summaryrefslogtreecommitdiffstats
path: root/scripts/leaking_addresses.pl
blob: b10fd606cef6b02a46739ecfc9b49aa4a0a7d062 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
#!/usr/bin/env perl
#
# (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.
#  - 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.

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;

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');

# 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.

# 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');

sub help
{
	my ($exitcode) = @_;

	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

	# View summary report.
	$0 --input-raw scan.out --squash-by-filename

Scans the running (64 bit) kernel for potential leaking addresses.

EOM
	exit($exitcode);
}

GetOptions(
	'd|debug'		=> \$debug,
	'h|help'		=> \$help,
	'version'		=> \$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,
) 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()) {
	printf "\nScript does not support your architecture, sorry.\n";
	printf "\nCurrently we support: \n\n";
	foreach(@SUPPORTED_ARCHITECTURES) {
		printf "\t%s\n", $_;
	}

	my $archname = $Config{archname};
	printf "\n\$ perl -MConfig -e \'print \"\$Config{archname}\\n\"\'\n";
	printf "%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());
}

sub is_x86_64
{
	my $archname = $Config{archname};

	if ($archname =~ m/x86_64/) {
		return 1;
	}
	return 0;
}

sub is_ppc64
{
	my $archname = $Config{archname};

	if ($archname =~ m/powerpc/ and $archname =~ m/64/) {
		return 1;
	}
	return 0;
}

sub is_false_positive
{
	my ($match) = @_;

	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;
		}
	}

	return 0;
}

# 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;
	}

	# 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) {
		if (!is_false_positive($1)) {
			return 1;
		}
	}

	return 0;
}

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, $paths_abs, $paths_any) = @_;

	foreach (@$paths_abs) {
		return 1 if (/^$path$/);
	}

	my($filename, $dirs, $suffix) = fileparse($path);
	foreach (@$paths_any) {
		return 1 if (/^$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) = @_;

	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 (skip_parse($file)) {
		dprint "skipping file: $file\n";
		return;
	}
	dprint "parsing: $file\n";

	open my $fh, "<", $file or return;
	while ( <$fh> ) {
		if (may_leak_address($_)) {
			print $file . ': ' . $_;
		}
	}
	close $fh;
}


# True if we should skip walking this directory.
sub skip_walk
{
	my ($path) = @_;
	return skip($path, \@skip_walk_dirs_abs, \@skip_walk_dirs_any)
}

# Recursively walk directory tree.
sub walk
{
	my @dirs = @_;

	while (my $pwd = shift @dirs) {
		next if (skip_walk($pwd));
		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);

			if (-d $path) {
				push @dirs, $path;
			} else {
				timed_parse_file($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;
}