Amazon authentication v4 support

[karensg]

First of all, lots of compliments for your great job!

Would it be possible to update the version of amazon authentication to v4 and update the code example for it. At this moment, all Amazon regions support v4. However, Frankfurt is the first region that does not support v2 any more. It would be great to use this library for those buckets as well.

Cheers,
Karens

[danialfarid]

Are you sure you are on the current github?

[karensg]

If I am correct, the signing in the example and in the demo happens with v2.
More on signing with v4

[danialfarid]

Could you submit a PR?

[karensg]

I am not sure I will be able to do that. Just a suggestion that it will be more important in the future

[Hnus]

+1 Does not work with Frankfurt

[bourgeois247]

For those who want or need to use version 4 authentication for AWS S3 uploads, just change the data attributes given in the ng-file-upload documentation to the v4 parameters. These are the parameters you need to consider:

1. key // the key to store the file on S3, could be file name or customized
2. acl, // sets the access to the uploaded file in the bucket: private, public-read, .
3. policy //as described here
4. 'X-amz-credential' //also described in the link above
5. 'X-amz-algorithm': 'AWS4-HMAC-SHA256'
6. 'X-amz-date': //as described in the link above
7. 'X-amz-expires': //as described in the link above
8. 'X-amz-signature': //as described in the link above
9. 'Content-Type': file.type !== '' ? file.type : 'application/octet-stream', // content type of the file (NotEmpty)
10. file: file //the actual file object to be uploaded

You don't need to get a signed url, you can use the format [YOUR_BUCKET_NAME].s3.amazonaws.com. The policy and signature parameters are to be generated on the server. A sample Php implementation of generating those can be found here.

Hope that helps someone, cheers.

[danialfarid]

@bourgeois247 Thanks, If you could create a wiki page with code sample would be great. I have already added a link to this comment in the readme but a wiki would be much better.

[bourgeois247]

@danialfarid sure, will do

[notbrain]

@bourgeois247 Do you have a working example with AWS V4 auth somewhere? Would greatly appreciate any pointers, haven't been successful.

[flosky]

Hey guys,
I was strugling with that as well. Especially because this is only needed in two regions, so the support is not that great.
This is my source code (with a node.js backend). Notice that the signature must be hex encoded (took me a while to figure that out)

    app.use('/sign_s3', function(req, res) {

        const date = new Date().toISOString().replace(/[\.\-:]/gi, "").substr(0, 15) + "Z";
        const dateNowRaw = date.substr(0, date.indexOf("T"));

        const expirationDate = new Date();
        expirationDate.setHours(expirationDate.getHours() + 1);
        const expiration = expirationDate.toISOString();

        const credentials = '<myAwsId>/' + dateNowRaw + '/eu-central-1/s3/aws4_request';
        const policy = {
            expiration: expiration,
            conditions: [
                {"bucket": "<myBucketName>"},
                {"acl": "private"},
                ["starts-with", "$key", ''],
                ['starts-with', '$Content-Type', ''],
                {"x-amz-credential": credentials},
                {"x-amz-algorithm": "AWS4-HMAC-SHA256"},
                {"x-amz-date": date}
            ]
        };

        const base64Policy = new Buffer(JSON.stringify(policy), "utf-8").toString("base64");

        const dateKey = crypto.createHmac('sha256', "AWS4" + "<myPrivateAwsKey>").update(dateNowRaw).digest();
        const dateRegionKey = crypto.createHmac('sha256', dateKey).update('eu-central-1').digest();
        const dateRegionServiceKey = crypto.createHmac('sha256', dateRegionKey).update('s3').digest();
        const signingKey = crypto.createHmac('sha256', dateRegionServiceKey).update('aws4_request').digest();

        const signature = crypto.createHmac('sha256', signingKey).update(base64Policy).digest('hex');

        res.status(200).json({
            signature: signature,
            policy: base64Policy,
            date: date,
            credentials: credentials,
            expiration: expiration
        });
    });

On the client:

            // make request to your own backend to get signature and other data
            var signature = response.data.signature;
            var policyBase64 = response.data.policy;
            var date = response.data.date;
            var credentials = response.data.credentials;
            var expiration = response.data.expiration;

            Upload.upload({
                url: 'https://<myBucketName>.s3.amazonaws.com/',
                method: 'POST',
                data: {
                    key: file.name,
                    acl: 'private',
                    Policy: policyBase64,
                    'X-Amz-Credential' : credentials,
                    'X-Amz-Algorithm': 'AWS4-HMAC-SHA256',
                    'X-Amz-Date': date,
                    'X-Amz-Signature': signature,
                    "Content-Type": contentType,
                    file: file
                }
            }).then(successHandler, errorHandler, progressHandler);

Hope that helps

[rnemec]

@flosky, thank you for the effort putting it together (incl. the hex encoding).
One more piece to add to the solution: if somebody is using role (and thus temporary credentials), you usually get the access key and secret key from the default credentials, but these are "temporary credentials" and in order to get the signing working with the temporary ones, you have to add a tag "X-Amz-Security-Token" to both the policy.credentials array as well as in the upload.data.
The value is credentials.sessionToken (obtained on the server).
I also suggest to add the sessionToken to the object returned from "/s3_sign" so the client has the value to put into the upload.data.
Hope this helps at least one happy S3 uploader.

[redterror]

A note to any Ruby users doing this, take note that Base64.encode64 introduces newlines in the output string, and this throws off the signature. Use Base64.strict_encode64 instead.

[redterror]

@rnemec - In the credential scope string, is this the target format for use with a temporary session token:

<AccessKeyId>/<SessionToken>/<YYYYMMDD>/<region>/<service>/aws4_request

The AWS docs aren't clear on exactly how to format with a session token - can you clarify?