winmail.dat attachment causes "An internal error has occurred." error when attempting to view the email message

[stephansfourie]

In Roundcube version 1.6.6 a user is attempting to open an email which contains a winmail.dat attachment. They see an "An internal error has occurred." error in the message pane.

The Roundcube logs on the server reports the following:

[22-May-2024 10:02:20 Africa/Johannesburg] PHP Fatal error: Uncaught TypeError: strlen(): Argument #1 ($string) must be of type string, array given in /opt/roundcubemail-1.6.6/program/lib/Roundcube/rcube_message.php:1108 Stack trace: #0 /opt/roundcubemail-1.6.6/program/lib/Roundcube/rcube_message.php(875): rcube_message->tnef_decode() #1 /opt/roundcubemail-1.6.6/program/lib/Roundcube/rcube_message.php(129): rcube_message->parse_structure() #2 /opt/roundcubemail-1.6.6/program/actions/mail/show.php(63): rcube_message->__construct() #3 /opt/roundcubemail-1.6.6/program/include/rcmail.php(282): rcmail_action_mail_show->run() #4 /opt/roundcubemail-1.6.6/index.php(278): rcmail->action_handler() #5 {main} thrown in /opt/roundcubemail-1.6.6/program/lib/Roundcube/rcube_message.php on line 1108

I've attempted to disable 'tnef_decode' in the config by setting it to 'false' but that didn't help. No other errors are reported in other logs, eg. PHP, Apache etc.

The email opens normally in Thunderbird when downloading it and opening it.

[pabzm]

Can you provide us with the email that triggers this (stripped from personal information)? Or the attachment?

[alecpl]

It is related to this change 2521475 and the fact that PHP become stricter.

[alecpl]

I suspect that it happens when RTF to HTML conversion fails for any reason. Don't you see also "Failed to extract RTF/HTML content from TNEF attachment" in the log?

I think 6d8dd2c should prevent the fatal error from happening, but to fix the conversion error we'd need a sample message.