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fix(activesync): harden auth header, Autodiscover parsing/XML escaping, and ValidateCert #74

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Merged
TDannhauer merged 4 commits into from
Jul 2, 2026
Merged

fix(activesync): harden auth header, Autodiscover parsing/XML escaping, and ValidateCert #74

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cc385d9
fix(activesync): harden HTTP Basic auth header parsing
TDannhauer Jul 2, 2026
bffd305
fix(activesync): harden Autodiscover parsing and escape XML responses
TDannhauer Jul 2, 2026
36ded68
fix(activesync): correct ValidateCert OpenSSL result handling
TDannhauer Jul 2, 2026
1e7b07c
docs(activesync): note ValidateCert validator extraction in H6 todo
TDannhauer Jul 2, 2026
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8 changes: 6 additions & 2 deletions lib/Horde/ActiveSync/Credentials.php
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Original file line number Diff line number Diff line change
Expand Up @@ -98,8 +98,12 @@ protected function _getCredentials()
: (!empty($serverVars['REDIRECT_HTTP_AUTHORIZATION'])
? $serverVars['REDIRECT_HTTP_AUTHORIZATION']
: $serverVars['Authorization']);
$hash = base64_decode(str_replace('Basic ', '', $authorization));
if (strpos($hash, ':') !== false) {
// Strip only a leading, case-insensitive "Basic " scheme token
// (str_replace() would remove the token anywhere in the string),
// and decode strictly so malformed input yields no credentials
// rather than garbage.
$hash = base64_decode(preg_replace('/^\s*Basic\s+/i', '', $authorization), true);
if ($hash !== false && strpos($hash, ':') !== false) {
[$user, $pass] = explode(':', $hash, 2);
}
} else {
Expand Down
81 changes: 59 additions & 22 deletions lib/Horde/ActiveSync/Request/Autodiscover.php
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Original file line number Diff line number Diff line change
Expand Up @@ -67,8 +67,27 @@ public function handle(?Horde_Controller_Request $request = null)
if (empty($values) && empty($username)) {
throw new Horde_Exception_AuthenticationFailure('No username provided.');
} elseif (!empty($values)) {
// Override the username; AUTODISCOVER MUST use email address.
$credentials->username = $values[2]['value'];
// Override the username; AUTODISCOVER MUST use the email address.
// Locate the EMailAddress element by tag name instead of relying on
// a fixed offset ($values[2]), which breaks (and can select the
// wrong node) if a client reorders or adds elements. The wire value
// is always an email address per the Autodiscover protocol; mapping
// it to the backend username (email, AD/LDAP, plain username, ...)
// is handled downstream by the driver's getUsernameFromEmail().
$email = null;
foreach ($values as $value) {
if (!empty($value['tag']) && $value['tag'] == 'EMAILADDRESS'
&& isset($value['value'])) {
$email = trim($value['value']);
break;
}
}
if ($email !== null && $email !== '') {
$credentials->username = $email;
} elseif (empty($username)) {
// No EMailAddress element and no username from the auth header.
throw new Horde_Exception_AuthenticationFailure('No username provided.');
}
}

if (!$this->_activeSync->authenticate($credentials)) {
Expand Down Expand Up @@ -107,6 +126,24 @@ public function handle(?Horde_Controller_Request $request = null)
*/
protected function _handle() {}

/**
* Escape a value for safe inclusion in the XML responses built below.
*
* The interpolated values (email, display name, schemas echoed back from
* the client request, backend host names, etc.) are otherwise concatenated
* straight into the response markup, which both corrupts the XML for values
* containing metacharacters and allows content injection for the
* client-supplied schema values.
*
* @param mixed $value The value to escape.
*
* @return string The XML-escaped value.
*/
protected function _xmlEscape($value)
{
return htmlspecialchars((string) $value, ENT_QUOTES | ENT_XML1, 'UTF-8');
}

/**
* Build the appropriate response string to send back to the client.
*
Expand Down Expand Up @@ -136,17 +173,17 @@ protected function _buildResponseString($properties)
return '<?xml version="1.0" encoding="utf-8"?>
<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
<Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/mobilesync/responseschema/2006">
<Culture>' . $properties['culture'] . '</Culture>
<Culture>' . $this->_xmlEscape($properties['culture']) . '</Culture>
<User>
<DisplayName>' . $properties['display_name'] . '</DisplayName>
<EMailAddress>' . $properties['email'] . '</EMailAddress>
<DisplayName>' . $this->_xmlEscape($properties['display_name']) . '</DisplayName>
<EMailAddress>' . $this->_xmlEscape($properties['email']) . '</EMailAddress>
</User>
<Action>
<Settings>
<Server>
<Type>MobileSync</Type>
<Url>' . $properties['url'] . '</Url>
<Name>' . $properties['url'] . '</Name>
<Url>' . $this->_xmlEscape($properties['url']) . '</Url>
<Name>' . $this->_xmlEscape($properties['url']) . '</Name>
</Server>
</Settings>
</Action>
Expand All @@ -159,9 +196,9 @@ protected function _buildResponseString($properties)
}

$xml = '<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
<Response xmlns="' . $properties['response_schema'] . '">
<Response xmlns="' . $this->_xmlEscape($properties['response_schema']) . '">
<User>
<DisplayName>' . $properties['display_name'] . '</DisplayName>
<DisplayName>' . $this->_xmlEscape($properties['display_name']) . '</DisplayName>
</User>
<Account>
<AccountType>email</AccountType>
Expand All @@ -170,9 +207,9 @@ protected function _buildResponseString($properties)
if (!empty($properties['imap'])) {
$xml .= '<Protocol>
<Type>IMAP</Type>
<Server>' . $properties['imap']['host'] . '</Server>
<Port>' . $properties['imap']['port'] . '</Port>
<LoginName>' . $properties['username'] . '</LoginName>
<Server>' . $this->_xmlEscape($properties['imap']['host']) . '</Server>
<Port>' . $this->_xmlEscape($properties['imap']['port']) . '</Port>
<LoginName>' . $this->_xmlEscape($properties['username']) . '</LoginName>
<DomainRequired>off</DomainRequired>
<SPA>off</SPA>
' . $this->_getEncryptionValue('imap', $properties) . '
Expand All @@ -182,9 +219,9 @@ protected function _buildResponseString($properties)
if (!empty($properties['pop'])) {
$xml .= '<Protocol>
<Type>POP3</Type>
<Server>' . $properties['pop']['host'] . '</Server>
<Port>' . $properties['pop']['port'] . '</Port>
<LoginName>' . $properties['username'] . '</LoginName>
<Server>' . $this->_xmlEscape($properties['pop']['host']) . '</Server>
<Port>' . $this->_xmlEscape($properties['pop']['port']) . '</Port>
<LoginName>' . $this->_xmlEscape($properties['username']) . '</LoginName>
<DomainRequired>off</DomainRequired>
<SPA>off</SPA>
' . $this->_getEncryptionValue('pop', $properties) . '
Expand All @@ -194,9 +231,9 @@ protected function _buildResponseString($properties)
if (!empty($properties['smtp'])) {
$xml .= '<Protocol>
<Type>SMTP</Type>
<Server>' . $properties['smtp']['host'] . '</Server>
<Port>' . $properties['smtp']['port'] . '</Port>
<LoginName>' . $properties['username'] . '</LoginName>
<Server>' . $this->_xmlEscape($properties['smtp']['host']) . '</Server>
<Port>' . $this->_xmlEscape($properties['smtp']['port']) . '</Port>
<LoginName>' . $this->_xmlEscape($properties['username']) . '</LoginName>
<DomainRequired>off</DomainRequired>
<SPA>off</SPA>
' . $this->_getEncryptionValue('smtp', $properties) . '
Expand All @@ -218,7 +255,7 @@ protected function _buildResponseString($properties)
protected function _getEncryptionValue($type, $properties)
{
if (!empty($properties[$type]['encryption'])) {
return '<Encryption>' . $properties[$type]['encryption'] . '</Encryption>';
return '<Encryption>' . $this->_xmlEscape($properties[$type]['encryption']) . '</Encryption>';
}
// Older version of autodiscover.
if (!empty($properties[$type]['ssl'])) {
Expand All @@ -244,14 +281,14 @@ protected function _buildFailureResponse($email, $status, $response_schema)
{
return '<?xml version="1.0" encoding="utf-8"?>
<Autodiscover xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
<Response xmlns="' . $response_schema . '">
<Response xmlns="' . $this->_xmlEscape($response_schema) . '">
<Culture>en:us</Culture>
<User>
<EMailAddress>' . $email . '</EMailAddress>
<EMailAddress>' . $this->_xmlEscape($email) . '</EMailAddress>
</User>
<Action>
<Error>
<Status>' . $status . '</Status>
<Status>' . $this->_xmlEscape($status) . '</Status>
<Message>Unable to autoconfigure the supplied email address.</Message>
<DebugData>MailUser</DebugData>
</Error>
Expand Down
13 changes: 9 additions & 4 deletions lib/Horde/ActiveSync/Request/ValidateCert.php
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Original file line number Diff line number Diff line change
Expand Up @@ -120,16 +120,21 @@ protected function _handle()

// Valid purpose/trusted?
// @TODO: CRL support, CHAIN support
// openssl_x509_checkpurpose() returns true (valid + trusted for the
// purpose), false (invalid purpose OR untrusted), or -1 on error.
// Check the -1 error case with a strict comparison first, since -1
// is loosely truthy and was previously masked by a typo ($results)
// that left this branch dead.
$result = openssl_x509_checkpurpose($cert_pem, X509_PURPOSE_SMIME_SIGN, [$this->_activeSync->certPath]);
if ($result === false) {
if ($result === -1) {
// Unspecified error.
$cert_status[$key] = self::STATUS_UNKNOWN;
} elseif ($result === false) {
// @TODO:
Comment thread
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// checkpurpose returns false if either the purpose is invalid OR
// the certificate is untrusted, so we should validate the
// trust before we send back any errors.
$cert_status[$key] = self::STATUS_PURPOSE_INVALID;
} elseif ($results == -1) {
// Unspecified error.
$cert_status[$key] = self::STATUS_UNKNOWN;
} else {
// If checkpurpose passes, it's valid AND trusted.
$cert_status[$key] = self::STATUS_SUCCESS;
Expand Down
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