fix

cmd/telesrv-admin/addserverlink.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"net/http"
+	"net/url"
+	"strconv"
+)
+
+// handleAddServerLinkAPI builds an owpg://addserver link (see the desktop
+// and Android clients' handling of that scheme) carrying only this server's
+// host and port, so an operator can hand it out as a ready-made "add my
+// server" button/QR code.
+//
+// Deliberately carries nothing else -- no name, description, key, or DC.
+// Anyone who can get a link in front of a user (a forum post, a chat
+// message, an intercepted share) controls whatever it contains; if it also
+// carried the RSA key, a link with a forged key pointed at an attacker's own
+// host would be indistinguishable from a real one, and the client would
+// trust it outright as "this server's identity" -- a real MITM vector, not
+// a hypothetical one. host+port alone can't misrepresent anything: the
+// client always fetches name/description/key/DC itself, straight from
+// whatever actually answers at that address (ServerInfoPath), the same way
+// it already does for a hand-typed address in the "Add Server" form.
+func (s *server) handleAddServerLinkAPI(w http.ResponseWriter, r *http.Request) {
+	q := url.Values{}
+	q.Set("host", s.cfg.AdvertiseHost)
+	q.Set("port", strconv.Itoa(s.cfg.ServerPort))
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"link": "owpg://addserver?" + q.Encode(),
+	})
+}