Developers of Sympa

[Olivier Salaun - CRU <address@concealed>]

Hervé Maza wrote :
> When  sympa parses 2 messages in the same second for the same moderated
> list, the 2 messages receive the same key for moderation. The editor
> receives the two messages, but is unable to moderate all of them, since
> only one remains in spool/mod. 

This bug has been reported to us a month ago.

> It's a low probability, but this incident
> already occured (twice) in a list. The reason on that is the clause
> "srand(time)" in List::send_to_editor. Due to the precision of time
> function, srand(time) forces rand function to produce same sequence if
> several messages are parsed in less than 1 second.
> To avoid this problem, I plan to simply remove srand(time) instruction.
> Does this change make the mod key really predictable ?

No as far as the cookie is used, it's not predictable.

We solved the problem with a sleep(1) before processing the key.
But we plan to adopt a proper solution such as :

        MD5 (   messageID or a MD5(msg)
                + listname
                + list/site's cookie
        )

This prevents from generating the same key for 2 messages.

Olivier Salaün
Comite Reseaux des universites