[ejabberd] [ANN] ejabberd 16.06

Jérôme Sautret jerome.sautret at process-one.net
Wed Jun 29 17:59:12 MSK 2016

We are proud to introduce our new ejabberd release, ejabberd 16.06. As
usual it includes many bug fixes, but also several improvements.

The big improvement in this release is a new Access Control List (ACL)
infrastructure. ACL rules are used in ejabberd config file to define
fine-grained access to ejabberd features.

In ejabberd 16.06, the ACL configuration has been much improved to
make it both simpler to use and easier to read. Moreover, ACL and
access rules are not mandatory anymore when configuring access
restrictions for a feature or a module: You can just inline the user,
for example, making small configuration much easier to setup properly.

To make you even more comfortable, our new code is still supporting
the old syntax and you can mix old and new syntax. It means that you
can still use your existing configuration file and that you can
migrate incrementally, as needed.

## The new ACL syntax

New access rule will look like this:

        - allow: admins
        - deny: blocked
        - allow:
          - user: "peter at server.com"
          - ip: ""
        - allow: moderators

This is an example definition for `my_access` rule. It is composed of
four groups. They are evaluated from top to bottom order. the first
with all listed acl rules evaluated as true is used as result. If none
of them matches, evaluation fallback to default value `deny`. Above
definition can be parsed as: if user belongs to ACL definition
`admins`, return `allow`, if not, and user belongs to ACL definition
`blocked`, return `deny`. otherwise for user "peter at server.com" when
connected from ip: "" return `allow`, and for users in
ACL definition `moderators` return `allow` as well, in all other cases
return `deny`.

We can see in this example two new additions that were introduced in
this rewrite:

- you can now directly specify ACL definitions inside access rules
(you no longer will be required to define ACL rules for each case)
- you now have the ability to require a match on several ACL rules
types at this same time (in the example: ip and user).
You can use any rule that is allowed inside acl: sections (like user,
server, resource, user_glob, etc.) and one additional rule that is
allowed only inside access_rules: section, `acl: NameOfACL` that will
look for definition of NameOfAcl inside `acl:` section and use it for
matching. If you have only one ACL rule name to use you can use short
form `- allow: acl_rule`, additionally `- allow: all` or `- deny: all`
can be shorted still to `- allow` and '- deny`.

Shapers can also be specified using new syntax, but they now go into
`shaper_rules:` section and they look like that:

        - 100: admin
        - 10: all

Rules defined in `access:` section will use old syntax, and work as
before, so you don't need to update your old config, to adapt it to
that change.

At last, one can define module specific access rules directly in
modules configuration section, this is simpler to understand when
reading configuration.

Let's get a simple example of the changes. With previous ACL
implementation, one could have this:

          - "XXX.XXX.XXX.XXX/32"
          - "aleksey": "localhost"
        admin: allow
        local: allow
        all: allow
        bad_servers: deny
        all: allow
        admin: none
        all: normal
        access: muc
        access_create: muc_create
        access_persistent: muc_create
        access_admin: muc_admin

Which can be translated to this since ejabberd 16.06 with new ACL

        user: "aleksey at localhost"
        - deny:
          - ip: "XXX.XXX.XXX.XXX/32"
        - allow
        - none: admin
        - normal
          - allow
          - allow: local
          - allow: local
          - allow: admin

Shorter and clearer. Please also note that you can use the JID
literally as a string. The previous awkward `username: domain` syntax
can go away.

## Changes
This is a selection of the most relevant changes:

### Config
- New ACL infrastructure
- Add shorter version of some common access rules definitions
- Allow `@` inside acl rules `user`, `user_glob` or `user_regexp` to
pass both user and server
  in single string
- Add acl rule `access_rules_validator` and `shaper_rules_validator`
for use in `mod_opt_type` and `opt_type` callback functions.
- Allow using shapers defined by name like in s2s_shaper: fast
- Allow mod_opt_type and opt_type to transform values passed to it, and support
better error reporting
- Do not call `transform_terms` multiple times in configuration
processing when merging them
- Don't halt program when `include_config_file` is missing/can't be read
- Allow again multiple fqdn values in configuration

### Commands

- Allow passing username and ip to `ejabberd_commands`, and use it in
- Fix path to epmd in ejabberdctl
- push_roster: must convert read strings to binaries
- `set_presence`: Fix command API
- Fix for `modules_update_specs` command
- Add ejabberdctl commands to manage oauth tokens.

### Core

- Bounce messages sent to server JID
- Fix C2S session leak in rare cases
- Fix handling of queued stanzas on session timeout
- Give more time to stop and kill epmd
- When stopping ejabberd, stop modules after broadcasting c2s shutdown
- XEP-0198: Use different error message for bounces
- XEP-0198: Add 'h' attribute to  element
- XEP-0198: Also count stanzas when socket is closed

### Databases

- Fix pgsql compatibility on `delete_old_messages` command
- Handle Redis connection in a separate module
- Report in SQL when scram is enabled but the stored password isn't
- Update SQL escaping
- Use MEDIUMTEXT type for muc_room.opts in MySQL schema

### MAM

- Send unique stanza id and archived tag also in the message carbons
- Fix "assume_mam_usage: if_enabled"
- Fix typo in `mod_mam:select()`
- Updated support of XEP-0313 from version 0.4 to 0.5.1
- Mnesia: Avoid cleanup on bag when disc_only, switch in memory
- Mnesia: Don't exceed table size limit
- Mnesia: Use transactions when writing

### Client State Indication

- Fix handling of chat states
- Simplify check for carbon-copied chat states
- Simplify handling of PEP stanzas
- Pass chat states of other resources
- Unwrap carbon copies when checking for chat states
- Add `queue_pep` option
- Queue chat state notifications
- Move CSI queue handling code from `ejabberd_c2s`
- When stopping, delete only the configured hooks

### Other modules

- ext_mod: Set HTTP/1.0 so Github accepts the request
- gen_mod: Compile early to remove undefined behaviour warning
- mod_http_upload: Let client retry HTTP upload on file size mismatch
- mod_last: Produce mod_last entry on account creation
- mod_muc_room: Notify on affiliation changes
- mod_register: Check password with jid:resourceprep when registering account
- mod_roster: respect roster item changes introduced with
`roster_process_item` hooks upon pushing
- PubSub: Fix PubSub RSM on `get_items`
- PubSub: Add support for PubSub publishing options
- PEP: Fix sender in case of explicit pep subscriptions
- ejabberd_xmlrpc: Report error when conversion of argument type fails

## Feedback

As usual, the release is tagged in the Git source code repository on Github:

The source package and binary installers are available at ProcessOne:

If you suspect that you've found a bug, please search or fill a bug
report on Github:

Jérôme Sautret

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