Error 3 : "URL using bad/illegal format or missing URL" when sending a mail with php-curl in oauth2 authentification mode

[philprl]

Body

Greetings everyone,

I use a web server written in PHP 8.3 on apache 2.4 under Windows 10 on my local PC machine.
From this web server, I can send mails using php-curl version 8.4.0 (php_curl.dll library).
When sending the mail in basic authentification mode (login+password ESMTP) it works.
When sending the mail in oauth2 authentification mode (after receiving with success the token from the identity server oauth2) I have the following error 3 : "URL using bad/illegal format or missing URL".
Here, the following code in PHP :

function read_cb($ch, $fp, $length)
{
	return fread($fp, $length);
}

//SMTP server
$smtpServer		= "smtp.office365.com";
$smtpPort		= 587;
$smtpUsername	= "the username";
$smtpPassword	= "the password in basic authentification mode (ESMTP)";
$oauth2_token	= "the token previously returned with success by the identity server in OAUTH2 authentification mode";
//Mail to send
$from			= "sender@example.com";
$to				= "recipient@example.com";
$subject		        = "Test Email";
$body			= "This is a test email.";
//Authentification mode (basic or oauth2)
$auth_mode		= "token_type=Bearer";

$url                         = "smtp://".$smtpServer;
$headers		       = [];
$fpIn    		       = fopen('php://temp', 'r+');
$string		       = "From: ".$from. "\r\n";
$string		      .= "To: ".$to."\r\n";
$string		      .= "Date: ".date('r')."\r\n";
$string		      .= "Subject: ". $subject."\r\n";
$string		      .= "\r\n";
$string		      .= $body;
fwrite($fpIn,  $string);
rewind($fpIn);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_PORT, $smtpPort);
curl_setopt($ch, CURLOPT_USERNAME, $smtpUsername);
	
if(	$auth_mode=="AUTH=LOGIN")
{
	curl_setopt($ch, CURLOPT_PASSWORD, $smtpPassword);
}
else
{
	curl_setopt($ch, CURLOPT_XOAUTH2_BEARER, $oauth2_token);
}
curl_setopt($ch, CURLOPT_LOGIN_OPTIONS, $auth_mode);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);
curl_setopt($ch, CURLOPT_MAIL_FROM, $from);
curl_setopt($ch, CURLOPT_MAIL_RCPT, array($to));
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_READFUNCTION, 'read_cb');
curl_setopt($ch, CURLOPT_INFILE, $fpIn);
curl_setopt($ch, CURLOPT_UPLOAD, true);
curl_setopt($ch, CURLOPT_USE_SSL, CURLUSESSL_TRY);
curl_setopt($ch, CURLOPT_VERBOSE, true);

$response = curl_exec($ch);
if ($response === false)
	$error = curl_errno($ch).' = '.curl_strerror(curl_errno($ch));
else
	$error = '';
curl_close($ch);

if ($error!= '')
	echo "Error sending mail : ".$error;
else
	echo "mail sent with success";

In the apache24/logs/error.log file, I have :

• IPv6: (none)
• IPv4: 40.99.153.146, 52.98.227.130, 52.98.227.178, 40.99.217.98
• Trying 40.99.153.146:587...
• Connected to smtp.office365.com (40.99.153.146) port 587
• Closing connection
• Host smtp.office365.com:587 was resolved.
• IPv6: (none)
• IPv4: 40.101.137.18, 40.99.217.146, 52.98.234.242, 52.98.227.178
• Trying 40.101.137.18:587...
• Connected to smtp.office365.com (40.101.137.18) port 587
• Closing connection
• Host smtp.office365.com:587 was resolved.
• IPv6: (none)
• IPv4: 40.99.220.194, 40.99.153.146, 52.98.178.162, 40.99.214.50, 52.98.227.242, 52.97.233.50, 52.97.233.82, 52.98.229.2
• Trying 40.99.220.194:587...
• Connected to smtp.office365.com (40.99.220.194) port 587
• Closing connection
• Host smtp.office365.com:587 was resolved.
• IPv6: (none)
• IPv4: 52.98.235.2, 52.97.233.82, 40.101.137.2, 52.97.233.34, 52.97.201.34, 52.98.241.2, 40.101.138.2, 40.101.137.18
• Trying 52.98.235.2:587...
• Connected to smtp.office365.com (52.98.235.2) port 587
• Closing connection

Notice that :
When I send the mail also in oauth2 authentification mode with an application written in C langage using libcurl's curl_easy_*() fonctions with the same options, with the same SMTP server, same port 587 , on the same Windows 10 PC machine that works....

My web server application is well registered on Microsoft Azure identity server https://azure.microsoft.com/

At this time, I have not solved the problem, any idea ?
Best regards

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[denis23x]

Hi @philprl

Maybe there is a problem with encoding?

In PHP there's

• urlencode()
• urldecode()