Qfyilyi

I'm uploading a dummy file to Google Cloud Storage, and then signing a read/write URL before passing it to another service hosted separately. Unfortunately, I'm receiving a 403 response, with the message:

The request signature we calculated does not match the signature you provided. Check your Google secret key and signing method.

The code I'm using to create the dummy object and sign the URL:

const string BASE64_JSON_CREDS = "UklQIFN0YW4gTGVl"; // credentials of service account with "Storage Admin" role (entire json file as received from Google's Console)

const string BUCKET = "testbucket";

const string FILENAME = "test.jpg";

byte imageBytes = File.ReadAllBytes(@"test.jpg");



GoogleCredential credentials = null;

using (var stream = new MemoryStream(Convert.FromBase64String(BASE64_JSON_CREDS)))

{

    credentials = GoogleCredential.FromStream(stream);

}



StorageClient storageClient = StorageClient.Create(credentials);

var bucket = await storageClient.GetBucketAsync(BUCKET);

await storageClient.UploadObjectAsync(bucket.Name, FILENAME, null, new MemoryStream());



var scopedCreds = credentials.CreateScoped("https://www.googleapis.com/auth/devstorage.read_write").UnderlyingCredential as ServiceAccountCredential;

var urlSigner = UrlSigner.FromServiceAccountCredential(scopedCreds);

var url = urlSigner.Sign(bucket.Name, FILENAME, TimeSpan.FromHours(100));

Some test code I've written for the sake of this question (I've also tried HttpWebRequest):

var handler = new HttpClientHandler()

{

//    Proxy = new WebProxy("localhost", 8888)

};

var client = new HttpClient(handler);

var content = new ByteArrayContent(imageBytes, 0, imageBytes.Length);

content.Headers.Remove("Content-Type");

var response = await client.PutAsync(url, content);

if (response.IsSuccessStatusCode)

{

    Console.WriteLine("yay");

}

else

{

    Console.WriteLine(await response.Content.ReadAsStringAsync());

}

Console.ReadKey();

When proxied through Fiddler, the request looks like this:

PUT https://storage.googleapis.com/testbucket/test.jpg?GoogleAccessId=testbucket@testproject.iam.gserviceaccount.com&Expires=1543209340&Signature=j1cagZ9MHZQAIeYrzbm95MWsIdFMvX1Em13il%2F2nEB1qx9xGB6%2BUzt6vo2OVuRp2TlW1G1TtyX32lxbH%2Fb51dr49eFBcSSm9H8rSXtuEXci02dY%2Fe%2FV0n4kpVwDjpiq4QVSMM%2BaCEdrUtPxT69BSoDuRqh6UHkeOL6VqLgcHGKQcXraZCrEaCXCJfNBwBlPcoXzOD708Nasl99ahxGwcPY6s1FXLCiAiP0VDJSRrPqbE8LHyRLLTgCk9r2H4pEW%2BpGpjEWj3DVpDC334%2BQQFttzDNuZQnUMtZi%2BGz5rqQbU5hBLgthb%2B13884uL4eUalnoSuRfR9JPKIJP7xk3%2FH4g%3D%3D HTTP/1.1

Content-Length: 21925

Host: storage.googleapis.com



{IMAGE_CONTENT}

And the response is:

HTTP/1.1 403 Forbidden

X-GUploader-UploadID: AEnB2UoklkZmIP8odWSx14Y0ZDgxjM8ZM94SCfNgAONG1giFTd9cncH8bAMK3s7I7v2DC1NwVirOrNbTjnBzdS2o1tOGX2pLBg

Content-Type: application/xml; charset=UTF-8

Content-Length: 314

Date: Thu, 22 Nov 2018 01:15:39 GMT

Server: UploadServer

Alt-Svc: quic=":443"; ma=2592000; v="44,43,39,35"



<?xml version='1.0' encoding='UTF-8'?><Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your Google secret key and signing method.</Message><StringToSign>PUT





1543209340

/testbucket/test.jpg</StringToSign></Error>

Looking at Google's UrlSigner code, the lines listed above are:

var signatureLines = new List<string>

{

    requestMethod.ToString(),

    contentMD5,

    contentType,

    expiryUnixSeconds

};

I found suggestion in this question that the Content-Type header does need to be set, so I made the following changes:

// New signing code

var headers = new Dictionary<string, IEnumerable<string>>() { { "Content-Type", new string { "image/jpeg" } } };

var url = urlSigner.Sign(bucket.Name, FILENAME, TimeSpan.FromHours(100), requestHeaders: headers);



// New put code (I removed the line removing Content-Type)

var content = new ByteArrayContent(imageBytes, 0, imageBytes.Length);

content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("image/jpeg");

but this hasn't fixed things. The new "StringToSign" value reflects the change:

PUT



image/jpeg

1543214247

/teams-storage-test-bucket/test.jpg

So the headers it should (to my mind) be checking for are correct vs what's being sent. The generated URL works for GET (I can download the empty file), but not for the PUT. Is there a solution?

In your call to Sign() include the HTTP Method and Content-Type headers:

urlSigner.Sign(bucket.Name, FILENAME, TimeSpan.FromHours(100), HttpMethod.Put, contentHeaders: new Dictionary<string, IEnumerable<string>> { { "Content-Type", new { "image/jpeg" } } });