[Dovecot] SSL renegotiation vulnerability (Was: dovecot evaluation on a 30 gb mailbox)

[Timo Sirainen]

On 25.10.2011, at 21.51, Timo Sirainen wrote:

> On 25.10.2011, at 21.13, Timo Sirainen wrote:
> 
>>> Could the reason he hasn't found such a setting be that SSL renegotiate
>>> isn't supported at all in dovecot...?
>> 
>> Looking at the OpenSSL code, I don't see any way to disable it. Or possibly with some undocumented kludgy way, but I don't really know enough about OpenSSL to implement it.
> 
> Actually, the attached patch works for v2.0. I'm not really sure yet if I should add a setting for it, force it always or just wait for SSL people to figure out something else. I think I'll do the last option for now.
> 
> In any case, I noticed there was some memory "leaking" when doing SSL renegotiation and that definitely needs to be fixed: http://hg.dovecot.org/dovecot-2.0/rev/ad2ebc237570

I don't know if I'm doing something wrong, but I can't even cause a DoS. Even while all imap-login processes are eating 100% CPU (almost 500 handshakes/second), I can successfully log in with another client.