tty: Handle problem if line discipline does not have receive_buf

[linux/fpc-iii.git] / scripts / leaking_addresses.pl

#!/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).
#
# You can configure the behaviour of the script;
#
#  - By adding paths, for directories you do not want to walk;
#     absolute paths: @skip_walk_dirs_abs
#     directory names: @skip_walk_dirs_any
#
#  - By adding paths, for files you do not want to parse;
#     absolute paths: @skip_parse_files_abs
#     file names: @skip_parse_files_any
#
# The use of @skip_xxx_xxx_any causes files to be skipped where ever they occur.
# For example adding 'fd' to @skip_walk_dirs_any causes the fd/ directory to be
# skipped for all PID sub-directories of /proc
#
# The same thing can be achieved by passing command line options to --dont-walk
# and --dont-parse. If absolute paths are supplied to these options they are
# appended to the @skip_xxx_xxx_abs arrays. If file names are supplied to these
# options, they are appended to the @skip_xxx_xxx_any arrays.
#
# 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;
my @dont_walk = ();
my @dont_parse = ();

# 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/kernel/debug/tracing/trace_pipe',
                            '/sys/kernel/security/apparmor/revision');

# Do not parse thes 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',
                          'stderr',
                          'stdin',
                          'stdout');

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

        print << "EOM";
Usage: $P [OPTIONS]
Version: $V

Options:

        --dont-walk=<dir>      Don't walk tree starting at <dir>.
        --dont-parse=<file>    Don't parse <file>.
        -d, --debug                Display debugging output.
        -h, --help, --version      Display this help and exit.

If an absolute path is passed to --dont_XXX then this path is skipped. If a
single filename is passed then this file/directory will be skipped when
appearing under any subdirectory.

Example:

        # Just scan dmesg output.
        scripts/leaking_addresses.pl --dont_walk_abs /proc --dont_walk_abs /sys

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

EOM
        exit($exitcode);
}

GetOptions(
        'dont-walk=s'           => \@dont_walk,
        'dont-parse=s'          => \@dont_parse,
        'd|debug'               => \$debug,
        'h|help'                => \$help,
        'version'               => \$help
) or help(1);

help(0) if ($help);

push_to_global();

parse_dmesg();
walk(@DIRS);

exit 0;

sub debug_arrays
{
        print 'dirs_any: ' . join(", ", @skip_walk_dirs_any) . "\n";
        print 'dirs_abs: ' . join(", ", @skip_walk_dirs_abs) . "\n";
        print 'parse_any: ' . join(", ", @skip_parse_files_any) . "\n";
        print 'parse_abs: ' . join(", ", @skip_parse_files_abs) . "\n";
}

sub dprint
{
        printf(STDERR @_) if $debug;
}

sub push_in_abs_any
{
        my ($in, $abs, $any) = @_;

        foreach my $path (@$in) {
                if (File::Spec->file_name_is_absolute($path)) {
                        push @$abs, $path;
                } elsif (index($path,'/') == -1) {
                        push @$any, $path;
                } else {
                        print 'path error: ' . $path;
                }
        }
}

# Push command line options to global arrays.
sub push_to_global
{
        push_in_abs_any(\@dont_walk, \@skip_walk_dirs_abs, \@skip_walk_dirs_any);
        push_in_abs_any(\@dont_parse, \@skip_parse_files_abs, \@skip_parse_files_any);
}

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

        if ($match =~ '\b(0x)?(f|F){16}\b' or
            $match =~ '\b(0x)?0{16}\b') {
                return 1;
        }

        # 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 = '\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 = @_;
        my %seen;

        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);
                        }
                }
        }
}