Handling user lockout / revoking authorization using JWT token in .net core

Handling user lockout / revoking authorization using JWT token in .net core

Handling user lockout and revoking authorization in a .NET Core application using JWT (JSON Web Tokens) involves implementing some additional logic in your authentication and authorization processes. Below, I'll provide a general guide on how you can achieve this. Please note that this is a conceptual guide, and you might need to adapt the code to fit your specific application architecture and requirements.

User Lockout:

• Enhance User Model: 

Add a property to your user model to track the lockout status and potentially a lockout end date.

1. public class ApplicationUser : IdentityUser  
2. {  
3.     // Other properties  
4.   
5.     public bool IsLockedOut { get; set; }  
6.     public DateTime? LockoutEndDateUtc { get; set; }  
7. }  

 

Lockout Logic:

Implement logic in your authentication process to check if a user is locked out before generating a JWT.

1. var user = await userManager.FindByNameAsync(username);
2. 
   
3.             if (user != null && !user.IsLockedOut)
4.             {
5.                 // Validate password, etc.
6. 
   
7.                 // If successful, generate JWT
8.             }
9.             else if (user != null && user.IsLockedOut)
10.             {
11.                 // Handle locked-out user (e.g., return an error)
12.             }

 

• Lockout Policy: 

Configure lockout policy in your Startup.cs or IdentityConfig.cs. 

1. services.Configure<IdentityOptions>(options =>  
2. {  
3.     options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(30);  
4.     options.Lockout.MaxFailedAccessAttempts = 5;  
5. });  

Revoking Authorization:

• Token Blacklisting:

Maintain a blacklist of tokens that have been revoked. This could be stored in a database or an in-memory cache.

1. // Example using an in-memory cache  
2. public class TokenBlacklistService  
3. {  
4.     private readonly IMemoryCache _cache;  
5.   
6.     public TokenBlacklistService(IMemoryCache cache)  
7.     {  
8.         _cache = cache;  
9.     }  
10.   
11.     public void AddToBlacklist(string token, TimeSpan expiration)  
12.     {  
13.         _cache.Set(token, true, expiration);  
14.     }  
15.   
16.     public bool IsTokenBlacklisted(string token)  
17.     {  
18.         return _cache.TryGetValue(token, out _);  
19.     }  
20. }  

•  Check Token Validity:

Before processing a request with a JWT, check if the token is blacklisted. 

1. var token = // Get token from request header or cookie  
2.   
3. if (!tokenBlacklistService.IsTokenBlacklisted(token))  
4. {  
5.     // Process the request  
6. }  
7. else  
8. {  
9.     // Token is blacklisted, handle accordingly (e.g., return unauthorized)  
10. }  

• Revoking Tokens:

When you need to revoke a user's authorization, add their token to the blacklist.

1. var token = // Get token to revoke  
2.   
3. tokenBlacklistService.AddToBlacklist(token, TimeSpan.FromDays(1));