dovecot - May 2010 - SSL Bug

Hi,

After many hours of testing, I've finally tracked down the issue I have
been having with dovecot's SSL support. The problem is that the SSL
certs result in "TLS handshaking: SSL_accept() syscall failed:
Connection reset by peer" errors *if the certificate granted is not
granted for client use*.

For servers, I normally generate SSL certificates specifically for
servers:

[ server_ca_extensions ]
basicConstraints = CA:false
keyUsage = keyEncipherment
extendedKeyUsage = 1.3.6.1.5.5.7.3.1

If you just do that, then the SSL certificate doesn't work in dovecot
(it will work fine in Apache, or Postfix etc etc). You also need the
certificate to be valide for client side work:

[ client_and_server_ca_extensions ]
basicConstraints = CA:false
keyUsage = digitalSignature, keyEncipherment
extendedKeyUsage = 1.3.6.1.5.5.7.3.2, 1.3.6.1.5.5.7.3.1

I believe this is a fault with Dovecot. This is with the Debian package
for Dovecot 1.2.11 (Version: 1:1.2.11-1). The default self-signed
certificate the Debian post-install script generates pops out a
certificate that is valid for everything, which is why it works by
default out of the box.

Matthew

On Sun, 2010-05-16 at 00:52 +0100, Matthew Sackman wrote:
> After many hours of testing, I've finally tracked down the issue I have
> been having with dovecot's SSL support. The problem is that the SSL
> certs result in "TLS handshaking: SSL_accept() syscall failed:
> Connection reset by peer" errors *if the certificate granted is not
> granted for client use*.
Most likely client decided that the cert wasn't valid and disconnected.
> If you just do that, then the SSL certificate doesn't work in dovecot
> (it will work fine in Apache, or Postfix etc etc). You also need the
> certificate to be valide for client side work:
..
> I believe this is a fault with Dovecot.
Maybe it's just that the email clients don't like it, while web browsers
don't care as much? Although I'd guess email clients also wouldn't
like
Postfix..

Anyway, I don't really know what I could do about this. Except add a
check to log an error if keyUsage doesn't contain digitalSignature, but
I don't know if that's a good idea either.