无法在Azure中使用系统分配托管标识使用Blob存储操作

Question

获取"服务器验证请求失败。请确保包括签名在内的授权标头的值正确形成。"使用C#语言在Azure中尝试使用系统分配托管标识时出错。

接下来是步骤

• 创建了一个启用标识（系统分配）的新VM
• 使用存储帐户中的角色分配在IAM中添加虚拟机
• 能够使用C#
• 但在阅读blob时遇到异常，下面是异常的详细信息

Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
   at Microsoft.Azure.Storage.Core.Executor.Executor.<ExecuteAsync>d__1`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Storage.Blob.CloudBlockBlob.<DownloadTextAsync>d__72.MoveNext()

课程

    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                var blob = new AzureCloudBlob();
                Console.WriteLine(blob.ReadBlob());
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
                Console.WriteLine(ex.StackTrace);
            }
        }
    }

AzureCloudBlob类，用于使用系统分配的托管Idenitity访问令牌连接和读取blob

    class AzureCloudBlob
    {
        public CloudBlockBlob CreateConnection()
        {
            var token = GetToken();
            var tokenCredentials = new TokenCredential(token);
            var storageCredentials = new StorageCredentials(tokenCredentials);
            var serviceUri = new Uri("https://mystorageacc.blob.core.windows.net/practice/blob.txt");

            return new CloudBlockBlob(serviceUri, storageCredentials);
        }

        public string ReadBlob()
        {
            var client = CreateConnection();
            var blobClient = client.DownloadTextAsync();
            var data = blobClient.Result;
            return data;
        }

        public string GetToken()
        {
            var request = (HttpWebRequest)WebRequest.Create("http://169.254.169.254/metadata/identity/oauth2/token?api-version=2018-02-01&resource=https://management.azure.com/");
            request.Headers["Metadata"] = "true";
            request.Method = "GET";

            try
            {
                var response = (HttpWebResponse)request.GetResponse();
                var streamResponse = new StreamReader(response.GetResponseStream());
                string stringResponse = streamResponse.ReadToEnd();
                var list = (Dictionary<string, string>)JsonConvert.DeserializeObject(stringResponse, typeof(Dictionary<string, string>));
                string accessToken = list["access_token"];
                Console.WriteLine(accessToken);
                return accessToken;
            }
            catch (Exception e)
            {
                string errorText = String.Format("{0} \n\n{1}", e.Message, e.InnerException != null ? e.InnerException.Message : "Acquire token failed");
                Console.WriteLine(errorText);
                return errorText;
            }
        }
    }

Answer 1

如果您想使用Azure AD auth访问Azure存储，我们应该使用resource=https://storage.azure.com/获取Azure广告访问令牌。但是你使用资源=https://management.azure.com/。请把它换掉。此外，请注意，您需要为MSI分配正确的角色。该角色应该是存储Blob数据读取器、存储Blob数据参与者或存储Blob数据所有者。

具体步骤如下

>

在Azure VM上启用系统分配的托管标识

$vm = Get-AzVM -ResourceGroupName myResourceGroup -Name myVM
Update-AzVM -ResourceGroupName myResourceGroup -VM $vm -AssignIdentity:$SystemAssigned

在存储帐户作用域上将角色分配给MSI

$sp =Get-AzADServicePrincipal -displayname "<your VM name>"
New-AzRoleAssignment -ObjectId $sp.id `
    -RoleDefinitionName "Storage Blob Data Reader" `
    -Scope  "/subscriptions/<subscription>/resourceGroups/sample-resource-group/providers/Microsoft.Storage/storageAccounts/<storage-account>"

密码

class Program
{
    static void Main(string[] args)
    {
        //get token
        string accessToken = GetMSIToken("https://storage.azure.com/");

        //create token credential
        TokenCredential tokenCredential = new TokenCredential(accessToken);

        //create storage credentials
        StorageCredentials storageCredentials = new StorageCredentials(tokenCredential);

        Uri blobAddress = new Uri("<URI to blob file>");

        //create block blob using storage credentials
        CloudBlockBlob blob = new CloudBlockBlob(blobAddress, storageCredentials);

        //retrieve blob contents
        Console.WriteLine(blob.DownloadText());
        Console.ReadLine();
    }

    static string GetMSIToken(string resourceID)
    {
        string accessToken = string.Empty;
        // Build request to acquire MSI token
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://169.254.169.254/metadata/identity/oauth2/token?api-version=2018-02-01&resource=" + resourceID);
        request.Headers["Metadata"] = "true";
        request.Method = "GET";

        try
        {
            // Call /token endpoint
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            // Pipe response Stream to a StreamReader, and extract access token
            StreamReader streamResponse = new StreamReader(response.GetResponseStream());
            string stringResponse = streamResponse.ReadToEnd();
            JavaScriptSerializer j = new JavaScriptSerializer();
            Dictionary<string, string> list = (Dictionary<string, string>)j.Deserialize(stringResponse, typeof(Dictionary<string, string>));
            accessToken = list["access_token"];
            return accessToken;
        }
        catch (Exception e)
        {
            string errorText = String.Format("{0} \n\n{1}", e.Message, e.InnerException != null ? e.InnerException.Message : "Acquire token failed");
            return accessToken;
        }
    }
}