Presigner Host Injection accesses an invalid property

[cuuupid]

Describe the bug

The bug exists in the s3-request-presigner package. Specifically, attempting to presign an existing request using presigner.presign(request) fails with a string error (cannot trim undefined).

This is caused by the SignatureV4 module attempting to access the host header, which does not exist. Issue #1988 addressed this and a PR was implemented to fill the host header automatically from the hostname property of the request. However, this fix introduces a bug as the property path is invalid.

While the fix retrieves the host header from the .hostname property of an HttpRequest object, this property path actually does not exist; the correct property path is .endpoint.hostname. Simply changing it to this or adding a || .endpoint.hostname would work here.

The line to fix:

aws-sdk-js-v3/packages/s3-request-presigner/src/presigner.ts

Line 47 in 648a41a

requestToSign.headers.host = requestToSign.hostname;

A temporary workaround for others is to inject the .hostname property into the request before presigning. The above fix will then retrieve the .hostname property to populate the host header.

const req = new HttpRequest(endpoint, region)
req.hostname = req.endpoint.hostname
const url = await presigner.presign(req)

A similar bug occurs with the protocol which is sometimes undefined, resulting in presigned urls that begin with undefined//.

Your environment

Node.js 16.4.0

SDK version number

@aws-sdk/s3-request-presigner@3.28.0

Is the issue in the browser/Node.js/ReactNative?

Node.js

Details of the browser/Node.js/ReactNative version

v16.4.0

Steps to reproduce

const client = new S3(...) // with your credentials
const presigner = new S3RequestPresigner({...client.config, sha256: Hash.bind(null, "sha256")})

const objectUrl = '...' // some S3 object URL
const region = '...'
const endpoint = parseUrl(objectUrl) // @aws-sdk/url-parser
const req = new HttpRequest(endpoint, region)

const url = await presigner.presign(req)
console.log(formatUrl(urlReq)) // @aws-sdk/util-format-url

Observed behavior

Error:

Uncaught TypeError: Cannot read property 'trim' of undefined
    at Object.getCanonicalHeaders (...path to project.../node_modules/@aws-sdk/signature-v4/dist/cjs/getCanonicalHeaders.js:20:62)
    at SignatureV4.presign (...path to project.../node_modules/@aws-sdk/signature-v4/dist/cjs/SignatureV4.js:41:56)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)

While the error message refers to Signaturev4, the issue is actually in s3-request-presigner as described above.

[AllanZhengYP]

Hi @pshah123

There's a line in question in your code snippet:

const req = new HttpRequest(endpoint, region) // Which HttpRequest?

Current HttpRequest does include the hostname:

aws-sdk-js-v3/packages/protocol-http/src/httpRequest.ts

Lines 7 to 10 in b1a3975

	export class HttpRequest implements HttpMessage, Endpoint {
	public method: string;
	public protocol: string;
	public hostname: string;

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