1 files changed, 88 insertions, 0 deletions
diff --git a/yubiserve.php b/yubiserve.php
new file mode 100644
index 0000000..946a8fa
--- /dev/null
+++ b/yubiserve.php
@@ -0,0 +1,88 @@
+<?
+/*
+
+Written by Alessio Periloso <nospam *at* periloso.it>
+Version 1.0: 21/05/2010
+
+Licensed under GPL License (see LICENSE file)
+
+*/
+
+require_once 'yubiserve-config.php';
+require_once 'yubiserve-utils.php';
+
+if (!isset($_REQUEST["otp"]))
+  die ("ERR Missing OTP\n");
+$otp = trim($_REQUEST["otp"]);
+
+if ((strlen($otp)<32) || (strlen($otp)>48)) {
+  syslog(LOG_INFO, "Malformed OTP: $otp");
+  die ("ERR Malformed OTP\n");
+}
+
+if (!preg_match("/^([cbdefghijklnrtuv]{0,16})([cbdefghijklnrtuv]{32})$/", $otp, $matches)) {
+  syslog(LOG_INFO, "Invalid OTP format: $otp");
+  die("ERR Invalid OTP format\n");
+ }
+
+$id = $matches[1];
+$modhex_ciphertext = $matches[2];
+
+$results = @$db->query("SELECT aeskey, internalname FROM yubikeys WHERE publicname = '$id' AND active = 'true'");
+if ($results === false) {
+  syslog(LOG_INFO, "Unknown yubikey (internalname: $id)");
+  die("ERR Unknown yubikey\n");
+}
+
+$row = $results->fetchAll(SQLITE_ASSOC);
+if (count($row)>1) {
+  syslog(LOG_INFO, "Multiple keys returned! OTP: $otp");
+  die("ERR Malformed OTP");
+} elseif (count($row)<1) {
+  syslog(LOG_INFO, "Unknown yubikey (internalname: $id)");
+  die("ERR Unknown yubikey\n");
+}
+
+$aeskey = $row[0]['aeskey'];
+$internalname = $row[0]['internalname'];
+
+$ciphertext = modhex2hex($modhex_ciphertext);
+$plaintext = aes128ecb_decrypt($aeskey, $ciphertext);
+
+$uid = substr($plaintext, 0, 12);
+if (strcmp($uid, $internalname) != 0) {
+  syslog(LOG_ERR, "UID error: $otp $plaintext: $uid vs $internalname");
+  die("ERR Corrupt OTP\n");
+}
+
+if (!crc_is_good($plaintext)) {
+  syslog(LOG_ERR, "CRC error: $otp: $plaintext");
+  die("ERR Corrupt OTP\n");
+}
+
+$counter = substr($plaintext, 14, 2) . substr($plaintext, 12, 2);
+$low = substr($plaintext, 18, 2) . substr($plaintext, 16, 2);
+$high = substr($plaintext, 20, 2);
+$use = substr($plaintext, 22, 2);
+
+$timestamp = hexdec($high . $low);
+$internalcounter = hexdec($counter . $use);
+
+#print("$counter $use $high $low\n");
+
+$results = @$db->query("SELECT counter, time FROM yubikeys WHERE publicname = '$id' AND active = 'true' AND counter < $internalcounter");
+$row = @$results->fetchAll(SQLITE_ASSOC);
+
+if (count($row)!=1) {
+  syslog(LOG_ERR, "REPLAYED OTP for yubikey $id (same counter)");
+  die("ERR Replayed OTP");
+} elseif ((($row[0] >> 8) == ($internalcounter >> 8)) && ($row[1] <= $timestamp)) {
+  syslog(LOG_ERR, "REPLAYED OTP for yubikey $id (same timestamp)");
+  die("ERR Replayed OTP");
+}
+
+print "OK Authentication success";
+$results = $db->query("UPDATE yubikeys SET counter = $internalcounter, time = $timestamp WHERE publicname = '$id'");
+
+unset($db);
+?>