# (c) 2017 Tobin C. Harding <me@tobin.cc>
# Licensed under the terms of the GNU GPL License version 2
#
-# leaking_addresses.pl: Scan 64 bit kernel for potential leaking addresses.
+# 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.
+
#
-# You may like to set kptr_restrict=2 before running script
-# (see Documentation/sysctl/kernel.txt).
+# 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 Term::ANSIColor qw(:constants);
use Getopt::Long qw(:config no_auto_abbrev);
use Config;
+use bigint qw/hex/;
+use feature 'state';
my $P = $0;
-my $V = '0.01';
# Directories to scan.
my @DIRS = ('/proc', '/sys');
# Timer for parsing each file, in seconds.
my $TIMEOUT = 10;
-# Script can only grep for kernel addresses on the following architectures. If
-# your architecture is not listed here and has a grep'able kernel address please
-# consider submitting a patch.
-my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64');
+# 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 $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.
-
-# Do not parse these files (absolute path).
-my @skip_parse_files_abs = ('/proc/kmsg',
- '/proc/kcore',
- '/proc/fs/ext4/sdb1/mb_groups',
- '/proc/1/fd/3',
- '/sys/firmware/devicetree',
- '/proc/device-tree',
- '/sys/kernel/debug/tracing/trace_pipe',
- '/sys/kernel/security/apparmor/revision');
-
-# Do not parse these files under any subdirectory.
-my @skip_parse_files_any = ('0',
- '1',
- '2',
- 'pagemap',
- 'events',
- 'access',
- 'registers',
- 'snapshot_raw',
- 'trace_pipe_raw',
- 'ptmx',
- 'trace_pipe');
-
-# Do not walk these directories (absolute path).
-my @skip_walk_dirs_abs = ();
-
-# Do not walk these directories under any subdirectory.
-my @skip_walk_dirs_any = ('self',
- 'thread-self',
- 'cwd',
- 'fd',
- 'usbmon',
- 'stderr',
- 'stdin',
- 'stdout');
+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
{
print << "EOM";
Usage: $P [OPTIONS]
-Version: $V
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.
- -d, --debug Display debugging output.
- -h, --help, --version Display this help and exit.
-
-Examples:
-
- # Scan kernel and dump raw results.
- $0
-
- # Scan kernel and save results to file.
- $0 --output-raw scan.out
+ -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, --version Display this help and exit.
- # View summary report.
- $0 --input-raw scan.out --squash-by-filename
-
-Scans the running (64 bit) kernel for potential leaking addresses.
+Scans the running kernel for potential leaking addresses.
EOM
exit($exitcode);
'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);
exit(128);
}
-if (!is_supported_architecture()) {
+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 = $Config{archname};
- printf "\n\$ perl -MConfig -e \'print \"\$Config{archname}\\n\"\'\n";
- printf "%s\n", $archname;
+ my $archname = `uname -m`;
+ printf("Machine hardware name (`uname -m`): %s\n", $archname);
exit(129);
}
sub is_supported_architecture
{
- return (is_x86_64() or is_ppc64());
+ return (is_x86_64() or is_ppc64() or is_ix86_32());
}
-sub is_x86_64
+sub is_32bit
{
- my $archname = $Config{archname};
-
- if ($archname =~ m/x86_64/) {
+ # Allow --32-bit or --page-offset-32-bit to override
+ if ($opt_32bit or $page_offset_32bit) {
return 1;
}
- return 0;
+
+ 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
{
- my $archname = $Config{archname};
+ state $is = is_arch('ppc64');
+ return $is;
+}
- if ($archname =~ m/powerpc/ and $archname =~ m/64/) {
- return 1;
+# Gets config option value from kernel config file.
+# Returns "" on error or if config option not found.
+sub get_kernel_config_option
+{
+ my ($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 "$0: system(gunzip < /proc/config.gz) failed\n";
+ return "";
+ } else {
+ @config_files = ($tmp_file);
+ }
+ } else {
+ my $file = '/boot/config-' . `uname -r`;
+ chomp $file;
+ @config_files = ($file, '/boot/config');
}
- return 0;
+
+ foreach my $file (@config_files) {
+ dprint("parsing config file: %s\n", $file);
+ $value = option_from_file($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
$match =~ '\b(0x)?0{16}\b') {
return 1;
}
- if (is_x86_64) {
- # vsyscall memory region, we should probably check against a range here.
- if ($match =~ '\bf{10}600000\b' or
- $match =~ '\bf{10}601000\b') {
- return 1;
- }
+ if (is_x86_64() and is_in_vsyscall_memory_region($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
{
return 0;
}
- # One of these is guaranteed to be true.
- if (is_x86_64()) {
- $address_re = '\b(0x)?ffff[[:xdigit:]]{12}\b';
- } elsif (is_ppc64()) {
- $address_re = '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b';
- }
-
- while (/($address_re)/g) {
+ $address_re = get_address_re();
+ while ($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 $cmd, '-|', 'dmesg';
# True if we should skip this path.
sub skip
{
- my ($path, $paths_abs, $paths_any) = @_;
+ my ($path) = @_;
- foreach (@$paths_abs) {
+ foreach (@skip_abs) {
return 1 if (/^$path$/);
}
my($filename, $dirs, $suffix) = fileparse($path);
- foreach (@$paths_any) {
+ foreach (@skip_any) {
return 1 if (/^$filename$/);
}
return 0;
}
-sub skip_parse
-{
- my ($path) = @_;
- return skip($path, \@skip_parse_files_abs, \@skip_parse_files_any);
-}
-
sub timed_parse_file
{
my ($file) = @_;
return;
}
- if (skip_parse($file)) {
- dprint "skipping file: $file\n";
+ if (! -T $file) {
return;
}
- dprint "parsing: $file\n";
open my $fh, "<", $file or return;
while ( <$fh> ) {
close $fh;
}
-
-# True if we should skip walking this directory.
-sub skip_walk
+# Checks if the actual path name is leaking a kernel address.
+sub check_path_for_leaks
{
my ($path) = @_;
- return skip($path, \@skip_walk_dirs_abs, \@skip_walk_dirs_any)
+
+ if (may_leak_address($path)) {
+ printf("Path name may contain address: $path\n");
+ }
}
# Recursively walk directory tree.
my @dirs = @_;
while (my $pwd = shift @dirs) {
- next if (skip_walk($pwd));
next if (!opendir(DIR, $pwd));
my @files = readdir(DIR);
closedir(DIR);
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, $path;
- } else {
- timed_parse_file($path);
+ next;
}
+
+ dprint "parsing: $path\n";
+ timed_parse_file($path);
}
}
}
git.samba.org / sfrench / cifs-2.6.git / blobdiff