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=== Policies

Policies control different aspects of the <<provisioning,provisioning>> process. They can be used to fine-tune and adapt
the overall mechanism to the particularities of the specific domain in which a given Apache Syncope deployment is running.

[[policy-composition]]
[TIP]
.Policy Composition
====
When defining policies and associating them with different realms and resources, it is common to observe that several policies
of the same type have to be enforced on the same user, group or any object.

In such cases, Apache Syncope transparently composes all of the candidate policies and obtains a single applicable policy
which contains all the conditions of the composing policies; this process, however, is not guaranteed to be successful,
as different policies of the same type might provide conflicting clauses.
====

[[policies-account]]
==== Account

Account policies allow the imposition of constraints on username values, and are involved in the authentication process.

[NOTE]
====
When set for realm R, an account policy is enforced on all Users of R and sub-realms.

When set for resource R, an account policy is enforced on all Users that have R assigned.
====

When defining an account policy, the following information must be provided:

* max authentication attempts - how many times Users are allowed to fail authentication before getting suspended
* propagate suspension - when suspended as a consequence of too many authentication failures, should Users also be
suspended on associated resources or not?
* pass-through resources - which <<external-resource-details,external resources>> are involved with
<<pass-through-authentication,pass-through authentication>>
* rules - set of account rules to evaluate with the current policy

===== Account Rules

Account rules define constraints to apply to username values.

The default account rule (enforced by
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/DefaultAccountRule.java[DefaultAccountRule^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/DefaultAccountRule.java[DefaultAccountRule^]
endif::[]
and configurable via
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/common/lib/src/main/java/org/apache/syncope/common/lib/policy/DefaultAccountRuleConf.java[DefaultAccountRuleConf^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/common/lib/src/main/java/org/apache/syncope/common/lib/policy/DefaultAccountRuleConf.java[DefaultAccountRuleConf^]
endif::[]
) contains the following controls:

* maximum length - the maximum length to allow; `0` means no limit set;
* minimum length - the minimum length to allow; `0` means no limit set;
* pattern - http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html[Java regular expression pattern^] to
match; `NULL` means no match is attempted;
* all uppercase - are lowercase characters allowed?
* all lowercase - are uppercase characters allowed?
* words not permitted - list of words that cannot be present, even as a substring;
* schemas not permitted - list of <<schema,schemas>> whose values cannot be present, even as a substring;
* prefixes not permitted - list of strings that cannot be present as a prefix;
* suffixes not permitted - list of strings that cannot be present as a suffix.

[TIP]
====
Writing custom account rules means:

. providing configuration parameters in an implementation of
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/common/lib/src/main/java/org/apache/syncope/common/lib/policy/AccountRuleConf.java[AccountRuleConf^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/common/lib/src/main/java/org/apache/syncope/common/lib/policy/AccountRuleConf.java[AccountRuleConf^]
endif::[]
. implementing enforcement in an implementation of
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/AccountRule.java[AccountRule^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/AccountRule.java[AccountRule^]
endif::[]
annotated via
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/AccountRuleConfClass.java[@AccountRuleConfClass^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/AccountRuleConfClass.java[@AccountRuleConfClass^]
endif::[]
referring to the configuration class
====

===== Pass-through Authentication

During user authentication, if the <<policy-composition,resulting>> applicable account policy defines pass-through
resources, the provided credentials are verified first against the internal storage, then against each configured
external resource (provided that the underlying <<connector-instance-details,connector instance>> has the `AUTHENTICATE`
capability set): the first check that succeeds will successfully authenticate the user.

This feature allows, for example, to reuse credentials contained in Identity Stores (without extracting them),
instead of storing password values in the internal storage. It also facilitates implementing authentication chains.

[[policies-password]]
==== Password

Password policies allow the imposition of constraints on password values.

[NOTE]
====
When set for realm R, a password policy is enforced on all Users of R and sub-realms.

When set for resource R, a password policy is enforced on all Users that have R assigned.
====

When defining a password policy, the following information must be provided:

* allow null password - whether a password is mandatory for Users or not
* history length - how many values shall be considered in the history
* rules - set of password rules to evaluate with the current policy

===== Password Rules

Password rules define constraints to apply to password values.

Some implementations are provided out-of-the-box, custom ones can be provided on given deployment.

[TIP]
====
Writing custom password rules means:

. providing configuration parameters in an implementation of
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/common/lib/src/main/java/org/apache/syncope/common/lib/policy/PasswordRuleConf.java[PasswordRuleConf^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/common/lib/src/main/java/org/apache/syncope/common/lib/policy/PasswordRuleConf.java[PasswordRuleConf^]
endif::[]
. implementing enforcement in an implementation of
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/PasswordRule.java[PasswordRule^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/PasswordRule.java[PasswordRule^]
endif::[]
annotated via
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/PasswordRuleConfClass.java[@PasswordRuleConfClass^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-api/src/main/java/org/apache/syncope/core/persistence/api/dao/PasswordRuleConfClass.java[@PasswordRuleConfClass^]
endif::[]
referring to the configuration class
====

====== Default Password Rule

The default password rule (enforced by
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/DefaultPasswordRule.java[DefaultPasswordRule^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/DefaultPasswordRule.java[DefaultPasswordRule^]
endif::[]
and configurable via
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/common/lib/src/main/java/org/apache/syncope/common/lib/policy/DefaultPasswordRuleConf.java[DefaultPasswordRuleConf^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/common/lib/src/main/java/org/apache/syncope/common/lib/policy/DefaultPasswordRuleConf.java[DefaultPasswordRuleConf^]
endif::[]
) contains the following controls:

* maximum length - the maximum length to allow; `0` means no limit set;
* minimum length - the minimum length to allow; `0` means no limit set;
* non-alphanumeric required
* alphanumeric required
* digit required
* lowercase required
* uppercase required
* must start with digit
* must not start with digit
* must end with digit
* must not end with digit
* must start with alphanumeric
* must start with non-alphanumeric
* must not start with alphanumeric
* must not start with non-alphanumeric
* must end with alphanumeric
* must end with non-alphanumeric
* must not end with alphanumeric
* must not end with non-alphanumeric
* username allowed - whether a username value can be used
* words not permitted - list of words that cannot be present, even as a substring;
* schemas not permitted - list of <<schema,schemas>> whose values cannot be present, even as a substring;
* prefixes not permitted - list of strings that cannot be present as a prefix;
* suffixes not permitted - list of strings that cannot be present as a suffix.

====== "Have I Been Pwned?" Password Rule

This password rule (enforced by
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/HaveIBeenPwnedPasswordRule.java[HaveIBeenPwnedPasswordRule^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/persistence-jpa/src/main/java/org/apache/syncope/core/persistence/jpa/dao/HaveIBeenPwnedPasswordRule.java[HaveIBeenPwnedPasswordRule^]
endif::[]
and configurable via
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/common/lib/src/main/java/org/apache/syncope/common/lib/policy/HaveIBeenPwnedPasswordRuleConf.java[HaveIBeenPwnedPasswordRuleConf^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/common/lib/src/main/java/org/apache/syncope/common/lib/policy/HaveIBeenPwnedPasswordRuleConf.java[HaveIBeenPwnedPasswordRuleConf^]
endif::[]
) checks the provided password values against the popular
https://haveibeenpwned.com["Have I Been Pwned?"^] service.

[[policies-pull]]
==== Pull

Pull policies are evaluated during the execution of <<tasks-pull,pull tasks>> and are meant to:

. help match existing Users, Groups and Any Objects during <<provisioning-pull,pull>>, thus generating update events
(rather than create)
. determine which action shall be taken in case such match is not unique (e.g. what to do if the same external account
can be mapped to two distinct Users in Apache Syncope?)

[NOTE]
====
When set for resource R, a pull policy is enforced on all Users, Groups and Any Objects pulled from R.
====

When defining a pull policy, the following information must be provided:

* conflict resolution action
** `IGNORE` - do nothing
** `FIRSTMATCH` - pull first matching object only
** `LASTMATCH` - pull last matching object only
** `ALL` - pull all matching objects
* rules - set of correlation rules to evaluate with the current policy; for each defined <<anytype,Any Type>>, a
different rule is required

===== Pull Correlation Rules

Pull correlation rules define how to match objects received from <<connector-instance-details,connector instances>>
with existing Users, Groups or Any Objects.

The 
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/provisioning-java/src/main/java/org/apache/syncope/core/provisioning/java/pushpull/PlainAttrsPullCorrelationRule.java[default^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/provisioning-java/src/main/java/org/apache/syncope/core/provisioning/java/pushpull/PlainAttrsPullCorrelationRule.java[default^]
endif::[]
implementation attempts to match entities on the basis of the values of the provided plain attributes,
according to the available <<mapping,mapping>>.

[TIP]
====
Custom pull correlation rules can be provided by implementing the
ifeval::["{snapshotOrRelease}" == "release"]
https://github.com/apache/syncope/blob/syncope-{docVersion}/core/provisioning-api/src/main/java/org/apache/syncope/core/provisioning/api/pushpull/PullCorrelationRule.java[PullCorrelationRule^]
endif::[]
ifeval::["{snapshotOrRelease}" == "snapshot"]
https://github.com/apache/syncope/tree/2_0_X/core/provisioning-api/src/main/java/org/apache/syncope/core/provisioning/api/pushpull/PullCorrelationRule.java[PullCorrelationRule^]
endif::[]
interface.
====

[[policies-push]]
==== Push

Push policies are evaluated during the execution of <<tasks-push,push tasks>>.

[NOTE]
====
When set for resource R, a push policy is enforced on all Users, Groups and Any Objects pushed to R.
====
