Gerar tokens de prova de posse para chaves sem interrupção e atualizar certificados programaticamente

Você pode usar os métodos addKey e removeKey definidos no aplicativo e recursos servicePrincipal para acumular as chaves expiradas por programação.

Como parte da validação do pedido para estes métodos, é verificada uma prova de posse (PoP) de uma chave existente antes de os métodos poderem ser invocados. A prova é representada por um JSON Web Token (JWT) autoassinado. Este token tem de ser assinado com a chave privada de um dos certificados válidos existentes da aplicação. O tempo de vida recomendado para o token é de 10 minutos.

Este artigo fornece exemplos de código em C# para demonstrar como:

1. Calcule a asserção do cliente com um certificado válido existente.
2. Gere o token PoP com a chave de asserção de cliente gerada.
3. Utilize o token PoP para carregar um novo certificado para o objeto de principal de serviço ou aplicação com o método addKey .
4. Utilize o token PoP para remover um certificado do objeto de principal de serviço ou aplicação com o método removeKey .

Importante

As aplicações que não têm certificados válidos existentes porque os certificados ainda não foram adicionados ou os certificados existentes expiraram não podem utilizar esta ação de serviço. Em vez disso, utilize a operação Atualizar aplicação para atualizar a propriedade keyCredential .

Pré-requisitos

• Ter um certificado de cliente válido na aplicação de destino ou principal de serviço.
  • Precisa dos detalhes de um vertificado existente válido para gerar a chave de asserção de cliente e o token PoP.
    • Para fins de teste, pode utilizar um certificado autoassinado. Para saber como criar um certificado autoassinado, veja Criar um certificado público autoassinado para autenticar a sua aplicação.
    • Exporte o certificado com a respetiva chave privada no .pfx formato. Em alternativa, pode atualizar o script para exigir apenas o certificado público sem a chave privada.
• O ID de cliente (denominado appId na API) e o ID de objeto (denominado ID na API) da aplicação ou do principal de serviço para o qual está a gerar o token PoP.

Código de exemplo

O token deve conter os seguintes argumentos:

• aud: o público tem de ser 00000002-0000-0000-c000-000000000000.
• iss: O emissor deve ser o ID da aplicação ou do objeto servicePrincipal que inicia o pedido.
• nbf: Não antes do tempo.
• exp: O tempo de expiração deve ser o valor de nbf + 10 minutos.

Program.cs

using System;
using System.Security.Cryptography.X509Certificates;
using System.Net;
using System.Net.Http;
using Microsoft.IdentityModel.Tokens;

namespace SampleCertCall
{
    class Program
    {
        static void Main(string[] args)
        {
            //=============================
            // Global variables which will be used to store app registation info, you can use appsettings.json to store such data
            //=============================
            string clientId = "Enter_the_Application_Id_Here"; //client ID or appId of the target app or service principal
            string tenantID = "Enter_the_Tenant_Id_Here"; // Tenant ID value
            string scopes = "https://graph.microsoft.com/.default"; // The "https://graph.microsoft.com/.default" is required in the client credentials flow, see the consent documentation (https://learn.microsoft.com/en-us/entra/identity-platform/scopes-oidc#the-default-scope)
            string objectId = "Enter_the_Object_Id_Here"; // The object ID is the identifier of the app or service principal you want to work with. Depending on the endpoint you use, it can be either the application objectId (https://graph.microsoft.com/v1.0/applications)) or the service principal objectId (https://graph.microsoft.com/v1.0/ServicePrincipals)).
            string api = "Graph_API/ENDPOINT"; // Choose the graph endpoint you need to use, depending on whether you are working with (https://graph.microsoft.com/v1.0/applications) or (https://graph.microsoft.com/v1.0/servicePrincipals)
            string aud_POP = "00000002-0000-0000-c000-000000000000"; // audience for client assertion must always be 00000002-0000-0000-c000-000000000000
            string aud_ClientAssertion = "https://login.microsoftonline.com/{YOUR_TENANT_ID_HERE}/v2.0"; // audience for PoP must always be in the format https://login.microsoftonline.com/{YOUR_TENANT_ID_HERE}/v2.0

            // pfxFilePath -> Use an existing valid cert used/uploaded to the app or service principal to generate access token and PoP token.
            string pfxFilePath = "Current_Active_Certificate_Path"; // Replace the file path with the location of your certificate.
            string password = "Current_Active_Certificate_Password"; // If applicable, replace the password value with your certificate password.
            X509Certificate2 signingCert = null;
            try
            {
                if (!password.IsNullOrEmpty())
                    signingCert = new X509Certificate2(pfxFilePath, password);
                else
                    signingCert = new X509Certificate2(pfxFilePath);
            }
            catch (System.Security.Cryptography.CryptographicException ex)
            {
                Console.WriteLine("Check the old/uploaded certificate {CertificateDiskPath}, you need to add a correct certificate path and/or password for this sample to work\n" + ex.Message);
                Environment.Exit(-1);
            }

            // newCerFilePath -> This is the new cert which will be uploaded. The cert can also be stored in Azure Key Vault.
            string newCerFilePath = "New_Certificate_Path"; // Replace the file path with the location of your new certificate to be uploaded using the Graph API.
            string newCertPassword = "New_Certificate_Password"; // If applicable, replace the password value with your new certificate password.
            X509Certificate2 newCert = null;
            try
            {
                if (newCertPassword != "")
                    newCert = new X509Certificate2(newCerFilePath, newCertPassword);
                else
                    newCert = new X509Certificate2(newCerFilePath);
            }
            catch (System.Security.Cryptography.CryptographicException ex)
            {
                Console.WriteLine("Check the new certificate {NewCertificateDiskPath}, you need to add a correct certificate path and/or password for this sample to work\n" + ex.Message);
                Environment.Exit(-1);
            }

             //========================
             //Get acessToken via client assertion
             //========================
             var client_assertion = Helper.GenerateClientAssertion(aud_ClientAssertion, clientId, signingCert);
             var token = Helper.GenerateAccessTokenWithClientAssertion(client_assertion, clientId, tenantID);

            //========================
            //Get PoP Token
            //========================
            var poP = Helper.GeneratePoPToken(objectId, aud_POP, signingCert);

            // Get the new certificate info which will be uploaded via Microsoft Graph API call
            var key = Helper.GetCertificateKey(newCert);
            var graphClient = Helper.GetGraphClient(scopes, tenantID, clientId, signingCert);

            int choice = -1;
            while (choice != 0)
            {
                Console.WriteLine("\n=================================================");
                Console.WriteLine("Please choose one of the following options:");
                Console.WriteLine("=================================================");
                Console.WriteLine("0. Exit");
                Console.WriteLine("1. Display access token");
                Console.WriteLine("2. Display client assertion");
                Console.WriteLine("3. Display PoP token");
                Console.WriteLine("4. Display certificate Info");
                Console.WriteLine("5. Upload certificate using Graph SDK");
                Console.WriteLine("6. Upload certificate using Graph API");
                Console.WriteLine("7. Delete certificate using Graph SDK");
                Console.WriteLine("8. Delete certificate using Graph API");
                Console.WriteLine("\nEnter the choose number here:");
                choice = Int32.TryParse(Console.ReadLine(), out choice) ? choice : -1;

                HttpStatusCode code;
                KeyCredential response;
                string certID;
                Guid val;

                // Process user choice
                switch (choice)
                {
                    case 0:
                        // Exit the program
                        Console.WriteLine("\nGoodbye...\n");
                        break;
                    case 1:
                        // Display access token
                        Console.WriteLine("\n\"Access Token Value is:\"\n__________________");
                        Console.WriteLine($"Access Token: {token}");
                        Console.WriteLine("__________________\n");
                        break;
                    case 2:
                        // Display client assertion
                        Console.WriteLine("\n\"Client Assertion Token Value is\"\n__________________");
                        Console.WriteLine($"client_assertion: {client_assertion}");
                        Console.WriteLine("__________________\n");
                        break;
                    case 3:
                        // Display client assertion
                        Console.WriteLine("\n\"Proof of Possession Token Value is\"\n__________________");
                        Console.WriteLine($"PoP token: {poP}");
                        Console.WriteLine("__________________\n");
                        break;
                    case 4:
                        // Display certificate key
                        Helper.DisplayCertificateInfo(newCert);
                        break;
                    case 5:
                        // Call the addKey SDK using Graph SDK
                        if (newCertPassword != "")
                        {
                            response = GraphSDK.AddKeyWithPassword_GraphSDKAsync(poP, objectId, key, newCertPassword, graphClient).GetAwaiter().GetResult();
                        }
                        else
                        {
                            response = GraphSDK.AddKey_GraphSDKAsync(poP, objectId, key, graphClient).GetAwaiter().GetResult();
                        }
                        if (response != null)
                        {
                            Console.WriteLine("\n______________________");
                            Console.WriteLine("Uploaded Successfully!");
                            Console.WriteLine("______________________\n");
                        }
                        else
                        {
                            Console.WriteLine("\n______________________");
                            Console.WriteLine("Something went wrong!");
                            Console.WriteLine("______________________\n");
                        }

                        break;
                    case 6:
                        // Call the addKey API directly without using SDK
                        if (!password.IsNullOrEmpty())
                        {
                            code = GraphAPI.AddKeyWithPassword(poP, objectId, api, token, key, newCertPassword);
                        }
                        else
                        {
                            code = GraphAPI.AddKey(poP, objectId, api, token, key);
                        }
                        if (code == HttpStatusCode.OK)
                        {
                            Console.WriteLine("\n______________________");
                            Console.WriteLine("Uploaded Successfully!");
                            Console.WriteLine("______________________\n");
                        }
                        else
                        {
                            Console.WriteLine("\n______________________");
                            Console.WriteLine("Something went wrong!");
                            Console.WriteLine("HTTP Status code is " + code);
                            Console.WriteLine("______________________\n");
                        }
                        break;
                    case 7:
                        // Call the removeKey API using Graph SDK
                        Console.WriteLine("\nEnter certificate ID that you want to delete:");
                        certID = Console.ReadLine();

                        if (Guid.TryParse(certID, out val))
                        {
                            var res = GraphSDK.RemoveKey_GraphSDKAsync(poP, objectId, certID, graphClient).GetAwaiter().GetResult();

                            if (res)
                            {
                                Console.WriteLine("\n______________________");
                                Console.WriteLine("Cert Deleted Successfully!");
                                Console.WriteLine("_____________________\n");
                            }
                            else
                            {
                                Console.WriteLine("\n______________________");
                                Console.WriteLine("Something Went Wrong!");
                                Console.WriteLine("ERROR: Unable to delete certificate");
                                Console.WriteLine("______________________\n");
                            }
                        }
                        else
                        {
                            Console.WriteLine("\n______________________");
                            Console.WriteLine("ERROR: Invalid Certificate ID");
                            Console.WriteLine("______________________\n");
                        }
                        break;
                    case 8:
                        // Call the removeKey API directly without using API
                        Console.WriteLine("\nEnter certificate ID that you want to delete:");
                        certID = Console.ReadLine();
                        try
                        {
                            if (Guid.TryParse(certID, out val))
                            {
                                code = GraphAPI.RemoveKey(poP, objectId, api, certID, token);

                                if (code == HttpStatusCode.NoContent)
                                {
                                    Console.WriteLine("\n______________________");
                                    Console.WriteLine("Cert Deleted Successfully!");
                                    Console.WriteLine("______________________\n");
                                }
                                else
                                {
                                    Console.WriteLine("\n______________________");
                                    Console.WriteLine("Something went wrong!");
                                    Console.WriteLine("HTTP Status code is " + code);
                                    Console.WriteLine("______________________\n");
                                }
                            }
                            else
                            {
                                Console.WriteLine("\n------------------------------");
                                Console.WriteLine("ERROR: Invalid Certificate ID");
                                Console.WriteLine("______________________________\n");
                            }
                        }

                        catch (HttpRequestException ex)
                        {
                            Console.WriteLine(ex.InnerException.Message);
                            Console.WriteLine("\n______________________");
                            Console.WriteLine("ERROR: " + ex.Message);
                            Console.WriteLine("______________________\n");
                        }
                        break;
                    default:
                        Console.WriteLine("\n______________________");
                        Console.WriteLine("Invalid choice");
                        Console.WriteLine("______________________\n");
                        break;
                }

            }
        }
    }
}

Helper.cs

using Azure.Identity;
using Microsoft.Graph;
using Microsoft.IdentityModel.JsonWebTokens;
using Microsoft.IdentityModel.Tokens;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Security.Cryptography.X509Certificates;

namespace SampleCertCall
{
    class Helper
    {
        public static string GenerateClientAssertion(string aud, string clientId, X509Certificate2 signingCert)
        {
            Guid guid = Guid.NewGuid();

            // aud and iss are the only required claims.
            var claims = new Dictionary<string, object>()
            {
                { "aud", aud },
                { "iss", clientId },
                { "sub", clientId },
                { "jti", guid}
            };

            // token validity should not be more than 10 minutes
            var now = DateTime.UtcNow;
            var securityTokenDescriptor = new SecurityTokenDescriptor
            {
                Claims = claims,
                NotBefore = now,
                Expires = now.AddMinutes(10),
                SigningCredentials = new X509SigningCredentials(signingCert)
            };

            var handler = new JsonWebTokenHandler();
            // Get Client Assertion
            var client_assertion = handler.CreateToken(securityTokenDescriptor);

            return client_assertion;
        }

        public static string GenerateAccessTokenWithClientAssertion(string client_assertion, string clientId, string tenantID)
        {
            // GET ACCESS TOKEN
            var data = new[]
            {
                new KeyValuePair<string, string>("client_id", clientId),
                new KeyValuePair<string, string>("client_assertion_type", "urn:ietf:params:oauth:client-assertion-type:jwt-bearer"),
                new KeyValuePair<string, string>("client_assertion", client_assertion),
                new KeyValuePair<string, string>("grant_type", "client_credentials"),
                new KeyValuePair<string, string>("scope", "https://graph.microsoft.com/.default"),
            };

            var client = new HttpClient();
            var url = $"https://login.microsoftonline.com/{tenantID}/oauth2/v2.0/token";
            var res = client.PostAsync(url, new FormUrlEncodedContent(data)).GetAwaiter().GetResult();
            var token = "";
            using (HttpResponseMessage response = res)
            {
                response.EnsureSuccessStatusCode();
                string responseBody = response.Content.ReadAsStringAsync().GetAwaiter().GetResult();
                JObject obj = JObject.Parse(responseBody);
                token = (string)obj["access_token"];
            }

            return token;
        }

        public static string GeneratePoPToken(string objectId, string aud, X509Certificate2 signingCert)
        {
            Guid guid = Guid.NewGuid();

            // aud and iss are the only required claims.
            var claims = new Dictionary<string, object>()
            {
                { "aud", aud },
                { "iss", objectId }
            };

            // token validity should not be more than 10 minutes
            var now = DateTime.UtcNow;
            var securityTokenDescriptor = new SecurityTokenDescriptor
            {
                Claims = claims,
                NotBefore = now,
                Expires = now.AddMinutes(10),
                SigningCredentials = new X509SigningCredentials(signingCert)
            };

            var handler = new JsonWebTokenHandler();
            var poP = handler.CreateToken(securityTokenDescriptor);
            // Console.WriteLine("\n\"Generate Proof of Possession Token:\"\n--------------------------------------------");
            // Console.WriteLine($"PoP: {poP}");

            return poP;
        }

        public static string GetCertificateKey(X509Certificate2 cert)
        {
            return Convert.ToBase64String(cert.GetRawCertData());
        }

        public static void DisplayCertificateInfo(X509Certificate2 cert)
        {

            Console.WriteLine("\n[Certificate info which will be used in the request body {keyCredential resource type}]");
            Console.WriteLine("__________________________________________________________________________________________\n");
            Console.WriteLine($"customKeyIdentifier (Thumbprint):  {cert.Thumbprint}");
            Console.WriteLine("");
            Console.WriteLine($"key: {Convert.ToBase64String(cert.GetRawCertData())}");
            Console.WriteLine("");
            Console.WriteLine($"displayName: {cert.Subject}");
            Console.WriteLine("");
            Console.WriteLine($"startDateTime: {Convert.ToDateTime(cert.GetEffectiveDateString()).ToString("yyyy-MM-ddTHH:mm:ssZ")}");
            Console.WriteLine("");
            Console.WriteLine($"endDateTime: {Convert.ToDateTime(cert.GetExpirationDateString()).ToString("yyyy-MM-ddTHH:mm:ssZ")}");
            Console.WriteLine("__________________________________________________________________________________________\n");
        }

        public static GraphServiceClient GetGraphClient(string scopes, string tenantId, string clientId, X509Certificate2 signingCert)
        {
            // using Azure.Identity;
            var options = new ClientCertificateCredentialOptions
            {
                AuthorityHost = AzureAuthorityHosts.AzurePublicCloud
            };

            // https://docs.microsoft.com/dotnet/api/azure.identity.clientcertificatecredential
            var clientCertificateCredential = new ClientCertificateCredential(
                tenantId, clientId, signingCert, options);

            var graphClient = new GraphServiceClient(clientCertificateCredential, [scopes]);

            return graphClient;
        }

    }
}

GraphAPI.cs

using Newtonsoft.Json;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;


namespace SampleCertCall
{
    class GraphAPI
    {
        public static HttpStatusCode AddKeyWithPassword(string poP, string objectId, string api, string accessToken, string key, string password)
        {
            var client = new HttpClient();
            var url = $"{api}/{objectId}/addKey";

            var defaultRequestHeaders = client.DefaultRequestHeaders;
            if (defaultRequestHeaders.Accept == null || !defaultRequestHeaders.Accept.Any(m => m.MediaType == "application/json"))
            {
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            }
            defaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

            var payload = new
            {
                keyCredential = new
                {
                    type = "X509CertAndPassword",
                    usage = "Sign",
                    key,
                },
                passwordCredential = new
                {
                    secretText = password,
                },
                proof = poP
            };
            var stringPayload = JsonConvert.SerializeObject(payload);
            var httpContent = new StringContent(stringPayload, Encoding.UTF8, "application/json");

            var res = client.PostAsync(url, httpContent).Result;

            return res.StatusCode;
        }

        public static HttpStatusCode AddKey(string poP, string objectId, string api, string accessToken, string key)
        {
            var client = new HttpClient();
            var url = $"{api}/{objectId}/addKey";

            var defaultRequestHeaders = client.DefaultRequestHeaders;
            if (defaultRequestHeaders.Accept == null || !defaultRequestHeaders.Accept.Any(m => m.MediaType == "application/json"))
            {
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            }
            defaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

            string pass = null;
            var payload = new
            {
                keyCredential = new
                {
                    type = "AsymmetricX509Cert",
                    usage = "Verify",
                    key,
                },
                passwordCredential = pass,
                proof = poP
            };
            var stringPayload = JsonConvert.SerializeObject(payload);
            var httpContent = new StringContent(stringPayload, Encoding.UTF8, "application/json");

            var res = client.PostAsync(url, httpContent).Result;

            return res.StatusCode;
        }

        public static HttpStatusCode RemoveKey(string poP, string objectId, string api, string keyId, string accessToken)
        {
            var client = new HttpClient();
            var url = $"{api}/{objectId}/removeKey";
            var defaultRequestHeaders = client.DefaultRequestHeaders;
            if (defaultRequestHeaders.Accept == null || !defaultRequestHeaders.Accept.Any(m => m.MediaType == "application/json"))
            {
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            }
            defaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);

            var payload = new
            {
                keyId,
                proof = poP
            };
            var stringPayload = JsonConvert.SerializeObject(payload);
            var httpContent = new StringContent(stringPayload, Encoding.UTF8, "application/json");


            var res = client.PostAsync(url, httpContent).Result;
            var contents = res.Content.ReadAsStringAsync().Result;

            if (res.Content.ReadAsStringAsync().Result.Contains("No credentials found to be removed"))
            {
                throw new HttpRequestException("CertID Not Found", new HttpRequestException(contents, null, res.StatusCode));
            }

            if (res.Content.ReadAsStringAsync().Result.Contains("Access Token missing or malformed"))
            {
                throw new HttpRequestException("proof-of-possession (PoP) token is invalid", new HttpRequestException(contents, null, res.StatusCode));
            }

            return res.StatusCode;
        }
    }
}

GraphSDK.cs

using Microsoft.Graph;
// using Microsoft.Graph.ServicePrincipals.Item.AddKey; // Dependencies for the AddKey service principal method
// using Microsoft.Graph.ServicePrincipals.Item.RemoveKey; // Dependencies for the RemoveKey service principal method
using Microsoft.Graph.Applications.Item.AddKey;
using Microsoft.Graph.Applications.Item.RemoveKey;
using Microsoft.Graph.Models;
using System;
using System.Threading.Tasks;


namespace SampleCertCall
{
    class GraphSDK
    {
        // Using GraphSDK instead of calling the API directly
        public static async Task<KeyCredential> AddKey_GraphSDKAsync(string proof, string objectId, string key, GraphServiceClient graphClient)
        {
            var requestBody = new AddKeyPostRequestBody
            {
                KeyCredential = new KeyCredential
                {
                    Type = "AsymmetricX509Cert",
                    Usage = "Verify",
                    Key = Convert.FromBase64String(key)
                },
                PasswordCredential = null,
                Proof = proof
            };

            // var res = await graphClient.ServicePrincipals[objectId].AddKey.PostAsync(requestBody); // Uncomment this to upload a certificate to a service principal and the using statement at the top
            var res = await graphClient.Applications[objectId].AddKey.PostAsync(requestBody);

            return res;
        }

        public static async Task<KeyCredential> AddKeyWithPassword_GraphSDKAsync(string proof, string objectId, string key, string password, GraphServiceClient graphClient)
        {
            var requestBody = new AddKeyPostRequestBody
            {
                KeyCredential = new KeyCredential
                {
                    Type = "X509CertAndPassword",
                    Usage = "Sign",
                    Key = Convert.FromBase64String(key)
                },
                PasswordCredential = new PasswordCredential
                {
                    SecretText = password
                },
                Proof = proof
            };

            // var res = await graphClient.ServicePrincipals[objectId] // Uncomment this to upload a certificate to a service principal and the using statement at the top
            var res = await graphClient.Applications[objectId] // Upload a certificate to the application
                        .AddKey
                        .PostAsync(requestBody);

            return res;
        }

        public static async Task<bool> RemoveKey_GraphSDKAsync(string proof, string objectId, string certID, GraphServiceClient graphClient)
        {
            var keyId = Guid.Parse(certID);

            try
            {
                var requestBody = new RemoveKeyPostRequestBody
                {
                    KeyId = keyId,
                    Proof = proof
                };

                // await graphClient.ServicePrincipals[objectId] // Uncomment this to remove a certificate from a service principal and the using statement at the top
                await graphClient.Applications[objectId] // Remove a certificate from the application
                    .RemoveKey
                    .PostAsync(requestBody);

                return true;
            }
            catch (Exception ex)
            {
                Console.Write($"Exception RemoveKey_GraphSDKAsync: {Environment.NewLine}{ex.Message}{Environment.NewLine}{ex.StackTrace}");

                return false;
            }
        }
    }
}

Também pode gerar a prova com a assinatura no Azure KeyVault. É importante ter em atenção que o caráter de preenchimento '=' não pode ser incluído no cabeçalho E payload JWT ou é devolvido um erro de Authentication_MissingOrMalformed .

Conteúdo relacionado

Agora que tem o token PoP, pode utilizá-lo para:

• Adicione uma chave ou remova uma chave da sua aplicação.
• Adicione uma chave ou remova uma chave do principal de serviço.

Para saber mais sobre as asserções de cliente, veja Credenciais de certificado de autenticação de aplicações da plataforma de identidades da Microsoft.