support plain text database input

src/gen_dcs_classifier.pl

@@ -34,6 +34,7 @@ use Carp;
 use Crypt::RC4;
 use Digest::MD5 (qw(md5));
 use MIME::Base64;
+use Fcntl qw(SEEK_SET);
 
 # avoid dependency
 # use Carp::Assert;
@@ -380,31 +381,56 @@ sub load_classifier_db($$) {
     open($fh, '<', $fname) || die 'cant open '.$fname.' '.$!;
     binmode($fh);
 
-    my $crypt_data;
-    {
-	my $b64;
+    # files starting with a # are considered un-encrypted
+    my $plainmode;
+    die 'error reading '.$fname.' '.$!
+	unless (defined(read ($fh, $plainmode, 1)));
+    die 'seek error on '.$fname.' '.$!
+	unless (seek($fh, 0, SEEK_SET));
+
+    undef $plainmode if ($plainmode ne "#");
+
+    my $plain;
+    my $hash_plain;
+
+    unless (defined($plainmode)) {
+	my $crypt_data;
+	{
+	    my $b64;
+	    my $sz = (-s $fh);
+	    my $res = read ($fh, $b64, $sz);
+	    die 'error reading '.$fname.' '.$! if (! defined($res));
+	    die 'only read '.$res.' bytes of '.$sz if ($res < $sz);
+	    $crypt_data = decode_base64($b64);
+	    die 'no data after base64 decode'
+		unless (defined($crypt_data) && (length($crypt_data)) > 0);
+	}
+
+	$plain = RC4(compute_key($secret), substr($crypt_data, 32));
+
+	die 'no data after decrypt'
+	    unless (defined($plain) && (length($plain)) > 0);
+
+	# check hash
+
+	my $h_file = substr($crypt_data, 0, 32);
+	$hash_plain = unpack('H*', md5($plain));
+
+	die 'checksum error: file '.$h_file.' decrypt '.$hash_plain
+	    if ($h_file ne $hash_plain);
+    } else {
 	my $sz = (-s $fh);
-	my $res = read ($fh, $b64, $sz);
+	my $res = read ($fh, $plain, $sz);
 	die 'error reading '.$fname.' '.$! if (! defined($res));
 	die 'only read '.$res.' bytes of '.$sz if ($res < $sz);
-	$crypt_data = decode_base64($b64);
-	die 'no data after base64 decode' unless (defined($crypt_data) && (length($crypt_data)) > 0)
+	$hash_plain = unpack('H*', md5($plain));
+	die 'no data from plain file'
+	    unless (defined($plain) && (length($plain)) > 0);
     }
 
     close($fh);
 
-    my $decrypt = RC4(compute_key($secret), substr($crypt_data, 32));
-    my $h_file;
-    {
-	$h_file = substr($crypt_data, 0, 32);
-	my $h_decrypt = unpack('H*', md5($decrypt));
-
-	die 'checksum error: file '.$h_file.' decrypt '.$h_decrypt
-	    if ($h_file ne $h_decrypt);
-
-    }
-
-    return wantarray ? (\$decrypt, $h_file) : \$decrypt;
+    return wantarray ? (\$plain, $hash_plain) : \$plain;
 }
 
 sub enum_name($$) {