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UA-.NETStandard/Docs/RoleBasedUserManagement.md
romanett 6d85d8007b document role based user mangement (#2528)
* document role based user mangement
2024-02-22 11:36:22 +01:00

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# Role Based User Management
## Overview
OPC UA Supports role based user management in a way that assigns permissions to nodes.
Those permissions are then assigned to a role.
The role is assigned to one or multiple Identities by the Server.
Since #2444 the OPC UA .NET Standard Stack implements the well known roles from:
[UA Part 3: Address Space Model - 4.9.2 Well Known Roles](https://reference.opcfoundation.org/Core/Part3/v105/docs/4.9.2)
- Anonymous
- AuthenticatedUser
- Observer
- Operator
- Engineer
- Supervisor
- ConfigureAdmin
- SecurityAdmin
## Implementation
To get started using well known roles in your server the first thing you have to do is returning a RoleBasedIdentity in the overriden SessionManager_ImpersonateUser Method.
[ReferenceServer.cs (SessionManager_ImpersonateUser)](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Applications/Quickstarts.Servers/ReferenceServer/ReferenceServer.cs#L229C22-L229C52)
[ReferenceServer.cs (new RoleBasedIdentity)](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Applications/Quickstarts.Servers/ReferenceServer/ReferenceServer.cs#L327)
You can add as many roles to your returned identity as needed.
All well knwon roles are created as static properties in the Role class of the server:
[RoleBasedIdentity.cs](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Server/RoleBasedUserManagement/RoleBasedIdentity.cs)
If you want to add additional roles you can refer to the GDS implementation which adds some user defined roles.
To make it easier to implement a real user name / pw implementation, avoiding hardcoded passwords, the Server Library provides an interface and a sample implementation for a users database:
[RoleBasedUserManagement/UserDatabase](https://github.com/OPCFoundation/UA-.NETStandard/tree/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Server/RoleBasedUserManagement/UserDatabase)
```C#
public interface IUserDatabase
{
/// <summary>
/// Initialize User Database
/// </summary>
void Initialize();
/// <summary>
/// Register new user
/// </summary>
/// <param name="userName">the username</param>
/// <param name="password">the password</param>
/// <param name="roles">the role of the new user</param>
/// <returns>true if registered sucessfull</returns>
bool CreateUser(string userName, string password, IEnumerable<Role> roles);
/// <summary>
/// Delete existring user
/// </summary>
/// <param name="userName">the user to delete</param>
/// <returns>true if deleted sucessfully</returns>
bool DeleteUser(string userName);
/// <summary>
/// checks if the provided credentials fit a user
/// </summary>
/// <param name="userName">the username</param>
/// <param name="password">the password</param>
/// <returns>true if userName + PW combination is correct</returns>
bool CheckCredentials(string userName, string password);
/// <summary>
/// returns the Role of the provided user
/// </summary>
/// <param name="userName"></param>
/// <returns>the Role of the provided users</returns>
/// <exception cref="ArgumentException">When the user is not found</exception>
IEnumerable<Role> GetUserRoles(string userName);
/// <summary>
/// changes the password of an existing users
/// </summary>
/// <param name="userName"></param>
/// <param name="oldPassword"></param>
/// <param name="newPassword"></param>
/// <returns>true if change was sucessfull</returns>
bool ChangePassword(string userName, string oldPassword, string newPassword);
}
```
An implementation targeting SQL Server using Entity Framework 6 is available in the Samples Repo:
[SqlUsersDatabase.cs](https://github.com/OPCFoundation/UA-.NETStandard-Samples/blob/e100ac787507988da95223a031af76fe57b5e11d/Samples/GDS/Server/SqlUsersDatabase.cs)
To enable the authorization for your servers methods you can take a look at the HasApplicationSecureAdminAccess method of the ConfigurationNodeManager:
[ConfigurationNodeManager.cs](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Server/Configuration/ConfigurationNodeManager.cs#L300C9-L319C10)
This method verifies the current session has the needed roles to access the methods.
## GDS
The GDS supports some additional well known roles starting with
[GDS: implement ApplicationSelfAdmin privilege in GlobalDiscoverySampleServer by romanett · Pull Request #2338](https://github.com/OPCFoundation/UA-.NETStandard/pull/2338)
[UA Part 12: Discovery and Global Services - 6.2 Roles and Privileges](https://reference.opcfoundation.org/GDS/v105/docs/6.2)
[UA Part 12: Discovery and Global Services - 7.2 Roles and Privileges](https://reference.opcfoundation.org/GDS/v105/docs/7.2)
- DiscoveryAdmin
- SecurityAdmin
- CertificateAuthorityAdmin
- RegistrationAuthorityAdmin
[GdsRole.cs](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Gds.Server.Common/GdsRole.cs)
Additionally the ApplicationSelfAdmin privilege is supported.
In the UA .NET Standard Stack the ApplicationSelfAdmin privilege is implemented using a user defined role.
To store its users the GDS implements the IUserDatabase interface from the server library.
[Opc.Ua.Server/RoleBasedUserManagement/UserDatabase](https://github.com/OPCFoundation/UA-.NETStandard/tree/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Server/RoleBasedUserManagement/UserDatabase)
The JsonUserDatabase path is stored in the GDS Configuration:
[GlobalDiscoveryServerConfiguration.cs](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Gds.Server.Common/GlobalDiscoveryServerConfiguration.cs#L91)
The GDS allows library users to supply their own implementation using the constructor:
[GlobalDiscoverySampleServer.cs](https://github.com/OPCFoundation/UA-.NETStandard/blob/61edad9d6361b566baa5fdd69a23e7ac58c3433d/Libraries/Opc.Ua.Gds.Server.Common/GlobalDiscoverySampleServer.cs#L55C2-L63C10)
## Limitations
- Does not really make use of the permissions <-> roles
- Does not implement the RoleBasedSecurity Information Model from: [](https://reference.opcfoundation.org/Core/Part18/v105/docs/)