648 lines
13 KiB
Perl
Executable File
648 lines
13 KiB
Perl
Executable File
#!/usr/bin/env perl
|
|
# SPDX-License-Identifier: GPL-2.0-only
|
|
#
|
|
# (c) 2017 Tobin C. Harding <me@tobin.cc>
|
|
#
|
|
# leaking_addresses.pl: Scan the kernel for potential leaking addresses.
|
|
# - Scans dmesg output.
|
|
# - Walks directory tree and parses each file (for each directory in @DIRS).
|
|
#
|
|
# Use --debug to output path before parsing, this is useful to find files that
|
|
# cause the script to choke.
|
|
|
|
#
|
|
# When the system is idle it is likely that most files under /proc/PID will be
|
|
# identical for various processes. Scanning _all_ the PIDs under /proc is
|
|
# unnecessary and implies that we are thoroughly scanning /proc. This is _not_
|
|
# the case because there may be ways userspace can trigger creation of /proc
|
|
# files that leak addresses but were not present during a scan. For these two
|
|
# reasons we exclude all PID directories under /proc except '1/'
|
|
|
|
use warnings;
|
|
use strict;
|
|
use POSIX;
|
|
use File::Basename;
|
|
use File::Spec;
|
|
use Cwd 'abs_path';
|
|
use Term::ANSIColor qw(:constants);
|
|
use Getopt::Long qw(:config no_auto_abbrev);
|
|
use Config;
|
|
use bigint qw/hex/;
|
|
use feature 'state';
|
|
|
|
my $P = $0;
|
|
|
|
# Directories to scan.
|
|
my @DIRS = ('/proc', '/sys');
|
|
|
|
# Timer for parsing each file, in seconds.
|
|
my $TIMEOUT = 10;
|
|
|
|
# Kernel addresses vary by architecture. We can only auto-detect the following
|
|
# architectures (using `uname -m`). (flag --32-bit overrides auto-detection.)
|
|
my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64', 'x86');
|
|
|
|
# Command line options.
|
|
my $help = 0;
|
|
my $debug = 0;
|
|
my $raw = 0;
|
|
my $output_raw = ""; # Write raw results to file.
|
|
my $input_raw = ""; # Read raw results from file instead of scanning.
|
|
my $suppress_dmesg = 0; # Don't show dmesg in output.
|
|
my $squash_by_path = 0; # Summary report grouped by absolute path.
|
|
my $squash_by_filename = 0; # Summary report grouped by filename.
|
|
my $kernel_config_file = ""; # Kernel configuration file.
|
|
my $opt_32bit = 0; # Scan 32-bit kernel.
|
|
my $page_offset_32bit = 0; # Page offset for 32-bit kernel.
|
|
|
|
# Skip these absolute paths.
|
|
my @skip_abs = (
|
|
'/proc/kmsg',
|
|
'/proc/device-tree',
|
|
'/proc/1/syscall',
|
|
'/sys/firmware/devicetree',
|
|
'/sys/kernel/debug/tracing/trace_pipe',
|
|
'/sys/kernel/security/apparmor/revision');
|
|
|
|
# Skip these under any subdirectory.
|
|
my @skip_any = (
|
|
'pagemap',
|
|
'events',
|
|
'access',
|
|
'registers',
|
|
'snapshot_raw',
|
|
'trace_pipe_raw',
|
|
'ptmx',
|
|
'trace_pipe',
|
|
'fd',
|
|
'usbmon');
|
|
|
|
sub help
|
|
{
|
|
my ($exitcode) = @_;
|
|
|
|
print << "EOM";
|
|
|
|
Usage: $P [OPTIONS]
|
|
|
|
Options:
|
|
|
|
-o, --output-raw=<file> Save results for future processing.
|
|
-i, --input-raw=<file> Read results from file instead of scanning.
|
|
--raw Show raw results (default).
|
|
--suppress-dmesg Do not show dmesg results.
|
|
--squash-by-path Show one result per unique path.
|
|
--squash-by-filename Show one result per unique filename.
|
|
--kernel-config-file=<file> Kernel configuration file (e.g /boot/config)
|
|
--32-bit Scan 32-bit kernel.
|
|
--page-offset-32-bit=o Page offset (for 32-bit kernel 0xABCD1234).
|
|
-d, --debug Display debugging output.
|
|
-h, --help Display this help and exit.
|
|
|
|
Scans the running kernel for potential leaking addresses.
|
|
|
|
EOM
|
|
exit($exitcode);
|
|
}
|
|
|
|
GetOptions(
|
|
'd|debug' => \$debug,
|
|
'h|help' => \$help,
|
|
'o|output-raw=s' => \$output_raw,
|
|
'i|input-raw=s' => \$input_raw,
|
|
'suppress-dmesg' => \$suppress_dmesg,
|
|
'squash-by-path' => \$squash_by_path,
|
|
'squash-by-filename' => \$squash_by_filename,
|
|
'raw' => \$raw,
|
|
'kernel-config-file=s' => \$kernel_config_file,
|
|
'32-bit' => \$opt_32bit,
|
|
'page-offset-32-bit=o' => \$page_offset_32bit,
|
|
) or help(1);
|
|
|
|
help(0) if ($help);
|
|
|
|
if ($input_raw) {
|
|
format_output($input_raw);
|
|
exit(0);
|
|
}
|
|
|
|
if (!$input_raw and ($squash_by_path or $squash_by_filename)) {
|
|
printf "\nSummary reporting only available with --input-raw=<file>\n";
|
|
printf "(First run scan with --output-raw=<file>.)\n";
|
|
exit(128);
|
|
}
|
|
|
|
if (!(is_supported_architecture() or $opt_32bit or $page_offset_32bit)) {
|
|
printf "\nScript does not support your architecture, sorry.\n";
|
|
printf "\nCurrently we support: \n\n";
|
|
foreach(@SUPPORTED_ARCHITECTURES) {
|
|
printf "\t%s\n", $_;
|
|
}
|
|
printf("\n");
|
|
|
|
printf("If you are running a 32-bit architecture you may use:\n");
|
|
printf("\n\t--32-bit or --page-offset-32-bit=<page offset>\n\n");
|
|
|
|
my $archname = `uname -m`;
|
|
printf("Machine hardware name (`uname -m`): %s\n", $archname);
|
|
|
|
exit(129);
|
|
}
|
|
|
|
if ($output_raw) {
|
|
open my $fh, '>', $output_raw or die "$0: $output_raw: $!\n";
|
|
select $fh;
|
|
}
|
|
|
|
parse_dmesg();
|
|
walk(@DIRS);
|
|
|
|
exit 0;
|
|
|
|
sub dprint
|
|
{
|
|
printf(STDERR @_) if $debug;
|
|
}
|
|
|
|
sub is_supported_architecture
|
|
{
|
|
return (is_x86_64() or is_ppc64() or is_ix86_32());
|
|
}
|
|
|
|
sub is_32bit
|
|
{
|
|
# Allow --32-bit or --page-offset-32-bit to override
|
|
if ($opt_32bit or $page_offset_32bit) {
|
|
return 1;
|
|
}
|
|
|
|
return is_ix86_32();
|
|
}
|
|
|
|
sub is_ix86_32
|
|
{
|
|
state $arch = `uname -m`;
|
|
|
|
chomp $arch;
|
|
if ($arch =~ m/i[3456]86/) {
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
sub is_arch
|
|
{
|
|
my ($desc) = @_;
|
|
my $arch = `uname -m`;
|
|
|
|
chomp $arch;
|
|
if ($arch eq $desc) {
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
sub is_x86_64
|
|
{
|
|
state $is = is_arch('x86_64');
|
|
return $is;
|
|
}
|
|
|
|
sub is_ppc64
|
|
{
|
|
state $is = is_arch('ppc64');
|
|
return $is;
|
|
}
|
|
|
|
# Gets config option value from kernel config file.
|
|
# Returns "" on error or if config option not found.
|
|
sub get_kernel_config_option
|
|
{
|
|
my ($option) = @_;
|
|
my $value = "";
|
|
my $tmp_file = "";
|
|
my @config_files;
|
|
|
|
# Allow --kernel-config-file to override.
|
|
if ($kernel_config_file ne "") {
|
|
@config_files = ($kernel_config_file);
|
|
} elsif (-R "/proc/config.gz") {
|
|
my $tmp_file = "/tmp/tmpkconf";
|
|
|
|
if (system("gunzip < /proc/config.gz > $tmp_file")) {
|
|
dprint("system(gunzip < /proc/config.gz) failed\n");
|
|
return "";
|
|
} else {
|
|
@config_files = ($tmp_file);
|
|
}
|
|
} else {
|
|
my $file = '/boot/config-' . `uname -r`;
|
|
chomp $file;
|
|
@config_files = ($file, '/boot/config');
|
|
}
|
|
|
|
foreach my $file (@config_files) {
|
|
dprint("parsing config file: $file\n");
|
|
$value = option_from_file($option, $file);
|
|
if ($value ne "") {
|
|
last;
|
|
}
|
|
}
|
|
|
|
if ($tmp_file ne "") {
|
|
system("rm -f $tmp_file");
|
|
}
|
|
|
|
return $value;
|
|
}
|
|
|
|
# Parses $file and returns kernel configuration option value.
|
|
sub option_from_file
|
|
{
|
|
my ($option, $file) = @_;
|
|
my $str = "";
|
|
my $val = "";
|
|
|
|
open(my $fh, "<", $file) or return "";
|
|
while (my $line = <$fh> ) {
|
|
if ($line =~ /^$option/) {
|
|
($str, $val) = split /=/, $line;
|
|
chomp $val;
|
|
last;
|
|
}
|
|
}
|
|
|
|
close $fh;
|
|
return $val;
|
|
}
|
|
|
|
sub is_false_positive
|
|
{
|
|
my ($match) = @_;
|
|
|
|
if (is_32bit()) {
|
|
return is_false_positive_32bit($match);
|
|
}
|
|
|
|
# 64 bit false positives.
|
|
|
|
if ($match =~ '\b(0x)?(f|F){16}\b' or
|
|
$match =~ '\b(0x)?0{16}\b') {
|
|
return 1;
|
|
}
|
|
|
|
if (is_x86_64() and is_in_vsyscall_memory_region($match)) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
sub is_false_positive_32bit
|
|
{
|
|
my ($match) = @_;
|
|
state $page_offset = get_page_offset();
|
|
|
|
if ($match =~ '\b(0x)?(f|F){8}\b') {
|
|
return 1;
|
|
}
|
|
|
|
if (hex($match) < $page_offset) {
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
# returns integer value
|
|
sub get_page_offset
|
|
{
|
|
my $page_offset;
|
|
my $default_offset = 0xc0000000;
|
|
|
|
# Allow --page-offset-32bit to override.
|
|
if ($page_offset_32bit != 0) {
|
|
return $page_offset_32bit;
|
|
}
|
|
|
|
$page_offset = get_kernel_config_option('CONFIG_PAGE_OFFSET');
|
|
if (!$page_offset) {
|
|
return $default_offset;
|
|
}
|
|
return $page_offset;
|
|
}
|
|
|
|
sub is_in_vsyscall_memory_region
|
|
{
|
|
my ($match) = @_;
|
|
|
|
my $hex = hex($match);
|
|
my $region_min = hex("0xffffffffff600000");
|
|
my $region_max = hex("0xffffffffff601000");
|
|
|
|
return ($hex >= $region_min and $hex <= $region_max);
|
|
}
|
|
|
|
# True if argument potentially contains a kernel address.
|
|
sub may_leak_address
|
|
{
|
|
my ($line) = @_;
|
|
my $address_re;
|
|
|
|
# Signal masks.
|
|
if ($line =~ '^SigBlk:' or
|
|
$line =~ '^SigIgn:' or
|
|
$line =~ '^SigCgt:') {
|
|
return 0;
|
|
}
|
|
|
|
if ($line =~ '\bKEY=[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b' or
|
|
$line =~ '\b[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b') {
|
|
return 0;
|
|
}
|
|
|
|
$address_re = get_address_re();
|
|
while ($line =~ /($address_re)/g) {
|
|
if (!is_false_positive($1)) {
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
sub get_address_re
|
|
{
|
|
if (is_ppc64()) {
|
|
return '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b';
|
|
} elsif (is_32bit()) {
|
|
return '\b(0x)?[[:xdigit:]]{8}\b';
|
|
}
|
|
|
|
return get_x86_64_re();
|
|
}
|
|
|
|
sub get_x86_64_re
|
|
{
|
|
# We handle page table levels but only if explicitly configured using
|
|
# CONFIG_PGTABLE_LEVELS. If config file parsing fails or config option
|
|
# is not found we default to using address regular expression suitable
|
|
# for 4 page table levels.
|
|
state $ptl = get_kernel_config_option('CONFIG_PGTABLE_LEVELS');
|
|
|
|
if ($ptl == 5) {
|
|
return '\b(0x)?ff[[:xdigit:]]{14}\b';
|
|
}
|
|
return '\b(0x)?ffff[[:xdigit:]]{12}\b';
|
|
}
|
|
|
|
sub parse_dmesg
|
|
{
|
|
open my $cmd, '-|', 'dmesg';
|
|
while (<$cmd>) {
|
|
if (may_leak_address($_)) {
|
|
print 'dmesg: ' . $_;
|
|
}
|
|
}
|
|
close $cmd;
|
|
}
|
|
|
|
# True if we should skip this path.
|
|
sub skip
|
|
{
|
|
my ($path) = @_;
|
|
|
|
foreach (@skip_abs) {
|
|
return 1 if (/^$path$/);
|
|
}
|
|
|
|
my($filename, $dirs, $suffix) = fileparse($path);
|
|
foreach (@skip_any) {
|
|
return 1 if (/^$filename$/);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
sub timed_parse_file
|
|
{
|
|
my ($file) = @_;
|
|
|
|
eval {
|
|
local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required.
|
|
alarm $TIMEOUT;
|
|
parse_file($file);
|
|
alarm 0;
|
|
};
|
|
|
|
if ($@) {
|
|
die unless $@ eq "alarm\n"; # Propagate unexpected errors.
|
|
printf STDERR "timed out parsing: %s\n", $file;
|
|
}
|
|
}
|
|
|
|
sub parse_file
|
|
{
|
|
my ($file) = @_;
|
|
|
|
if (! -R $file) {
|
|
return;
|
|
}
|
|
|
|
if (! -T $file) {
|
|
return;
|
|
}
|
|
|
|
open my $fh, "<", $file or return;
|
|
while ( <$fh> ) {
|
|
chomp;
|
|
if (may_leak_address($_)) {
|
|
printf("$file: $_\n");
|
|
}
|
|
}
|
|
close $fh;
|
|
}
|
|
|
|
# Checks if the actual path name is leaking a kernel address.
|
|
sub check_path_for_leaks
|
|
{
|
|
my ($path) = @_;
|
|
|
|
if (may_leak_address($path)) {
|
|
printf("Path name may contain address: $path\n");
|
|
}
|
|
}
|
|
|
|
# Recursively walk directory tree.
|
|
sub walk
|
|
{
|
|
my @dirs = @_;
|
|
|
|
while (my $pwd = shift @dirs) {
|
|
next if (!opendir(DIR, $pwd));
|
|
my @files = readdir(DIR);
|
|
closedir(DIR);
|
|
|
|
foreach my $file (@files) {
|
|
next if ($file eq '.' or $file eq '..');
|
|
|
|
my $path = "$pwd/$file";
|
|
next if (-l $path);
|
|
|
|
# skip /proc/PID except /proc/1
|
|
next if (($path =~ /^\/proc\/[0-9]+$/) &&
|
|
($path !~ /^\/proc\/1$/));
|
|
|
|
next if (skip($path));
|
|
|
|
check_path_for_leaks($path);
|
|
|
|
if (-d $path) {
|
|
push @dirs, $path;
|
|
next;
|
|
}
|
|
|
|
dprint("parsing: $path\n");
|
|
timed_parse_file($path);
|
|
}
|
|
}
|
|
}
|
|
|
|
sub format_output
|
|
{
|
|
my ($file) = @_;
|
|
|
|
# Default is to show raw results.
|
|
if ($raw or (!$squash_by_path and !$squash_by_filename)) {
|
|
dump_raw_output($file);
|
|
return;
|
|
}
|
|
|
|
my ($total, $dmesg, $paths, $files) = parse_raw_file($file);
|
|
|
|
printf "\nTotal number of results from scan (incl dmesg): %d\n", $total;
|
|
|
|
if (!$suppress_dmesg) {
|
|
print_dmesg($dmesg);
|
|
}
|
|
|
|
if ($squash_by_filename) {
|
|
squash_by($files, 'filename');
|
|
}
|
|
|
|
if ($squash_by_path) {
|
|
squash_by($paths, 'path');
|
|
}
|
|
}
|
|
|
|
sub dump_raw_output
|
|
{
|
|
my ($file) = @_;
|
|
|
|
open (my $fh, '<', $file) or die "$0: $file: $!\n";
|
|
while (<$fh>) {
|
|
if ($suppress_dmesg) {
|
|
if ("dmesg:" eq substr($_, 0, 6)) {
|
|
next;
|
|
}
|
|
}
|
|
print $_;
|
|
}
|
|
close $fh;
|
|
}
|
|
|
|
sub parse_raw_file
|
|
{
|
|
my ($file) = @_;
|
|
|
|
my $total = 0; # Total number of lines parsed.
|
|
my @dmesg; # dmesg output.
|
|
my %files; # Unique filenames containing leaks.
|
|
my %paths; # Unique paths containing leaks.
|
|
|
|
open (my $fh, '<', $file) or die "$0: $file: $!\n";
|
|
while (my $line = <$fh>) {
|
|
$total++;
|
|
|
|
if ("dmesg:" eq substr($line, 0, 6)) {
|
|
push @dmesg, $line;
|
|
next;
|
|
}
|
|
|
|
cache_path(\%paths, $line);
|
|
cache_filename(\%files, $line);
|
|
}
|
|
|
|
return $total, \@dmesg, \%paths, \%files;
|
|
}
|
|
|
|
sub print_dmesg
|
|
{
|
|
my ($dmesg) = @_;
|
|
|
|
print "\ndmesg output:\n";
|
|
|
|
if (@$dmesg == 0) {
|
|
print "<no results>\n";
|
|
return;
|
|
}
|
|
|
|
foreach(@$dmesg) {
|
|
my $index = index($_, ': ');
|
|
$index += 2; # skid ': '
|
|
print substr($_, $index);
|
|
}
|
|
}
|
|
|
|
sub squash_by
|
|
{
|
|
my ($ref, $desc) = @_;
|
|
|
|
print "\nResults squashed by $desc (excl dmesg). ";
|
|
print "Displaying [<number of results> <$desc>], <example result>\n";
|
|
|
|
if (keys %$ref == 0) {
|
|
print "<no results>\n";
|
|
return;
|
|
}
|
|
|
|
foreach(keys %$ref) {
|
|
my $lines = $ref->{$_};
|
|
my $length = @$lines;
|
|
printf "[%d %s] %s", $length, $_, @$lines[0];
|
|
}
|
|
}
|
|
|
|
sub cache_path
|
|
{
|
|
my ($paths, $line) = @_;
|
|
|
|
my $index = index($line, ': ');
|
|
my $path = substr($line, 0, $index);
|
|
|
|
$index += 2; # skip ': '
|
|
add_to_cache($paths, $path, substr($line, $index));
|
|
}
|
|
|
|
sub cache_filename
|
|
{
|
|
my ($files, $line) = @_;
|
|
|
|
my $index = index($line, ': ');
|
|
my $path = substr($line, 0, $index);
|
|
my $filename = basename($path);
|
|
|
|
$index += 2; # skip ': '
|
|
add_to_cache($files, $filename, substr($line, $index));
|
|
}
|
|
|
|
sub add_to_cache
|
|
{
|
|
my ($cache, $key, $value) = @_;
|
|
|
|
if (!$cache->{$key}) {
|
|
$cache->{$key} = ();
|
|
}
|
|
push @{$cache->{$key}}, $value;
|
|
}
|