mirror of https://github.com/status-im/consul.git
299 lines
17 KiB
Markdown
299 lines
17 KiB
Markdown
---
|
|
layout: "docs"
|
|
page_title: "ACL System"
|
|
sidebar_current: "docs-acl-system"
|
|
description: |-
|
|
Consul provides an optional Access Control List (ACL) system which can be used to control access to data and APIs. The ACL system is a Capability-based system that relies on tokens which can have fine grained rules applied to them. It is very similar to AWS IAM in many ways.
|
|
---
|
|
|
|
-> **1.4.0 and later:** This guide only applies in Consul versions 1.4.0 and later. The documentation for the legacy ACL system is [here](/docs/acl/acl-legacy.html)
|
|
|
|
# ACL System
|
|
|
|
Consul provides an optional Access Control List (ACL) system which can be used to control access to data and APIs.
|
|
The ACL is [Capability-based](https://en.wikipedia.org/wiki/Capability-based_security), relying on tokens which
|
|
are associated with policies to determine which fine grained rules can be applied. Consul's capability based
|
|
ACL system is very similar to the design of [AWS IAM](https://aws.amazon.com/iam/).
|
|
|
|
To learn how to setup the ACL system on an existing Consul datacenter, use the [Bootstrapping The ACL System guide](https://learn.hashicorp.com/consul/day-0/acl-guide?utm_source=consul.io&utm_medium=docs).
|
|
|
|
## ACL System Overview
|
|
|
|
The ACL system is designed to be easy to use and fast to enforce while providing administrative insight.
|
|
At the highest level, there are two major components to the ACL system:
|
|
|
|
* **ACL Policies** - Policies allow the grouping of a set of rules into a logical unit that can be reused and linked with
|
|
many tokens.
|
|
|
|
* **ACL Tokens** - Requests to Consul are authorized by using bearer token. Each ACL token has a public
|
|
Accessor ID which is used to name a token, and a Secret ID which is used as the bearer token used to
|
|
make requests to Consul.
|
|
|
|
For many scenarios policies and tokens are sufficient, but more advanced setups
|
|
may benefit from additional components in the ACL system:
|
|
|
|
* **ACL Roles** - Roles allow for the grouping of a set of policies and service
|
|
identities into a reusable higher-level entity that can be applied to many
|
|
tokens. (Added in Consul 1.5.0)
|
|
|
|
* **ACL Service Identities** - Service identities are a policy template for
|
|
expressing a link to a policy suitable for use in [Consul
|
|
Connect](/docs/connect/index.html). At authorization time this acts like an
|
|
additional policy was attached, the contents of which are described further
|
|
below. These are directly attached to tokens and roles and are not
|
|
independently configured. (Added in Consul 1.5.0)
|
|
|
|
* **ACL Auth Methods and Binding Rules** - To learn more about these topics,
|
|
see the [dedicated auth methods documentation page](/docs/acl/acl-auth-methods.html).
|
|
|
|
ACL tokens, policies, roles, auth methods, and binding rules are managed by
|
|
Consul operators via Consul's [ACL API](/api/acl/acl.html),
|
|
[ACL CLI](/docs/commands/acl.html), or systems like
|
|
[HashiCorp's Vault](https://www.vaultproject.io/docs/secrets/consul/index.html).
|
|
|
|
If the ACL system becomes inoperable, you can follow the
|
|
[reset procedure](https://learn.hashicorp.com/consul/security-networking/acl-troubleshooting?utm_source=consul.io&utm_medium=docs) at any time.
|
|
|
|
### ACL Policies
|
|
|
|
An ACL policy is a named set of rules and is composed of the following elements:
|
|
|
|
* **ID** - The policy's auto-generated public identifier.
|
|
* **Name** - A unique meaningful name for the policy.
|
|
* **Description** - A human readable description of the policy. (Optional)
|
|
* **Rules** - Set of rules granting or denying permissions. See the [Rule Specification](/docs/acl/acl-rules.html#rule-specification) documentation for more details.
|
|
* **Datacenters** - A list of datacenters the policy is valid within.
|
|
* **Namespace** - **Enterprise Only** - The namespace this policy resides within. (Added in Consul Enterprise 1.7.0)
|
|
|
|
-> **Consul Enterprise Namespacing** - Rules defined in a policy in any namespace other than `default` will be [restricted](/docs/acl/acl-rules.html#namespace-rules-enterprise) to being able to grant a subset of the overall privileges and only affecting that single namespace.
|
|
|
|
#### Builtin Policies
|
|
|
|
* **Global Management** - Grants unrestricted privileges to any token that uses it. When created it will be named `global-management`
|
|
and will be assigned the reserved ID of `00000000-0000-0000-0000-000000000001`. This policy can be renamed but modification
|
|
of anything else including the rule set and datacenter scoping will be prevented by Consul.
|
|
|
|
* **Namespace Management** - **Enterprise Only** - Every namespace created will have a policy injected with the name `namespace-management`. This policy gets injected with a randomized UUID and may be managed like any other user-defined policy
|
|
within the Namespace. (Added in Consul Enterprise 1.7.0)
|
|
|
|
### ACL Service Identities
|
|
|
|
-> Added in Consul 1.5.0
|
|
|
|
An ACL service identity is an [ACL policy](/docs/acl/acl-system.html#acl-policies) template for expressing a link to a policy
|
|
suitable for use in [Consul Connect](/docs/connect/index.html). They are usable
|
|
on both tokens and roles and are composed of the following elements:
|
|
|
|
* **Service Name** - The name of the service.
|
|
* **Datacenters** - A list of datacenters the effective policy is valid within. (Optional)
|
|
|
|
Services participating in the service mesh will need privileges to both _be
|
|
discovered_ and to _discover other healthy service instances_. Suitable
|
|
policies tend to all look nearly identical so a service identity is a policy
|
|
template to aid in avoiding boilerplate policy creation.
|
|
|
|
During the authorization process, the configured service identity is automatically
|
|
applied as a policy with the following preconfigured [ACL
|
|
rules](/docs/acl/acl-system.html#acl-rules-and-scope):
|
|
|
|
```hcl
|
|
// Allow the service and its sidecar proxy to register into the catalog.
|
|
service "<Service Name>" {
|
|
policy = "write"
|
|
}
|
|
service "<Service Name>-sidecar-proxy" {
|
|
policy = "write"
|
|
}
|
|
|
|
// Allow for any potential upstreams to be resolved.
|
|
service_prefix "" {
|
|
policy = "read"
|
|
}
|
|
node_prefix "" {
|
|
policy = "read"
|
|
}
|
|
```
|
|
|
|
The [API documentation for roles](/api/acl/roles.html#sample-payload) has some
|
|
examples of using a service identity.
|
|
|
|
-> **Consul Enterprise Namespacing** - Service Identity rules will be scoped to the single namespace that
|
|
the corresponding ACL Token or Role resides within.
|
|
|
|
### ACL Roles
|
|
|
|
-> Added in Consul 1.5.0
|
|
|
|
An ACL role is a named set of policies and service identities and is composed
|
|
of the following elements:
|
|
|
|
* **ID** - The role's auto-generated public identifier.
|
|
* **Name** - A unique meaningful name for the role.
|
|
* **Description** - A human readable description of the role. (Optional)
|
|
* **Policy Set** - The list of policies that are applicable for the role.
|
|
* **Service Identity Set** - The list of service identities that are applicable for the role.
|
|
* **Namespace** - **Enterprise Only** - The namespace this policy resides within. (Added in Consul Enterprise 1.7.0)
|
|
|
|
-> **Consul Enterprise Namespacing** - Roles may only link to policies defined in the same namespace as the role itself.
|
|
|
|
### ACL Tokens
|
|
|
|
ACL tokens are used to determine if the caller is authorized to perform an action. An ACL token is composed of the following
|
|
elements:
|
|
|
|
* **Accessor ID** - The token's public identifier.
|
|
* **Secret ID** -The bearer token used when making requests to Consul.
|
|
* **Description** - A human readable description of the token. (Optional)
|
|
* **Policy Set** - The list of policies that are applicable for the token.
|
|
* **Role Set** - The list of roles that are applicable for the token. (Added in Consul 1.5.0)
|
|
* **Service Identity Set** - The list of service identities that are applicable for the token. (Added in Consul 1.5.0)
|
|
* **Locality** - Indicates whether the token should be local to the datacenter it was created within or created in
|
|
the primary datacenter and globally replicated.
|
|
* **Expiration Time** - The time at which this token is revoked. (Optional; Added in Consul 1.5.0)
|
|
* **Namespace** - **Enterprise Only** - The namespace this policy resides within. (Added in Consul Enterprise 1.7.0)
|
|
|
|
-> **Consul Enterprise Namespacing** - Tokens may only link to policies and roles defined in the same namespace as
|
|
the token itself.
|
|
|
|
#### Builtin Tokens
|
|
|
|
During cluster bootstrapping when ACLs are enabled both the special `anonymous` and the `master` token will be
|
|
injected.
|
|
|
|
* **Anonymous Token** - The anonymous token is used when a request is made to Consul without specifying a bearer token.
|
|
The anonymous token's description and policies may be updated but Consul will prevent this token's deletion. When created,
|
|
it will be assigned `00000000-0000-0000-0000-000000000002` for its Accessor ID and `anonymous` for its Secret ID.
|
|
|
|
* **Master Token** - When a master token is present within the Consul configuration, it is created and will be linked
|
|
With the builtin Global Management policy giving it unrestricted privileges. The master token is created with the Secret ID
|
|
set to the value of the configuration entry.
|
|
|
|
#### Authorization
|
|
|
|
The token Secret ID is passed along with each RPC request to the servers. Consul's
|
|
[HTTP endpoints](/api/index.html) can accept tokens via the `token`
|
|
query string parameter, the `X-Consul-Token` request header, or an
|
|
[RFC6750](https://tools.ietf.org/html/rfc6750) authorization bearer token. Consul's
|
|
[CLI commands](/docs/commands/index.html) can accept tokens via the
|
|
`token` argument, or the `CONSUL_HTTP_TOKEN` environment variable. The CLI
|
|
commands can also accept token values stored in files with the `token-file`
|
|
argument, or the `CONSUL_HTTP_TOKEN_FILE` environment variable.
|
|
|
|
If no token is provided for an HTTP request then Consul will use the default ACL token
|
|
if it has been configured. If no default ACL token was configured then the anonymous
|
|
token will be used.
|
|
|
|
#### ACL Rules and Scope
|
|
|
|
The rules from all policies, roles, and service identities linked with a token are combined to form that token's
|
|
effective rule set. Policy rules can be defined in either a whitelist or blacklist
|
|
mode depending on the configuration of [`acl_default_policy`](/docs/agent/options.html#acl_default_policy).
|
|
If the default policy is to "deny" access to all resources, then policy rules can be set to
|
|
whitelist access to specific resources. Conversely, if the default policy is “allow” then policy rules can
|
|
be used to explicitly deny access to resources.
|
|
|
|
The following table summarizes the ACL resources that are available for constructing
|
|
rules:
|
|
|
|
| Resource | Scope |
|
|
| ------------------------ | ----- |
|
|
| [`acl`](#acl-rules) | Operations for managing the ACL system [ACL API](/api/acl/acl.html) |
|
|
| [`agent`](#agent-rules) | Utility operations in the [Agent API](/api/agent.html), other than service and check registration |
|
|
| [`event`](#event-rules) | Listing and firing events in the [Event API](/api/event.html) |
|
|
| [`key`](#key-value-rules) | Key/value store operations in the [KV Store API](/api/kv.html) |
|
|
| [`keyring`](#keyring-rules) | Keyring operations in the [Keyring API](/api/operator/keyring.html) |
|
|
| [`node`](#node-rules) | Node-level catalog operations in the [Catalog API](/api/catalog.html), [Health API](/api/health.html), [Prepared Query API](/api/query.html), [Network Coordinate API](/api/coordinate.html), and [Agent API](/api/agent.html) |
|
|
| [`operator`](#operator-rules) | Cluster-level operations in the [Operator API](/api/operator.html), other than the [Keyring API](/api/operator/keyring.html) |
|
|
| [`query`](#prepared-query-rules) | Prepared query operations in the [Prepared Query API](/api/query.html)
|
|
| [`service`](#service-rules) | Service-level catalog operations in the [Catalog API](/api/catalog.html), [Health API](/api/health.html), [Prepared Query API](/api/query.html), and [Agent API](/api/agent.html) |
|
|
| [`session`](#session-rules) | Session operations in the [Session API](/api/session.html) |
|
|
|
|
Since Consul snapshots actually contain ACL tokens, the [Snapshot API](/api/snapshot.html)
|
|
requires a token with "write" privileges for the ACL system.
|
|
|
|
The following resources are not covered by ACL policies:
|
|
|
|
1. The [Status API](/api/status.html) is used by servers when bootstrapping and exposes
|
|
basic IP and port information about the servers, and does not allow modification
|
|
of any state.
|
|
|
|
2. The datacenter listing operation of the
|
|
[Catalog API](/api/catalog.html#list-datacenters) similarly exposes the names of known
|
|
Consul datacenters, and does not allow modification of any state.
|
|
|
|
3. The [connect CA roots endpoint](/api/connect/ca.html#list-ca-root-certificates) exposes just the public TLS certificate which other systems can use to verify the TLS connection with Consul.
|
|
|
|
Constructing rules from these policies is covered in detail on the
|
|
[ACL Rules](/docs/acl/acl-rules.html) page.
|
|
|
|
-> **Consul Enterprise Namespacing** - In addition to directly linked policies, roles and service identities, Consul Enterprise
|
|
will include the ACL policies and roles defined in the [Namespaces definition](/docs/enterprise/namespaces/index.html#namespace-definition). (Added in Consul Enterprise 1.7.0)
|
|
|
|
## Configuring ACLs
|
|
|
|
ACLs are configured using several different configuration options. These are marked
|
|
as to whether they are set on servers, clients, or both.
|
|
|
|
| Configuration Option | Servers | Clients | Purpose |
|
|
| -------------------- | ------- | ------- | ------- |
|
|
| [`acl.enabled`](/docs/agent/options.html#acl_enabled) | `REQUIRED` | `REQUIRED` | Controls whether ACLs are enabled |
|
|
| [`acl.default_policy`](/docs/agent/options.html#acl_default_policy) | `OPTIONAL` | `N/A` | Determines whitelist or blacklist mode |
|
|
| [`acl.down_policy`](/docs/agent/options.html#acl_down_policy) | `OPTIONAL` | `OPTIONAL` | Determines what to do when the remote token or policy resolution fails |
|
|
| [`acl.role_ttl`](/docs/agent/options.html#acl_role_ttl) | `OPTIONAL` | `OPTIONAL` | Determines time-to-live for cached ACL Roles |
|
|
| [`acl.policy_ttl`](/docs/agent/options.html#acl_policy_ttl) | `OPTIONAL` | `OPTIONAL` | Determines time-to-live for cached ACL Policies |
|
|
| [`acl.token_ttl`](/docs/agent/options.html#acl_token_ttl) | `OPTIONAL` | `OPTIONAL` | Determines time-to-live for cached ACL Tokens |
|
|
|
|
A number of special tokens can also be configured which allow for bootstrapping the ACL
|
|
system, or accessing Consul in special situations:
|
|
|
|
| Special Token | Servers | Clients | Purpose |
|
|
| ------------- | ------- | ------- | ------- |
|
|
| [`acl.tokens.agent_master`](/docs/agent/options.html#acl_tokens_agent_master) | `OPTIONAL` | `OPTIONAL` | Special token that can be used to access [Agent API](/api/agent.html) when remote bearer token resolution fails; used for setting up the cluster such as doing initial join operations, see the [ACL Agent Master Token](#acl-agent-master-token) section for more details |
|
|
| [`acl.tokens.agent`](/docs/agent/options.html#acl_tokens_agent) | `OPTIONAL` | `OPTIONAL` | Special token that is used for an agent's internal operations, see the [ACL Agent Token](#acl-agent-token) section for more details |
|
|
| [`acl.tokens.master`](/docs/agent/options.html#acl_tokens_master) | `OPTIONAL` | `N/A` | Special token used to bootstrap the ACL system, see the [Bootstrapping ACLs](https://learn.hashicorp.com/consul/advanced/day-1-operations/acl-guide) guide for more details |
|
|
| [`acl.tokens.default`](/docs/agent/options.html#acl_tokens_default) | `OPTIONAL` | `OPTIONAL` | Default token to use for client requests where no token is supplied; this is often configured with read-only access to services to enable DNS service discovery on agents |
|
|
|
|
All of these tokens except the `master` token can all be introduced or updated via the [/v1/agent/token API](/api/agent.html#update-acl-tokens).
|
|
|
|
#### ACL Agent Master Token
|
|
|
|
Since the [`acl.tokens.agent_master`](/docs/agent/options.html#acl_tokens_agent_master) is designed to be used when the Consul servers are not available, its policy is managed locally on the agent and does not need to have a token defined on the Consul servers via the ACL API. Once set, it implicitly has the following policy associated with it
|
|
|
|
```hcl
|
|
agent "<node name of agent>" {
|
|
policy = "write"
|
|
}
|
|
node_prefix "" {
|
|
policy = "read"
|
|
}
|
|
```
|
|
|
|
#### ACL Agent Token
|
|
|
|
The [`acl.tokens.agent`](/docs/agent/options.html#acl_tokens_agent) is a special token that is used for an agent's internal operations. It isn't used directly for any user-initiated operations like the [`acl.tokens.default`](/docs/agent/options.html#acl_tokens_default), though if the `acl.tokens.agent_token` isn't configured the `acl.tokens.default` will be used. The ACL agent token is used for the following operations by the agent:
|
|
|
|
1. Updating the agent's node entry using the [Catalog API](/api/catalog.html), including updating its node metadata, tagged addresses, and network coordinates
|
|
2. Performing [anti-entropy](/docs/internals/anti-entropy.html) syncing, in particular reading the node metadata and services registered with the catalog
|
|
3. Reading and writing the special `_rexec` section of the KV store when executing [`consul exec`](/docs/commands/exec.html) commands
|
|
|
|
Here's an example policy sufficient to accomplish the above for a node called `mynode`:
|
|
|
|
```hcl
|
|
node "mynode" {
|
|
policy = "write"
|
|
}
|
|
service_prefix "" {
|
|
policy = "read"
|
|
}
|
|
key_prefix "_rexec" {
|
|
policy = "write"
|
|
}
|
|
```
|
|
|
|
The `service_prefix` policy needs read access for any services that can be registered on the agent. If [remote exec is disabled](/docs/agent/options.html#disable_remote_exec), the default, then the `key_prefix` policy can be omitted.
|
|
|
|
## Next Steps
|
|
|
|
Setup ACLs with the [Bootstrapping the ACL System guide](https://learn.hashicorp.com/consul/security-networking/production-acls?utm_source=consul.io&utm_medium=docs) or continue reading about
|
|
[ACL rules](/docs/acl/acl-rules.html).
|