the
208 # display command in $1.
209 _pax_list_files() {
210 local f cmd
211 cmd=$1
212 shift
213 for f in "$@"; do
214 ${cmd} " ${f}"
215 done
216 }
217
218 fi

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