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#!/usr/bin/perl
# Copyright (C) 2009 Red Hat Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
use strict;
use warnings;
die("NOEXEC_CHECK not set") unless(exists($ENV{NOEXEC_CHECK}));
my @files = split(/ /, $ENV{NOEXEC_CHECK});
FILES: foreach my $file (@files) {
my $output;
my @cmd = ('readelf', '-l', $file);
open($output, '-|', @cmd)
or die("$0: failed to run: '".join(' ', @cmd)."': $!\n");
my $offset;
my $line = 1;
# Find the offset of the Flags field
while(<$output>) {
next unless(/^\s*Type\b/);
my @lines;
push(@lines, $_);
# Look for a Flg field on this line (32 bit)
$offset = index($_, 'Flg ');
if(-1 == $offset) {
# 64 bit is split over 2 lines. Look for a Flags field on the next
# line
$_ = <$output>;
$offset = index($_, 'Flags ');
$line = 2;
push(@lines, $_);
}
die("Unrecognised header: ".join("\n", @lines)) if(-1 == $offset);
last;
}
# Find the GNU_STACK entry
while(<$output>) {
next unless(/^\s*GNU_STACK\b/);
# Skip over input lines according to the header
for(my $i = 1; $i < $line; $i++) {
$_ = <$output>;
}
my $flags = substr($_, $offset, 3);
$flags =~ /^[ R][ W]([ E])$/ or die("Unrecognised flags: $flags");
if('E' eq $1) {
print "***** $file has an executable stack *****\n";
exit(1);
}
next FILES;
}
die("Didn't find GNU_STACK entry");
}
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