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
|
#!/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.
#
# You may like to set kptr_restrict=2 before running script
# (see Documentation/sysctl/kernel.txt).
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);
my $P = $0;
my $V = '0.01';
# Directories to scan.
my @DIRS = ('/proc', '/sys');
# Command line options.
my $help = 0;
my $debug = 0;
# Do not parse these files (absolute path).
my @skip_parse_files_abs = ('/proc/kmsg',
'/proc/kcore',
'/proc/fs/ext4/sdb1/mb_groups',
'/proc/1/fd/3',
'/sys/firmware/devicetree',
'/proc/device-tree',
'/sys/kernel/debug/tracing/trace_pipe',
'/sys/kernel/security/apparmor/revision');
# Do not parse these files under any subdirectory.
my @skip_parse_files_any = ('0',
'1',
'2',
'pagemap',
'events',
'access',
'registers',
'snapshot_raw',
'trace_pipe_raw',
'ptmx',
'trace_pipe');
# Do not walk these directories (absolute path).
my @skip_walk_dirs_abs = ();
# Do not walk these directories under any subdirectory.
my @skip_walk_dirs_any = ('self',
'thread-self',
'cwd',
'fd',
'usbmon',
'stderr',
'stdin',
'stdout');
sub help
{
my ($exitcode) = @_;
print << "EOM";
Usage: $P [OPTIONS]
Version: $V
Options:
-d, --debug Display debugging output.
-h, --help, --version Display this help and exit.
Scans the running (64 bit) kernel for potential leaking addresses.
EOM
exit($exitcode);
}
GetOptions(
'd|debug' => \$debug,
'h|help' => \$help,
'version' => \$help
) or help(1);
help(0) if ($help);
parse_dmesg();
walk(@DIRS);
exit 0;
sub dprint
{
printf(STDERR @_) if $debug;
}
sub is_false_positive
{
my ($match) = @_;
if ($match =~ '\b(0x)?(f|F){16}\b' or
$match =~ '\b(0x)?0{16}\b') {
return 1;
}
if ($match =~ '\bf{10}600000\b' or# vsyscall memory region, we should probably check against a range here.
$match =~ '\bf{10}601000\b') {
return 1;
}
return 0;
}
# True if argument potentially contains a kernel address.
sub may_leak_address
{
my ($line) = @_;
my $address = '\b(0x)?ffff[[:xdigit:]]{12}\b';
# Signal masks.
if ($line =~ '^SigBlk:' or
$line =~ '^SigCgt:') {
return 0;
}
if ($line =~ '\bKEY=[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b' or
$line =~ '\b[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b') {
return 0;
}
while (/($address)/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($path, \@skip_parse_files_abs, \@skip_parse_files_any);
}
sub parse_file
{
my ($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, $path;
} else {
parse_file($path);
}
}
}
}
|
