[thirdparty/kernel/stable.git] / scripts / leaking_addresses.pl

#!/usr/bin/env perl
# SPDX-License-Identifier: GPL-2.0-only
#
# (c) 2017 Tobin C. Harding <me@tobin.cc>
#
# 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 File::Basename;
use File::Spec;
use Cwd 'abs_path';
use Term::ANSIColor qw(:constants);
use Getopt::Long qw(:config no_auto_abbrev);
use Config;
use bigint qw/hex/;
use feature 'state';

my $P = $0;

# Directories to scan.
my @DIRS = ('/proc', '/sys');

# Timer for parsing each file, in seconds.
my $TIMEOUT = 10;

# 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 $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.
my $kernel_config_file = "";	# Kernel configuration file.
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
{
	my ($exitcode) = @_;

	print << "EOM";

Usage: $P [OPTIONS]

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.
	--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			Display this help and exit.

Scans the running kernel for potential leaking addresses.

EOM
	exit($exitcode);
}

GetOptions(
	'd|debug'		=> \$debug,
	'h|help'		=> \$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,
	'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);

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() 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 "\t%s\n", $_;
	}
	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);

	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() or is_ix86_32());
}

sub is_32bit
{
	# Allow --32-bit or --page-offset-32-bit to override
	if ($opt_32bit or $page_offset_32bit) {
		return 1;
	}

	return is_ix86_32();
}

sub is_ix86_32
{
       state $arch = `uname -m`;

       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.
# Returns "" on error or if config option not found.
sub get_kernel_config_option
{
	my ($option) = @_;
	my $value = "";
	my $tmp_file = "";
	my @config_files;

	# Allow --kernel-config-file to override.
	if ($kernel_config_file ne "") {
		@config_files = ($kernel_config_file);
	} elsif (-R "/proc/config.gz") {
		my $tmp_file = "/tmp/tmpkconf";

		if (system("gunzip < /proc/config.gz > $tmp_file")) {
			dprint("system(gunzip < /proc/config.gz) failed\n");
			return "";
		} else {
			@config_files = ($tmp_file);
		}
	} else {
		my $file = '/boot/config-' . `uname -r`;
		chomp $file;
		@config_files = ($file, '/boot/config');
	}

	foreach my $file (@config_files) {
		dprint("parsing config file: $file\n");
		$value = option_from_file($option, $file);
		if ($value ne "") {
			last;
		}
	}

	if ($tmp_file ne "") {
		system("rm -f $tmp_file");
	}

	return $value;
}

# Parses $file and returns kernel configuration option value.
sub option_from_file
{
	my ($option, $file) = @_;
	my $str = "";
	my $val = "";

	open(my $fh, "<", $file) or return "";
	while (my $line = <$fh> ) {
		if ($line =~ /^$option/) {
			($str, $val) = split /=/, $line;
			chomp $val;
			last;
		}
	}

	close $fh;
	return $val;
}

sub is_false_positive
{
	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;
	}

	if (is_x86_64() and is_in_vsyscall_memory_region($match)) {
		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) = @_;

	my $hex = hex($match);
	my $region_min = hex("0xffffffffff600000");
	my $region_max = hex("0xffffffffff601000");

	return ($hex >= $region_min and $hex <= $region_max);
}

# 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;
	}

	$address_re = get_address_re();
	while ($line =~ /($address_re)/g) {
		if (!is_false_positive($1)) {
			return 1;
		}
	}

	return 0;
}

sub get_address_re
{
	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
{
	# We handle page table levels but only if explicitly configured using
	# CONFIG_PGTABLE_LEVELS.  If config file parsing fails or config option
	# is not found we default to using address regular expression suitable
	# for 4 page table levels.
	state $ptl = get_kernel_config_option('CONFIG_PGTABLE_LEVELS');

	if ($ptl == 5) {
		return '\b(0x)?ff[[:xdigit:]]{14}\b';
	}
	return '\b(0x)?ffff[[:xdigit:]]{12}\b';
}

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) = @_;

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

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

	return 0;
}

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 (! -T $file) {
		return;
	}

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

# Checks if the actual path name is leaking a kernel address.
sub check_path_for_leaks
{
	my ($path) = @_;

	if (may_leak_address($path)) {
		printf("Path name may contain address: $path\n");
	}
}

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

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

			# 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;
				next;
			}

			dprint("parsing: $path\n");
			timed_parse_file($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;
}
Commit	Line	Data
136fc5c4	1	#!/usr/bin/env perl
4f19048f	2	# SPDX-License-Identifier: GPL-2.0-only
136fc5c4 TH	3	#
136fc5c4 TH	4	# (c) 2017 Tobin C. Harding <me@tobin.cc>
136fc5c4	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
136fc5c4 TH	11	# cause the script to choke.
136fc5c4	12
472c9e10 TH	13	#
	14	# When the system is idle it is likely that most files under /proc/PID will be
	15	# identical for various processes. Scanning _all_ the PIDs under /proc is
	16	# unnecessary and implies that we are thoroughly scanning /proc. This is _not_
	17	# the case because there may be ways userspace can trigger creation of /proc
	18	# files that leak addresses but were not present during a scan. For these two
	19	# reasons we exclude all PID directories under /proc except '1/'
	20
136fc5c4 TH	21	use warnings;
	22	use strict;
	23	use POSIX;
	24	use File::Basename;
	25	use File::Spec;
	26	use Cwd 'abs_path';
	27	use Term::ANSIColor qw(:constants);
	28	use Getopt::Long qw(:config no_auto_abbrev);
62139c12	29	use Config;
87e37588	30	use bigint qw/hex/;
2f042c93	31	use feature 'state';
136fc5c4 TH	32
136fc5c4 TH	33	my $P = $0;
136fc5c4 TH	34
	35	# Directories to scan.
	36	my @DIRS = ('/proc', '/sys');
	37
dd98c252 TH	38	# Timer for parsing each file, in seconds.
	39	my $TIMEOUT = 10;
	40
1410fe4e TH	41	# Kernel addresses vary by architecture. We can only auto-detect the following
	42	# architectures (using `uname -m`). (flag --32-bit overrides auto-detection.)
	43	my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64', 'x86');
62139c12	44
136fc5c4 TH	45	# Command line options.
	46	my $help = 0;
	47	my $debug = 0;
d09bd8da TH	48	my $raw = 0;
	49	my $output_raw = ""; # Write raw results to file.
	50	my $input_raw = ""; # Read raw results from file instead of scanning.
d09bd8da TH	51	my $suppress_dmesg = 0; # Don't show dmesg in output.
	52	my $squash_by_path = 0; # Summary report grouped by absolute path.
	53	my $squash_by_filename = 0; # Summary report grouped by filename.
f9d2a42d	54	my $kernel_config_file = ""; # Kernel configuration file.
1410fe4e TH	55	my $opt_32bit = 0; # Scan 32-bit kernel.
1410fe4e TH	56	my $page_offset_32bit = 0; # Page offset for 32-bit kernel.
136fc5c4	57
b401f56f TH	58	# Skip these absolute paths.
	59	my @skip_abs = (
	60	'/proc/kmsg',
	61	'/proc/device-tree',
2ad74293	62	'/proc/1/syscall',
b401f56f TH	63	'/sys/firmware/devicetree',
	64	'/sys/kernel/debug/tracing/trace_pipe',
	65	'/sys/kernel/security/apparmor/revision');
	66
	67	# Skip these under any subdirectory.
	68	my @skip_any = (
	69	'pagemap',
	70	'events',
	71	'access',
	72	'registers',
	73	'snapshot_raw',
	74	'trace_pipe_raw',
	75	'ptmx',
	76	'trace_pipe',
	77	'fd',
	78	'usbmon');
136fc5c4 TH	79
	80	sub help
	81	{
	82	my ($exitcode) = @_;
	83
	84	print << "EOM";
d09bd8da	85
136fc5c4	86	Usage: $P [OPTIONS]
136fc5c4 TH	87
	88	Options:
	89
15d60a35 TH	90	-o, --output-raw=<file> Save results for future processing.
	91	-i, --input-raw=<file> Read results from file instead of scanning.
	92	--raw Show raw results (default).
	93	--suppress-dmesg Do not show dmesg results.
	94	--squash-by-path Show one result per unique path.
	95	--squash-by-filename Show one result per unique filename.
f9d2a42d	96	--kernel-config-file=<file> Kernel configuration file (e.g /boot/config)
1410fe4e TH	97	--32-bit Scan 32-bit kernel.
1410fe4e TH	98	--page-offset-32-bit=o Page offset (for 32-bit kernel 0xABCD1234).
15d60a35	99	-d, --debug Display debugging output.
9ac060a7	100	-h, --help Display this help and exit.
d09bd8da	101
1410fe4e	102	Scans the running kernel for potential leaking addresses.
136fc5c4 TH	103
	104	EOM
	105	exit($exitcode);
	106	}
	107
	108	GetOptions(
136fc5c4 TH	109	'd\|debug' => \$debug,
136fc5c4 TH	110	'h\|help' => \$help,
d09bd8da TH	111	'o\|output-raw=s' => \$output_raw,
	112	'i\|input-raw=s' => \$input_raw,
	113	'suppress-dmesg' => \$suppress_dmesg,
	114	'squash-by-path' => \$squash_by_path,
	115	'squash-by-filename' => \$squash_by_filename,
	116	'raw' => \$raw,
f9d2a42d	117	'kernel-config-file=s' => \$kernel_config_file,
1410fe4e TH	118	'32-bit' => \$opt_32bit,
1410fe4e TH	119	'page-offset-32-bit=o' => \$page_offset_32bit,
136fc5c4 TH	120	) or help(1);
	121
	122	help(0) if ($help);
	123
d09bd8da TH	124	if ($input_raw) {
	125	format_output($input_raw);
	126	exit(0);
	127	}
	128
	129	if (!$input_raw and ($squash_by_path or $squash_by_filename)) {
	130	printf "\nSummary reporting only available with --input-raw=<file>\n";
	131	printf "(First run scan with --output-raw=<file>.)\n";
	132	exit(128);
	133	}
	134
1410fe4e	135	if (!(is_supported_architecture() or $opt_32bit or $page_offset_32bit)) {
62139c12 TH	136	printf "\nScript does not support your architecture, sorry.\n";
	137	printf "\nCurrently we support: \n\n";
	138	foreach(@SUPPORTED_ARCHITECTURES) {
	139	printf "\t%s\n", $_;
	140	}
6efb7458	141	printf("\n");
62139c12	142
1410fe4e TH	143	printf("If you are running a 32-bit architecture you may use:\n");
	144	printf("\n\t--32-bit or --page-offset-32-bit=<page offset>\n\n");
	145
6efb7458 TH	146	my $archname = `uname -m`;
6efb7458 TH	147	printf("Machine hardware name (`uname -m`): %s\n", $archname);
62139c12 TH	148
	149	exit(129);
	150	}
	151
d09bd8da TH	152	if ($output_raw) {
	153	open my $fh, '>', $output_raw or die "$0: $output_raw: $!\n";
	154	select $fh;
	155	}
	156
136fc5c4 TH	157	parse_dmesg();
	158	walk(@DIRS);
	159
	160	exit 0;
	161
136fc5c4 TH	162	sub dprint
	163	{
	164	printf(STDERR @_) if $debug;
	165	}
	166
62139c12 TH	167	sub is_supported_architecture
62139c12 TH	168	{
1410fe4e TH	169	return (is_x86_64() or is_ppc64() or is_ix86_32());
	170	}
	171
	172	sub is_32bit
	173	{
	174	# Allow --32-bit or --page-offset-32-bit to override
	175	if ($opt_32bit or $page_offset_32bit) {
	176	return 1;
	177	}
	178
	179	return is_ix86_32();
	180	}
	181
	182	sub is_ix86_32
	183	{
5e4bac34	184	state $arch = `uname -m`;
1410fe4e TH	185
	186	chomp $arch;
	187	if ($arch =~ m/i[3456]86/) {
	188	return 1;
	189	}
	190	return 0;
62139c12 TH	191	}
62139c12 TH	192
5eb0da05	193	sub is_arch
62139c12	194	{
5eb0da05 TH	195	my ($desc) = @_;
	196	my $arch = `uname -m`;
	197
	198	chomp $arch;
	199	if ($arch eq $desc) {
	200	return 1;
	201	}
	202	return 0;
	203	}
62139c12	204
5eb0da05 TH	205	sub is_x86_64
5eb0da05 TH	206	{
5e4bac34 TH	207	state $is = is_arch('x86_64');
5e4bac34 TH	208	return $is;
62139c12 TH	209	}
	210
	211	sub is_ppc64
	212	{
5e4bac34 TH	213	state $is = is_arch('ppc64');
5e4bac34 TH	214	return $is;
62139c12 TH	215	}
62139c12 TH	216
f9d2a42d TH	217	# Gets config option value from kernel config file.
	218	# Returns "" on error or if config option not found.
	219	sub get_kernel_config_option
	220	{
	221	my ($option) = @_;
	222	my $value = "";
	223	my $tmp_file = "";
	224	my @config_files;
	225
	226	# Allow --kernel-config-file to override.
	227	if ($kernel_config_file ne "") {
	228	@config_files = ($kernel_config_file);
	229	} elsif (-R "/proc/config.gz") {
	230	my $tmp_file = "/tmp/tmpkconf";
	231
	232	if (system("gunzip < /proc/config.gz > $tmp_file")) {
0f299433	233	dprint("system(gunzip < /proc/config.gz) failed\n");
f9d2a42d TH	234	return "";
	235	} else {
	236	@config_files = ($tmp_file);
	237	}
	238	} else {
	239	my $file = '/boot/config-' . `uname -r`;
	240	chomp $file;
	241	@config_files = ($file, '/boot/config');
	242	}
	243
	244	foreach my $file (@config_files) {
0f299433	245	dprint("parsing config file: $file\n");
f9d2a42d TH	246	$value = option_from_file($option, $file);
	247	if ($value ne "") {
	248	last;
	249	}
	250	}
	251
	252	if ($tmp_file ne "") {
	253	system("rm -f $tmp_file");
	254	}
	255
	256	return $value;
	257	}
	258
	259	# Parses $file and returns kernel configuration option value.
	260	sub option_from_file
	261	{
	262	my ($option, $file) = @_;
	263	my $str = "";
	264	my $val = "";
	265
	266	open(my $fh, "<", $file) or return "";
	267	while (my $line = <$fh> ) {
	268	if ($line =~ /^$option/) {
	269	($str, $val) = split /=/, $line;
	270	chomp $val;
	271	last;
	272	}
	273	}
	274
	275	close $fh;
	276	return $val;
	277	}
	278
136fc5c4 TH	279	sub is_false_positive
136fc5c4 TH	280	{
7e5758f7 TH	281	my ($match) = @_;
7e5758f7 TH	282
1410fe4e TH	283	if (is_32bit()) {
	284	return is_false_positive_32bit($match);
	285	}
	286
	287	# 64 bit false positives.
	288
7e5758f7 TH	289	if ($match =~ '\b(0x)?(f\|F){16}\b' or
	290	$match =~ '\b(0x)?0{16}\b') {
	291	return 1;
	292	}
136fc5c4	293
87e37588 TH	294	if (is_x86_64() and is_in_vsyscall_memory_region($match)) {
87e37588 TH	295	return 1;
7e5758f7	296	}
136fc5c4	297
7e5758f7	298	return 0;
136fc5c4 TH	299	}
136fc5c4 TH	300
1410fe4e TH	301	sub is_false_positive_32bit
	302	{
	303	my ($match) = @_;
	304	state $page_offset = get_page_offset();
	305
	306	if ($match =~ '\b(0x)?(f\|F){8}\b') {
	307	return 1;
	308	}
	309
	310	if (hex($match) < $page_offset) {
	311	return 1;
	312	}
	313
	314	return 0;
	315	}
	316
	317	# returns integer value
	318	sub get_page_offset
	319	{
	320	my $page_offset;
	321	my $default_offset = 0xc0000000;
	322
	323	# Allow --page-offset-32bit to override.
	324	if ($page_offset_32bit != 0) {
	325	return $page_offset_32bit;
	326	}
	327
	328	$page_offset = get_kernel_config_option('CONFIG_PAGE_OFFSET');
	329	if (!$page_offset) {
	330	return $default_offset;
	331	}
	332	return $page_offset;
	333	}
	334
87e37588 TH	335	sub is_in_vsyscall_memory_region
	336	{
	337	my ($match) = @_;
	338
	339	my $hex = hex($match);
	340	my $region_min = hex("0xffffffffff600000");
	341	my $region_max = hex("0xffffffffff601000");
	342
	343	return ($hex >= $region_min and $hex <= $region_max);
	344	}
	345
136fc5c4 TH	346	# True if argument potentially contains a kernel address.
	347	sub may_leak_address
	348	{
7e5758f7	349	my ($line) = @_;
62139c12	350	my $address_re;
136fc5c4	351
7e5758f7 TH	352	# Signal masks.
7e5758f7 TH	353	if ($line =~ '^SigBlk:' or
a11949ec	354	$line =~ '^SigIgn:' or
7e5758f7 TH	355	$line =~ '^SigCgt:') {
	356	return 0;
	357	}
136fc5c4	358
7e5758f7 TH	359	if ($line =~ '\bKEY=[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b' or
7e5758f7 TH	360	$line =~ '\b[[:xdigit:]]{14} [[:xdigit:]]{16} [[:xdigit:]]{16}\b') {
136fc5c4	361	return 0;
7e5758f7	362	}
136fc5c4	363
2f042c93	364	$address_re = get_address_re();
2306a677	365	while ($line =~ /($address_re)/g) {
7e5758f7 TH	366	if (!is_false_positive($1)) {
	367	return 1;
	368	}
	369	}
136fc5c4	370
7e5758f7	371	return 0;
136fc5c4 TH	372	}
136fc5c4 TH	373
2f042c93 TH	374	sub get_address_re
2f042c93 TH	375	{
1410fe4e	376	if (is_ppc64()) {
2f042c93	377	return '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b';
1410fe4e TH	378	} elsif (is_32bit()) {
1410fe4e TH	379	return '\b(0x)?[[:xdigit:]]{8}\b';
2f042c93	380	}
1410fe4e TH	381
1410fe4e TH	382	return get_x86_64_re();
2f042c93 TH	383	}
	384
	385	sub get_x86_64_re
	386	{
	387	# We handle page table levels but only if explicitly configured using
	388	# CONFIG_PGTABLE_LEVELS. If config file parsing fails or config option
	389	# is not found we default to using address regular expression suitable
	390	# for 4 page table levels.
	391	state $ptl = get_kernel_config_option('CONFIG_PGTABLE_LEVELS');
	392
	393	if ($ptl == 5) {
	394	return '\b(0x)?ff[[:xdigit:]]{14}\b';
	395	}
	396	return '\b(0x)?ffff[[:xdigit:]]{12}\b';
	397	}
	398
136fc5c4 TH	399	sub parse_dmesg
	400	{
	401	open my $cmd, '-\|', 'dmesg';
	402	while (<$cmd>) {
	403	if (may_leak_address($_)) {
	404	print 'dmesg: ' . $_;
	405	}
	406	}
	407	close $cmd;
	408	}
	409
	410	# True if we should skip this path.
	411	sub skip
	412	{
b401f56f	413	my ($path) = @_;
136fc5c4	414
b401f56f	415	foreach (@skip_abs) {
136fc5c4 TH	416	return 1 if (/^$path$/);
	417	}
	418
	419	my($filename, $dirs, $suffix) = fileparse($path);
b401f56f	420	foreach (@skip_any) {
136fc5c4 TH	421	return 1 if (/^$filename$/);
	422	}
	423
	424	return 0;
	425	}
	426
dd98c252 TH	427	sub timed_parse_file
	428	{
	429	my ($file) = @_;
	430
	431	eval {
	432	local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required.
	433	alarm $TIMEOUT;
	434	parse_file($file);
	435	alarm 0;
	436	};
	437
	438	if ($@) {
	439	die unless $@ eq "alarm\n"; # Propagate unexpected errors.
	440	printf STDERR "timed out parsing: %s\n", $file;
	441	}
	442	}
	443
136fc5c4 TH	444	sub parse_file
	445	{
	446	my ($file) = @_;
	447
	448	if (! -R $file) {
	449	return;
	450	}
	451
e2858cad TH	452	if (! -T $file) {
	453	return;
	454	}
	455
136fc5c4 TH	456	open my $fh, "<", $file or return;
	457	while ( <$fh> ) {
	458	if (may_leak_address($_)) {
	459	print $file . ': ' . $_;
	460	}
	461	}
	462	close $fh;
	463	}
	464
c73dff59 TH	465	# Checks if the actual path name is leaking a kernel address.
	466	sub check_path_for_leaks
	467	{
	468	my ($path) = @_;
	469
	470	if (may_leak_address($path)) {
	471	printf("Path name may contain address: $path\n");
	472	}
	473	}
	474
136fc5c4 TH	475	# Recursively walk directory tree.
	476	sub walk
	477	{
	478	my @dirs = @_;
136fc5c4 TH	479
136fc5c4 TH	480	while (my $pwd = shift @dirs) {
136fc5c4 TH	481	next if (!opendir(DIR, $pwd));
	482	my @files = readdir(DIR);
	483	closedir(DIR);
	484
	485	foreach my $file (@files) {
	486	next if ($file eq '.' or $file eq '..');
	487
	488	my $path = "$pwd/$file";
	489	next if (-l $path);
	490
472c9e10 TH	491	# skip /proc/PID except /proc/1
	492	next if (($path =~ /^\/proc\/[0-9]+$/) &&
	493	($path !~ /^\/proc\/1$/));
	494
b401f56f TH	495	next if (skip($path));
b401f56f TH	496
c73dff59 TH	497	check_path_for_leaks($path);
c73dff59 TH	498
136fc5c4 TH	499	if (-d $path) {
136fc5c4 TH	500	push @dirs, $path;
b401f56f	501	next;
136fc5c4	502	}
b401f56f	503
0f299433	504	dprint("parsing: $path\n");
b401f56f	505	timed_parse_file($path);
136fc5c4 TH	506	}
	507	}
	508	}
d09bd8da TH	509
	510	sub format_output
	511	{
	512	my ($file) = @_;
	513
	514	# Default is to show raw results.
	515	if ($raw or (!$squash_by_path and !$squash_by_filename)) {
	516	dump_raw_output($file);
	517	return;
	518	}
	519
	520	my ($total, $dmesg, $paths, $files) = parse_raw_file($file);
	521
	522	printf "\nTotal number of results from scan (incl dmesg): %d\n", $total;
	523
	524	if (!$suppress_dmesg) {
	525	print_dmesg($dmesg);
	526	}
	527
	528	if ($squash_by_filename) {
	529	squash_by($files, 'filename');
	530	}
	531
	532	if ($squash_by_path) {
	533	squash_by($paths, 'path');
	534	}
	535	}
	536
	537	sub dump_raw_output
	538	{
	539	my ($file) = @_;
	540
	541	open (my $fh, '<', $file) or die "$0: $file: $!\n";
	542	while (<$fh>) {
	543	if ($suppress_dmesg) {
	544	if ("dmesg:" eq substr($_, 0, 6)) {
	545	next;
	546	}
	547	}
	548	print $_;
	549	}
	550	close $fh;
	551	}
	552
	553	sub parse_raw_file
	554	{
	555	my ($file) = @_;
	556
	557	my $total = 0; # Total number of lines parsed.
	558	my @dmesg; # dmesg output.
	559	my %files; # Unique filenames containing leaks.
	560	my %paths; # Unique paths containing leaks.
	561
	562	open (my $fh, '<', $file) or die "$0: $file: $!\n";
	563	while (my $line = <$fh>) {
	564	$total++;
	565
	566	if ("dmesg:" eq substr($line, 0, 6)) {
	567	push @dmesg, $line;
	568	next;
	569	}
	570
	571	cache_path(\%paths, $line);
	572	cache_filename(\%files, $line);
573	}
574
575	return $total, \@dmesg, \%paths, \%files;
576	}
577
578	sub print_dmesg
579	{
580	my ($dmesg) = @_;
581
582	print "\ndmesg output:\n";
583
584	if (@$dmesg == 0) {
585	print "<no results>\n";
586	return;
587	}
588
589	foreach(@$dmesg) {
590	my $index = index($_, ': ');
591	$index += 2; # skid ': '
592	print substr($_, $index);
593	}
594	}
595
596	sub squash_by
597	{
598	my ($ref, $desc) = @_;
599
600	print "\nResults squashed by $desc (excl dmesg). ";
601	print "Displaying [<number of results> <$desc>], <example result>\n";
602
603	if (keys %$ref == 0) {
604	print "<no results>\n";
605	return;
606	}
607
608	foreach(keys %$ref) {
609	my $lines = $ref->{$_};
610	my $length = @$lines;
611	printf "[%d %s] %s", $length, $_, @$lines[0];
612	}
613	}
614
615	sub cache_path
616	{
617	my ($paths, $line) = @_;
618
619	my $index = index($line, ': ');
620	my $path = substr($line, 0, $index);
621
622	$index += 2; # skip ': '
623	add_to_cache($paths, $path, substr($line, $index));
624	}
625
626	sub cache_filename
627	{
628	my ($files, $line) = @_;
629
630	my $index = index($line, ': ');
631	my $path = substr($line, 0, $index);
632	my $filename = basename($path);
633
634	$index += 2; # skip ': '
635	add_to_cache($files, $filename, substr($line, $index));
636	}
637
638	sub add_to_cache
639	{
640	my ($cache, $key, $value) = @_;
641
642	if (!$cache->{$key}) {
643	$cache->{$key} = ();
644	}
645	push @{$cache->{$key}}, $value;
646	}