Symfony version(s) affected

6.1

Description

I tried to encrypt a email via smime, my code looks like this:

$email = (new Email())
                    ->from('test@test.de')
                    ->to('test@test.de')
                    ->subject('Subject')
                    ->text('TEST123');

$encrypter = new SMimeEncrypter('/tmp/test.pem');
$encryptedEmail = $encrypter->encrypt($email);

I will get this error from symfony/openssl.

Failed to encrypt S/Mime message. Error: "error:0909006C:PEM routines:get_name:no start line".

Now i figured out that the passed cert file path will be "normalized" (https://github.com/symfony/mime/blob/6.1/Crypto/SMimeEncrypter.php#L36-L38 & https://github.com/symfony/mime/blob/6.1/Crypto/SMime.php#L24-L31) from

/tmp/test.pem

to

file:///tmp/test.pem

Which will be passed as third parameter to the openssl_pkcs7_encrypt method.
Which seems not accepting that format and only accepts certificates as string(array).

Either a lone X.509 certificate, or an array of X.509 certificates. 

How to reproduce

The Descriptions has all important information to reproduce the issue.
Just an E-Mail Object which will be passt to the encrypt method of the SMimeEncrypter class.

Possible Solution

I tested it with a raw php file which look the following and it it works fine.

<?php
if (openssl_pkcs7_encrypt("message.txt", "encrypted.txt", file_get_contents("/tmp/test.pem"), [], 0, OPENSSL_CIPHER_AES_256_CBC)) {
    echo 'encrypted';
}

So instead of passing file://PATH it works with file_get_contents('PATH') in my raw php file.
As quick fix i replaced the normalizeFilePath call with file_get_contents (https://github.com/symfony/mime/blob/6.1/Crypto/SMimeEncrypter.php#L36-L38).

Additional Context

@sstok implemented that 4 years ago, so maybe he has an idea what happens.