Authorization Policy

Istio Authorization Policy enables access control on workloads in the mesh.

Authorization policy supports CUSTOM, DENY and ALLOW actions for access control. When CUSTOM, DENY and ALLOW actions are used for a workload at the same time, the CUSTOM action is evaluated first, then the DENY action, and finally the ALLOW action. The evaluation is determined by the following rules:

  1. If there are any CUSTOM policies that match the request, evaluate and deny the request if the evaluation result is deny.
  2. If there are any DENY policies that match the request, deny the request.
  3. If there are no ALLOW policies for the workload, allow the request.
  4. If any of the ALLOW policies match the request, allow the request.
  5. Deny the request.

Istio Authorization Policy also supports the AUDIT action to decide whether to log requests. AUDIT policies do not affect whether requests are allowed or denied to the workload. Requests will be allowed or denied based solely on CUSTOM, DENY and ALLOW actions.

A request will be internally marked that it should be audited if there is an AUDIT policy on the workload that matches the request. A separate plugin must be configured and enabled to actually fulfill the audit decision and complete the audit behavior. The request will not be audited if there are no such supporting plugins enabled. Currently, the only supported plugin is the Stackdriver plugin.

Here is an example of Istio Authorization Policy:

It sets the action to “ALLOW” to create an allow policy. The default action is “ALLOW” but it is useful to be explicit in the policy.

It allows requests from:

  • service account “cluster.local/ns/default/sa/sleep” or
  • namespace “test”

to access the workload with:

  • “GET” method at paths of prefix “/info” or,
  • “POST” method at path “/data”.

when the request has a valid JWT token issued by “https://accounts.google.com”.

Any other requests will be denied.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: httpbin
  namespace: foo
spec:
  action: ALLOW
  rules:
  - from:
    - source:
        principals: ["cluster.local/ns/default/sa/sleep"]
    - source:
        namespaces: ["test"]
    to:
    - operation:
        methods: ["GET"]
        paths: ["/info*"]
    - operation:
        methods: ["POST"]
        paths: ["/data"]
    when:
    - key: request.auth.claims[iss]
      values: ["https://accounts.google.com"]

The following is another example that sets action to “DENY” to create a deny policy. It denies requests from the “dev” namespace to the “POST” method on all workloads in the “foo” namespace.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: httpbin
  namespace: foo
spec:
  action: DENY
  rules:
  - from:
    - source:
        namespaces: ["dev"]
    to:
    - operation:
        methods: ["POST"]

The following authorization policy sets the action to “AUDIT”. It will audit any GET requests to the path with the prefix “/user/profile”.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  namespace: ns1
  name: anyname
spec:
  selector:
    matchLabels:
      app: myapi
  action: AUDIT
  rules:
  - to:
    - operation:
        methods: ["GET"]
        paths: ["/user/profile/*"]

Authorization Policy scope (target) is determined by “metadata/namespace” and an optional “selector”.

  • “metadata/namespace” tells which namespace the policy applies. If set to root namespace, the policy applies to all namespaces in a mesh.
  • workload “selector” can be used to further restrict where a policy applies.

For example,

The following authorization policy applies to all workloads in namespace foo. It allows nothing and effectively denies all requests to workloads in namespace foo.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
 name: allow-nothing
 namespace: foo
spec:
  {}

The following authorization policy allows all requests to workloads in namespace foo.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
 name: allow-all
 namespace: foo
spec:
 rules:
 - {}

The following authorization policy applies to workloads containing label “app: httpbin” in namespace bar. It allows nothing and effectively denies all requests to the selected workloads.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-nothing
  namespace: bar
spec:
  selector:
    matchLabels:
      app: httpbin

The following authorization policy applies to workloads containing label “version: v1” in all namespaces in the mesh. (Assuming the root namespace is configured to “istio-system”).

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
 name: allow-nothing
 namespace: istio-system
spec:
 selector:
   matchLabels:
     version: v1

AuthorizationPolicy

AuthorizationPolicy enables access control on workloads.

FieldTypeDescriptionRequired
selectorWorkloadSelector

Optional. The selector decides where to apply the authorization policy. The selector will match with workloads in the same namespace as the authorization policy. If the authorization policy is in the root namespace, the selector will additionally match with workloads in all namespaces.

If not set, the selector will match all workloads.

No
rulesRule[]

Optional. A list of rules to match the request. A match occurs when at least one rule matches the request.

If not set, the match will never occur. This is equivalent to setting a default of deny for the target workloads if the action is ALLOW.

No
actionAction

Optional. The action to take if the request is matched with the rules. Default is ALLOW if not specified.

No
providerExtensionProvider (oneof)

Specifies detailed configuration of the CUSTOM action. Must be used only with CUSTOM action.

No

Rule

Rule matches requests from a list of sources that perform a list of operations subject to a list of conditions. A match occurs when at least one source, one operation and all conditions matches the request. An empty rule is always matched.

Any string field in the rule supports Exact, Prefix, Suffix and Presence match:

  • Exact match: “abc” will match on value “abc”.
  • Prefix match: “abc*” will match on value “abc” and “abcd”.
  • Suffix match: “*abc” will match on value “abc” and “xabc”.
  • Presence match: “*” will match when value is not empty.
FieldTypeDescriptionRequired
fromFrom[]

Optional. from specifies the source of a request.

If not set, any source is allowed.

No
toTo[]

Optional. to specifies the operation of a request.

If not set, any operation is allowed.

No
whenCondition[]

Optional. when specifies a list of additional conditions of a request.

If not set, any condition is allowed.

No

Source

Source specifies the source identities of a request. Fields in the source are ANDed together.

For example, the following source matches if the principal is “admin” or “dev” and the namespace is “prod” or “test” and the ip is not “1.2.3.4”.

principals: ["admin", "dev"]
namespaces: ["prod", "test"]
notIpBlocks: ["1.2.3.4"]
FieldTypeDescriptionRequired
principalsstring[]

Optional. A list of peer identities derived from the peer certificate. The peer identity is in the format of "<TRUST_DOMAIN>/ns/<NAMESPACE>/sa/<SERVICE_ACCOUNT>", for example, "cluster.local/ns/default/sa/productpage". This field requires mTLS enabled and is the same as the source.principal attribute.

If not set, any principal is allowed.

No
notPrincipalsstring[]

Optional. A list of negative match of peer identities.

No
requestPrincipalsstring[]

Optional. A list of request identities derived from the JWT. The request identity is in the format of "<ISS>/<SUB>", for example, "example.com/sub-1". This field requires request authentication enabled and is the same as the request.auth.principal attribute.

If not set, any request principal is allowed.

No
notRequestPrincipalsstring[]

Optional. A list of negative match of request identities.

No
namespacesstring[]

Optional. A list of namespaces derived from the peer certificate. This field requires mTLS enabled and is the same as the source.namespace attribute.

If not set, any namespace is allowed.

No
notNamespacesstring[]

Optional. A list of negative match of namespaces.

No
ipBlocksstring[]

Optional. A list of IP blocks, populated from the source address of the IP packet. Single IP (e.g. “1.2.3.4”) and CIDR (e.g. “1.2.3.0/24”) are supported. This is the same as the source.ip attribute.

If not set, any IP is allowed.

No
notIpBlocksstring[]

Optional. A list of negative match of IP blocks.

No
remoteIpBlocksstring[]

Optional. A list of IP blocks, populated from X-Forwarded-For header or proxy protocol. To make use of this field, you must configure the numTrustedProxies field of the gatewayTopology under the meshConfig when you install Istio or using an annotation on the ingress gateway. See the documentation here: Configuring Gateway Network Topology. Single IP (e.g. “1.2.3.4”) and CIDR (e.g. “1.2.3.0/24”) are supported. This is the same as the remote.ip attribute.

If not set, any IP is allowed.

No
notRemoteIpBlocksstring[]

Optional. A list of negative match of remote IP blocks.

No

Operation

Operation specifies the operations of a request. Fields in the operation are ANDed together.

For example, the following operation matches if the host has suffix “.example.com” and the method is “GET” or “HEAD” and the path doesn’t have prefix “/admin”.

hosts: ["*.example.com"]
methods: ["GET", "HEAD"]
notPaths: ["/admin*"]
FieldTypeDescriptionRequired
hostsstring[]

Optional. A list of hosts as specified in the HTTP request. The match is case-insensitive. See the security best practices for recommended usage of this field.

If not set, any host is allowed. Must be used only with HTTP.

No
notHostsstring[]

Optional. A list of negative match of hosts as specified in the HTTP request. The match is case-insensitive.

No
portsstring[]

Optional. A list of ports as specified in the connection.

If not set, any port is allowed.

No
notPortsstring[]

Optional. A list of negative match of ports as specified in the connection.

No
methodsstring[]

Optional. A list of methods as specified in the HTTP request. For gRPC service, this will always be “POST”.

If not set, any method is allowed. Must be used only with HTTP.

No
notMethodsstring[]

Optional. A list of negative match of methods as specified in the HTTP request.

No
pathsstring[]

Optional. A list of paths as specified in the HTTP request. See the Authorization Policy Normalization for details of the path normalization. For gRPC service, this will be the fully-qualified name in the form of “/package.service/method”.

If not set, any path is allowed. Must be used only with HTTP.

No
notPathsstring[]

Optional. A list of negative match of paths.

No

Condition

Condition specifies additional required attributes.

FieldTypeDescriptionRequired
keystring

The name of an Istio attribute. See the full list of supported attributes.

Yes
valuesstring[]

Optional. A list of allowed values for the attribute. Note: at least one of values or not_values must be set.

No
notValuesstring[]

Optional. A list of negative match of values for the attribute. Note: at least one of values or not_values must be set.

No

AuthorizationPolicy.ExtensionProvider

FieldTypeDescriptionRequired
namestring

Specifies the name of the extension provider. The list of available providers is defined in the MeshConfig. Note, currently at most 1 extension provider is allowed per workload. Different workloads can use different extension provider.

No

Rule.From

From includes a list or sources.

FieldTypeDescriptionRequired
sourceSource

Source specifies the source of a request.

No

Rule.To

To includes a list or operations.

FieldTypeDescriptionRequired
operationOperation

Operation specifies the operation of a request.

No

AuthorizationPolicy.Action

Action specifies the operation to take.

NameDescription
ALLOW

Allow a request only if it matches the rules. This is the default type.

DENY

Deny a request if it matches any of the rules.

AUDIT

Audit a request if it matches any of the rules.

CUSTOM

The CUSTOM action allows an extension to handle the user request if the matching rules evaluate to true. The extension is evaluated independently and before the native ALLOW and DENY actions. When used together, A request is allowed if and only if all the actions return allow, in other words, the extension cannot bypass the authorization decision made by ALLOW and DENY action. Extension behavior is defined by the named providers declared in MeshConfig. The authorization policy refers to the extension by specifying the name of the provider. One example use case of the extension is to integrate with a custom external authorization system to delegate the authorization decision to it.

Note: The CUSTOM action is currently an alpha feature and is subject to breaking changes in later versions.

The following authorization policy applies to an ingress gateway and delegates the authorization check to a named extension “my-custom-authz” if the request path has prefix “/admin/”.

apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: ext-authz
  namespace: istio-system
spec:
  selector:
    matchLabels:
      app: istio-ingressgateway
  action: CUSTOM
  provider:
    name: "my-custom-authz"
  rules:
  - to:
    - operation:
        paths: ["/admin/*"]
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