When the user submits his credentials to my api, I call an external api to authenticate the user. After that, a token gets generated on the external api and will be sent to me. For that I implemented the HandleAuthenticateAsync function from the AuthenticationHandler:
protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
{
//before this: make call to external api to get the access token
var claims = new[] {
new Claim(ClaimTypes.Name, submittedToken),
};
var identity = new ClaimsIdentity(claims, Scheme.Name);
var principal = new ClaimsPrincipal(identity);
var ticket = new AuthenticationTicket(principal, Scheme.Name);
return AuthenticateResult.Success(ticket);
}
I have implemented a custom AuthorizationHandler which I want to check for the access token that you got when you successfully authenticate. Note that the actual authentication and authorization is done by an external api which is a custom implementation. Here is the function:
public class IsAuthorizedRequirement : AuthorizationHandler<IsAuthorizedRequirement>, IAuthorizationRequirement
{
public AuthenticateHandlerHelperFunctions AuthenticateHandlerHelper;
public IsAuthorizedRequirement()
{
AuthenticateHandlerHelper = new AuthenticateHandlerHelperFunctions();
}
protected override async Task HandleRequirementAsync(AuthorizationHandlerContext context, IsAuthorizedRequirement requirement)
{
if(!context.User.HasClaim(c => c.Type == ClaimTypes.Name))
{
context.Fail();
return;
}
var token = context.User.FindFirst(c => c.Type == ClaimTypes.Name).Value;
if (!string.IsNullOrEmpty(token))
{
context.Fail();
return;
}
var checkedToken = await AuthenticateHandlerHelper.CheckAccessToken(token);
if (checkedToken == null)
{
context.Fail();
return;
}
context.Succeed(requirement);
}
}
The CheckAccessToken function makes a simple HTTP Post Request to the external Api where I get back if the token is still valid or not. Is this a valid implementation especially when multiple users are using this? Especially the claims that I use: Are they created for each user or will the content inside ClaimsType.Name be overwritten each time a user makes a request? Currently I have no way to test this so I just wanted to know if I am on the right track for this. Thanks
Is this a valid implementation especially when multiple users are using this?
I strongly stand against this approach. Implementation like this mean you would call external API for validate and generate token(or cookie or any form of authenticated certificate) on external server for each and any of your request(which require authentication).
It's could be consider acceptable if we have some special cases on just some endpoints. But for the whole API/Web server. Please don't use this approach.
Especially the claims that I use: Are they created for each user or will the content inside ClaimsType.Name be overwritten each time a user makes a request?
They'll create for each request. As I can see in the code there are no part for generate cookie or some form of retaining user information for the client to attach next request afterward.
Related
What I need to do
I'm developing an application using ASP.NET CORE and I actually encountered a problem using the Identity implementation.
In the official doc infact there is no reference about the multiple session, and this is bad because I developed a SaaS application; in particular a user subscribe a paid plan to access to a specific set of features and him can give his credentials to other users so they can access for free, this is a really bad scenario and I'll lose a lot of money and time.
What I though
After searching a lot on the web I found many solutions for the older version of ASP.NET CORE, so I'm not able to test, but I understood that the usually the solution for this problem is related to store the user time stamp (which is a GUID generated on the login) inside the database, so each time the user access to a restricted page and there are more session (with different user timestamp) the old session will closed.
I don't like this solution because an user can easily copy the cookie of the browser and share it will other users.
I though to store the information of the logged in user session inside the database, but this will require a lot of connection too.. So my inexperience with ASP.NET CORE and the lack of resource on the web have sent me in confusion.
Someone could share a generic idea to implement a secure solution for prevent multiple user login?
I've created a github repo with the changes to the default .net core 2.1 template needed to only allow single sessions. https://github.com/xKloc/IdentityWithSession
Here is the gist.
First, override the default UserClaimsPrincipalFactory<IdentityUser> class with a custom one that will add your session to the user claims. Claims are just a key/value pair that will be stored in the user's cookie and also on the server under the AspNetUserClaims table.
Add this class anywhere in your project.
public class ApplicationClaimsPrincipalFactory : UserClaimsPrincipalFactory<IdentityUser>
{
private readonly UserManager<IdentityUser> _userManager;
public ApplicationClaimsPrincipalFactory(UserManager<IdentityUser> userManager, IOptions<IdentityOptions> optionsAccessor) : base(userManager, optionsAccessor)
{
_userManager = userManager;
}
public async override Task<ClaimsPrincipal> CreateAsync(IdentityUser user)
{
// find old sessions and remove
var claims = await _userManager.GetClaimsAsync(user);
var session = claims.Where(e => e.Type == "session");
await _userManager.RemoveClaimsAsync(user, session);
// add new session claim
await _userManager.AddClaimAsync(user, new Claim("session", Guid.NewGuid().ToString()));
// create principal
var principal = await base.CreateAsync(user);
return principal;
}
}
Next we will create an authorization handler that will check that the session is valid on every request.
The handler will match the session claim from the user's cookie to the session claim stored in the database. If they match, the user is authorized to continue. If they don't match, the user will get a Access Denied message.
Add these two classes anywhere in your project.
public class ValidSessionRequirement : IAuthorizationRequirement
{
}
public class ValidSessionHandler : AuthorizationHandler<ValidSessionRequirement>
{
private readonly UserManager<IdentityUser> _userManager;
private readonly SignInManager<IdentityUser> _signInManager;
public ValidSessionHandler(UserManager<IdentityUser> userManager, SignInManager<IdentityUser> signInManager)
{
_userManager = userManager ?? throw new ArgumentNullException(nameof(userManager));
_signInManager = signInManager ?? throw new ArgumentNullException(nameof(signInManager));
}
protected override async Task HandleRequirementAsync(AuthorizationHandlerContext context, ValidSessionRequirement requirement)
{
// if the user isn't authenticated then no need to check session
if (!context.User.Identity.IsAuthenticated)
return;
// get the user and session claim
var user = await _userManager.GetUserAsync(context.User);
var claims = await _userManager.GetClaimsAsync(user);
var serverSession = claims.First(e => e.Type == "session");
var clientSession = context.User.FindFirst("session");
// if the client session matches the server session then the user is authorized
if (serverSession?.Value == clientSession?.Value)
{
context.Succeed(requirement);
}
return;
}
}
Finally, just register these new classes in start up so they get called.
Add this code to your Startup class under the ConfigureServices method, right below services.AddDefaultIdentity<IdentityUser>()
.AddEntityFrameworkStores<ApplicationDbContext>();
// build default authorization policy
var defaultPolicy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
.AddRequirements(new ValidSessionRequirement())
.Build();
// add authorization to the pipe
services.AddAuthorization(options =>
{
options.DefaultPolicy = defaultPolicy;
});
// register new claims factory
services.AddScoped<IUserClaimsPrincipalFactory<IdentityUser>, ApplicationClaimsPrincipalFactory>();
// register valid session handler
services.AddTransient<IAuthorizationHandler, ValidSessionHandler>();
You can use UpdateSecurityStamp to invalidate any existing authentication cookies. For example:
public async Task<IActionResult> Login(LoginViewModel model)
{
var user = await _userManager.FindByEmailAsync(model.Email);
if (user == null)
{
ModelState.AddModelError(string.Empty, "Invalid username/password.");
return View();
}
if (await _userManager.ValidatePasswordAsync(user, model.Password))
{
await _userManager.UpdateSecurityStampAsync(user);
var result = await _signInManager.SignInAsync(user, isPersistent: false);
// handle `SignInResult` cases
}
}
By updating the security stamp will cause all existing auth cookies to be invalid, basically logging out all other devices where the user is logged in. Then, you sign in the user on this current device.
Best way is to do something similar to what Google, Facebook and others do -- detect if user is logging in from a different device. For your case, I believe you would want to have a slight different behavior -- instead of asking access, you'll probably deny it. It's almost like you're creating a license "per device", or a "single tenant" license.
This Stack Overflow thread talks about this solution.
The most reliable way to detect a device change is to create a
fingerprint of the browser/device the browser is running on. This is a
complex topic to get 100% right, and there are commercial offerings
that are pretty darn good but not flawless.
Note: if you want to start simple, you could start with a Secure cookie, which is less likely to be exposed to cookie theft via eavesdropping. You could store a hashed fingerprint, for instance.
There are some access management solutions (ForgeRock, Oracle Access Management) that implement this Session Quota functionality. ForgeRock has a community version and its source code is available on Github, maybe you can take a look at how it is implemented there. There is also a blog post from them giving a broad view of the functionality (https://blogs.forgerock.org/petermajor/2013/01/session-quota-basics/)
If this is too complex for your use case, what I would do is combine the "shared memory" approach that you described with an identity function, similar to what Fabio pointed out in another answer.
I have an api that is protected by JWT and Authorize attribute and at the client I use jquery ajax call to deal with it.
This works fine, however I now need to be able to secure downloading of files so I can't set a header Bearer value, can it be done in the URI as an url parameter?
=-=-=-=-
UPDATE: This is what I ended up doing for my scenario which is an in-house project and very low volume but security is important and it might need to scale in future:
When user logs in I generate a random download key and put it in their user record in the db along with the expiry date of their JWT and return the download key to the client. The download route is protected to only allow a download if there is a query parameter that has the download key and that key exists in the user records and that expiry date has not passed. This way the dl key is unique per user, valid as long as the user's auth session is valid and can be revoked easily.
This is a common problem.
Whenever you want to reference images or other files directly from an API in a single page application's HTML, there isn't a way to inject the Authorization request header between the <img> or <a> element and the request to the API. You can sidestep this by using some fairly new browser features as described here, but you may need to support browsers that lack this functionality.
Fortunately, RFC 6750 specifies a way to do exactly what you're asking via the "URI Query Parameter" authentication approach. If you follow its convention, you would accept JWTs using the following format:
https://server.example.com/resource?access_token=mF_9.B5f-4.1JqM&p=q
As stated in another answer and in RFC 6750 itself, you should be doing this only when necessary. From the RFC:
Because of the security weaknesses associated with the URI method (see Section 5), including the high likelihood that the URL containing the access token will be logged, it SHOULD NOT be used unless it is impossible to transport the access token in the "Authorization" request header field or the HTTP request entity-body.
If you still decide to implement "URI Query Parameter" authentication, you can use the Invio.Extensions.Authentication.JwtBearer library and call AddQueryStringAuthentication() extension method on JwtBearerOptions. Or, if you want to do it manually, you can certainly do that as well. Here's a code sample that shows both ways as extensions of the Microsoft.AspNetCore.Authentication.JwtBearer library.
public void ConfigureServices(IServiceCollection services) {
services
.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
.AddJwtBearer(
options => {
var authentication = this.configuration.GetSection("Authentication");
options.TokenValidationParameters = new TokenValidationParameters {
ValidIssuers = authentication["Issuer"],
ValidAudience = authentication["ClientId"],
IssuerSigningKey = new SymmetricSecurityKey(
Encoding.UTF8.GetBytes(authentication["ClientSecret"])
)
};
// OPTION 1: use `Invio.Extensions.Authentication.JwtBearer`
options.AddQueryStringAuthentication();
// OPTION 2: do it manually
options.Events = new JwtBearerEvents {
OnMessageReceived = (context) => {
StringValues values;
if (!context.Request.Query.TryGetValue("access_token", out values)) {
return Task.CompletedTask;
}
if (values.Count > 1) {
context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
context.Fail(
"Only one 'access_token' query string parameter can be defined. " +
$"However, {values.Count:N0} were included in the request."
);
return Task.CompletedTask;
}
var token = values.Single();
if (String.IsNullOrWhiteSpace(token)) {
context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
context.Fail(
"The 'access_token' query string parameter was defined, " +
"but a value to represent the token was not included."
);
return Task.CompletedTask;
}
context.Token = token;
return Task.CompletedTask;
}
};
}
);
}
You can use a middleware to set the authorization header from the query param:
public class SecureDownloadUrlsMiddleware
{
private readonly RequestDelegate next;
public SecureDownloadUrlsMiddleware(RequestDelegate next)
{
this.next = next;
}
public async Task Invoke(HttpContext context /* other dependencies */)
{
// get the token from query param
var token = context.Request.Query["t"];
// set the authorization header only if it is empty
if (string.IsNullOrEmpty(context.Request.Headers["Authorization"]) &&
!string.IsNullOrEmpty(token))
{
context.Request.Headers["Authorization"] = $"Bearer {token}";
}
await next(context);
}
}
and then in Startup.cs use the middleware before the authentication middleware:
app.UseMiddleware(typeof(SecureDownloadUrlsMiddleware));
app.UseAuthentication();
Although it is technically possible to include a JWT in the URL, it is strongly discouraged. See the quote from here, which explains why it's a bad idea:
Don't pass bearer tokens in page URLs: Bearer tokens SHOULD NOT be
passed in page URLs (for example, as query string parameters).
Instead, bearer tokens SHOULD be passed in HTTP message headers or
message bodies for which confidentiality measures are taken. Browsers,
web servers, and other software may not adequately secure URLs in the
browser history, web server logs, and other data structures. If bearer
tokens are passed in page URLs, attackers might be able to steal them
from the history data, logs, or other unsecured locations.
However, if you have no choice or just don't care about security practices, see Technetium's answer.
If you still need it,you have to set jwt token on localStorage.After,you have to create a new header with the following code:
'functionName'():Headers{
let header =new Headers();
let token = localStorage.getItem('token')
header.append('Authorization',`Bearer ${token}`);
return header;
}
Add Hader to http requests.
return this.http.get('url',new RequestOptions({headers:this.'serviceName'.'functionName'()}))
Although this is a bit outside of the box, I would advice you to do the same as this is the best scalable solution when developing in the .NET environment.
Use Azure Storage! Or any other similar online cloud storage solution.
It makes sure your web app is separate from your files, so you don't have to worry about moving an application to a different web environment.
Web storage is mostly more expensive then azure storage (1GB with about 3000 operations (read/write/list) costs in total about $0.03.
When you scale your application where downtime is more critical, point 1 also applies when you use a swapping/staging technique.
Azure storage takes care of the expiry of so called Shared Access Tokens (SAS)
For the sake of simplicity for you, I will just include my code here so you don't have to google the rest
So what I do in my case, all my files are saved as Attachments within the database (not the actual file of course).
When someone requests an attachment, I do a quick check to see if the expire date has passed and if so we should generate a new url.
//where ever you want this to happen, in the controller before going to the client for example
private async Task CheckSasExpire(IEnumerable<AttachmentModel> attachments)
{
foreach (AttachmentModel attachment in attachments)
{
await CheckSasExpire(attachment);
}
}
private async Task CheckSasExpire(AttachmentModel attachment)
{
if (attachment != null && attachment.LinkExpireDate < DateTimeOffset.UtcNow && !string.IsNullOrWhiteSpace(attachment.AzureContainer))
{
Enum.TryParse(attachment.AzureContainer, out AzureStorage.ContainerEnum container);
string url = await _azureStorage.GetFileSasLocator(attachment.Filename, container);
attachment.FileUrl = url;
attachment.LinkExpireDate = DateTimeOffset.UtcNow.AddHours(1);
await _attachmentRepository.UpdateAsync(attachment.AttachmentId, attachment);
}
}
AzureStorage.ContainerEnum is just an internal enum to easily track the container certain files are stored in, but these can be strings of course
And my AzureStorage class:
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
public async Task<string> GetFileSasLocator(string filename, ContainerEnum container, DateTimeOffset expire = default(DateTimeOffset))
{
var cont = await GetContainer(container);
CloudBlockBlob blockBlob = cont.GetBlockBlobReference(filename);
DateTimeOffset expireDate = DateTimeOffset.UtcNow.AddHours(1);//default
if (expire != default(DateTimeOffset) && expire > expireDate)
{
expireDate = expire.ToUniversalTime();
}
SharedAccessBlobPermissions permission = SharedAccessBlobPermissions.Read;
var sasConstraints = new SharedAccessBlobPolicy
{
SharedAccessStartTime = DateTime.UtcNow.AddMinutes(-30),
SharedAccessExpiryTime = expireDate,
Permissions = permission
};
var sasToken = blockBlob.GetSharedAccessSignature(sasConstraints);
return blockBlob.Uri + sasToken;
}
private async Task<CloudBlobContainer> GetContainer(ContainerEnum container)
{
//CloudConfigurationManager.GetSetting("StorageConnectionString")
CloudStorageAccount storageAccount = CloudStorageAccount.Parse(_config["StorageConnectionString"]);
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
string containerName = container.ToString().ToLower();
CloudBlobContainer cloudContainer = blobClient.GetContainerReference(containerName);
await cloudContainer.CreateIfNotExistsAsync();
return cloudContainer;
}
So this will produce url's like so: http://127.0.0.1:10000/devstoreaccount1/invoices/NL3_2002%20-%202019-04-12.pdf?sv=2018-03-28&sr=b&sig=gSiohA%2BGwHj09S45j2Deh%2B1UYP1RW1Fx5VGeseNZmek%3D&st=2019-04-18T14%3A16%3A55Z&se=2019-04-18T15%3A46%3A55Z&sp=r
Of course you have to apply your own authentication logic when retrieving the attachments, if the user is allowed to view the file or not. But that can all be done with the JWT token and in the controller or the repository. I wouldn't worry about the URL being a public url, if one is so mighty to get that URL... within one hour... well then reduce the expire date :D
We're evaluating service stack v.4.5.6.0 for a Web API and we want clients to be able to authenticate using basic auth or credentials but we do not want them to be able to provide a basic auth header in place of a JWT token or session cookie when using our services. While I realize this is somewhat arbitrary, is there a way to exclude routes from specific providers or force the use of a token/cookie to authenticate once they've logged in?
Auth config from AppHost:
private void ConfigureAuth(Container container)
{
var appSettings = new AppSettings();
this.Plugins.Add(new AuthFeature(() => new CustomAuthUserSession(),
new IAuthProvider[]
{
new CredentialsAuthProvider(),
new BasicAuthProvider(),
new JwtAuthProvider(appSettings)
}) { IncludeAssignRoleServices = false, MaxLoginAttempts = 10} );
var userRepository = new CustomUserAuthRepository(container.TryResolve<IDbConnectionFactory>());
container.Register<IAuthRepository>(userRepository);
}
ServiceStack lets you decide which AuthProviders you want your Services to be authenticated with, but it doesn't let you individually configure which adhoc AuthProviders applies to individual Services. Feel free to add this a feature request.
However if you want to ensure that a Service is only accessed via JWT you can add a check in your Services for FromToken which indicates the Session was populated by a JWT Token, e.g:
[Authenticate]
public class MyServices : Service
{
public object Any(MyRequest request)
{
var session = base.SessionAs<AuthUserSession>();
if (!session.FromToken)
throw HttpError.Unauthorized("Requires JWT Authentication");
//...
}
}
From v4.5.7 that's now available on MyGet you can also use the new session.AuthProvider property which indicates what AuthProvider was used to Authenticate the user, e.g:
public object Any(MyRequest request)
{
var session = base.SessionAs<AuthUserSession>();
if (session.AuthProvider != JwtAuthProvider.Name)
throw HttpError.Unauthorized("Requires JWT Authentication");
//...
}
Refer to the docs for different AuthProvider names for each AuthProvider.
I want to create Custom Bearer Token, with some additional information to be store in the token.
Just want to Use Create Token functionality.(something like FormsAuthentication) without using default implementation(ASP.NET Identity) of User Tables.
1) Custom Login method(MyLogin), that will create custom bearer token with additional information(IP Address embedded into token).
2) on subsequent request be able to inspect the additional information and reject(treat the request as unauthenticated) if the additional information does not match some rule.
In case i receive the bearer token and find the request is coming from different IP address then the one embedded inside it, clear/Invalidate the Bearer Token and treat the current request as UnAuthenticated.
I'm by no means an expert but this is the information i gathered.
This seems to be relatively simple to do with ASP.NET Identity.
You need to create your own implementation of a token provider which implements the IAuthenticationTokenProvider interface. You implement the create method so it creates the token just the way you want and then you supply your provider when configuring the authentication middleware.
The configuration in your starup class would look something like this:
public class Startup
{
public void Configuration(IAppBuilder app)
{
ConfigureOAuth(app);
//Rest of code is here;
}
public void ConfigureOAuth(IAppBuilder app)
{
OAuthAuthorizationServerOptions OAuthServerOptions = new OAuthAuthorizationServerOptions()
{
AllowInsecureHttp = true,
TokenEndpointPath = new PathString("/yourtokenendpoint"),
AccessTokenExpireTimeSpan = TimeSpan.FromDays(1),
Provider = new SimpleAuthorizationServerProvider(),
AccessTokenProvider = new YourCustomTokenProvider() // YourCustomTokenProvider implements IAuthenticationTokenProvider
};
OAuthBearerAuthenticationOptions bearerOptions = new OAuthBearerAuthenticationOptions()
{
AccessTokenProvider = new YourCustomTokenProvider() // YourCustomTokenProvider implements IAuthenticationTokenProvider
}
// Token Generation
app.UseOAuthAuthorizationServer(OAuthServerOptions);
app.UseOAuthBearerAuthentication(bearerOptions);
}
}
I have never done this myself but I hope this was of some use.
EDIT: To validate the the token you could create a custom action filter that you decorate your controller actions with. In this action filter you could validate the token and do whatever you like with the request. See this guide.
Is there an alternative to the session feature plugin in servicestack? In some scenarios I cannot use cookies to match the authorized session in my service implementation. Is there a possibility to resolve the session using a token in http header of the request? What is the preferred solution for that in case the browser is blocking cookies?
I'm using ServiceStack without the built-in auth and session providers.
I use a attribute as request filter to collect the user information (id and token), either from a cookie, request header or string parameter.
You can provide this information after the user takes login. You append a new cookie to the response and inject the id and token info on clientside when rendering the view, so you can use for http headers and query parameters for links.
public class AuthenticationAttribute : Attribute, IHasRequestFilter
{
public void RequestFilter(IHttpRequest request, IHttpResponse response, object dto)
{
var userAuth = new UserAuth { };
if(!string.IsNullOrWhiteSpace(request.GetCookieValue("auth"))
{
userAuth = (UserAuth)request.GetCookieValue("auth");
}
else if (!string.IsNullOrEmpty(request.Headers.Get("auth-key")) &&
!string.IsNullOrEmpty(request.Headers.Get("auth-id")))
{
userAuth.Id = request.Headers.Get("id");
userAuth.Token = request.Headers.Get("token");
}
authenticationService.Authenticate(userAuth.Id, userAuth.token);
}
public IHasRequestFilter Copy()
{
return new AuthenticationAttribute();
}
public int Priority { get { return -3; } } // negative are executed before global requests
}
If the user isn't authorized, i redirect him at this point.
My project supports SPA. If the user consumes the API with xmlhttprequests, the authentication stuff is done with headers. I inject that information on AngularJS when the page is loaded, and reuse it on all request (partial views, api consuming, etc). ServiceStack is powerful for this type of stuff, you can easily configure your AngularJS app and ServiceStack view engine to work side by side, validating every requests, globalizing your app, etc.
In case you don't have cookies and the requests aren't called by javascript, you can support the authentication without cookies if you always generate the links passing the id and token as query parameters, and pass them through hidden input on forms, for example.
#Guilherme Cardoso: In my current solution I am using a PreRequestFilters and the built-in session feature.
My workflow/workaround is the following:
When the user gets authorized I took the cookie and send it to the client by using an http header. Now the client can call services if the cookie is set in a http-header (Authorization) of the request.
To achieve this I redirect the faked authorization header to the cookie of the request using a PreRequestFilter. Now I am able to use the session feature. Feels like a hack but works for the moment ;-)
public class CookieRestoreFromAuthorizationHeaderPlugin : IPlugin
{
public void Register(IAppHost appHost)
{
appHost.PreRequestFilters.Add((req, res) =>
{
var cookieValue = req.GetCookieValue("ss-id");
if(!string.IsNullOrEmpty(cookieValue))
return;
var authorizationHeader = req.Headers.Get("Authorization");
if (!string.IsNullOrEmpty(authorizationHeader) && authorizationHeader.ToLower().StartsWith("basictoken "))
{
var cookie = Encoding.UTF8.GetString(Convert.FromBase64String(authorizationHeader.Split(' ').Last()));
req.Cookies.Add("ss-id",new Cookie("ss-id",cookie));
req.Items.Add("ss-id",cookie);
}
});
}
}