use warnings;
use Getopt::Long ();
+use Term::ANSIColor ();
our $VERSION = '0.01';
+# FUNCTIONS
+
+sub error_flags {
+ my ($message, $missing_flags_ref, $flag_renames_ref, $line) = @_;
+
+ # Rename flags if requested.
+ my @missing_flags = map {
+ (exists $flag_renames_ref->{$_})
+ ? $flag_renames_ref->{$_}
+ : $_
+ } @{$missing_flags_ref};
+
+ my $flags = join ' ', @missing_flags;
+ printf "%s (%s)%s %s",
+ error_color($message, 'red'), $flags, error_color(':', 'yellow'),
+ $line;
+}
+sub error_color {
+ my ($message, $color) = @_;
+
+ # Use colors when writing to a terminal.
+ if (-t STDOUT) {
+ return Term::ANSIColor::colored($message, $color);
+ } else {
+ return $message;
+ }
+}
+
+sub any_flags_used {
+ my ($line, @flags) = @_;
+
+ foreach my $flag (@flags) {
+ return 1 if $line =~ /\s$flag(\s|\\|$)/;
+ }
+
+ return 0;
+}
+sub all_flags_used {
+ my ($line, $missing_flags_ref, @flags) = @_;
+
+ my @missing_flags = ();
+ foreach my $flag (@flags) {
+ if ($line !~ /\s$flag(\s|\\|$)/) {
+ push @missing_flags, $flag;
+ }
+ }
+
+ if (scalar @missing_flags == 0) {
+ return 1;
+ }
+
+ @{$missing_flags_ref} = @missing_flags;
+ return 0;
+}
+
+# Modifies $missing_flags_ref array.
+sub pic_pie_conflict {
+ my ($line, $pie, $missing_flags_ref, @flags_pie) = @_;
+
+ return 0 if not $pie;
+ return 0 if not any_flags_used($line, ('-fPIC'));
+
+ my %flags = map { $_ => 1 } @flags_pie;
+
+ # Remove all PIE flags from @missing_flags as they are not required with
+ # -fPIC.
+ my @result = grep {
+ not exists $flags{$_}
+ } @{$missing_flags_ref};
+ @{$missing_flags_ref} = @result;
+
+ # We got a conflict when no flags are left, thus only PIE flags were
+ # missing. If other flags were missing abort because the conflict is not
+ # the problem.
+ return scalar @result == 0;
+}
+
+
+# CONSTANTS/VARIABLES
+
+# Regex to catch (GCC) compiler warnings.
+my $warning_regex = qr/^(.+?):([0-9]+):[0-9]+: warning: (.+?) \[(.+?)\]$/;
+
+# Expected hardening flags. All flags are used as regexps.
+my @cflags = (
+ '-g',
+ '-O2',
+ '-fstack-protector',
+ '--param=ssp-buffer-size=4',
+ '-Wformat',
+ '-Wformat-security',
+ '-Werror=format-security',
+);
+my @cflags_pie = (
+ '-fPIE',
+);
+my @cppflags = (
+ '-D_FORTIFY_SOURCE=2',
+);
+my @ldflags = (
+ '-Wl,(-z,)?relro',
+);
+my @ldflags_pie = (
+ '-fPIE',
+ '-pie',
+);
+my @ldflags_bindnow = (
+ '-Wl,(-z,)?now',
+);
+# All (hardening) flags.
+my @flags = (@cflags, @cflags_pie,
+ @cppflags,
+ @ldflags, @ldflags_pie, @ldflags_bindnow);
+# Renaming rules for the output so the regex parts are not visible.
+my %flag_renames = (
+ '-Wl,(-z,)?relro' => '-Wl,-z,relro',
+ '-Wl,(-z,)?now' => '-Wl,-z,now',
+);
+
+
+# MAIN
+
+# Additional hardening options.
+my $pie = 0;
+my $bindnow = 0;
+
# Parse command line arguments.
+my $option_all = 0;
my $option_help = 0;
my $option_version = 0;
if (not Getopt::Long::GetOptions(
'help|h|?' => \$option_help,
'version' => \$option_version,
+ 'pie' => \$pie,
+ 'bindnow' => \$bindnow,
+ 'all' => \$option_all,
)) {
require Pod::Usage;
Pod::Usage::pod2usage(2);
exit 0;
}
+if ($option_all) {
+ $pie = 1;
+ $bindnow = 1;
+}
+
+# Final exit code.
+my $exit = 0;
+
+# Input lines, contain only the lines with compiler commands.
+my @input = ();
+
+my $continuation = 0;
+while (my $line = <>) {
+ # Ignore compiler warnings for now.
+ next if $line =~ /$warning_regex/;
+
+ # One line may contain multiple commands (";"). Treat each one as single
+ # line.
+ my @line = split /(?<!\\);/, $line;
+ foreach $line (@line) {
+ # Add newline, drop all other whitespace at the end of a line.
+ $line =~ s/\s+$//;
+ $line .= "\n";
+
+ if ($continuation) {
+ $continuation = 0;
+
+ # Join lines, but leave the "\" in place so it's clear where the
+ # original line break was.
+ chomp $input[-1];
+ $input[-1] .= ' ' . $line;
+
+ } else {
+ # Ignore lines with no compiler commands.
+ next if $line !~ /\b(cc\b|gcc\b|g\+\+|c\+\+)/;
+
+ # Ignore false positives.
+ #
+ # `./configure` output.
+ if ($line =~ /^checking /) {
+ next;
+ }
+
+ push @input, $line;
+ }
+
+ # Line continuation, line ends with "\".
+ if ($line =~ /\\\s*$/) {
+ $continuation = 1;
+ }
+ }
+}
+
+if (scalar @input == 0) {
+ print "No compiler commands!\n";
+ $exit |= 1;
+ exit $exit;
+}
+
+# Check if additional hardening options were used. Used to ensure they are
+# used for the complete build.
+foreach my $line (@input) {
+ $pie = 1 if any_flags_used($line, @cflags_pie, @ldflags_pie);
+ $bindnow = 1 if any_flags_used($line, @ldflags_bindnow);
+}
+
+if ($pie) {
+ @cflags = (@cflags, @cflags_pie);
+ @ldflags = (@ldflags, @ldflags_pie);
+}
+if ($bindnow) {
+ @ldflags = (@ldflags, @ldflags_bindnow);
+}
+
+foreach my $line (@input) {
+ # Is this a compiler or linker command?
+ my $compiler = 1;
+ my $linker = 0;
+
+ # Linker commands.
+ if ($line =~ /\s-l[A-Za-z0-9.-]+(\s|\\|$)/
+ or $line =~ /^libtool: link: /
+ or $line =~ m{\s*/bin/bash (\.\./)+libtool\s+--tag=CC\s+--mode=link}) {
+ $compiler = 0;
+ $linker = 1;
+ }
+
+ # If there are source files then it's compiling/linking in one step and we
+ # must check both.
+ if ($line =~ /\.(c|cc|cpp)\b/) {
+ $compiler = 1;
+ }
+
+ # Check hardening flags.
+ my @missing;
+ if ($compiler and not all_flags_used($line, \@missing, @cflags)
+ # Libraries linked with -fPIC don't have to (and can't) be linked
+ # with -fPIE as well. It's no error if only PIE flags are missing.
+ and not pic_pie_conflict($line, $pie, \@missing, @cflags_pie)) {
+ error_flags('CFLAGS missing', \@missing, \%flag_renames, $line);
+ $exit |= 1 << 2;
+ }
+ if ($compiler and not all_flags_used($line, \@missing, @cppflags)) {
+ error_flags('CPPFLAGS missing', \@missing, \%flag_renames, $line);
+ $exit |= 1 << 2;
+ }
+ if ($linker and not all_flags_used($line, \@missing, @ldflags)
+ # Same here, -fPIC conflicts with -fPIE.
+ and not pic_pie_conflict($line, $pie, \@missing, @ldflags_pie)) {
+ error_flags('LDFLAGS missing', \@missing, \%flag_renames, $line);
+ $exit |= 1 << 2;
+ }
+}
+
+exit $exit;
+
__END__
B<blhc> [-h -? --help]
+B<blhc> [--pie] [--bindnow] [--all]
+
--help available options
--version version number and license
+ --pie force +pie check
+ --bindnow force +bindbow check
+ --all force +all (+pie, +bindnow) check
=head1 DESCRIPTION
Print version number and license.
+=item B<--pie>
+
+Force check for all +pie hardening flags. By default it's auto detected.
+
+=item B<--bindnow>
+
+Force check for all +bindnow hardening flags. By default it's auto detected.
+
+=item B<--all>
+
+Force check for all +all (+pie, +bindnow) hardening flags. By default it's
+auto detected.
+
+=back
+
+Auto detection only works if at least one command uses the required hardening
+flag (e.g. -fPIE). Then it's required for all other commands as well.
+
+=head1 EXIT STATUS
+
+The exit status is a "bit mask", each listed status is ORed when the error
+condition occurs to get the result.
+
+=over 8
+
+=item B<0>
+
+Success.
+
+=item B<1>
+
+No compiler commands were found.
+
+=item B<2>
+
+Invalid arguments/options given to blhc.
+
+=item B<4>
+
+Missing hardening flags.
+
=back
=head1 AUTHOR
ruderich.org/simon / blhc / blhc.git / blobdiff