reverseproxy: Use correct cases for websocket related headers (#6621)

Co-authored-by: Francis Lavoie <lavofr@gmail.com>

WeidiDeng committed Oct 11, 2024 at 17:02 UTC 48ce47f1d44da485fbbf6be536a0e3822763f313

2 files changed +26

modules/caddyhttp/reverseproxy/reverseproxy.go

+25

@@ -569,6 +569,30 @@ func (h *Handler) proxyLoopIteration(r *http.Request, origReq *http.Request, w h

569 return false, proxyErr

570 }

571

572 +// Mapping of the canonical form of the headers, to the RFC 6455 form,

573 +// i.e. `WebSocket` with uppercase 'S'.

574 +var websocketHeaderMapping = map[string]string{

575 + "Sec-Websocket-Accept": "Sec-WebSocket-Accept",

576 + "Sec-Websocket-Extensions": "Sec-WebSocket-Extensions",

577 + "Sec-Websocket-Key": "Sec-WebSocket-Key",

578 + "Sec-Websocket-Protocol": "Sec-WebSocket-Protocol",

579 + "Sec-Websocket-Version": "Sec-WebSocket-Version",

580 +}

581 +

582 +// normalizeWebsocketHeaders ensures we use the standard casing as per

583 +// RFC 6455, i.e. `WebSocket` with uppercase 'S'. Most servers don't

584 +// care about this difference (read headers case insensitively), but

585 +// some do, so this maximizes compatibility with upstreams.

586 +// See https://github.com/caddyserver/caddy/pull/6621

587 +func normalizeWebsocketHeaders(header http.Header) {

588 + for k, rk := range websocketHeaderMapping {

589 + if v, ok := header[k]; ok {

590 + delete(header, k)

591 + header[rk] = v

592 + }

593 + }

594 +}

595 +

596 // prepareRequest clones req so that it can be safely modified without

597 // changing the original request or introducing data races. It then

598 // modifies it so that it is ready to be proxied, except for directing

@@ -655,6 +679,7 @@ func (h Handler) prepareRequest(req *http.Request, repl *caddy.Replacer) (*http.

679 if reqUpType != "" {

680 req.Header.Set("Connection", "Upgrade")

681 req.Header.Set("Upgrade", reqUpType)

682 + normalizeWebsocketHeaders(req.Header)

683 }

684

685 // Set up the PROXY protocol info

modules/caddyhttp/reverseproxy/streaming.go

@@ -66,6 +66,7 @@ func (h *Handler) handleUpgradeResponse(logger *zap.Logger, wg *sync.WaitGroup,

66 // write header first, response headers should not be counted in size

67 // like the rest of handler chain.

68 copyHeader(rw.Header(), res.Header)

69 + normalizeWebsocketHeaders(rw.Header())

70 rw.WriteHeader(res.StatusCode)

72 logger.Debug("upgrading connection")