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https://github.com/Yubico/yubikey-val.git
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Don't echo (unsanitized) OTP/NONCE values back to client when
sending error codes. Reported by Paul van Empelen.
This commit is contained in:
parent
3d9722d1d4
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2
Makefile
2
Makefile
@ -1,4 +1,4 @@
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VERSION = 2.9
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VERSION = 2.10
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PACKAGE = yubikey-val
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CODE = COPYING Makefile NEWS ykval-checksum-clients.php \
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ykval-common.php ykval-config.php ykval-db.php ykval-db.sql \
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43
NEWS
43
NEWS
@ -1,3 +1,46 @@
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* Version 2.10 unreleased
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* Don't echo (unsanitized) OTP/NONCE values back to client when
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sending error codes. Reported by Paul van Empelen.
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Resolving this problem protects (arguably buggy) clients against
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an attack. Prior versions of the Yubico C and PHP clients do not
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appear to exhibit this bug. We provide an analysis of the issue
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below so that you can review client implementations for the
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problem. Note that you do not have to fix clients if you are
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using this server version (or later), although we recommend it
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anyway.
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If the client sends a OTP value that ends with '%0astatus=OK' the
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server output will contain a line 'status=ok' before the real
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status code status=MISSING_PARAMETER. Note lower-casing of the
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injected status code, so that it doesn't match a correct
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'status=OK' response. Note also that the OTP value would fail
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normal input validation checks in the client.
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If the client sends a NONCE value that ends with '%0astatus=OK'
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the output will contain a line consisting of 'status=OK' before
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the correct status=MISSING_PARAMETER. However, the NONCE value is
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generated by client code internally and does not come from any
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untrusted source, thus the impact here is limited -- if an
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attacker is able to trick a client into sending a crafted NONCE
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value the attacker is normally able to modify the client code
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somehow, and can thus trick the client in other ways as well.
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Similar issues apply to the ID field, which is normally also under
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control of the trusted client code and not something an attacker
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could influence.
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Thus, this server-side fix solve a client-side issue that we
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believe would only occur when both of these conditions are true:
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1) the client does not do proper input validation of the OTP, and
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2) the client incorrectly parses 'status=ok' as 'status=OK'.
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or when the following condition is true
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A) the client can be tricked into sending a crafted NONCE or ID
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value.
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* Version 2.9 released 2011-05-09
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* Support multiple IP authorizations in ykval-revoke.php.
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@ -56,7 +56,7 @@ if ($protocol_version>=2.0) {
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/* Nonce is required from protocol 2.0 */
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if(!$nonce) {
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$myLog->log(LOG_NOTICE, 'Nonce is missing and protocol version >= 2.0');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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}
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@ -76,51 +76,51 @@ if ($protocol_version>=2.0) {
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if ($otp == '') {
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$myLog->log(LOG_NOTICE, 'OTP is missing');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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if (strlen($otp) < TOKEN_LEN || strlen ($otp) > OTP_MAX_LEN) {
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$myLog->log(LOG_NOTICE, 'Incorrect OTP length: ' . $otp);
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sendResp(S_BAD_OTP, $apiKey, $extra);
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sendResp(S_BAD_OTP);
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exit;
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}
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if (preg_match("/^[cbdefghijklnrtuv]+$/", $otp)==0) {
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$myLog->log(LOG_NOTICE, 'Invalid OTP: ' . $otp);
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sendResp(S_BAD_OTP, $apiKey, $extra);
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sendResp(S_BAD_OTP);
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exit;
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}
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if (preg_match("/^[0-9]+$/", $client)==0){
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$myLog->log(LOG_NOTICE, 'id provided in request must be an integer');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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}
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if ($timeout && preg_match("/^[0-9]+$/", $timeout)==0) {
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$myLog->log(LOG_NOTICE, 'timeout is provided but not correct');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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}
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if ($nonce && preg_match("/^[A-Za-z0-9]+$/", $nonce)==0) {
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$myLog->log(LOG_NOTICE, 'NONCE is provided but not correct');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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}
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if ($nonce && (strlen($nonce) < 16 || strlen($nonce) > 40)) {
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$myLog->log(LOG_NOTICE, 'Nonce too short or too long');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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if ($sl && (preg_match("/^[0-9]+$/", $sl)==0 || ($sl<0 || $sl>100))) {
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$myLog->log(LOG_NOTICE, 'SL is provided but not correct');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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}
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// NOTE: Timestamp parameter is not checked since current protocol says that 1 means request timestamp
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// and anything else is discarded.
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@ -129,7 +129,7 @@ if ($sl && (preg_match("/^[0-9]+$/", $sl)==0 || ($sl<0 || $sl>100))) {
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//
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if ($client <= 0) {
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$myLog->log(LOG_NOTICE, 'Client ID is missing');
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sendResp(S_MISSING_PARAMETER, $apiKey, $extra);
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sendResp(S_MISSING_PARAMETER);
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exit;
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}
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@ -142,14 +142,14 @@ $sync->addField('ip', $_SERVER['REMOTE_ADDR']);
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$sync->addField('otp', $otp);
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if (! $sync->isConnected()) {
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sendResp(S_BACKEND_ERROR, $apiKey, $extra);
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sendResp(S_BACKEND_ERROR);
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exit;
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}
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$cd=$sync->getClientData($client);
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if(!$cd) {
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$myLog->log(LOG_NOTICE, 'Invalid client id ' . $client);
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sendResp(S_NO_SUCH_CLIENT, $apikey, $extra);
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sendResp(S_NO_SUCH_CLIENT);
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exit;
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}
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$myLog->log(LOG_DEBUG,"Client data:", $cd);
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@ -173,7 +173,7 @@ if ($h != '') {
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// Compare it
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if ($hmac != $h) {
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$myLog->log(LOG_DEBUG, 'client hmac=' . $h . ', server hmac=' . $hmac);
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sendResp(S_BAD_SIGNATURE, $apiKey, $extra);
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sendResp(S_BAD_SIGNATURE, $apiKey);
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exit;
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}
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}
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@ -190,7 +190,7 @@ if ($protocol_version<2.0) {
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//
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$urls = otp2ksmurls ($otp, $client);
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if (!is_array($urls)) {
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sendResp(S_BACKEND_ERROR, $apiKey, $extra);
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sendResp(S_BACKEND_ERROR, $apiKey);
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exit;
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}
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@ -198,7 +198,7 @@ if (!is_array($urls)) {
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//
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$otpinfo = KSMdecryptOTP($urls);
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if (!is_array($otpinfo)) {
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sendResp(S_BAD_OTP, $apiKey, $extra);
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sendResp(S_BAD_OTP, $apiKey);
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exit;
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}
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$myLog->log(LOG_DEBUG, "Decrypted OTP:", $otpinfo);
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@ -210,14 +210,14 @@ $yk_publicname=$devId;
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$localParams = $sync->getLocalParams($yk_publicname);
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if (!$localParams) {
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$myLog->log(LOG_NOTICE, 'Invalid Yubikey ' . $yk_publicname);
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sendResp(S_BACKEND_ERROR, $apiKey, $extra);
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sendResp(S_BACKEND_ERROR, $apiKey);
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exit;
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}
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$myLog->log(LOG_DEBUG, "Auth data:", $localParams);
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if ($localParams['active'] != 1) {
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$myLog->log(LOG_NOTICE, 'De-activated Yubikey ' . $devId);
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sendResp(S_BAD_OTP, $apiKey, $extra);
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sendResp(S_BAD_OTP, $apiKey);
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exit;
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}
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@ -254,7 +254,7 @@ if ($sync->countersHigherThanOrEqual($localParams, $otpParams)) {
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if(!$sync->updateDbCounters($otpParams)) {
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$myLog->log(LOG_CRIT, "Failed to update yubikey counters in database");
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sendResp(S_BACKEND_ERROR, $apiKey, $extra);
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sendResp(S_BACKEND_ERROR, $apiKey);
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exit;
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}
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@ -262,7 +262,7 @@ if(!$sync->updateDbCounters($otpParams)) {
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if (!$sync->queue($otpParams, $localParams)) {
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$myLog->log(LOG_CRIT, "ykval-verify:critical:failed to queue sync requests");
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sendResp(S_BACKEND_ERROR, $apiKey, $extra);
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sendResp(S_BACKEND_ERROR, $apiKey);
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exit;
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}
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