Security Basics

Note on Network security

This document covers only the 2.0 authentication and authorization features. For a look at network security in Riak, see Security and Firewalls.

As of version 2.0, Riak administrators can selectively apportion access to a wide variety of Riak’s functionality, including accessing, modifying, and deleting objects, changing bucket properties, and running MapReduce jobs.

Terminology

• Authentication is the process of identifying a user.
• Authorization is verifying whether a user has access to perform the requested operation.
• Groups can have permissions assigned to them, but cannot be authenticated.
• Users can be authenticated and authorized; permissions (authorization) may be granted directly or via group membership.
• Sources are used to define authentication mechanisms. A user cannot be authenticated to Riak until a source is defined.

Security Checklist

There are a few key steps that all applications will need to undertake when turning on Riak security. Missing one of these steps will almost certainly break your application, so make sure that you have done each of the following before enabling security:

1. Because Riak security requires a secure SSL connection, you will need to generate appropriate SSL certs, enable SSL and establish a certificate configuration on each node. If you enable security without having established a functioning SSL connection, all requests to Riak will fail.
2. Define users and, optionally, groups
3. Define an authentication source for each user
4. Grant the necessary permissions to each user (and/or group)
5. Check any Erlang MapReduce code for invocations of Riak modules other than riak_kv_mapreduce. Enabling security will prevent those from succeeding unless those modules are available via the add_path mechanism documented in Installing Custom Code.
6. Make sure that your client software will work properly:
   • It must pass authentication information with each request
   • It must support HTTPS or encrypted Protocol Buffers traffic
   • If using HTTPS, the proper port (presumably 443) is open from client to server
   • Code that uses Riak’s deprecated link walking feature will not work with security enabled
7. If you have applications that rely on an already existing Riak cluster, make sure that those applications are prepared to gracefully transition into using Riak security once security is enabled.

Security should be enabled only after all of the above steps have been performed and your security setup has been properly vetted.

Clients that use Protocol Buffers will typically have to be reconfigured/restarted with the proper credentials once security is enabled.

Security Basics

Riak security may be checked, enabled, or disabled by an administrator through the command line. This allows an administrator to change security settings for the whole cluster quickly without needing to change settings on a node-by-node basis.

Note: Currently, Riak security commands can be run only through the command line, using the riak-admin security command. In future versions of Riak, administrators may have the option of issuing those commands through the Protocol Buffers and HTTP interfaces.

Enabling Security

Warning: Enable security with caution

Enabling security will change the way your client libraries and your applications interact with Riak.

Once security is enabled, all client connections must be encrypted and all permissions will be denied by default. Do not enable this in production until you have worked through the security checklist above and tested everything in a non-production environment.

Riak security is disabled by default. To enable it:

riak-admin security enable

As per the warning above, do not enable security in production without taking the appropriate precautions.

All users, groups, authentication sources, and permissions can be configured while security is disabled, allowing you to create a security configuration of any level of complexity without prematurely impacting the service. This should be borne in mind when you are managing users and managing sources.

Disabling Security

If you disable security, this means that you have disabled all of the various permissions checks that take place when executing operations against Riak. Users, groups, and other security attributes remain available for configuration while security is disabled, and will be applied if and when security is re-enabled.

riak-admin security disable

While security is disabled, clients will need to be reconfigured to no longer require TLS and send credentials.

Checking Security Status

To check whether security is currently enabled for the cluster, use the status command:

riak-admin security status

This command will usually return Enabled or Disabled, but if security is enabled on a mixed-mode cluster (running a combination of Riak 2.0 and older versions) it will indicate that security is enabled but not yet available.

User Management

Riak security enables you to control authorization by creating, modifying, and deleting user characteristics and granting users selective access to Riak functionality (and also to revoke access). Users can be assigned one or more of the following characteristics:

• username
• groups
• password

You may also assign users characteristics beyond those listed above—e.g., listing email addresses or other information—but those values will carry no special significance for Riak.

Note: The username is the one user characteristic that cannot be changed once a user has been created.

Retrieve a Current User or Group List

A list of currently existing users can be accessed at any time:

riak-admin security print-users

The same goes for groups:

riak-admin security print-groups

Example output, assuming user named riakuser with an assigned password:

+----------+--------+----------------------+------------------------------+
| username | groups |       password       |           options            |
+----------+--------+----------------------+------------------------------+
| riakuser |        |983e8ae1421574b8733824|              []              |
+----------+--------+----------------------+------------------------------+

Note: All passwords are displayed in encrypted form in console output.

If the user riakuser were assigned to the group dev and a name of lucius, the output would look like this:

+----------+----------------+----------------------+---------------------+
| username |     groups     |       password       |       options       |
+----------+----------------+----------------------+---------------------+
| riakuser |      dev       |983e8ae1421574b8733824| [{"name","lucius"}] |
+----------+----------------+----------------------+---------------------+

If you’d like to see which permissions have been assigned to riakuser, you would need to use the print-grants command, detailed below.

The security print-user or security-print-group (singular) commands can be used with a name as argument to see the same information as above, except for only that user or group.

Permissions Grants For a Single User or Group

You can retrieve authorization information about a specific user or group using the print-grants command, which takes the form of riak-admin security print-grants <username>.

The output will look like this if the user riakuser has been explicitly granted a riak_kv.get permission on the bucket shopping_list and inherits a set of permissions from the admin group:

Inherited permissions (user/riakuser)

+--------+----------+----------+----------------------------------------+
| group  |   type   |  bucket  |                 grants                 |
+--------+----------+----------+----------------------------------------+
| admin  |    *     |    *     |      riak_kv.get, riak_kv.delete,      |
|        |          |          |              riak_kv.put               |
+--------+----------+----------+----------------------------------------+

Dedicated permissions (user/riakuser)

+----------+-------------+----------------------------------------+
|   type   |   bucket    |                 grants                 |
+----------+-------------+----------------------------------------+
|   ANY    |shopping_list|               riak_kv.get              |
+----------+-------------+----------------------------------------+

Cumulative permissions (user/riakuser)

+----------+-------------+----------------------------------------+
|   type   |   bucket    |                 grants                 |
+----------+-------------+----------------------------------------+
|    *     |      *      |      riak_kv.get, riak_kv.delete,      |
|          |             |               riak_kv.put              |
|   ANY    |shopping_list|               riak_kv.get              |
+----------+-------------+----------------------------------------+

Note: The term admin is not a reserved term in Riak security. It is used here only for illustrative purposes.

Because the same name can represent both a user and a group, a prefix (user/ or group/) can be used before the name (e.g., print-grants user/admin). If a name collides and no prefix is supplied, grants for both will be listed separately.

Add Group

For easier management of permissions across several users, it is possible to create groups to be assigned to those users.

riak-admin security add-group admin

Add User

To create a user with the username riakuser, we use the add-user command:

riak-admin security add-user riakuser

Using the command this way will create the user riakuser without any characteristics beyond a username, which is the only attribute that you must assign upon user creation.

Alternatively, a password—or other attributes—can be assigned to the user upon creation. Here, we’ll assign a password:

riak-admin security add-user riakuser password=Test1234

Assigning a Password and Altering Existing User Characteristics

While passwords and other characteristics can be set upon user creation, it often makes sense to change user characteristics after the user has already been created. Let’s say that the user riakuser was created without a password (or created with a password that we’d like to change). The alter-user command can be used to modify our riakuser user:

riak-admin security alter-user riakuser password=opensesame

When creating or altering a user, any number of <option>=<value> pairs can be appended to the end of the command. Any non-standard options will be stored and displayed via the riak-admin security print-users command.

riak-admin security alter-user riakuser name=bill age=47 fav_color=red

Now, the print-users command should return this:

+----------+--------+----------+--------------------------------------------------+
| username | groups | password |                     options                      |
+----------+--------+----------+--------------------------------------------------+
| riakuser |        |          |[{"fav_color","red"},{"age","47"},{"name","bill"}]|
+----------+--------+----------+--------------------------------------------------+

Note: Usernames cannot be changed using the alter-user command. For example, running riak-admin security alter-user riakuser username=other-name, will instead add the {"username","other-name"} tuple to riakuser’s options.

Managing Groups for a User

If we have a user riakuser and we’d like to assign her to the admin group, we assign the value admin to the option groups:

riak-admin security alter-user riakuser groups=admin

If we’d like to make the user riakuser both an admin and an archoverlord:

riak-admin security alter-user riakuser groups=admin,archoverlord

There is no way to incrementally add groups; even if riakuser was already an admin, it is necessary to list it again when adding the archoverlord group. Thus, to remove a group from a user, use alter-user and list all other groups.

If the user should be removed from all groups, use groups= with no list:

riak-admin security alter-user riakuser groups=

Managing Groups for Groups

Groups can be added to other groups for cascading permissions.

riak-admin security alter-group admin groups=dev

Deleting a User or Group

If you’d like to remove a user, use the del-user command:

riak-admin security del-user riakuser

For groups, use the del-group command:

riak-admin security del-group admin

Adding or Deleting Multiple Users

The riak-admin security command does not currently allow you to add or delete multiple users using a single command. Instead, they must be added or deleted one by one.

Managing Permissions

Permission to perform a wide variety of operations against Riak can be granted to—or revoked from—users via the grant and revoke commands.

Basic Form

The grant command takes one of the following forms:

riak-admin security grant <permissions> on any to all|{<user>|<group>[,...]}
riak-admin security grant <permissions> on <bucket-type> to all|{<user>|<group>[,...]}
riak-admin security grant <permissions> on <bucket-type> <bucket> to all|{<user>|<group>[,...]}

The revoke command is essentially the same, except that to is replaced with from of to:

riak-admin security revoke <permissions> on any from all|{<user>|<group>[,...]}
riak-admin security revoke <permissions> on <bucket-type> from all|{<user>|<group>[,...]}
riak-admin security revoke <permissions> on <bucket-type> <bucket> from all|{<user>|<group>[,...]}

If you select any, this means that the permission (or set of permissions) is granted/revoked for all buckets and bucket types. If you specify a bucket type only, then the permission is granted/revoked for all buckets of that type. If you specify a bucket type and a bucket, the permission is granted/revoked only for that bucket type/bucket combination.

Note: You cannot grant/revoke permissions with respect to a bucket alone. You must specify either a bucket type by itself or a bucket type and bucket. This limitation reflects the naming structure underlying buckets and bucket types.

Selecting all grants or revokes a permission (or set of permissions) for all users in all groups. When specifying the user(s)/group(s) to which you want to apply a permission (or set of permissions), you may list any number of users or groups comma-separated with no whitespace. Here is an example of granting multiple permissions across all buckets and bucket types to multiple users:

riak-admin security grant riak_kv.get,riak_search.query on any to jane,ahmed

If the same name is used for both a user and a group, the grant command will ask for the name to be prefixed with user/ or group/ to disambiguate.

Key/Value Permissions

Permissions that can be granted for basic key/value access functionality:

If you’d like to create, for example, a client account that is allowed only to run GET and PUT requests on all buckets:

riak-admin security add-user client
riak-admin security grant riak_kv.get,riak_kv.put on any to client

MapReduce Permissions

Permission to perform MapReduce jobs can be assigned using riak_kv.mapreduce. The following example grants MapReduce permissions to the user mapreduce-power-user for all buckets and bucket types:

riak-admin security grant riak_kv.mapreduce on any to mapreduce-power-user

Bucket Type Permissions

In versions 2.0 and later, Riak users can manage bucket types in addition to setting bucket properties. riak-admin security allows you to manage the following bucket type-related permissions:

Managing Sources

While user management enables you to control authorization with regard to users, security sources provide you with an interface for managing means of authentication. If you create users and grant them access to some or all of Riak’s functionality as described in the User Management section, you will then need to define security sources required for authentication.

An more in-depth tutorial can be found in Managing Security Sources.

Add Source

Riak security sources may be applied to a specific user, multiple users, or all users (all).

Available Sources

Example: Adding a Trusted Source

Security sources can be added either to a specific user, multiple users, or all users (all).

In general, the add-source command takes the following form:

riak-admin security add-source all|<users> <CIDR> <source> [<option>=<value>[...]]

Using all indicates that the authentication source can be added to all users. A source can be added to a specific user, e.g. add-source superuser, or to a list of users separated by commas, e.g. add-source jane,bill,admin.

Let’s say that we want to give all users trusted access to securables (without a password) when requests come from localhost:

riak-admin security add-source all 127.0.0.1/32 trust

At that point, the riak-admin security print-sources command would print the following:

+--------------------+------------+----------+----------+
|       users        |    cidr    |  source  | options  |
+--------------------+------------+----------+----------+
|        all         |127.0.0.1/32|  trust   |    []    |
+--------------------+------------+----------+----------+

Deleting Sources

If we wish to remove the trust source that we granted to all in the example above, we can simply use the del-source command and specify the CIDR.

riak-admin security del-source all 127.0.0.1/32

Note that this does not require that you specify which type of source is being deleted. You only need to specify the user(s) or all, because only one source can be applied to a user or all at any given time.

The following command would remove the source for riakuser on localhost, regardless of which source is being used:

riak-admin security del-source riakuser 127.0.0.1/32

riak-admin security del-source all 127.0.0.1/32 password
riak-admin security del-source riakuser 127.0.0.1/32 password

More Usage Examples

This section provides only a very brief overview of the syntax for working with sources. For more information on using the trust, password, pam, and certificate sources, please see our Managing Security Sources document.

Security Ciphers

To view a list of currently available security ciphers or change Riak’s preferences, use the ciphers command:

riak-admin security ciphers

That command by itself will return a large list of available ciphers:

Configured ciphers

ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256: ...

Valid ciphers(35)

ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256: ...

Unknown/Unsupported ciphers(32)

ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256: ...

To alter the list, i.e. to constrain it and/or to set preferred ciphers higher in the list:

riak-admin security ciphers DHE-RSA-AES256-SHA:AES128-GCM-SHA256

The list of configured ciphers should now look like this:

Configured ciphers

DHE-RSA-AES256-SHA:AES128-GCM-SHA256

Valid ciphers(1)

DHE-RSA-AES256-SHA

Unknown/Unsupported ciphers(1)

AES128-GCM-SHA256

A list of available ciphers on a server can be obtained using the openssl command:

openssl ciphers

That should return a list structured like this:

DHE-RSA-AES256-SHA:DHE-DSS-AES256-SHA:AES256-SHA:EDH-RSA-DES-CBC3-SHA: # and so on

Riak’s cipher preferences were taken from Mozilla’s Server-Side TLS documentation.

Client vs. Server Cipher Order

By default, Riak prefers the cipher order that you set on the server, i.e. the honor_cipher_order setting is set to on. If you prefer, however, that clients’ preferred cipher order dictate which cipher is chosen, set honor_cipher_order to off.

Note on Erlang versions

Riak’s default cipher order behavior has the potential to crash Erlang VMs that do not support it. Erlang VMs that are known to support it include Basho’s patched version of Erlang R16. Instructions on installing it can be found in Installing Erlang. This issue should not affect Erlang 17.0 and later.

Enabling SSL

In order to use any authentication or authorization features, you must enable SSL for Riak. SSL is disabled by default, but you will need to enable it prior to enabling security. If you are using Protocol Buffers as a transport protocol for Riak (which we strongly recommend), enabling SSL on a given node requires only that you specify a host and port for the node as well as a certification configuration.

If, however, you are using the HTTP API for Riak and would like to configure HTTPS, you will need to not only establish a certificate configuration but also specify an HTTPS host and port. The following configuration would establish port 8088 on localhost as the HTTPS port:

listener.https.$name = 127.0.0.1:8088

# By default, "internal" is used as the "name" setting

{riak_core, [
             %% Other configs
             {https, [{"127.0.0.1", 8088}]},
             %% Other configs
            ]}

TLS Settings

When using Riak security, you can choose which versions of SSL/TLS are allowed. By default, only TLS 1.2 is allowed, but this version can be disabled and others enabled by setting the following configurable parameters to on or off:

• tls_protocols.tlsv1
• tls_protocols.tlsv1.1
• tls_protocols.tlsv1.2
• tls_protocols.sslv3

Three things to note:

• Among the four available options, only TLS version 1.2 is enabled by default
• You can enable more than one protocol at a time
• We strongly recommend that you do not use SSL version 3 unless absolutely necessary

Certificate Configuration

If you are using any of the available security sources, including trust-based authentication, you will need to do so over a secure SSL connection. In order to establish a secure connection, you will need to ensure that each Riak node’s configuration files point to the proper paths for your generated certs. By default, Riak assumes that all certs are stored in each node’s /etc directory.

If you are using the newer, riak.conf-based configuration system, you can change the location of the /etc directory by modifying the platform_etc_dir. More information can be found in our documentation on configuring directories.

If you are using the older, app.config-based configuration system, these paths can be set in the ssl subsection of the riak_core section. The corresponding parameters are shown in the example below:

{riak_core, [
    %% Other configs

    {ssl, [
           {certfile, "./etc/cert.pem"},
           {keyfile, "./etc/key.pem"},
           {cacertfile, "./etc/cacertfile.pem"}
          ]},

    %% Other configs
]}

Referer Checks and Certificate Revocation Lists

In order to provide safeguards against cross-site-scripting (XSS) and request-forgery attacks, Riak performs secure referer checks by default. Those checks make it impossible to serve data directly from Riak. To disable those checks, set the secure_referer_check parameter to off.

If you are using certificate-based authentication, Riak will check the certificate revocation list (CRL) of connecting clients’ certificate by default. To disable this behavior, set the check_crl parameter to off.