Call Create File on Azure File Service REST Api

Question

I am trying to create a file in Azure File Service: https://docs.microsoft.com/en-us/rest/api/storageservices/create-file

I've seen and read multiple threads about this issue, but I can't figure out what might be the problem in my case... Most likely I am missing some small thing in the request which I cannot find.

The error I am getting: The MAC signature found in the HTTP request (...) is not the same as any computed signature.

The signature string I've used:

PUT
\n
\n
\n
\n
text/plain // Content-Type
\n
\n
\n
\n
\n
\n
x-ms-content-length:1000
x-ms-date:Tue, 20 Apr 2021 19:23:30 GMT
x-ms-type:file
x-ms-version:2015-02-21
/account/share/test

Authorization header:

SharedKey account:XXXXXXXXXX

I've used the HMACSHA256 for hashing the authorization header and signature string, it all works when I use other endpoint (List Shares: https://docs.microsoft.com/en-us/rest/api/storageservices/list-shares), but I can't make it work for the file. I've seen this topic AZURE File Service - Upload PDF through REST API and I believe I am using very similar request, but with no success...

I appreciate any help : )

Edit: I am not sure if I correctly set the content headers. For example, does the x-ms-content-length should be placed in the CanonicalizedHeaders string?

Edit2: With regard to what Ivan Yang wrote, I made the code to work, but only when my CanonicalizedHeaders are built like that:

        CanonicalizedHeaders := 'x-ms-content-length:1200'
                + LF + 'x-ms-date:' + UTCDateTimeText
                + LF + 'x-ms-file-attributes:Archive' + LF + 'x-ms-file-creation-time:Now' + LF + 'x-ms-file-last-write-time:Now' + LF + 'x-ms-file-permission:Inherit'
                + LF + 'x-ms-type:file' + LF + 'x-ms-version:2019-02-02';

If I have them in different order, then it crashes:

     CanonicalizedHeaders := 'x-ms-date:' + UTCDateTimeText + LF +
                                'x-ms-content-length:1200' + LF +
                                'x-ms-version:2019-02-02' + LF +
                                'x-ms-file-attributes:Archive' + LF +
                                'x-ms-file-creation-time:Now' + LF +
                                'x-ms-file-last-write-time:Now' + LF +
                                'x-ms-file-permission:Inherit' + LF +
                                'x-ms-type:file';

How come does this make a difference?

Answer 1

Your signature string is incorrect(you're missing some "\n"). I'm using the x-ms-version:2019-02-02 instead of the older one x-ms-version:2015-02-21, and the correct signature string should look like this one:

           "PUT\n"
            + "\n" // content encoding
            + "\n" // content language
            + "\n" // content length
            + "\n" // content md5
            + content_type  + "\n" // content type
            + "\n" // date
            + "\n" // if modified since
            + "\n" // if match
            + "\n" // if none match
            + "\n" // if unmodified since
            + "\n" // range
            + "x-ms-content-length:" + content_length
            + "\nx-ms-date:" + dt.ToString("R")
            + "\nx-ms-file-attributes:Archive" + "\nx-ms-file-creation-time:Now" + "\nx-ms-file-last-write-time:Now" + "\nx-ms-file-permission:Inherit"
            + "\nx-ms-type:file" + "\nx-ms-version:" + apiversion + "\n" // headers
            + "/{0}/{1}/{2}", Account, FileShare, FileName);

Here is the c# code using create file api:

using System;
using System.Globalization;
using System.Net;
using System.Security.Cryptography;

namespace ConsoleApp25
{
    class Program
    {
        static void Main(string[] args)
        {
            string Account = "storage_account_name";
            string Key = "storage_account_key";
            string FileShare = "file_share_name";
            string FileName = "test555.txt";
            string apiversion = "2019-02-02";
            int content_length = 1200;
            string content_type = "text/plain";

            DateTime dt = DateTime.UtcNow;
            string StringToSign = String.Format("PUT\n"
                + "\n" // content encoding
                + "\n" // content language
                + "\n" // content length
                + "\n" // content md5
                + content_type  + "\n" // content type
                + "\n" // date
                + "\n" // if modified since
                + "\n" // if match
                + "\n" // if none match
                + "\n" // if unmodified since
                + "\n" // range
                + "x-ms-content-length:" + content_length
                + "\nx-ms-date:" + dt.ToString("R")
                + "\nx-ms-file-attributes:Archive" + "\nx-ms-file-creation-time:Now" + "\nx-ms-file-last-write-time:Now" + "\nx-ms-file-permission:Inherit"
                + "\nx-ms-type:file" + "\nx-ms-version:" + apiversion + "\n" // headers
                + "/{0}/{1}/{2}", Account, FileShare, FileName);

            string auth = SignThis(StringToSign, Key, Account);
            string method = "PUT";
            string urlPath = string.Format("https://{0}.file.core.windows.net/{1}/{2}", Account, FileShare, FileName);
            Uri uri = new Uri(urlPath);
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
            request.Method = method;
            request.ContentLength = 0;

            request.Headers.Add("x-ms-content-length", $"{content_length}");
            request.Headers.Add("Content-Type", content_type);
            request.Headers.Add("x-ms-type", "file");
            request.Headers.Add("x-ms-date", dt.ToString("R"));
            request.Headers.Add("x-ms-version", apiversion);
            request.Headers.Add("x-ms-file-attributes", "Archive"); //note it is case-sensitive.
            request.Headers.Add("x-ms-file-permission", "Inherit");
            request.Headers.Add("x-ms-file-creation-time", "Now");
            request.Headers.Add("x-ms-file-last-write-time", "Now");
            request.Headers.Add("Authorization", auth);
           

            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                //read the response code
                Console.WriteLine("the response is:" + response.StatusCode);
            }

            Console.WriteLine("**completed**");
            Console.ReadLine();
        }

        private static String SignThis(String StringToSign, string Key, string Account)
        {
            String signature = string.Empty;
            byte[] unicodeKey = Convert.FromBase64String(Key);
            using (HMACSHA256 hmacSha256 = new HMACSHA256(unicodeKey))
            {
                Byte[] dataToHmac = System.Text.Encoding.UTF8.GetBytes(StringToSign);
                signature = Convert.ToBase64String(hmacSha256.ComputeHash(dataToHmac));
            }

            String authorizationHeader = String.Format(
                  CultureInfo.InvariantCulture,
                  "{0} {1}:{2}",
                  "SharedKey",
                  Account,
                  signature);

            return authorizationHeader;
        }

    }
}