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136fc5c4 TH |
1 | #!/usr/bin/env perl |
2 | # | |
3 | # (c) 2017 Tobin C. Harding <me@tobin.cc> | |
4 | # Licensed under the terms of the GNU GPL License version 2 | |
5 | # | |
1410fe4e | 6 | # leaking_addresses.pl: Scan the kernel for potential leaking addresses. |
136fc5c4 TH |
7 | # - Scans dmesg output. |
8 | # - Walks directory tree and parses each file (for each directory in @DIRS). | |
9 | # | |
136fc5c4 TH |
10 | # Use --debug to output path before parsing, this is useful to find files that |
11 | # cause the script to choke. | |
136fc5c4 TH |
12 | |
13 | use warnings; | |
14 | use strict; | |
15 | use POSIX; | |
16 | use File::Basename; | |
17 | use File::Spec; | |
18 | use Cwd 'abs_path'; | |
19 | use Term::ANSIColor qw(:constants); | |
20 | use Getopt::Long qw(:config no_auto_abbrev); | |
62139c12 | 21 | use Config; |
87e37588 | 22 | use bigint qw/hex/; |
2f042c93 | 23 | use feature 'state'; |
136fc5c4 TH |
24 | |
25 | my $P = $0; | |
26 | my $V = '0.01'; | |
27 | ||
28 | # Directories to scan. | |
29 | my @DIRS = ('/proc', '/sys'); | |
30 | ||
dd98c252 TH |
31 | # Timer for parsing each file, in seconds. |
32 | my $TIMEOUT = 10; | |
33 | ||
1410fe4e TH |
34 | # Kernel addresses vary by architecture. We can only auto-detect the following |
35 | # architectures (using `uname -m`). (flag --32-bit overrides auto-detection.) | |
36 | my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64', 'x86'); | |
62139c12 | 37 | |
136fc5c4 TH |
38 | # Command line options. |
39 | my $help = 0; | |
40 | my $debug = 0; | |
d09bd8da TH |
41 | my $raw = 0; |
42 | my $output_raw = ""; # Write raw results to file. | |
43 | my $input_raw = ""; # Read raw results from file instead of scanning. | |
d09bd8da TH |
44 | my $suppress_dmesg = 0; # Don't show dmesg in output. |
45 | my $squash_by_path = 0; # Summary report grouped by absolute path. | |
46 | my $squash_by_filename = 0; # Summary report grouped by filename. | |
f9d2a42d | 47 | my $kernel_config_file = ""; # Kernel configuration file. |
1410fe4e TH |
48 | my $opt_32bit = 0; # Scan 32-bit kernel. |
49 | my $page_offset_32bit = 0; # Page offset for 32-bit kernel. | |
136fc5c4 | 50 | |
b401f56f TH |
51 | # Skip these absolute paths. |
52 | my @skip_abs = ( | |
53 | '/proc/kmsg', | |
54 | '/proc/device-tree', | |
55 | '/sys/firmware/devicetree', | |
56 | '/sys/kernel/debug/tracing/trace_pipe', | |
57 | '/sys/kernel/security/apparmor/revision'); | |
58 | ||
59 | # Skip these under any subdirectory. | |
60 | my @skip_any = ( | |
61 | 'pagemap', | |
62 | 'events', | |
63 | 'access', | |
64 | 'registers', | |
65 | 'snapshot_raw', | |
66 | 'trace_pipe_raw', | |
67 | 'ptmx', | |
68 | 'trace_pipe', | |
69 | 'fd', | |
70 | 'usbmon'); | |
136fc5c4 TH |
71 | |
72 | sub help | |
73 | { | |
74 | my ($exitcode) = @_; | |
75 | ||
76 | print << "EOM"; | |
d09bd8da | 77 | |
136fc5c4 TH |
78 | Usage: $P [OPTIONS] |
79 | Version: $V | |
80 | ||
81 | Options: | |
82 | ||
15d60a35 TH |
83 | -o, --output-raw=<file> Save results for future processing. |
84 | -i, --input-raw=<file> Read results from file instead of scanning. | |
85 | --raw Show raw results (default). | |
86 | --suppress-dmesg Do not show dmesg results. | |
87 | --squash-by-path Show one result per unique path. | |
88 | --squash-by-filename Show one result per unique filename. | |
f9d2a42d | 89 | --kernel-config-file=<file> Kernel configuration file (e.g /boot/config) |
1410fe4e TH |
90 | --32-bit Scan 32-bit kernel. |
91 | --page-offset-32-bit=o Page offset (for 32-bit kernel 0xABCD1234). | |
15d60a35 TH |
92 | -d, --debug Display debugging output. |
93 | -h, --help, --version Display this help and exit. | |
d09bd8da | 94 | |
1410fe4e | 95 | Scans the running kernel for potential leaking addresses. |
136fc5c4 TH |
96 | |
97 | EOM | |
98 | exit($exitcode); | |
99 | } | |
100 | ||
101 | GetOptions( | |
136fc5c4 TH |
102 | 'd|debug' => \$debug, |
103 | 'h|help' => \$help, | |
d09bd8da TH |
104 | 'version' => \$help, |
105 | 'o|output-raw=s' => \$output_raw, | |
106 | 'i|input-raw=s' => \$input_raw, | |
107 | 'suppress-dmesg' => \$suppress_dmesg, | |
108 | 'squash-by-path' => \$squash_by_path, | |
109 | 'squash-by-filename' => \$squash_by_filename, | |
110 | 'raw' => \$raw, | |
f9d2a42d | 111 | 'kernel-config-file=s' => \$kernel_config_file, |
1410fe4e TH |
112 | '32-bit' => \$opt_32bit, |
113 | 'page-offset-32-bit=o' => \$page_offset_32bit, | |
136fc5c4 TH |
114 | ) or help(1); |
115 | ||
116 | help(0) if ($help); | |
117 | ||
d09bd8da TH |
118 | if ($input_raw) { |
119 | format_output($input_raw); | |
120 | exit(0); | |
121 | } | |
122 | ||
123 | if (!$input_raw and ($squash_by_path or $squash_by_filename)) { | |
124 | printf "\nSummary reporting only available with --input-raw=<file>\n"; | |
125 | printf "(First run scan with --output-raw=<file>.)\n"; | |
126 | exit(128); | |
127 | } | |
128 | ||
1410fe4e | 129 | if (!(is_supported_architecture() or $opt_32bit or $page_offset_32bit)) { |
62139c12 TH |
130 | printf "\nScript does not support your architecture, sorry.\n"; |
131 | printf "\nCurrently we support: \n\n"; | |
132 | foreach(@SUPPORTED_ARCHITECTURES) { | |
133 | printf "\t%s\n", $_; | |
134 | } | |
6efb7458 | 135 | printf("\n"); |
62139c12 | 136 | |
1410fe4e TH |
137 | printf("If you are running a 32-bit architecture you may use:\n"); |
138 | printf("\n\t--32-bit or --page-offset-32-bit=<page offset>\n\n"); | |
139 | ||
6efb7458 TH |
140 | my $archname = `uname -m`; |
141 | printf("Machine hardware name (`uname -m`): %s\n", $archname); | |
62139c12 TH |
142 | |
143 | exit(129); | |
144 | } | |
145 | ||
d09bd8da TH |
146 | if ($output_raw) { |
147 | open my $fh, '>', $output_raw or die "$0: $output_raw: $!\n"; | |
148 | select $fh; | |
149 | } | |
150 | ||
136fc5c4 TH |
151 | parse_dmesg(); |
152 | walk(@DIRS); | |
153 | ||
154 | exit 0; | |
155 | ||
136fc5c4 TH |
156 | sub dprint |
157 | { | |
158 | printf(STDERR @_) if $debug; | |
159 | } | |
160 | ||
62139c12 TH |
161 | sub is_supported_architecture |
162 | { | |
1410fe4e TH |
163 | return (is_x86_64() or is_ppc64() or is_ix86_32()); |
164 | } | |
165 | ||
166 | sub is_32bit | |
167 | { | |
168 | # Allow --32-bit or --page-offset-32-bit to override | |
169 | if ($opt_32bit or $page_offset_32bit) { | |
170 | return 1; | |
171 | } | |
172 | ||
173 | return is_ix86_32(); | |
174 | } | |
175 | ||
176 | sub is_ix86_32 | |
177 | { | |
178 | my $arch = `uname -m`; | |
179 | ||
180 | chomp $arch; | |
181 | if ($arch =~ m/i[3456]86/) { | |
182 | return 1; | |
183 | } | |
184 | return 0; | |
62139c12 TH |
185 | } |
186 | ||
5eb0da05 | 187 | sub is_arch |
62139c12 | 188 | { |
5eb0da05 TH |
189 | my ($desc) = @_; |
190 | my $arch = `uname -m`; | |
191 | ||
192 | chomp $arch; | |
193 | if ($arch eq $desc) { | |
194 | return 1; | |
195 | } | |
196 | return 0; | |
197 | } | |
62139c12 | 198 | |
5eb0da05 TH |
199 | sub is_x86_64 |
200 | { | |
201 | return is_arch('x86_64'); | |
62139c12 TH |
202 | } |
203 | ||
204 | sub is_ppc64 | |
205 | { | |
5eb0da05 | 206 | return is_arch('ppc64'); |
62139c12 TH |
207 | } |
208 | ||
f9d2a42d TH |
209 | # Gets config option value from kernel config file. |
210 | # Returns "" on error or if config option not found. | |
211 | sub get_kernel_config_option | |
212 | { | |
213 | my ($option) = @_; | |
214 | my $value = ""; | |
215 | my $tmp_file = ""; | |
216 | my @config_files; | |
217 | ||
218 | # Allow --kernel-config-file to override. | |
219 | if ($kernel_config_file ne "") { | |
220 | @config_files = ($kernel_config_file); | |
221 | } elsif (-R "/proc/config.gz") { | |
222 | my $tmp_file = "/tmp/tmpkconf"; | |
223 | ||
224 | if (system("gunzip < /proc/config.gz > $tmp_file")) { | |
225 | dprint "$0: system(gunzip < /proc/config.gz) failed\n"; | |
226 | return ""; | |
227 | } else { | |
228 | @config_files = ($tmp_file); | |
229 | } | |
230 | } else { | |
231 | my $file = '/boot/config-' . `uname -r`; | |
232 | chomp $file; | |
233 | @config_files = ($file, '/boot/config'); | |
234 | } | |
235 | ||
236 | foreach my $file (@config_files) { | |
237 | dprint("parsing config file: %s\n", $file); | |
238 | $value = option_from_file($option, $file); | |
239 | if ($value ne "") { | |
240 | last; | |
241 | } | |
242 | } | |
243 | ||
244 | if ($tmp_file ne "") { | |
245 | system("rm -f $tmp_file"); | |
246 | } | |
247 | ||
248 | return $value; | |
249 | } | |
250 | ||
251 | # Parses $file and returns kernel configuration option value. | |
252 | sub option_from_file | |
253 | { | |
254 | my ($option, $file) = @_; | |
255 | my $str = ""; | |
256 | my $val = ""; | |
257 | ||
258 | open(my $fh, "<", $file) or return ""; | |
259 | while (my $line = <$fh> ) { | |
260 | if ($line =~ /^$option/) { | |
261 | ($str, $val) = split /=/, $line; | |
262 | chomp $val; | |
263 | last; | |
264 | } | |
265 | } | |
266 | ||
267 | close $fh; | |
268 | return $val; | |
269 | } | |
270 | ||
136fc5c4 TH |
271 | sub is_false_positive |
272 | { | |
7e5758f7 TH |
273 | my ($match) = @_; |
274 | ||
1410fe4e TH |
275 | if (is_32bit()) { |
276 | return is_false_positive_32bit($match); | |
277 | } | |
278 | ||
279 | # 64 bit false positives. | |
280 | ||
7e5758f7 TH |
281 | if ($match =~ '\b(0x)?(f|F){16}\b' or |
282 | $match =~ '\b(0x)?0{16}\b') { | |
283 | return 1; | |
284 | } | |
136fc5c4 | 285 | |
87e37588 TH |
286 | if (is_x86_64() and is_in_vsyscall_memory_region($match)) { |
287 | return 1; | |
7e5758f7 | 288 | } |
136fc5c4 | 289 | |
7e5758f7 | 290 | return 0; |
136fc5c4 TH |
291 | } |
292 | ||
1410fe4e TH |
293 | sub is_false_positive_32bit |
294 | { | |
295 | my ($match) = @_; | |
296 | state $page_offset = get_page_offset(); | |
297 | ||
298 | if ($match =~ '\b(0x)?(f|F){8}\b') { | |
299 | return 1; | |
300 | } | |
301 | ||
302 | if (hex($match) < $page_offset) { | |
303 | return 1; | |
304 | } | |
305 | ||
306 | return 0; | |
307 | } | |
308 | ||
309 | # returns integer value | |
310 | sub get_page_offset | |
311 | { | |
312 | my $page_offset; | |
313 | my $default_offset = 0xc0000000; | |
314 | ||
315 | # Allow --page-offset-32bit to override. | |
316 | if ($page_offset_32bit != 0) { | |
317 | return $page_offset_32bit; | |
318 | } | |
319 | ||
320 | $page_offset = get_kernel_config_option('CONFIG_PAGE_OFFSET'); | |
321 | if (!$page_offset) { | |
322 | return $default_offset; | |
323 | } | |
324 | return $page_offset; | |
325 | } | |
326 | ||
87e37588 TH |
327 | sub is_in_vsyscall_memory_region |
328 | { | |
329 | my ($match) = @_; | |
330 | ||
331 | my $hex = hex($match); | |
332 | my $region_min = hex("0xffffffffff600000"); | |
333 | my $region_max = hex("0xffffffffff601000"); | |
334 | ||
335 | return ($hex >= $region_min and $hex <= $region_max); | |
336 | } | |
337 | ||
136fc5c4 TH |
338 | # True if argument potentially contains a kernel address. |
339 | sub may_leak_address | |
340 | { | |
7e5758f7 | 341 | my ($line) = @_; |
62139c12 | 342 | my $address_re; |
136fc5c4 | 343 | |
7e5758f7 TH |
344 | # Signal masks. |
345 | if ($line =~ '^SigBlk:' or | |
a11949ec | 346 | $line =~ '^SigIgn:' or |
7e5758f7 TH |
347 | $line =~ '^SigCgt:') { |
348 | return 0; | |
349 | } | |
136fc5c4 | 350 | |
7e5758f7 TH |
351 | if ($line =~ '\bKEY=[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b' or |
352 | $line =~ '\b[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b') { | |
136fc5c4 | 353 | return 0; |
7e5758f7 | 354 | } |
136fc5c4 | 355 | |
2f042c93 | 356 | $address_re = get_address_re(); |
62139c12 | 357 | while (/($address_re)/g) { |
7e5758f7 TH |
358 | if (!is_false_positive($1)) { |
359 | return 1; | |
360 | } | |
361 | } | |
136fc5c4 | 362 | |
7e5758f7 | 363 | return 0; |
136fc5c4 TH |
364 | } |
365 | ||
2f042c93 TH |
366 | sub get_address_re |
367 | { | |
1410fe4e | 368 | if (is_ppc64()) { |
2f042c93 | 369 | return '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b'; |
1410fe4e TH |
370 | } elsif (is_32bit()) { |
371 | return '\b(0x)?[[:xdigit:]]{8}\b'; | |
2f042c93 | 372 | } |
1410fe4e TH |
373 | |
374 | return get_x86_64_re(); | |
2f042c93 TH |
375 | } |
376 | ||
377 | sub get_x86_64_re | |
378 | { | |
379 | # We handle page table levels but only if explicitly configured using | |
380 | # CONFIG_PGTABLE_LEVELS. If config file parsing fails or config option | |
381 | # is not found we default to using address regular expression suitable | |
382 | # for 4 page table levels. | |
383 | state $ptl = get_kernel_config_option('CONFIG_PGTABLE_LEVELS'); | |
384 | ||
385 | if ($ptl == 5) { | |
386 | return '\b(0x)?ff[[:xdigit:]]{14}\b'; | |
387 | } | |
388 | return '\b(0x)?ffff[[:xdigit:]]{12}\b'; | |
389 | } | |
390 | ||
136fc5c4 TH |
391 | sub parse_dmesg |
392 | { | |
393 | open my $cmd, '-|', 'dmesg'; | |
394 | while (<$cmd>) { | |
395 | if (may_leak_address($_)) { | |
396 | print 'dmesg: ' . $_; | |
397 | } | |
398 | } | |
399 | close $cmd; | |
400 | } | |
401 | ||
402 | # True if we should skip this path. | |
403 | sub skip | |
404 | { | |
b401f56f | 405 | my ($path) = @_; |
136fc5c4 | 406 | |
b401f56f | 407 | foreach (@skip_abs) { |
136fc5c4 TH |
408 | return 1 if (/^$path$/); |
409 | } | |
410 | ||
411 | my($filename, $dirs, $suffix) = fileparse($path); | |
b401f56f | 412 | foreach (@skip_any) { |
136fc5c4 TH |
413 | return 1 if (/^$filename$/); |
414 | } | |
415 | ||
416 | return 0; | |
417 | } | |
418 | ||
dd98c252 TH |
419 | sub timed_parse_file |
420 | { | |
421 | my ($file) = @_; | |
422 | ||
423 | eval { | |
424 | local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required. | |
425 | alarm $TIMEOUT; | |
426 | parse_file($file); | |
427 | alarm 0; | |
428 | }; | |
429 | ||
430 | if ($@) { | |
431 | die unless $@ eq "alarm\n"; # Propagate unexpected errors. | |
432 | printf STDERR "timed out parsing: %s\n", $file; | |
433 | } | |
434 | } | |
435 | ||
136fc5c4 TH |
436 | sub parse_file |
437 | { | |
438 | my ($file) = @_; | |
439 | ||
440 | if (! -R $file) { | |
441 | return; | |
442 | } | |
443 | ||
e2858cad TH |
444 | if (! -T $file) { |
445 | return; | |
446 | } | |
447 | ||
136fc5c4 TH |
448 | open my $fh, "<", $file or return; |
449 | while ( <$fh> ) { | |
450 | if (may_leak_address($_)) { | |
451 | print $file . ': ' . $_; | |
452 | } | |
453 | } | |
454 | close $fh; | |
455 | } | |
456 | ||
136fc5c4 TH |
457 | # Recursively walk directory tree. |
458 | sub walk | |
459 | { | |
460 | my @dirs = @_; | |
136fc5c4 TH |
461 | |
462 | while (my $pwd = shift @dirs) { | |
136fc5c4 TH |
463 | next if (!opendir(DIR, $pwd)); |
464 | my @files = readdir(DIR); | |
465 | closedir(DIR); | |
466 | ||
467 | foreach my $file (@files) { | |
468 | next if ($file eq '.' or $file eq '..'); | |
469 | ||
470 | my $path = "$pwd/$file"; | |
471 | next if (-l $path); | |
472 | ||
b401f56f TH |
473 | next if (skip($path)); |
474 | ||
136fc5c4 TH |
475 | if (-d $path) { |
476 | push @dirs, $path; | |
b401f56f | 477 | next; |
136fc5c4 | 478 | } |
b401f56f TH |
479 | |
480 | dprint "parsing: $path\n"; | |
481 | timed_parse_file($path); | |
136fc5c4 TH |
482 | } |
483 | } | |
484 | } | |
d09bd8da TH |
485 | |
486 | sub format_output | |
487 | { | |
488 | my ($file) = @_; | |
489 | ||
490 | # Default is to show raw results. | |
491 | if ($raw or (!$squash_by_path and !$squash_by_filename)) { | |
492 | dump_raw_output($file); | |
493 | return; | |
494 | } | |
495 | ||
496 | my ($total, $dmesg, $paths, $files) = parse_raw_file($file); | |
497 | ||
498 | printf "\nTotal number of results from scan (incl dmesg): %d\n", $total; | |
499 | ||
500 | if (!$suppress_dmesg) { | |
501 | print_dmesg($dmesg); | |
502 | } | |
503 | ||
504 | if ($squash_by_filename) { | |
505 | squash_by($files, 'filename'); | |
506 | } | |
507 | ||
508 | if ($squash_by_path) { | |
509 | squash_by($paths, 'path'); | |
510 | } | |
511 | } | |
512 | ||
513 | sub dump_raw_output | |
514 | { | |
515 | my ($file) = @_; | |
516 | ||
517 | open (my $fh, '<', $file) or die "$0: $file: $!\n"; | |
518 | while (<$fh>) { | |
519 | if ($suppress_dmesg) { | |
520 | if ("dmesg:" eq substr($_, 0, 6)) { | |
521 | next; | |
522 | } | |
523 | } | |
524 | print $_; | |
525 | } | |
526 | close $fh; | |
527 | } | |
528 | ||
529 | sub parse_raw_file | |
530 | { | |
531 | my ($file) = @_; | |
532 | ||
533 | my $total = 0; # Total number of lines parsed. | |
534 | my @dmesg; # dmesg output. | |
535 | my %files; # Unique filenames containing leaks. | |
536 | my %paths; # Unique paths containing leaks. | |
537 | ||
538 | open (my $fh, '<', $file) or die "$0: $file: $!\n"; | |
539 | while (my $line = <$fh>) { | |
540 | $total++; | |
541 | ||
542 | if ("dmesg:" eq substr($line, 0, 6)) { | |
543 | push @dmesg, $line; | |
544 | next; | |
545 | } | |
546 | ||
547 | cache_path(\%paths, $line); | |
548 | cache_filename(\%files, $line); | |
549 | } | |
550 | ||
551 | return $total, \@dmesg, \%paths, \%files; | |
552 | } | |
553 | ||
554 | sub print_dmesg | |
555 | { | |
556 | my ($dmesg) = @_; | |
557 | ||
558 | print "\ndmesg output:\n"; | |
559 | ||
560 | if (@$dmesg == 0) { | |
561 | print "<no results>\n"; | |
562 | return; | |
563 | } | |
564 | ||
565 | foreach(@$dmesg) { | |
566 | my $index = index($_, ': '); | |
567 | $index += 2; # skid ': ' | |
568 | print substr($_, $index); | |
569 | } | |
570 | } | |
571 | ||
572 | sub squash_by | |
573 | { | |
574 | my ($ref, $desc) = @_; | |
575 | ||
576 | print "\nResults squashed by $desc (excl dmesg). "; | |
577 | print "Displaying [<number of results> <$desc>], <example result>\n"; | |
578 | ||
579 | if (keys %$ref == 0) { | |
580 | print "<no results>\n"; | |
581 | return; | |
582 | } | |
583 | ||
584 | foreach(keys %$ref) { | |
585 | my $lines = $ref->{$_}; | |
586 | my $length = @$lines; | |
587 | printf "[%d %s] %s", $length, $_, @$lines[0]; | |
588 | } | |
589 | } | |
590 | ||
591 | sub cache_path | |
592 | { | |
593 | my ($paths, $line) = @_; | |
594 | ||
595 | my $index = index($line, ': '); | |
596 | my $path = substr($line, 0, $index); | |
597 | ||
598 | $index += 2; # skip ': ' | |
599 | add_to_cache($paths, $path, substr($line, $index)); | |
600 | } | |
601 | ||
602 | sub cache_filename | |
603 | { | |
604 | my ($files, $line) = @_; | |
605 | ||
606 | my $index = index($line, ': '); | |
607 | my $path = substr($line, 0, $index); | |
608 | my $filename = basename($path); | |
609 | ||
610 | $index += 2; # skip ': ' | |
611 | add_to_cache($files, $filename, substr($line, $index)); | |
612 | } | |
613 | ||
614 | sub add_to_cache | |
615 | { | |
616 | my ($cache, $key, $value) = @_; | |
617 | ||
618 | if (!$cache->{$key}) { | |
619 | $cache->{$key} = (); | |
620 | } | |
621 | push @{$cache->{$key}}, $value; | |
622 | } |