CODEWITHSUNDEEP
.netamazon-web-servicesaws-sdkaws-api-gatewayaws-lambda
Richard R
Richard R

Reputation: 1417

Is there a .NET library that can sign a request with AWS V4 Signature?

I have an API Gateway where I'm setting the authentication to use AWS_IAM. This requires that I sign each request with the AWS V4 signature and attach the HMAC in the header. I've found libraries to sign a request with the V4 signature in nodejs. But I cannot find a library to sign for me. Even the aws-sdk for .NET has this abstracted for their own specific use case. Is there a library out there (i've done a quick google search and found no results)? Or do I need to write out the hmac myself?

Upvotes: 18

Views: 20044

Answers (4)

eliod
eliod

Reputation: 39

When using SSO authentication, you also have a session token that you need to include in the http request.

After signing the request, add the session token inside the http header x-amz-security-token.

Here is an example of implementing this inside a search request:

var baseUrl = "es_url";
var indexName = "index_name";
var requestUri = new Uri($"{baseUrl}/{indexName}/_search");

var req = new HttpRequestMessage
{
    RequestUri = requestUri,
    Method = System.Net.Http.HttpMethod.Post,
    Content = new StringContent(query, Encoding.UTF8, "application/json")
};

var accessKeyId = "ACCESS_KEY";
var secretKey = "SECRET_KEY"
var sessionToken = "SESSION_TOKEN";

var signer = new AWS4RequestSigner(accessKeyId, secretKey);
req = await signer.Sign(req, "es", "us-west-2");

req.Headers.Add("x-amz-security-token", sessionToken);

var client = new HttpClient();
var response = await client.SendAsync(req);

Upvotes: 2

FantasticFiasco
FantasticFiasco

Reputation: 1193

An alternative to Aws4RequestSigner is AwsSignatureVersion4. I think its API is easier to work with, but I am biased since I am the author of the latter.

Upvotes: 8

ChiefGearHead
ChiefGearHead

Reputation: 121

While this is an old question, since AWS has not "prioritized accordingly" with regards to the .NET AWS SDK as stated in their comment above and this is still a relevant problem today, I found a good library that will take care of the AWS V4 request signing for you.

Here is the Nuget package.

Here is the GitHub source and implementation documentation.

In addition, I've found that for my API Gateway AWS_IAM Authorization to work with temporary security credentials, you also need to include the "x-amz-security-token" header with the current session token as it's value as well in your request.

Upvotes: 12

Mircea
Mircea

Reputation: 10566

you can read on how the signature is done and you can (if you want). I would recommend pulling in the AWS SDK for .NET and using the functionality from the SDK to actually perform the signature.

Here is the signer form the SDK:

https://github.com/aws/aws-sdk-net/blob/6c3be79bdafd5bfff1ab0bf5fec17abc66c7b516/sdk/src/Core/Amazon.Runtime/Internal/Auth/AWS4Signer.cs

You may need to adapt it (ie it knows about AWS services and endpoints by default)

Upvotes: 8

Related Questions