# (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.
+#
+# 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 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 $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.
-
-# 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 $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: $V
Options:
--squash-by-path Show one result per unique path.
--squash-by-filename Show one result per unique filename.
--kernel-config-file=<file> Kernel configuration file (e.g /boot/config)
+ --32-bit Scan 32-bit kernel.
+ --page-offset-32-bit=o Page offset (for 32-bit kernel 0xABCD1234).
-d, --debug Display debugging output.
-h, --help, --version Display this help and exit.
-Scans the running (64 bit) kernel for potential leaking addresses.
+Scans the running kernel for potential leaking addresses.
EOM
exit($exitcode);
'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("\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);
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 $archname = `uname -m`;
-
- if ($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_ppc64
+sub is_ix86_32
{
- my $archname = `uname -m`;
+ state $arch = `uname -m`;
- if ($archname =~ m/ppc64/) {
- return 1;
- }
- return 0;
+ 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 $is;
}
# Gets config option value from kernel config file.
{
my ($match) = @_;
+ if (is_32bit()) {
+ return is_false_positive_32bit($match);
+ }
+
+ # 64 bit false positives.
+
if ($match =~ '\b(0x)?(f|F){16}\b' or
$match =~ '\b(0x)?0{16}\b') {
return 1;
return 0;
}
+sub is_false_positive_32bit
+{
+ my ($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) = @_;
}
$address_re = get_address_re();
- while (/($address_re)/g) {
+ while ($line =~ /($address_re)/g) {
if (!is_false_positive($1)) {
return 1;
}
sub get_address_re
{
- if (is_x86_64()) {
- return get_x86_64_re();
- } elsif (is_ppc64()) {
+ if (is_ppc64()) {
return '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b';
+ } elsif (is_32bit()) {
+ return '\b(0x)?[[:xdigit:]]{8}\b';
}
+
+ return get_x86_64_re();
}
sub get_x86_64_re
# True if we should skip this path.
sub skip
{
- my ($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