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Verifying access in code

  • Articolo

The only time you don't need to be concerned about security concepts is when you're writing code that a user with the System Administrator security role runs. Because this role is all powerful and can't be edited, you can be assured that the user can do anything. In all other cases, you need to consider how security is applied.

  • If you're creating a client application, you should evaluate the user's privileges for a table or for a specific table record and control which commands you enable. If a user isn't allowed to create a table, you can disable the user interface in your app to allow creating a new table of that type. If they don't have read access to a table, your client application can choose to not display components related to viewing lists of that type of table.

  • If you're writing a synchronous plug-in, you can't attempt some data operation and throw away the exception. Any operation that fails within a synchronous plug-in causes the entire data transaction to be rolled back. If you have some part of the process that is optional depending on the user's privileges, you should check the user's privileges first.

There are two strategies you can apply to detect which operations a user can perform:

  • Test individual table records
  • Check the user's security privileges

These strategies are described below.

Test individual table records

User interaction with specific table records usually begins with a query. If a user has no access to any records for that table, the query returns no records, and there's nothing further the user can attempt except to create a new record. Testing whether the user can create a new record requires using the other strategy (mentioned above) to check the user's security privileges.

However, if the user was successful in retrieving table records using a query, you can then test a record using the RetrievePrincipalAccess message.

The following GetAccessRights static method uses the SDK RetrievePrincipalAccessRequest Class to retrieve a set of access rights that a user, team, or organization has for a record using the AccessRights Enum.

/// <summary>
/// Gets which access rights a user, team, or organization has for a specific record.
/// </summary>
/// <param name="service">Authenticated client implementing the IOrganizationService interface</param>
/// <param name="userOrTeamOrOrganization">The user, team, or organization to check</param>
/// <param name="entity">A reference to the entity to check.</param>
/// <returns>The access rights the user can perform.</returns>
static AccessRights GetAccessRights(
        IOrganizationService service,
        EntityReference userOrTeamOrOrganization,
        EntityReference entity)
{
    var request = new RetrievePrincipalAccessRequest()
    {
        Principal = userOrTeamOrOrganization,
        Target = entity
    };

    var response = (RetrievePrincipalAccessResponse)service.Execute(request);

    return response.AccessRights;
}

With the value returned by this method, you can use the Enum.HasFlag Method to return a Boolean value when the user has access to perform specific operations on the table.

The following code snippet shows how to use the GetAccessRights static method to test whether a user has access to append records to an account record using the AppendToAccess member.

var whoIAm = (WhoAmIResponse)service.Execute(new WhoAmIRequest());

var meRef = new EntityReference("systemuser", whoIAm.UserId);

QueryExpression query = new("account") { 
        ColumnSet = new ColumnSet("accountid"),
        TopCount = 1
};

EntityCollection accounts = service.RetrieveMultiple(query);

EntityReference accountRef = accounts
    .Entities
    .FirstOrDefault()
    .ToEntityReference();

AccessRights rights = GetAccessRights(service, meRef, accountRef);

var canAppendTo = rights.HasFlag(AccessRights.AppendToAccess);

With access to a table record, you can use the access rights returned to test any operations that apply to that record. But this test doesn't include capabilities that apply to other operations, such as creating a new record or any other privilege that isn't bound to a specific table. For these operations, you need to Check a user's security privileges.

Get principals with access to a record

Some data operations require another user have access to a record. If you have just one specific user, team, or organization, you can test using the RetrievePrincipalAccess message.

However, if you need a list of all the users, teams, or organizations that a record has been shared with, use the RetrieveSharedPrincipalsAndAccess message. RetrieveSharedPrincipalsAndAccess provides details about the access rights each user, team, or organization has because the record was shared with them.

The following GetSharedPrincipalsAndAccess static method uses the RetrieveSharedPrincipalsAndAccessRequest and RetrieveSharedPrincipalsAndAccessResponse classes to return an array of PrincipalAccess data with details about the principals and the access they have because the record was shared with them.

/// <summary>
/// Returns details about access principals have because a record was shared with them.
/// </summary>
/// <param name="service">Authenticated client implementing the IOrganizationService interface</param>
/// <param name="target">The record to check</param>
/// <returns>The principal access data for each user, team, or organization</returns>
static PrincipalAccess[] GetSharedPrincipalsAndAccess(
    IOrganizationService service,
    EntityReference target)
{
    var request = new RetrieveSharedPrincipalsAndAccessRequest()
    {
        Target = target
    };

    var response = (RetrieveSharedPrincipalsAndAccessResponse)service.Execute(request);

    return response.PrincipalAccesses;
}

Check a user's security privileges

When you don't have a specific table record to test, such as whether a user can create a new table record, you must rely on checking the user's security privileges. These privileges are stored in the Privilege table.

There are nearly 1000 individual privileges in the Dataverse database and the number grows with every table that is added to the system. You can retrieve a list of the privileges available in your environment by executing the following FetchXML query.

<fetch version='1.0' distinct='true' no-lock='true' >
  <entity name='privilege' >
    <attribute name='name' />
  </entity>
</fetch>

Tip

The XrmToolBox FetchXML Builder is a useful tool to compose and test FetchXML queries.

The value of the name attribute follows this naming convention pattern when the privilege applies to tables: "prv+Verb+Table SchemaName". The verb is one of Append, AppendTo, Assign, Create, Delete, Share, Write.

In addition to the privileges for tables, there are less than 100 other special privileges that aren't associated with tables. You can use the following query to retrieve these privileges.

<fetch version='1.0' distinct='true' no-lock='true' >

<entity name='privilege' >
  <attribute name='name' />
  <filter>
    <condition attribute='name' operator='not-begin-with' value='prvAppend' />
    <condition attribute='name' operator='not-begin-with' value='prvAssign' />
    <condition attribute='name' operator='not-begin-with' value='prvCreate' />
    <condition attribute='name' operator='not-begin-with' value='prvDelete' />
    <condition attribute='name' operator='not-begin-with' value='prvRead' />
    <condition attribute='name' operator='not-begin-with' value='prvShare' />
    <condition attribute='name' operator='not-begin-with' value='prvWrite' />
  </filter>
</entity>

</fetch>

Use these messages to retrieve privileges by privilege ID or name. They include privileges that the user might have from teams.

Message Web API function
SDK request class
RetrieveUserPrivilegeByPrivilegeId RetrieveUserPrivilegeByPrivilegeId Function
RetrieveUserPrivilegeByPrivilegeIdRequest Class
RetrieveUserPrivilegeByPrivilegeName RetrieveUserPrivilegeByPrivilegeName Function
RetrieveUserPrivilegeByPrivilegeNameRequest Class
RetrieveUserSetOfPrivilegesByIds RetrieveUserSetOfPrivilegesByIds Function
RetrieveUserSetOfPrivilegesByIdsRequest Class
RetrieveUserSetOfPrivilegesByNames RetrieveUserSetOfPrivilegesByNames Function
RetrieveUserSetOfPrivilegesByNamesRequest Class

Example: Check whether a user has a privilege

The following examples show the use of the RetrieveUserPrivilegeByPrivilegeName message. This message retrieves the list of privileges for a system user (user) from all direct roles associated with the system user and from all indirect roles associated with teams in which the system user is a member of based on the specified privilege name.

The following HasPrivilege static method returns whether the user has the named privilege.

/// <summary>
/// Returns whether specified user has a named privilege
/// </summary>
/// <param name="service">The IOrganizationService instance to use.</param>
/// <param name="systemUserId">The Id of the user.</param>
/// <param name="privilegeName">The name of the privilege.</param>
/// <returns></returns>
static bool HasPrivilege(IOrganizationService service,
        Guid systemUserId,
        string privilegeName)
{
    var request = new
        RetrieveUserPrivilegeByPrivilegeNameRequest
    {
        PrivilegeName = privilegeName,
        UserId = systemUserId
    };
    var response =
        (RetrieveUserPrivilegeByPrivilegeNameResponse)service
        .Execute(request);
    if (response.RolePrivileges.Length > 0)
    {
        return true;
    }
    return false;
}

More information:

Retrieve privileges for a security role

You can retrieve the privileges associated with a security role.

The following static GetRolePrivileges method retrieves the privileges associated with a role.

/// <summary>
/// Retrieves the privileges for a role.
/// </summary>
/// <param name="service">Authenticated client implementing the IOrganizationService interface</param>
/// <param name="roleId">The id of the role</param>
/// <returns>Privilege records associated to the role</returns>
static EntityCollection GetRolePrivileges(IOrganizationService service, Guid roleId) {

    Relationship roleprivileges_association = new("roleprivileges_association");

    var relationshipQueryCollection = new RelationshipQueryCollection();

    var relatedPrivileges = new QueryExpression("privilege")
    {
        ColumnSet = new ColumnSet("name")
    };

    relationshipQueryCollection.Add(roleprivileges_association, relatedPrivileges);

    var request = new RetrieveRequest()
    {
        ColumnSet = new ColumnSet(true),
        RelatedEntitiesQuery = relationshipQueryCollection,
        Target = new EntityReference("role", roleId)
    };

    var response = (RetrieveResponse)service.Execute(request);

    return response.Entity.RelatedEntities[roleprivileges_association];
}

More information: Retrieve with related rows

See Also

Plug-ins