From 4015bdba744ce13ff827d96c2b9b21956c64c94d Mon Sep 17 00:00:00 2001
From: Jan-Lukas Else <mail@jlelse.de>
Date: Wed, 8 Dec 2021 11:08:33 +0100
Subject: [PATCH] Reject webmentions where target equals source

---
 webmention.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/webmention.go b/webmention.go
index 3af4d65..da0324d 100644
--- a/webmention.go
+++ b/webmention.go
@@ -62,6 +62,11 @@ func (a *goBlog) handleWebmention(w http.ResponseWriter, r *http.Request) {
 		a.serveError(w, r, "target not allowed", http.StatusBadRequest)
 		return
 	}
+	if m.Target == m.Source {
+		a.debug("Webmention target and source are the same:", m.Target)
+		a.serveError(w, r, "target and source are the same", http.StatusBadRequest)
+		return
+	}
 	if err = a.queueMention(m); err != nil {
 		a.debug("Failed to queue webmention", err.Error())
 		a.serveError(w, r, err.Error(), http.StatusInternalServerError)