powershell - 带有私钥的 Azure Key Vault 下载证书

Question

我正在尝试下载我在多个 KeyVault 上拥有的证书，包括它们的私钥。通过 Azure 门户，我可以毫无问题地前往KeyVault，选择证书并单击“以 PFX/PEM 格式下载”

由于我必须在几个 keyvaults 上重复相同的操作，所以我正在寻找一种自动化的方式来完成它。到目前为止，我得出以下结论：

$objCertificate = (Get-AzKeyVaultCertificate -VaultName <Key Vault> -Name <Certificate Name>).Certificate
$bytCertificate = $objCertificate.Export('pfx',<Password>)
$strCertificate = [System.Convert]::ToBase64String($bytCertificate)
$strPath = Join-Path $env:TEMP "$($objCertificate.Subject).pfx"
$bytCertificate | Set-Content -Path $strPath -Force -Encoding Byte

问题是它仅使用公钥下载证书，并且我还需要包含在其中的私钥，就像我通过门户下载它时一样。你知道我可能会错过什么吗？

标签： powershellcertificateazure-keyvault

Answer 1

要获取私钥，您需要将其作为秘密（是的，这很奇怪），我在 PowerShell 中没有答案，但我希望我下面的 C# 代码可以为您提供一些有关如何操作的提示。

        /// <summary>
        /// Load a certificate (with private key) from Azure Key Vault
        ///
        /// Getting a certificate with private key is a bit of a pain, but the code below solves it.
        /// 
        /// Get the private key for Key Vault certificate
        /// https://github.com/heaths/azsdk-sample-getcert
        /// 
        /// See also these GitHub issues: 
        /// https://github.com/Azure/azure-sdk-for-net/issues/12742
        /// https://github.com/Azure/azure-sdk-for-net/issues/12083
        /// </summary>
        /// <param name="config"></param>
        /// <param name="certificateName"></param>
        /// <returns></returns>
        public static X509Certificate2 LoadCertificate(IConfiguration config, string certificateName)
        {
            string vaultUrl = config["Vault:Url"] ?? "";
            string clientId = config["Vault:ClientId"] ?? "";
            string tenantId = config["Vault:TenantId"] ?? "";
            string secret = config["Vault:Secret"] ?? "";

            Console.WriteLine($"Loading certificate '{certificateName}' from Azure Key Vault");

            var credentials = new ClientSecretCredential(tenantId: tenantId, clientId: clientId, clientSecret: secret);
            var certClient = new CertificateClient(new Uri(vaultUrl), credentials);
            var secretClient = new SecretClient(new Uri(vaultUrl), credentials);

            var cert = GetCertificateAsync(certClient, secretClient, certificateName);

            Console.WriteLine("Certificate loaded");
            return cert;
        }


        /// <summary>
        /// Helper method to get a certificate
        /// 
        /// Source https://github.com/heaths/azsdk-sample-getcert/blob/master/Program.cs
        /// </summary>
        /// <param name="certificateClient"></param>
        /// <param name="secretClient"></param>
        /// <param name="certificateName"></param>
        /// <returns></returns>
        private static X509Certificate2 GetCertificateAsync(CertificateClient certificateClient,
                                                                SecretClient secretClient,
                                                                string certificateName)
        {

            KeyVaultCertificateWithPolicy certificate = certificateClient.GetCertificate(certificateName);

            // Return a certificate with only the public key if the private key is not exportable.
            if (certificate.Policy?.Exportable != true)
            {
                return new X509Certificate2(certificate.Cer);
            }

            // Parse the secret ID and version to retrieve the private key.
            string[] segments = certificate.SecretId.AbsolutePath.Split('/', StringSplitOptions.RemoveEmptyEntries);
            if (segments.Length != 3)
            {
                throw new InvalidOperationException($"Number of segments is incorrect: {segments.Length}, URI: {certificate.SecretId}");
            }

            string secretName = segments[1];
            string secretVersion = segments[2];

            KeyVaultSecret secret = secretClient.GetSecret(secretName, secretVersion);

            // For PEM, you'll need to extract the base64-encoded message body.
            // .NET 5.0 preview introduces the System.Security.Cryptography.PemEncoding class to make this easier.
            if ("application/x-pkcs12".Equals(secret.Properties.ContentType, StringComparison.InvariantCultureIgnoreCase))
            {
                byte[] pfx = Convert.FromBase64String(secret.Value);
                return new X509Certificate2(pfx);
            }

            throw new NotSupportedException($"Only PKCS#12 is supported. Found Content-Type: {secret.Properties.ContentType}");
        }
    }
}