HTTP server does not validate `Host` header is present

[uNetworkingAB]

Version: Deno 2.0.0

I made a quick and simple standards test and found that Deno does not properly check for Content-Length vs. Transfer-Encoding. It must close the connection with error if both headers are present.

Also, the Host header is not checked.

[littledivy]

re request smuggling the spec says:

https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3

If a message is received with both a Transfer-Encoding and a Content-Length header field, the Transfer-Encoding overrides the Content-Length. Such a message might indicate an attempt to perform request smuggling (Section 9.5) or response splitting (Section 9.4) and ought to be handled as an error. A sender MUST remove the received Content-Length field prior to forwarding such a message downstream.

Deno correctly overrides the Content-Length header field when calling the request handler.

Deno.serve((req) => {
    console.log(req.headers)
})

Headers { host: "example.com", "transfer-encoding": "chunked" }

Although I don't really like this and it should just close connection with error.

[uNetworkingAB]

Ah, fair enough.

But Host is missing:

A server MUST respond with a 400 (Bad Request) status code to any HTTP/1.1 request message that lacks a Host header field [...]

[littledivy]

Opened hyperium/hyper#3777

[uNetworkingAB]

You're right, Deno does override Content-Length properly now that I updated the test. The only failure is re. Host header now.

✅ Overflowing negative Content-Length header: Response Status Code 400, Expected ranges: [[400,499]]
✅ Conflicting Transfer-Encoding and Content-Length in varying case: Response Status Code 200, Expected ranges: [[400,499],[200,299]]
✅ Request without HTTP version: Response Status Code 400, Expected ranges: [[400,599]]
✅ Invalid header characters: Response Status Code 400, Expected ranges: [[400,499]]
✅ Negative Content-Length header: Response Status Code 400, Expected ranges: [[400,499]]
✅ Non-numeric Content-Length header: Response Status Code 400, Expected ranges: [[400,499]]
✅ Header containing invalid control character: Response Status Code 400, Expected ranges: [[400,499]]
✅ Invalid HTTP version: Response Status Code 400, Expected ranges: [[400,499],[500,599]]
✅ Invalid prefix of request: Response Status Code 400, Expected ranges: [[400,499],[500,599]]
✅ Invalid line ending: Response Status Code 400, Expected ranges: [[400,499]]
✅ Request with Expect header: Response Status Code 200, Expected ranges: [[100,100],[200,299]]
✅ Valid GET request: Response Status Code 200, Expected ranges: [[200,299]]
✅ Valid GET request with edge cases: Response Status Code 200, Expected ranges: [[200,299]]
❌ Missing Host header: Response Status Code 200, Expected ranges: [[400,499]]
❌ Multiple Host headers: Response Status Code 200, Expected ranges: [[400,499]]
✅ Empty header value: Response Status Code 200, Expected ranges: [[200,299]]
✅ Valid POST request with body: Response Status Code 200, Expected ranges: [[200,299],[404,404]]
✅ Chunked Transfer-Encoding: Response Status Code 200, Expected ranges: [[200,299]]
✅ Fragmented HTTP version: Server waited successfully
✅ Fragmented field value 1: Server waited successfully
✅ Fragmented method: Server waited successfully
✅ Fragmented URL 1: Server waited successfully
✅ Fragmented URL 2: Server waited successfully
✅ Fragmented URL 3: Server waited successfully
✅ Fragmented request line: Server waited successfully
✅ Fragmented request line newline 1: Server waited successfully
✅ Fragmented request line newline 2: Server waited successfully
✅ Fragmented field name: Server waited successfully
✅ Fragmented field value 2: Server waited successfully
✅ Fragmented field value 3: Server waited successfully
✅ Fragmented field value 4: Server waited successfully
✅ Fragmented request: Server waited successfully
✅ Fragmented request termination: Server waited successfully

31 out of 33 tests passed.