The major goal is to simplify certificate management in ejabberd.
Currently it requires some effort from a user to configure certficates,
especially in the situation where a lot of virtual domains are hosted.
The task is splitted in several sub-tasks:
* Implement basic certificate validator. The validator should check all
configured certificates for existence, validity, duration and so on. The
validator should not perform any actions in the case of errors except
logging an error message. This is actually implemented by this commit.
* All certificates should be configured inside a single section (something
like 'certfiles') where ejabberd should parse them, check the full-chain,
find the corresponding private keys and, if needed, resort chains and
split the certficates into separate files for easy to use by fast_tls.
* Options like 'domain_certfile', 'c2s_certfile' or 's2s_certfile' should
probably be deprecated, since the process of matching certificates with the
corresponding virtual hosts should be done automatically and these options
only introduce configuration errors without any meaningful purpose.
The changes are very similar to those from previous commit:
* Now there is no need to pass validating function in
gen_mod:get_opt() and gen_mod:get_module_opt() functions,
because the modules' configuration keeps already validated values.
* New functions gen_mod:get_opt/2 and gen_mod:get_module_opt/3 are
introduced.
* Functions gen_mod:get_opt/4 and get_module_opt/5 are deprecated.
If the functions are still called, the "function" argument is
simply ignored.
* Validating callback Mod:listen_opt_type/1 is introduced to validate
listening options at startup.
Now 'From' and 'To' arguments must be omitted in functions
and structures related to routing.
The commit deprecates the following functions:
ejabberd_router:route/3 in favor of ejabberd_router:route/1
ejabberd_router:route_error/4 in favor of ejabberd_router:route_error/2
ejabberd_local:route_iq/4 in favor of ejabberd_local:route_iq/2
ejabberd_local:route_iq/5 in favor of ejabberd_local:route_iq/3
The format of {route, From, To, Packet} is changed in favor of {route, Packet}
If set to 'true' (this is the default), new processes spawned by
ejabberd_listener will be attached to the corresponding supervisor.
No such processes will be attached to a supervisor otherwise.
Setting this to 'false' will improve performance of high loaded
systems where new C2S/S2S processes are spawned very rapidly.
Generate an [info] message that logs whether an incoming s2s connection
is authenticated using the SASL EXTERNAL mechanism or via Server
Dialback. While at it, also mention whether TLS is enabled.
Handle "s2s_use_starttls: required_trusted" the same way for outgoing
s2s connections as for incoming connections. That is, check the remote
server's certificate (including the host name) and abort the connection
if verification fails.
Don't try to look up and close outgoing connections to a given server
when aborting incoming connections from that server due to certificate
verification errors. The ejabberd_s2s:find_connection/2 call actually
created one or more *new* connections if less than 'max_s2s_connections'
connections were found. Then, no more than one of those possibly new
connections were stopped by the ejabberd_s2s_out:stop_connection/1 call.
It's not really necessary to bother with outgoing connections at all,
here.
Prior to this commit, ejabberd handled certificate authentication for
incoming s2s connections like this:
1. Verify the certificate without checking the host name. On failure,
behave according to 's2s_use_starttls'. On success:
2. Offer SASL EXTERNAL.
3. If the remote server chooses SASL EXTERNAL, compare the authorization
identity against the certificate host name(s). On failure, abort the
connection unconditionally.
ejabberd now does this instead:
1. Verify the certificate and compare the certificate host name(s)
against the 'from' attribute of the stream header. On failure,
behave according to 's2s_use_starttls'. On success:
2. Offer SASL EXTERNAL.
3. If the remote server chooses SASL EXTERNAL, ignore the authorization
identity (if any) and consider the peer authenticated.
The old behavior was suggested by previous versions of XEP-0178, the new
behavior is suggested by the current version 1.1.
