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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 | # | |
6 | # leaking_addresses.pl: Scan 64 bit kernel for potential leaking addresses. | |
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. | |
12 | # | |
13 | # You may like to set kptr_restrict=2 before running script | |
14 | # (see Documentation/sysctl/kernel.txt). | |
15 | ||
16 | use warnings; | |
17 | use strict; | |
18 | use POSIX; | |
19 | use File::Basename; | |
20 | use File::Spec; | |
21 | use Cwd 'abs_path'; | |
22 | use Term::ANSIColor qw(:constants); | |
23 | use Getopt::Long qw(:config no_auto_abbrev); | |
62139c12 | 24 | use Config; |
136fc5c4 TH |
25 | |
26 | my $P = $0; | |
27 | my $V = '0.01'; | |
28 | ||
29 | # Directories to scan. | |
30 | my @DIRS = ('/proc', '/sys'); | |
31 | ||
dd98c252 TH |
32 | # Timer for parsing each file, in seconds. |
33 | my $TIMEOUT = 10; | |
34 | ||
62139c12 TH |
35 | # Script can only grep for kernel addresses on the following architectures. If |
36 | # your architecture is not listed here and has a grep'able kernel address please | |
37 | # consider submitting a patch. | |
38 | my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64'); | |
39 | ||
136fc5c4 TH |
40 | # Command line options. |
41 | my $help = 0; | |
42 | my $debug = 0; | |
d09bd8da TH |
43 | my $raw = 0; |
44 | my $output_raw = ""; # Write raw results to file. | |
45 | my $input_raw = ""; # Read raw results from file instead of scanning. | |
46 | ||
47 | my $suppress_dmesg = 0; # Don't show dmesg in output. | |
48 | my $squash_by_path = 0; # Summary report grouped by absolute path. | |
49 | my $squash_by_filename = 0; # Summary report grouped by filename. | |
136fc5c4 TH |
50 | |
51 | # Do not parse these files (absolute path). | |
52 | my @skip_parse_files_abs = ('/proc/kmsg', | |
53 | '/proc/kcore', | |
54 | '/proc/fs/ext4/sdb1/mb_groups', | |
55 | '/proc/1/fd/3', | |
1c1e3be0 TH |
56 | '/sys/firmware/devicetree', |
57 | '/proc/device-tree', | |
136fc5c4 TH |
58 | '/sys/kernel/debug/tracing/trace_pipe', |
59 | '/sys/kernel/security/apparmor/revision'); | |
60 | ||
a284733e | 61 | # Do not parse these files under any subdirectory. |
136fc5c4 TH |
62 | my @skip_parse_files_any = ('0', |
63 | '1', | |
64 | '2', | |
65 | 'pagemap', | |
66 | 'events', | |
67 | 'access', | |
68 | 'registers', | |
69 | 'snapshot_raw', | |
70 | 'trace_pipe_raw', | |
71 | 'ptmx', | |
72 | 'trace_pipe'); | |
73 | ||
74 | # Do not walk these directories (absolute path). | |
75 | my @skip_walk_dirs_abs = (); | |
76 | ||
77 | # Do not walk these directories under any subdirectory. | |
78 | my @skip_walk_dirs_any = ('self', | |
79 | 'thread-self', | |
80 | 'cwd', | |
81 | 'fd', | |
1c1e3be0 | 82 | 'usbmon', |
136fc5c4 TH |
83 | 'stderr', |
84 | 'stdin', | |
85 | 'stdout'); | |
86 | ||
87 | sub help | |
88 | { | |
89 | my ($exitcode) = @_; | |
90 | ||
91 | print << "EOM"; | |
d09bd8da | 92 | |
136fc5c4 TH |
93 | Usage: $P [OPTIONS] |
94 | Version: $V | |
95 | ||
96 | Options: | |
97 | ||
d09bd8da TH |
98 | -o, --output-raw=<file> Save results for future processing. |
99 | -i, --input-raw=<file> Read results from file instead of scanning. | |
100 | --raw Show raw results (default). | |
101 | --suppress-dmesg Do not show dmesg results. | |
102 | --squash-by-path Show one result per unique path. | |
103 | --squash-by-filename Show one result per unique filename. | |
104 | -d, --debug Display debugging output. | |
105 | -h, --help, --version Display this help and exit. | |
106 | ||
107 | Examples: | |
108 | ||
109 | # Scan kernel and dump raw results. | |
110 | $0 | |
111 | ||
112 | # Scan kernel and save results to file. | |
113 | $0 --output-raw scan.out | |
114 | ||
115 | # View summary report. | |
116 | $0 --input-raw scan.out --squash-by-filename | |
136fc5c4 | 117 | |
136fc5c4 TH |
118 | Scans the running (64 bit) kernel for potential leaking addresses. |
119 | ||
120 | EOM | |
121 | exit($exitcode); | |
122 | } | |
123 | ||
124 | GetOptions( | |
136fc5c4 TH |
125 | 'd|debug' => \$debug, |
126 | 'h|help' => \$help, | |
d09bd8da TH |
127 | 'version' => \$help, |
128 | 'o|output-raw=s' => \$output_raw, | |
129 | 'i|input-raw=s' => \$input_raw, | |
130 | 'suppress-dmesg' => \$suppress_dmesg, | |
131 | 'squash-by-path' => \$squash_by_path, | |
132 | 'squash-by-filename' => \$squash_by_filename, | |
133 | 'raw' => \$raw, | |
136fc5c4 TH |
134 | ) or help(1); |
135 | ||
136 | help(0) if ($help); | |
137 | ||
d09bd8da TH |
138 | if ($input_raw) { |
139 | format_output($input_raw); | |
140 | exit(0); | |
141 | } | |
142 | ||
143 | if (!$input_raw and ($squash_by_path or $squash_by_filename)) { | |
144 | printf "\nSummary reporting only available with --input-raw=<file>\n"; | |
145 | printf "(First run scan with --output-raw=<file>.)\n"; | |
146 | exit(128); | |
147 | } | |
148 | ||
62139c12 TH |
149 | if (!is_supported_architecture()) { |
150 | printf "\nScript does not support your architecture, sorry.\n"; | |
151 | printf "\nCurrently we support: \n\n"; | |
152 | foreach(@SUPPORTED_ARCHITECTURES) { | |
153 | printf "\t%s\n", $_; | |
154 | } | |
155 | ||
156 | my $archname = $Config{archname}; | |
157 | printf "\n\$ perl -MConfig -e \'print \"\$Config{archname}\\n\"\'\n"; | |
158 | printf "%s\n", $archname; | |
159 | ||
160 | exit(129); | |
161 | } | |
162 | ||
d09bd8da TH |
163 | if ($output_raw) { |
164 | open my $fh, '>', $output_raw or die "$0: $output_raw: $!\n"; | |
165 | select $fh; | |
166 | } | |
167 | ||
136fc5c4 TH |
168 | parse_dmesg(); |
169 | walk(@DIRS); | |
170 | ||
171 | exit 0; | |
172 | ||
136fc5c4 TH |
173 | sub dprint |
174 | { | |
175 | printf(STDERR @_) if $debug; | |
176 | } | |
177 | ||
62139c12 TH |
178 | sub is_supported_architecture |
179 | { | |
180 | return (is_x86_64() or is_ppc64()); | |
181 | } | |
182 | ||
183 | sub is_x86_64 | |
184 | { | |
185 | my $archname = $Config{archname}; | |
186 | ||
187 | if ($archname =~ m/x86_64/) { | |
188 | return 1; | |
189 | } | |
190 | return 0; | |
191 | } | |
192 | ||
193 | sub is_ppc64 | |
194 | { | |
195 | my $archname = $Config{archname}; | |
196 | ||
197 | if ($archname =~ m/powerpc/ and $archname =~ m/64/) { | |
198 | return 1; | |
199 | } | |
200 | return 0; | |
201 | } | |
202 | ||
136fc5c4 TH |
203 | sub is_false_positive |
204 | { | |
7e5758f7 TH |
205 | my ($match) = @_; |
206 | ||
207 | if ($match =~ '\b(0x)?(f|F){16}\b' or | |
208 | $match =~ '\b(0x)?0{16}\b') { | |
209 | return 1; | |
210 | } | |
136fc5c4 | 211 | |
62139c12 TH |
212 | if (is_x86_64) { |
213 | # vsyscall memory region, we should probably check against a range here. | |
214 | if ($match =~ '\bf{10}600000\b' or | |
215 | $match =~ '\bf{10}601000\b') { | |
216 | return 1; | |
217 | } | |
7e5758f7 | 218 | } |
136fc5c4 | 219 | |
7e5758f7 | 220 | return 0; |
136fc5c4 TH |
221 | } |
222 | ||
223 | # True if argument potentially contains a kernel address. | |
224 | sub may_leak_address | |
225 | { | |
7e5758f7 | 226 | my ($line) = @_; |
62139c12 | 227 | my $address_re; |
136fc5c4 | 228 | |
7e5758f7 TH |
229 | # Signal masks. |
230 | if ($line =~ '^SigBlk:' or | |
231 | $line =~ '^SigCgt:') { | |
232 | return 0; | |
233 | } | |
136fc5c4 | 234 | |
7e5758f7 TH |
235 | if ($line =~ '\bKEY=[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b' or |
236 | $line =~ '\b[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b') { | |
136fc5c4 | 237 | return 0; |
7e5758f7 | 238 | } |
136fc5c4 | 239 | |
62139c12 TH |
240 | # One of these is guaranteed to be true. |
241 | if (is_x86_64()) { | |
242 | $address_re = '\b(0x)?ffff[[:xdigit:]]{12}\b'; | |
243 | } elsif (is_ppc64()) { | |
244 | $address_re = '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b'; | |
245 | } | |
246 | ||
247 | while (/($address_re)/g) { | |
7e5758f7 TH |
248 | if (!is_false_positive($1)) { |
249 | return 1; | |
250 | } | |
251 | } | |
136fc5c4 | 252 | |
7e5758f7 | 253 | return 0; |
136fc5c4 TH |
254 | } |
255 | ||
256 | sub parse_dmesg | |
257 | { | |
258 | open my $cmd, '-|', 'dmesg'; | |
259 | while (<$cmd>) { | |
260 | if (may_leak_address($_)) { | |
261 | print 'dmesg: ' . $_; | |
262 | } | |
263 | } | |
264 | close $cmd; | |
265 | } | |
266 | ||
267 | # True if we should skip this path. | |
268 | sub skip | |
269 | { | |
270 | my ($path, $paths_abs, $paths_any) = @_; | |
271 | ||
272 | foreach (@$paths_abs) { | |
273 | return 1 if (/^$path$/); | |
274 | } | |
275 | ||
276 | my($filename, $dirs, $suffix) = fileparse($path); | |
277 | foreach (@$paths_any) { | |
278 | return 1 if (/^$filename$/); | |
279 | } | |
280 | ||
281 | return 0; | |
282 | } | |
283 | ||
284 | sub skip_parse | |
285 | { | |
286 | my ($path) = @_; | |
287 | return skip($path, \@skip_parse_files_abs, \@skip_parse_files_any); | |
288 | } | |
289 | ||
dd98c252 TH |
290 | sub timed_parse_file |
291 | { | |
292 | my ($file) = @_; | |
293 | ||
294 | eval { | |
295 | local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required. | |
296 | alarm $TIMEOUT; | |
297 | parse_file($file); | |
298 | alarm 0; | |
299 | }; | |
300 | ||
301 | if ($@) { | |
302 | die unless $@ eq "alarm\n"; # Propagate unexpected errors. | |
303 | printf STDERR "timed out parsing: %s\n", $file; | |
304 | } | |
305 | } | |
306 | ||
136fc5c4 TH |
307 | sub parse_file |
308 | { | |
309 | my ($file) = @_; | |
310 | ||
311 | if (! -R $file) { | |
312 | return; | |
313 | } | |
314 | ||
315 | if (skip_parse($file)) { | |
316 | dprint "skipping file: $file\n"; | |
317 | return; | |
318 | } | |
319 | dprint "parsing: $file\n"; | |
320 | ||
321 | open my $fh, "<", $file or return; | |
322 | while ( <$fh> ) { | |
323 | if (may_leak_address($_)) { | |
324 | print $file . ': ' . $_; | |
325 | } | |
326 | } | |
327 | close $fh; | |
328 | } | |
329 | ||
330 | ||
331 | # True if we should skip walking this directory. | |
332 | sub skip_walk | |
333 | { | |
334 | my ($path) = @_; | |
335 | return skip($path, \@skip_walk_dirs_abs, \@skip_walk_dirs_any) | |
336 | } | |
337 | ||
338 | # Recursively walk directory tree. | |
339 | sub walk | |
340 | { | |
341 | my @dirs = @_; | |
136fc5c4 TH |
342 | |
343 | while (my $pwd = shift @dirs) { | |
344 | next if (skip_walk($pwd)); | |
345 | next if (!opendir(DIR, $pwd)); | |
346 | my @files = readdir(DIR); | |
347 | closedir(DIR); | |
348 | ||
349 | foreach my $file (@files) { | |
350 | next if ($file eq '.' or $file eq '..'); | |
351 | ||
352 | my $path = "$pwd/$file"; | |
353 | next if (-l $path); | |
354 | ||
355 | if (-d $path) { | |
356 | push @dirs, $path; | |
357 | } else { | |
dd98c252 | 358 | timed_parse_file($path); |
136fc5c4 TH |
359 | } |
360 | } | |
361 | } | |
362 | } | |
d09bd8da TH |
363 | |
364 | sub format_output | |
365 | { | |
366 | my ($file) = @_; | |
367 | ||
368 | # Default is to show raw results. | |
369 | if ($raw or (!$squash_by_path and !$squash_by_filename)) { | |
370 | dump_raw_output($file); | |
371 | return; | |
372 | } | |
373 | ||
374 | my ($total, $dmesg, $paths, $files) = parse_raw_file($file); | |
375 | ||
376 | printf "\nTotal number of results from scan (incl dmesg): %d\n", $total; | |
377 | ||
378 | if (!$suppress_dmesg) { | |
379 | print_dmesg($dmesg); | |
380 | } | |
381 | ||
382 | if ($squash_by_filename) { | |
383 | squash_by($files, 'filename'); | |
384 | } | |
385 | ||
386 | if ($squash_by_path) { | |
387 | squash_by($paths, 'path'); | |
388 | } | |
389 | } | |
390 | ||
391 | sub dump_raw_output | |
392 | { | |
393 | my ($file) = @_; | |
394 | ||
395 | open (my $fh, '<', $file) or die "$0: $file: $!\n"; | |
396 | while (<$fh>) { | |
397 | if ($suppress_dmesg) { | |
398 | if ("dmesg:" eq substr($_, 0, 6)) { | |
399 | next; | |
400 | } | |
401 | } | |
402 | print $_; | |
403 | } | |
404 | close $fh; | |
405 | } | |
406 | ||
407 | sub parse_raw_file | |
408 | { | |
409 | my ($file) = @_; | |
410 | ||
411 | my $total = 0; # Total number of lines parsed. | |
412 | my @dmesg; # dmesg output. | |
413 | my %files; # Unique filenames containing leaks. | |
414 | my %paths; # Unique paths containing leaks. | |
415 | ||
416 | open (my $fh, '<', $file) or die "$0: $file: $!\n"; | |
417 | while (my $line = <$fh>) { | |
418 | $total++; | |
419 | ||
420 | if ("dmesg:" eq substr($line, 0, 6)) { | |
421 | push @dmesg, $line; | |
422 | next; | |
423 | } | |
424 | ||
425 | cache_path(\%paths, $line); | |
426 | cache_filename(\%files, $line); | |
427 | } | |
428 | ||
429 | return $total, \@dmesg, \%paths, \%files; | |
430 | } | |
431 | ||
432 | sub print_dmesg | |
433 | { | |
434 | my ($dmesg) = @_; | |
435 | ||
436 | print "\ndmesg output:\n"; | |
437 | ||
438 | if (@$dmesg == 0) { | |
439 | print "<no results>\n"; | |
440 | return; | |
441 | } | |
442 | ||
443 | foreach(@$dmesg) { | |
444 | my $index = index($_, ': '); | |
445 | $index += 2; # skid ': ' | |
446 | print substr($_, $index); | |
447 | } | |
448 | } | |
449 | ||
450 | sub squash_by | |
451 | { | |
452 | my ($ref, $desc) = @_; | |
453 | ||
454 | print "\nResults squashed by $desc (excl dmesg). "; | |
455 | print "Displaying [<number of results> <$desc>], <example result>\n"; | |
456 | ||
457 | if (keys %$ref == 0) { | |
458 | print "<no results>\n"; | |
459 | return; | |
460 | } | |
461 | ||
462 | foreach(keys %$ref) { | |
463 | my $lines = $ref->{$_}; | |
464 | my $length = @$lines; | |
465 | printf "[%d %s] %s", $length, $_, @$lines[0]; | |
466 | } | |
467 | } | |
468 | ||
469 | sub cache_path | |
470 | { | |
471 | my ($paths, $line) = @_; | |
472 | ||
473 | my $index = index($line, ': '); | |
474 | my $path = substr($line, 0, $index); | |
475 | ||
476 | $index += 2; # skip ': ' | |
477 | add_to_cache($paths, $path, substr($line, $index)); | |
478 | } | |
479 | ||
480 | sub cache_filename | |
481 | { | |
482 | my ($files, $line) = @_; | |
483 | ||
484 | my $index = index($line, ': '); | |
485 | my $path = substr($line, 0, $index); | |
486 | my $filename = basename($path); | |
487 | ||
488 | $index += 2; # skip ': ' | |
489 | add_to_cache($files, $filename, substr($line, $index)); | |
490 | } | |
491 | ||
492 | sub add_to_cache | |
493 | { | |
494 | my ($cache, $key, $value) = @_; | |
495 | ||
496 | if (!$cache->{$key}) { | |
497 | $cache->{$key} = (); | |
498 | } | |
499 | push @{$cache->{$key}}, $value; | |
500 | } |