dovecot - Dec 2010 - Problem with requiring client certificates for external connections

Folks,
	I'm trying to configure my dovecot installation to require client
certificates for external/Internet connections, while still allowing my
local network to not need certificates.

	This configuration is for Dovecot 2 (2.0.8 in Fedora 14), and I've
tried to use the "remote" block to give different definitions for my
local network vs the defaults.  While most options seem to be set fine,
if I set "auth_ssl_require_client_cert" to yes as the default, and
reset
it to no for my local network, dovecot still requests a client
certificate and fails as one is not supplied.

	Am I correct that it can be reset in a "remote" block, or is it
treated
differently to other options?  In fact do I have the configuration
correct, as there doesn't really seem to be anything documenting
"remote" or "remote_ip" or related items for Dovecot 2.

	Related to this, much of the documentation states that the variable is
"ssl_require_client_cert", seems to be accepted by ignored, vs
"auth_ssl_require_client_cert" which does have some effects.

	Also, in the configuration dump, it duplicates the netmask.

	The configuration is below, as generated with "dovecot -n".

Regards
Frank

# 2.0.8: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.36.1 x86_64 Fedora release 14 (Laughlin) ext4
auth_ssl_require_client_cert = yes
mail_location = maildir:/var/spool/maildir/%u
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope
encoded-character vacation subaddress comparator-i;ascii-numeric
relational regex imap4flags copy include variables body enotify
environment mailbox date
mbox_write_locks = fcntl
passdb {
  driver = pam
}
plugin {
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
postmaster_address = postmaster at crawford.emu.id.au
ssl = required
ssl_ca = </etc/pki/CA/cacert.pem
ssl_cert = </etc/pki/tls/certs/dovecot.crt
ssl_key = </etc/pki/tls/private/dovecot.key
ssl_verify_client_cert = yes
userdb {
  driver = passwd
}
protocol pop3 {
  pop3_uidl_format = %v.%u
}
remote 203.16.204.0/24/24 {
  auth_ssl_require_client_cert = no
  disable_plaintext_auth = no
  ssl = no
  ssl_verify_client_cert = no
}
remote fdd2:7aad:d478:1::/64/64 {
  auth_ssl_require_client_cert = no
  disable_plaintext_auth = no
  ssl = no
  ssl_verify_client_cert = no
}
remote 2001:44b8:62:140::/64/64 {
  auth_ssl_require_client_cert = no
  disable_plaintext_auth = no
  ssl = no
  ssl_verify_client_cert = no
}

Frank Crawford <frank <at> crawford.emu.id.au> writes:
> I'm trying to configure my dovecot installation to require client
> certificates for external/Internet connections, while still allowing
> my local network to not need certificates.
Exactly the same problem here on exactly the same platform (F-14), although I
used a slightly different config directives (local <remoteIP>).

First, the docs for dovecot 2 don't mention auth_ssl_require_client_cert at
all. However, it seems to be important.

Second, if I set the above three for external IP, one can still log in (after
being prompted for the client cert) by cancelling on the client side. It just
goes straight through, no cert required.

On the other hand, if I put those three in the global section but then turn
them off in local <localIP>, then local clients get asked for cert no
matter
what. Any client that doesn't have a valid client cert will fail.

So, this part of dovecot 2 is buggy. I tried downgrading back to 2.0.1. Same
result.

With dovecot 1 in F-13 I could at least run two daemons side by side easily.
Not possible any more, it seems (pid location hardcoded).

--
Bojan

Oh well, since I didn't get a response to this query, I might try a
related one.

What is the definition for the "remote" command, where should it be
used
and what commands can be used within it?

Is it documented anywhere?

This is for dovecot 2.0.8, with a configuration as listed below.

Thanks
Frank

On Sun, 2010-12-19 at 13:12 +1100, Frank Crawford wrote:
> Folks,
> 	I'm trying to configure my dovecot installation to require client
> certificates for external/Internet connections, while still allowing my
> local network to not need certificates.
> 
> 	This configuration is for Dovecot 2 (2.0.8 in Fedora 14), and I've
> tried to use the "remote" block to give different definitions for
my
> local network vs the defaults.  While most options seem to be set fine,
> if I set "auth_ssl_require_client_cert" to yes as the default,
and reset
> it to no for my local network, dovecot still requests a client
> certificate and fails as one is not supplied.
> 
> 	Am I correct that it can be reset in a "remote" block, or is it
treated
> differently to other options?  In fact do I have the configuration
> correct, as there doesn't really seem to be anything documenting
> "remote" or "remote_ip" or related items for Dovecot 2.
> 
> 	Related to this, much of the documentation states that the variable is
> "ssl_require_client_cert", seems to be accepted by ignored, vs
> "auth_ssl_require_client_cert" which does have some effects.
> 
> 	Also, in the configuration dump, it duplicates the netmask.
> 
> 	The configuration is below, as generated with "dovecot -n".
> 
> Regards
> Frank
> 
> # 2.0.8: /etc/dovecot/dovecot.conf
> # OS: Linux 2.6.36.1 x86_64 Fedora release 14 (Laughlin) ext4
> auth_ssl_require_client_cert = yes
> mail_location = maildir:/var/spool/maildir/%u
> managesieve_notify_capability = mailto
> managesieve_sieve_capability = fileinto reject envelope
> encoded-character vacation subaddress comparator-i;ascii-numeric
> relational regex imap4flags copy include variables body enotify
> environment mailbox date
> mbox_write_locks = fcntl
> passdb {
>   driver = pam
> }
> plugin {
>   sieve = ~/.dovecot.sieve
>   sieve_dir = ~/sieve
> }
> postmaster_address = postmaster at crawford.emu.id.au
> ssl = required
> ssl_ca = </etc/pki/CA/cacert.pem
> ssl_cert = </etc/pki/tls/certs/dovecot.crt
> ssl_key = </etc/pki/tls/private/dovecot.key
> ssl_verify_client_cert = yes
> userdb {
>   driver = passwd
> }
> protocol pop3 {
>   pop3_uidl_format = %v.%u
> }
> remote 203.16.204.0/24/24 {
>   auth_ssl_require_client_cert = no
>   disable_plaintext_auth = no
>   ssl = no
>   ssl_verify_client_cert = no
> }
> remote fdd2:7aad:d478:1::/64/64 {
>   auth_ssl_require_client_cert = no
>   disable_plaintext_auth = no
>   ssl = no
>   ssl_verify_client_cert = no
> }
> remote 2001:44b8:62:140::/64/64 {
>   auth_ssl_require_client_cert = no
>   disable_plaintext_auth = no
>   ssl = no
>   ssl_verify_client_cert = no
> }
>