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Revision 1.4 - (hide annotations) (download)
Sat Dec 2 11:33:04 2006 UTC (7 years, 8 months ago) by kevquinn
Branch: MAIN
Changes since 1.3: +122 -39 lines
fix bugs, implement suggestions from vapier

1 kevquinn 1.1 # Copyright 1999-2006 Gentoo Foundation
2     # Distributed under the terms of the GNU General Public License v2
3 kevquinn 1.4 # $Header: /var/cvsroot/gentoo-x86/eclass/pax-utils.eclass,v 1.3 2006/11/24 15:11:55 kevquinn Exp $
4 kevquinn 1.1
5     # Author:
6     # Kevin F. Quinn <kevquinn@gentoo.org>
7     #
8     # This eclass provides support for manipulating PaX markings on ELF
9 kevquinn 1.4 # 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 ${S}/{,usr/}bin/*)
67     #
68     #
69     #### host-is-pax
70     # Returns true if the host has a PaX-enabled kernel, false otherwise.
71     # Intended for use where the build process must be modified conditionally
72     # in order to satisfy PaX. Note; it is _not_ intended to indicate
73     # whether the final executables should satisfy PaX - executables should
74     # always be marked appropriately even if they're only going to be
75     # installed on a non-PaX system.
76 kevquinn 1.1
77     inherit eutils
78    
79 kevquinn 1.4 # Default to both EI and PT markings.
80     PAX_MARKINGS=${PAX_MARKINGS:="EI PT"}
81 kevquinn 1.1
82 kevquinn 1.4 # pax-mark <flags> {<ELF files>}
83 kevquinn 1.1 pax-mark() {
84 kevquinn 1.3 local f flags fail=0 failures=""
85 kevquinn 1.4 # Ignore '-' characters - in particular so that it doesn't matter if
86     # the caller prefixes with -
87 kevquinn 1.3 flags=${1//-}
88 kevquinn 1.2 shift
89 kevquinn 1.4 # Try chpax, for (deprecated) EI legacy marking.
90     if type -p chpax > /dev/null && hasq EI ${PAX_MARKINGS}; then
91 kevquinn 1.3 einfo "Legacy EI PaX marking -${flags}"
92 kevquinn 1.4 _pax_list_files echo "$@"
93     for f in "$@"; do
94     /sbin/chpax -${flags} "${f}" && continue
95 kevquinn 1.3 fail=1
96     failures="${failures} ${f}"
97     done
98 kevquinn 1.1 fi
99 kevquinn 1.4 # Try paxctl, then scanelf - paxctl takes precedence
100     # over scanelf.
101     if type -p paxctl > /dev/null && hasq PT ${PAX_MARKINGS}; then
102     # Try paxctl, the upstream supported tool.
103 kevquinn 1.3 einfo "PT PaX marking -${flags}"
104 kevquinn 1.4 _pax_list_files echo "$@"
105     for f in "$@"; do
106     /sbin/paxctl -q${flags} "${f}" && continue
107     /sbin/paxctl -qc${flags} "${f}" && continue
108     /sbin/paxctl -qC${flags} "${f}" && continue
109 kevquinn 1.3 fail=1
110     failures="${failures} ${f}"
111     done
112 kevquinn 1.4 elif type -p scanelf > /dev/null && [[ -n ${PAX_MARKINGS} ]]; then
113     # Try scanelf, Gentoo's swiss-army knife ELF utility
114     # Currently this sets EI and PT if it can, no option to
115     # control what it does.
116 kevquinn 1.3 einfo "Fallback PaX marking -${flags}"
117 kevquinn 1.4 _pax_list_files echo "$@"
118     /usr/bin/scanelf -Xxz ${flags} "$@"
119 kevquinn 1.2 else
120 kevquinn 1.4 # Out of options!
121 kevquinn 1.3 failures="$*"
122 kevquinn 1.2 fail=1
123 kevquinn 1.1 fi
124 kevquinn 1.3 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."
128     fi
129 kevquinn 1.2 return ${fail}
130     }
131    
132 kevquinn 1.4 # list-paxables {<files>}
133     list-paxables() {
134     file "$@" 2> /dev/null | grep ELF | sed -e 's/: .*$//'
135     }
136    
137     # host-is-pax
138     # Note: if procfs is not on /proc, this returns False (e.g. Gentoo/FBSD).
139 kevquinn 1.2 host-is-pax() {
140 kevquinn 1.4 grep -qs ^PaX: /proc/self/status
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 kevquinn 1.1 }

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