6b8cd38690
Add modhash to calculate the hash of kernel module (SLE-5661) OBS-URL: https://build.opensuse.org/request/show/703674 OBS-URL: https://build.opensuse.org/package/show/Base:System/mokutil?expand=0&rev=38
150 lines
3.3 KiB
Perl
150 lines
3.3 KiB
Perl
#!/usr/bin/perl
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#
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# Calculate the digest of the kernel module
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# It will strip kernel modules signature before calculation.
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#
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# Based on modsign-verify, written by Michal Marek
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# Authors:
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# Gary Lin <GLin@suse.com>
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# Joey Lee <JLee@suse.com>
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#
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my $USAGE = "Usage: modhash [-v] [-q] [-d <digest algorithm>] <module>\n";
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use strict;
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use warnings;
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use IPC::Open2;
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use Getopt::Long;
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use File::Temp qw(tempfile);
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my $verbose = 1;
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my $dgst = "sha256";
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GetOptions(
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"d=s" => \$dgst,
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"q|quiet" => sub { $verbose-- if $verbose; },
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"v|verbose" => sub { $verbose++; },
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"h|help" => sub {
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print $USAGE;
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exit(0);
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}
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) or die($USAGE);
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sub _verbose {
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my $level = shift;
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return if $verbose < $level;
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print STDERR @_;
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}
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sub info { _verbose(1, @_); }
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sub verbose { _verbose(2, @_); }
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sub debug { _verbose(3, @_); }
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if (@ARGV > 1) {
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print STDERR "Excess arguments\n";
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die($USAGE);
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} elsif (@ARGV < 1) {
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print STDERR "No module supplied\n";
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die($USAGE);
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}
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my $module_name = shift(@ARGV);
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if ($dgst ne "sha" and $dgst ne "sha1" and $dgst ne "sha256" and
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$dgst ne "sha384" and $dgst ne "sha512") {
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die("unsupported algorithm: $dgst");
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}
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#
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# Function to read the contents of a file into a variable.
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#
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sub read_file($)
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{
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my ($file) = @_;
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my $contents;
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my $len;
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open(FD, "<$file") || die $file;
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binmode FD;
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my @st = stat(FD);
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die $file if (!@st);
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$len = read(FD, $contents, $st[7]) || die $file;
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close(FD) || die $file;
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die "$file: Wanted length ", $st[7], ", got ", $len, "\n"
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if ($len != $st[7]);
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return $contents;
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}
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sub openssl_pipe($$) {
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my ($input, $cmd) = @_;
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my ($pid, $res);
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$pid = open2(*read_from, *write_to, $cmd) || die $cmd;
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binmode write_to;
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if (defined($input) && $input ne "") {
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print write_to $input || die "$cmd: $!";
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}
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close(write_to) || die "$cmd: $!";
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binmode read_from;
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read(read_from, $res, 4096) || die "$cmd: $!";
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close(read_from) || die "$cmd: $!";
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waitpid($pid, 0) || die;
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die "$cmd died: $?" if ($? >> 8);
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return $res;
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}
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my $module = read_file($module_name);
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my $module_len = length($module);
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my $magic_number = "~Module signature appended~\n";
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my $magic_len = length($magic_number);
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my $info_len = 12;
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if ($module_len < $magic_len) {
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die "Module size too short\n";
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}
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sub eat
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{
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my $length = shift;
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if ($module_len < $length) {
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die "Module size too short\n";
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}
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my $res = substr($module, -$length);
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$module = substr($module, 0, $module_len - $length);
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$module_len -= $length;
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return $res;
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}
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if (substr($module, -$magic_len) eq $magic_number) {
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$module = substr($module, 0, $module_len - $magic_len);
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$module_len -= $magic_len;
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my $info = eat($info_len);
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my ($algo, $hash, $id_type, $name_len, $key_len, $sig_len) =
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unpack("CCCCCxxxN", $info);
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my $signature = eat($sig_len);
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if ($id_type == 1) {
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if (unpack("n", $signature) == $sig_len - 2) {
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verbose ("signed module (X.509)\n");
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} else {
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die "Invalid signature format\n";
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}
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if ($algo != 1) {
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die "Unsupported signature algorithm\n";
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}
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$signature = substr($signature, 2);
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my $key_id = eat($key_len);
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my $name = eat($name_len);
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} elsif ($id_type == 2) {
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verbose ("signed module (PKCS#7)\n");
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}
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} else {
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verbose ("unsigned module\n");
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}
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verbose("Hash algorithm: $dgst\n");
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my $digest = openssl_pipe($module, "openssl dgst -$dgst");
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$digest =~ s/\(stdin\)= //;
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print "$module_name: $digest"
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