docs/books/modules/user-guide/authorization.adoc

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[id='authorizing-access-to-messaging-resources']
= Authorizing Access to Messaging Resources

You can configure _policies_ to secure messaging resources in your messaging environment. Policies ensure that only authorized users can access messaging endpoints through the router network, and that the resources on those endpoints are used in an authorized way.

{RouterName} provides the following types of policies:

Global policies::
Settings for the router. A global policy defines the maximum number of incoming user connections for the router (across all messaging endpoints), and defines how the router should use vhost policies.

Vhost policies::
Connection and AMQP resource limits for a router ingress port (called an AMQP virtual host, or vhost). A vhost policy defines what a client using a particular connection can access on any messaging endpoint in the router network.

The resource limits defined in global and vhost policies are applied to user connections only. The limits do not affect inter-router connections or router connections that are outbound to waypoints.

Access to an AMQP resource allowed by policy for a given user connection to a given vhost is granted across the entire router network. Access restrictions are applied only at the router port to which a client is connected and only to resource requests originated by the client.

== How {RouterName} Enforces Connection and Resource Limits

{RouterName} uses policies to determine whether to permit a connection, and if it is permitted, to apply the appropriate resource limits.

When a client creates a connection to the router, the router first determines whether to allow or deny the connection. This decision is based on the following criteria:

* Whether the connection will exceed the router’s global connection limit (defined in the global policy)

* Whether the connection will exceed the vhost’s connection limits (defined in the vhost policy that matches the host to which the connection is directed)

If the connection is allowed, the router assigns the user (the authenticated user name from the connection) to a user group, and enforces the user group’s resource limits for the lifetime of the connection.

== Setting Global Connection Limits

You can set the incoming connection limit for the router. This limit defines the total number of concurrent client connections that can be open for this router.

.Procedure

* In the router configuration file, add a `policy` section and set the `maxConnections`.
+
--
[options="nowrap",subs="+quotes"]
----
policy {
    maxConnections: 10000
}
----
`maxConnections`::
This limit is always enforced, even if no other policy settings have been defined. The limit is applied to all incoming connections regardless of remote host, authenticated user, or targeted vhost. The default (and the maximum) value is `65535`.
--

== Setting Connection and Resource Limits for Messaging Endpoints

You can define the connection limit and AMQP resource limits for a messaging endpoint by configuring a _vhost policy_. Vhost policies define what resources clients are permitted to access on a messaging endpoint over a particular connection.

[NOTE]
====
A vhost is typically the name of the host to which the client connection is directed. For example, if a client application opens a connection to the `amqp://mybroker.example.com:5672/queue01` URL, the vhost would be `mybroker.example.com`.
====

You can create vhost policies using either of the following methods:

* xref:configuring-vhost-policies-router[Configure vhost policies directly in the router configuration file]
* xref:configuring-vhost-policies-json[Configure vhost policies as JSON files]

[id='enabling-vhost-policies']
=== Enabling Vhost Policies

You must enable the router to use vhost policies before you can create the policies.

.Procedure

* In the router configuration file, add a `policy` section if one does not exist, and enable vhost policies for the router.
+
--
[options="nowrap",subs="+quotes"]
----
policy {
    ...
    enableVhostPolicy: true
    enableVhostNamePatterns: true | false
    defaultVhost: $default
}
----
`enableVhostPolicy`::
Enables the router to enforce the connection denials and resource limits defined in the configured vhost policies. The default is `false`, which means that the router will not enforce any vhost policies.

`enableVhostNamePatterns`::
Enables pattern matching for vhost hostnames. If set to `true`, you can use wildcards to specify a range of hostnames for a vhost. If set to `false`, vhost hostnames are treated as literal strings. This means that you must specify the exact hostname for each vhost. The default is `false`.

`defaultVhost`::
The name of the default vhost policy, which is applied to any connection for which a vhost policy has not been configured. The default is `$default`. If `defaultVhost` is not defined, then default vhost processing is disabled.
--

[id='configuring-vhost-policies-router']
=== Configuring Vhost Policies in the Router Configuration File

You can configure vhost policies in the router configuration file by configuring `vhost` entities. However, if multiple routers in your router network should be configured with the same vhost configuration, you will need to add the vhost configuration to each router’s configuration file.

.Prerequisites

Vhost policies must be enabled for the router. For more information, see xref:enabling-vhost-policies[].

.Procedure

. Add a `vhost` section and define the connection limits for the messaging endpoint.
+
--
The connection limits apply to all users that are connected to the vhost. These limits control the number of users that can be connected simultaneously to the vhost.

[options="nowrap",subs="+quotes"]
----
vhost {
    hostname: example.com
    maxConnections: 10000
    maxConnectionsPerUser: 100
    maxConnectionsPerHost: 100
    allowUnknownUser: true
    ...
}
----
`hostname`::
The literal hostname of the vhost (the messaging endpoint) or a pattern that matches the vhost hostname. This vhost policy will be applied to any client connection that is directed to the hostname that you specify. This name must be unique; you can only have one vhost policy per hostname.
+
If `enableVhostNamePatterns` is set to `true`, you can use wildcards to specify a pattern that matches a range of hostnames. For more information, see xref:pattern-matching-vhost-policy-hostnames[].

`maxConnections`::
The global maximum number of concurrent client connections allowed for this vhost. The default is 65535.

`maxConnectionsPerUser`::
The maximum number of concurrent client connections allowed for any user. The default is 65535.

`maxConnectionsPerHost`::
The maximum number of concurrent client connections allowed for any remote host (the host from which the client is connecting). The default is 65535.

`allowUnknownUser`::
Whether unknown users (users who are not members of a defined user group) are allowed to connect to the vhost. Unknown users are assigned to the $default user group and receive $default settings. The default is false, which means that unknown users are not allowed.
--

. In the `vhost` section, beneath the connection settings that you added, add a `groups` entity to define the resource limits.
+
--
You define resource limits by user group. A user group specifies the messaging resources the members of the group are allowed to access.

.User Groups in a Vhost Policy
====
This example shows three user groups: admin, developers, and $default:

[options="nowrap",subs="+quotes"]
----
vhost {
    ...
    groups: {
        admin: {
            users: admin1, admin2
            remoteHosts: 127.0.0.1, ::1
            sources: *
            targets: *
        }
        developers: {
            users: dev1, dev2, dev3
            remoteHosts: *
            sources: myqueue1, myqueue2
            targets: myqueue1, myqueue2
        }
        $default: {
            remoteHosts: *
            allowDynamicSource: true,
            allowAdminStatusUpdate: true,
            sources: myqueue1, myqueue2
            targets: myqueue1, myqueue2
        }
    }
}
----
`users`::
A list of authenticated users for this user group. Use commas to separate multiple users. A user may belong to only one vhost user group.

`remoteHosts`::
A list of remote hosts from which the users may connect. A host can be a hostname, IP address, or IP address range. Use commas to separate multiple hosts. To allow access from all remote hosts, specify a wildcard `*`. To deny access from all remote hosts, leave this attribute blank.

`maxConnectionsPerUser`::
The maximum number of connections that may be created by users in this user group. This value, if specified, overrides the vhost `maxConnectionsPerUser` value.

`maxConnectionsPerHost`::
The maximum number of concurrent connections that may be created by users in this user group from any of the permitted remote hosts. This value, if specified, overrides the vhost `maxConnectionsPerUser` value.

`allowDynamicSource`::
If true, connections from users in this group are permitted to attach receivers to dynamic sources.  This permits creation of listners to temporary addresses or termporary queues.  If false, use of dynamic sources is forbidden.

`allowAdminStatusUpdate`::
If true, connections from users in this group are permitted to modify the adminStatus of connections.  This permits termination of sender or receiver connections.  If false, the users of this group are prohibited from terminating any connections. Inter-router connections can never be terminated by any user under any circumstance. Defaults to true, no policy required.


`allowWaypointLinks`::
If true, connections from users in this group are permitted to attach links using waypoint capabilities.  This allows endpoints to act as waypoints (i.e. brokers) without the need for configuring auto-links.  If false, use of waypoint capabilities is forbidden.

`allowDynamicLinkRoutes`::
If true, connections from users in this group may dynamically create connection-scoped link route destinations.  This allows endpoints to act as link route destinations (i.e. brokers) without the need for configuring link-routes.  If false, creation of dynamic link route destintations is forbidden.

`allowFallbackLinks`::
If true, connections from users in this group are permitted to attach links using fallback-link capabilities.  This allows endpoints to act as fallback destinations (and sources) for addresses that have fallback enabled.  If false, use of fallback-link capabilities is forbidden.

`sources` | `sourcePattern`::
A list of AMQP source addresses from which users in this group may receive messages.
+
Use `sources` to specify one or more literal addresses. To specify multiple addresses, use a comma-separated list. To prevent users in this group from receiving messages from any addresses, leave this attribute blank. To allow access to an address specific to a particular user, specify the `${user}` token. For more information, see xref:methods-for-specifying-vhost-policy-source-target-addresses[].
+
Alternatively, you can use `sourcePattern` to match one or more addresses that correspond to a pattern. A pattern is a sequence of words delimited by either a `.` or `/` character. You can use wildcard characters to represent a word. The  `*` character matches exactly one word, and the `#` character matches any sequence of zero or more words.
+
To specify multiple address ranges, use a comma-separated list of address patterns. For more information, see xref:router-address-pattern-matching[Router Address Pattern Matching]. To allow access to address ranges that are specific to a particular user, specify the `${user}` token. For more information, see xref:methods-for-specifying-vhost-policy-source-target-addresses[].

`targets` | `targetPattern`::
A list of AMQP target addresses from which users in this group may send messages. You can specify multiple AMQP addresses and use user name substitution and address patterns the same way as with source addresses.
====
--

. If necessary, add any advanced user group settings to the vhost user groups.
+
The advanced user group settings enable you to define resource limits based on the AMQP connection open, session begin, and link attach phases of the connection. For more information, see link:{qdrouterdConfManPageUrl}#_vhost[vhost^] in the `qdrouterd.conf` man page.

[id='configuring-resource-limits-outgoing-connections']
=== Configuring Resource Limits for Outgoing Connections

If the router establishes an outgoing connection to an external AMQP container (such as a client or broker), you can restrict the resources that the external container can access on the router by configuring a connector vhost policy.

The resource limits that are defined in a connector vhost policy are applied to links that are initiated by the external AMQP container. The connector vhost policy does not restrict links that the router creates.

A connector vhost policy can only be applied to a connector with a `normal` or `route-container` role. You cannot apply connector vhost policies to connectors that have `inter-router` or `edge` roles.

.Prerequisites

Vhost policies are enabled for the router. For more information, see xref:enabling-vhost-policies[].

.Procedure

. In the router's configuration file, add a `vhost` section with a `$connector` user group.
+
--
[options="nowrap"]
----
vhost {
    hostname: my-connector-policy
    groups: {
        $connector: {
            sources: *
            targets: *
            maxSenders: 5
            maxReceivers: 10
            allowAnonymousSender: true
            allowWaypointLinks: true
        }
    }
}
----
`hostname`:: A unique name to identify the connector vhost policy. This name does not represent an actual hostname; therefore, choose a name that will not conflict with an actual vhost hostname.
`$connector`:: Identifies this vhost policy as a connector vhost policy.
--

. Apply the connector vhost policy to the connector that establishes the connection to the external AMQP container.
+
--
The following example applies the connector vhost policy that was configured in the previous step:

[options="nowrap"]
----
connector {
    host: 192.0.2.10
    port: 5672
    role: normal
    policyVhost: my-connector-policy
}
----
--

[id='configuring-vhost-policies-json']
=== Configuring Vhost Policies as JSON Files

As an alternative to using the router configuration file, you can configure vhost policies in JSON files. If you have multiple routers that need to share the same vhost configuration, you can put the vhost configuration JSON files in a location accessible to each router, and then configure the routers to apply the vhost policies defined in these JSON files.

.Prerequisites

* Vhost policies must be enabled for the router. For more information, see xref:enabling-vhost-policies[].

.Procedure

. In the router configuration file, specify the directory where you want to store the vhost policy definition JSON files.
+
--
[options="nowrap",subs="+quotes"]
----
policy {
    ...
    policyDir: __DIRECTORY_PATH__
}
----
`policyDir`::
The absolute path to the directory that holds vhost policy definition files in JSON format. The router processes all of the vhost policies in each JSON file that is in this directory.
--

. In the vhost policy definition directory, create a JSON file for each vhost policy.
+
--
.Vhost Policy Definition JSON File
====
[source,json,options="nowrap"]
----
[
    ["vhost", {
        "hostname": "example.com",
        "maxConnections": 10000,
        "maxConnectionsPerUser": 100,
        "maxConnectionsPerHost": 100,
        "allowUnknownUser": true,
        "groups": {
            "admin": {
                "users": ["admin1", "admin2"],
                "remoteHosts": ["127.0.0.1", "::1"],
                "sources": "*",
                "targets": "*"
            },
            "developers": {
                "users": ["dev1", "dev2", "dev3"],
                "remoteHosts": "*",
                "sources": ["myqueue1", "myqueue2"],
                "targets": ["myqueue1", "myqueue2"]
            },
            "$default": {
                "remoteHosts": "*",
                "allowDynamicSource": true,
                "sources": ["myqueue1", "myqueue2"],
                "targets": ["myqueue1", "myqueue2"]
            }
        }
    }]
]
----

For more information about these attributes, see xref:configuring-vhost-policies-router[].
====
--

[id='pattern-matching-vhost-policy-hostnames']
=== Pattern Matching for Vhost Policy Hostnames

In a vhost policy, vhost hostnames can be either literal hostnames or patterns that cover a range of hostnames.

A hostname pattern is a sequence of words with one or more of the following wildcard characters:

* `*` represents exactly one word
* `#` represents zero or more words

The following table shows some examples of hostname patterns:

[options="header"]
|===
| This pattern... | Matches... | But not...

a| `*.example.com`
a| `www.example.com`
a| `example.com`
`srv2.www.example.com`

a| `#.example.com`
a| `example.com`
`www.example.com`
`a.b.c.d.example.com`
a| `myhost.com`

a| `www.*.test.example.com`
a| `www.a.test.example.com`
a| `www.test.example.com`
`www.a.b.c.test.example.com`

a| `www.#.test.example.com`
a| `www.test.example.com`
`www.a.test.example.com`
`www.a.b.c.test.example.com`
a| `test.example.com`
|===

Vhost hostname pattern matching applies the following precedence rules:

[options="header"]
|===
| Policy pattern | Precedence
| Exact match | High
| *           | Medium
| #           | Low
|===

[NOTE]
====
{RouterName} does not permit you to create vhost hostname patterns that conflict with existing patterns. This includes patterns that can be reduced to be the same as an existing pattern. For example, you would not be able to create the `\#.#.\#.#.com` pattern if `#.com` already exists.
====

[id='methods-for-specifying-vhost-policy-source-target-addresses']
=== Methods for Specifying Vhost Policy Source and Target Addresses

If you want to allow or deny access to multiple addresses on a vhost, there are several methods you can use to match multiple addresses without having to specify each address individually.

The following table describes the methods a vhost policy can use to specify multiple source and target addresses:

[cols="33,67",options="header"]
|===
| To... | Do this...

| Allow all users in the user group to access all source or target addresses
a| Use a `*` wildcard character.

.Receive from Any Address
====
[source,options="nowrap"]
----
sources: *
----
====

| Prevent all users in the user group from accessing all source or target addresses
a| Do not specify a value.

.Prohibit Message Transfers to All Addresses
====
[source,options="nowrap"]
----
targets:
----
====

| Allow access to some resources specific to each user
a| Use the `${user}` username substitution token. You can use this token with `source`, `target`, `sourcePattern`, and `targetPattern`.

[NOTE]
====
You can only specify the `${user}` token once in an AMQP address name or pattern. If there are multiple tokens in an address, only the leftmost token will be substituted.
====

.Receive from a User-Specific Address
====
This definition allows the users in the user group to receive messages from any address that meets any of the following rules:

* Starts with the prefix `tmp_` and ends with the user name
* Starts with the prefix `temp` followed by any additional characters
* Starts with the user name, is followed by `-home-`, and ends with any additional characters
[source,options="nowrap"]
----
sources: tmp_${user}, temp*, ${user}-home-*
----
====

.User-Specific Address Patterns
====
This definition allows the users in the user group to receive messages from any address that meets any of the following rules:

* Starts with the prefix `tmp` and ends with the user name
* Starts with the prefix `temp` followed by zero or more additional characters
* Starts with the user name, is followed by `home`, and ends with one or more additional characters
[source,options="nowrap"]
----
sourcePattern: tmp.${user}, temp/#, ${user}.home/*
----
====

[NOTE]
====
In an address pattern (`sourcePattern` or `targetPattern`), the username substitution token must be either the first or last token in the pattern. The token must also be alone within its delimited field, which means that it cannot be concatenated with literal text prefixes or suffixes.
====

|===

=== Vhost Policy Examples

These examples demonstrate how to use vhost policies to authorize access to messaging resources.

.Defining Basic Resource Limits for a Messaging Endpoint
====
In this example, a vhost policy defines resource limits for clients connecting to the `example.com` host.

[source,json,options="nowrap"]
----
[
    ["vhost", {
        "hostname": "example.com",  // <1>
        "maxConnectionsPerUser": 10,  // <2>
        "allowUnknownUser": true,  // <3>
        "groups": {
            "admin": {
                "users": ["admin1", "admin2"],  // <4>
                "remoteHosts": ["127.0.0.1", "::1"],  // <5>
                "sources": "*",  // <6>
                "targets": "*"  // <7>
            },
            "$default": {
                "remoteHosts": "*",  // <8>
                "sources": ["news*", "sports*" "chat*"],  // <9>
                "targets": "chat*"  // <10>
            }
        }
    }]
]
----

<1> The rules defined in this vhost policy will be applied to any user connecting to `example.com`.

<2> Each user can open up to 10 connections to the vhost.

<3> Any user can connect to this vhost. Users that are not part of the `admin` group are assigned to the `$default` group.

<4> If the `admin1` or `admin2` user connects to the vhost, they are assigned to the `admin` user group.

<5> Users in the `admin` user group must connect from localhost. If the admin user attempts to connect from any other host, the connection will be denied.

<6> Users in the admin user group can receive from any address.

<7> Users in the admin user group can send to any address.

<8> Any non-admin user is permitted to connect from any host.

<9> Non-admin users are permitted to receive messages from any addresses that start with the `news`, `sports`, or `chat` prefixes.

<10> Non-admin users are permitted to send messages to any addresses that start with the `chat` prefix.
====

.Limiting Memory Consumption
====
By using the advanced vhost policy attributes, you can control how much system buffer memory a user connection can potentially consume.

In this example, a stock trading site provides services for stock traders. However, the site must also accept high-capacity, automated data feeds from stock exchanges. To prevent trading activity from consuming memory needed for the feeds, a larger amount of system buffer memory is allotted to the feeds than to the traders.

This example uses the `maxSessions` and `maxSessionWindow` attributes to set the buffer memory consumption limits for each AMQP session. These settings are passed directly to the AMQP connection and session negotiations, and do not require any processing cycles on the router.

This example does not show the vhost policy settings that are unrelated to buffer allocation.

[source,json,options="nowrap"]
----
[
    ["vhost", {
        "hostname": "traders.com",  // <1>
        "groups": {
            "traders": {
                "users": ["trader1", "trader2"],  // <2>
                "maxFrameSize": 10000,
                "maxSessionWindow": 5000000,  // <3>
                "maxSessions": 1  // <4>
            },
            "feeds": {
                "users": ["nyse-feed", "nasdaq-feed"],  // <5>
                "maxFrameSize": 60000,
                "maxSessionWindow": 1200000000,  // <6>
                "maxSessions": 3  // <7>
            }
        }
    }]
]
----

<1> The rules defined in this vhost policy will be applied to any user connecting to `traders.com`.

<2> The `traders` group includes `trader1`, `trader2`, and any other user defined in the list.

<3> At most, 5,000,000 bytes of data can be in flight on each session.

<4> Only one session per connection is allowed.

<5> The `feeds` group includes two users.

<6> At most, 1,200,000,000 bytes of data can be in flight on each session.

<7> Up to three sessions per connection are allowed.
====