I'm trying to call an Azure function from an API Management instance by using Managed Identity.
I have set a System Managed Identity to my APIM instance.
I have granted the Contributor role to this identity on the Azure Function App.
I have also change the App Service Authentication to AD.
Now I'm trying to call the function from an API.
I have two issues:
First One: when I use the authentication-managed-identity policy to get a token, I got an error when I use the audience https://myfunctionapp.azurewebsites.net. AD tells me that this app is not registered in the tenant
Second: If I retrieve a token for https://management.azure.com, I got a token but I received a 401 Unauthorized error from the Azure Function.
Maybe I'm just trying to get a token on the wrong audience, but unfortunately the audience of functions is not listed in the document (for service bus for example, there is a common URI to use, also for KeyVault, ...).
I think that I probably missed something in the picture...
Thanks.
You need to use the authentication-managed-identity policy to authenticate with a backend service using the managed identity of the API Management service.
https://learn.microsoft.com/en-us/azure/api-management/api-management-authentication-policies#ManagedIdentity
EDIT
1-In your APIM application on Azure AD,
grab the Application ID assigned for enterprise application.
2-Then go to Platform features in your Azure Function App, and click on Authentication / Authorization.
3-Select Azure Active Directory as the authentication provider, and the management mode "express".
4-Back to authentication-managed-identity policy, set the Application ID from step 1 as the resource.
you need to add the url in apim required resource. If you're planning to use delegated flow. To check if the issue is with the url registration you can use the AppId instead. This will at least tell you if the token can be retrieved.
Related
We aim to collect data from the Azure Management APIs. These APIs provide information on the resources we have running in Azure, the consumed budget, etc (example). Following our design choices, we prefer to exclusively use Azure Data Factory to make the HTTP requests and store the data into our data lakes. This is fairly obvious, using the REST linked service. However, we struggle to correctly set up the OAuth2 authentication dance with this method.
Our first idea was to store the token and the refresh token within the Azure Key Vault. A series of HTTP requests within the pipeline would then test whether the token is still valid or otherwise use the refresh token to get a new token. The downside to this approach is that the token within the Azure Key Vault is never updated, when needed, and that the logic becomes more complex.
Alternatively, we were trying to set up the authorization through combination of a registered app and service principal to our Azure AD account. The REST linked service within Data Factory can be created with a service principal, which would then handle most of the information of the scope and consent. The service principal is also accompanied with a Azure app, which would hold the token etc. Unfortunately, we are unable to make this setup function correctly.
Questions we have:
Can we actually use a service principal / app to store our OAuth2 tokens? If so, will these be automatically refreshed within our app?
How do we assign the correct privileges / authorizations to our app that it can use this (external) API?
Is the additional logic with HTTP calls within Azure Data Factory pipeline needed to update the tokens or can these apps / service principals handle this?
Thank you for your time and help!
It is not a good idea to store the tokens in the keyvault, because they will expire.
In your case, two options for you to use.
Use service principal to auth
Use managed identity to auth(best practice)
Steps to use service principal to auth:
1.Register an application with Azure AD and create a service principal.
2.Get values for signing in and create a new application secret.
3.To call the Azure REST API e.g. Resources - List you mentioned, your service principal needs the RBAC role in your subscription.
Navigate to the Azure portal -> Subscription -> add your service principal as a Contributor/Owner role in the subscription like below.
4.In the linked service, configure it like below, fix them with the values got from step 2.
Don't forget to replace the {subscriptionId} in the Base URL.
https://management.azure.com/subscriptions/{subscriptionId}/resources?api-version=2020-06-01
5.Test the linked service with a copy activity, it works fine.
Steps to use managed identity to auth:
1.Make sure your data factory has enabled the MSI(managed identity), if you create it in the portal or powershell, MSI will be enabled automatically, don't worry about that.
2.Navigate to the Subsctiption in the portal, add the role to the MSI like step 3 in Steps to use service principal to auth, just search for your ADF name in the bar, the MSI is essentially a service principal with the same name of your ADF, which is managed by azure.
3.Then in the linked service, just change it like below.
At last, answer your questions.
Can we actually use a service principal / app to store our OAuth2 tokens? If so, will these be automatically refreshed within our app?
As I mentioned, it is not a good idea, just use the service principal/MSI to auth like the steps above.
How do we assign the correct privileges / authorizations to our app that it can use this (external) API?
To use the Azure REST API, just assign the RBAC roles like above, specify the correct AAD resource e.g. https://management.azure.com in this case.
Is the additional logic with HTTP calls within Azure Data Factory pipeline needed to update the tokens or can these apps / service principals handle this?
No need to do other steps, when you use the configuration above, essentially it will use the client credential flow to get the token in the background for you automatically, then use the token to call the API.
All of the examples on the microsoft azure site having to do with a client application or a service principal having access to azure apis all show the graph apis as the example.
I got those to work, but what I need to do is access the azure service management apis.
If I take an auth token that works for the graph api and use it for the service management api, I get an "Authentication failed." error.
I have added the api permission for "azure service management" and the user_impersonation delegated permission type to my public client app, but the management apis still fail.
Am I going about this all wrong?
I get the idea that the service management apis are authenticated a different way since there's absolutely no mention of using them anywhere in any of the auth examples.
I suppose you are using the client application or a service principal to access azure resources. If so, you are using the client credential flow, but the user_impersonation of Azure Service Management API is a delegated permission, it will not take effect in this flow.
The permission is used to be consent by the user who login to the AD App e.g. in the auth code flow, when it has been consent by the user, the App will be able to represent the user to access the azure resources, note the permission is from the user, not the app. So if you want to use this flow, the user should have a role in the subscription or specific resources.
To access the azure resources with the client application or a service principal, you just need to add the service principal as an RBAC role in the Access control (IAM) of your subscription or specific resource, no need to add any API permission in Azure AD, see this link. Then the service principal will be able to access the azure resources.
When you getting the token to access the azure resources, e.g. call the REST APIs, the scope should be https://management.azure.com/.default, not the https://graph.microsoft.com/.default, you can just get the token for one resource in one time.
I've been using the Azure fluent management APIs (https://github.com/Azure/azure-libraries-for-net) with some success in .NET Core.
However, I want to prompt the user to enter some credentials for a Microsoft account. Those credentials would have access to one or more Azure tenants / subscriptions, so I'd like to be able to use the result to browse and manage resources there.
This is something very close to what I would believe Azure Data Studio does: you can enter some Azure creds, and your resources will appear in the app.
I'm trying to understand the best approach for this. There seem to be a billion sites out there when you talk about Azure AD app registrations, but I haven't found a fruitful specific search query yet. I know I can register an app, get a client ID and client secret. I know I can set it to be usable by organisational accounts in the current tenant, or all tenants.
I can add the "Azure Service Management (delegated permissions : user_impersonation)" permission to my API permissions section for the app, but what's next?
If I use Microsoft.Identity.Client (as in https://learn.microsoft.com/en-us/azure/active-directory/develop/quickstart-v2-netcore-daemon), I run into some questions:
AcquireTokenForClientAsync doesn't prompt the user - I guess because it's getting a token for the app to act with its own permissions?
AcquireTokenOnBehalfOfAsync wants a JWT.. great! I'll pass the one I got from AcquireTokenForClientAsync! Nope, AADSTS70002: Error validating credentials. AADSTS500137: The token issuer doesn't match the api version: A version 1 token cannot be used with the v2 endpoint.
I don't know what scope I want. https://management.azure.com/user_impersonation is apparently invalid.. https://management.azure.com/.default works, but is that right? It's a guess, combo of the former and a .default suffix I found for Graph API scopes online. Any docs on this?
I ultimately get a JWT and tenant ID back. I can't find a way to use a JWT with the Fluent management APIs.. and my account (for instance) is associated with 3 tenants or 5 different tenants / directories - so how do I choose?
That's just what I've tried, the appropriate route might be a different one. In summary: I want a .NET Core Console app to request user credentials, and then get access to the Azure resources they have access to, in order to perform some resource management.
AcquireTokenForClientAsync doesn't prompt the user - I guess because it's getting a token for the app to act with its own permissions?
You are using the OAuth 2.0 client credentials grant to access web-hosted resources by using the identity of an application. This type of grant commonly is used for server-to-server interactions that must run in the background, without immediate interaction with a user .
AADSTS70002: Error validating credentials. AADSTS500137: The token issuer doesn't match the api version: A version 1 token cannot be used with the v2 endpoint.
Azure AD provide two service : Azure AD V1.0 and Azure AD V2.0 . Please refer to Comparing the Azure AD v2.0 endpoint with the v1.0 endpoint . You can't use v1 token to acquire v2's token in a on-behalf-of flow .
AcquireTokenOnBehalfOfAsync wants a JWT.. great! I'll pass the one I got from AcquireTokenForClientAsync
AS pointed above , That function is used to acquire an access token for this application (usually a Web API) from the authority configured in the application, in order to access another downstream protected Web API on behalf of a user using the OAuth 2.0 On-Behalf-Of flow. So you can't use app token which acquire using Client Credential flow .
https://management.azure.com/.default works, but is that right? It's a guess, combo of the former and a .default suffix I found for Graph API scopes online. Any docs on this?
You are using the Azure Active Directory v2.0 and the OAuth 2.0 client credentials flow , when sending a POST request to the /token v2.0 endpoint ,the scope should be :
The value passed for the scope parameter in this request should be the resource identifier (Application ID URI) of the resource you want, affixed with the .default suffix. For the Microsoft Graph example, the value is https://graph.microsoft.com/.default. This value informs the v2.0 endpoint that of all the direct application permissions you have configured for your app, it should issue a token for the ones associated with the resource you want to use.
Please check the Get a tokensection in above document .
I ultimately get a JWT and tenant ID back. I can't find a way to use a JWT with the Fluent management APIs..
AFAIK , currently Azure AD V2.0 apps can use:
Its own API
Microsoft Outlook APIs
Microsoft Graph API
Azure AD V2.0 currently doesn't support Azure management APIs .
So you problem is you need to allows work and school accounts from Azure AD and personal Microsoft accounts (MSA) which works with Azure AD V2.0 , but you can't use Azure management APIs . You can use Azure management APIs in Azure AD V1.0 but it allows only work and school accounts to sign in to your application , unless you invite Microsoft accounts as guest user in Azure AD V1.0 ,but you need to configure to point to the tenant-specific endpoint :https://login.microsoftonline.com/{TenantId_or_Name}). during authentication if you want to login with MSA in v1.0 apps.
Update:
You can use Code flow and azure ad v1.0 endpoint , user will be redirect to AAD's login page and enter their credential. Here is code sample for .net Core .
With Azure AD V1.0 endpoint , requests are sent to an endpoint that multiplexes across all Azure AD tenants: https://login.microsoftonline.com/common . When Azure AD receives a request on the /common endpoint, it signs the user in and, as a consequence, discovers which tenant the user is from. See document here . But in this scenerio ,you can only use work and school accounts(AAD) account to login .
The code sample in your link is using Azure Service Principal for Authentication , no interactive user login . You can use OpenID Connect Owin Middleware for authentication in .net Core applications as shown here .
I have a web application running on Azure App Services. The front-end (javascript + html + css) communicates with the backend (Flask). Both are runing on the same app service instance.
My app is protected by Active Directory Authentication (configured using Azure Portal).
User authentication to the app works perfectly. When a user navigates to the app, they are redirected to the login for our azure AD tenant. When they try to sign in, their permission to the app is controlled by their membership to an azure AD group. This bit works as expected
The challenge is that the front-end needs to send authenticated requests in order for them to actually reach the backend. They must be authenticated using a service principal token, not the user's token. And to this end, we are using the new, recommended approach; Managed Service Identity (MSI), not the service principal account workflow directly.
There are 2 stages to this:
1) Adding the authorization header
2) Ensuring that the MSI principal has access (i.e. belongs to the AD group)
1) The server generates an access token using the below code:
credentials = azure_active_directory.MSIAuthentication()
session = credentials.signed_session()
return session.headers.get("Authorization")
We then add the {"Authorization": "Bearer "} header where is the result of the above code.
This appears to work as expected - we are seeing long alphanumeric access tokens
2) The tricky bit was ensuring the MSI was added to the AD group. The GUIs at myapps.microsoft.com and mygroups.microsoft.com only allow the adding of users. Instead, I used the Azure CLI and ran the following:
a) Retrieve MSI principal ID
msiobjectid=$(az webapp identity show --resource-group <resource-group-name> --name <azure app services name> --query principalId)
b) Add principal to group
az ad group member add --group <group name> --member-id $msiobjectid
We are still getting 401 Unauthorized and we have exhausted all documentation :(
I should note that I only completed step 2 (adding the principal to the azure AD group via Azure CLI) about an hour ago. Perhaps there is a delay?
Edit: my scenario is closest to https://github.com/uglide/azure-content/blob/master/articles/app-service-api/app-service-api-dotnet-service-principal-auth.md except a) I'm using MSI, not a direct service principal and b) I have an extra layer of authorization, which is the ad groups, restricting access to the app to a few users rather than the whole tenant.
I believe you got this all backwards.
Your scenario is SPA + backend.
What you need to implement is OAuth 2.0 implicit grant flow as described here.
Source for diagram: dzimchuk.net
With the resulting access_token placed in the user-agent's session storage you can then call your backend. Use adal.js to make your life easier.
Since your Python backend IS a confidential client, you can now request an access token from the MSI endpoint for the desired audience (Azure resource), call it then filter the results so that it matches your access rights logic.
Note that at the time of writing only a subset of Azure resources are able to consume MSI-issued access tokens.
Is it possible to gain access to the Azure Management APIs through the client ID and secret for a web app?
I have a web app through which i want to be able to manage Azure. I want to do this using the credentials of the application itself so that the current user does not have to be an azure administrator.
I have given the web app the necessary role on my subscriptions and obtained the access token through the client credentials grant flow in AD but i still get an unauthorized.
This is probably because the azure management API has no permission set other than delegated - the access works fine if i use the authorization code grant flow for the logged in user, but thats not what i want.
So to reiterate, if, given a web app that has RBAC to a subscription and is able to obtain an access token from AD, is there any way, without an interactive user, that the web app is able to use the management API??
Yes, you can obtain a token from AAD for a service principal and use that to manage resources as long as that service principal has all the access you need.
Make sure the token you get has a resource/audience of "https://management.azure.com" and is for the tenantId that the subscription is associated with.
You can also see this article from Brady Gaster that explains how to use Azure AD applications to manage Azure Services from an external app : http://www.bradygaster.com/post/using-windows-azure-active-directory-to-authenticate-the-management-libraries
EDIT : Azure AD supports Service to Service calls using OAuth 2.0 client credentials: https://msdn.microsoft.com/en-us/library/azure/dn645543.aspx
Hope this helps,
Julien