Not working with azure functions

[fildanrcs]

Hi,

I'm trying this module on a Windows 10 machine and I always get 'invalid signature' error.

Here is how I'm trying to use it. Once I get the request, I extract the parameters in the following way

            let headers = request.headers;
            let signatureField;
            if("SignatureCertChainUrl" in headers) signatureField = "SignatureCertChainUrl";
            if("signaturecertchainurl" in headers) signatureField = "signaturecertchainurl";
            let cert_url = headers[signatureField];
            let signature = headers.signature;
            let requestRawBody = JSON.stringify(request.body);

Then I call the promise method with the following params

            verifier(cert_url, signature, requestRawBody).then((res) => {
                resolve(true);
            }).catch((err) => {
                resolve(false);
            })

I get that it goes always in catch with the error: 'invalid signature'

Sorry for having poorly documented the issue before.

Thanks for the patience

[mreinstein]

@fildanrcs I don't understand your issue. Can you provide more details please?

[mreinstein]

issue unclear, please elaborate on what issue you are running into and we'll re-open as needed.

[fildanrcs]

Sorry, I've updated the issue description.

[mreinstein]

I suspect your problem is in let requestRawBody = JSON.stringify(request.body);.

Stringifying the request body is not the same as the raw body input. You need the raw, unaltered request body (before any middlewares parse this into an object.)

Which server framework are you using?

[fildanrcs]

I'm using Azure Functions, so I fear I've no control on the middleware underneath. Unfortunately I can't change this stack..

Do you have any other idea on how make the signature check by using the body in json format?

Thanks for the reply

[mreinstein]

You're going to need raw request body to use this. Perhaps this is already available via request.rawBody ?

https://github.com/Azure/azure-functions-host/issues/293 https://github.com/Azure/azure-functions-host/issues/1951

[fildanrcs]

Works perfectly.. It was my bad :) Thanks a lot!

[mreinstein]

glad it worked!

[fildanrcs]

Yep. I have to admit that I was fooled by this thread since I'm using Azure Functions based on Windows.

Wanted just to clarify the original mistake.

Regards

[mreinstein]

thanks for the clarification. Perhaps this issue will be useful to others trying the same thing (which is why I renamed your original title; to hopefully improve discoverability.)