From 3c68c0cb1cbcf4d25639f5d293ea1811f0bc92ce Mon Sep 17 00:00:00 2001
From: jesopo <github@lolnerd.net>
Date: Fri, 15 Apr 2022 13:55:22 +0000
Subject: [PATCH] run spamfilters against NICK

---
 extensions/filter.c   | 25 +++++++++++++++++++++++++
 modules/core/m_nick.c |  6 ++++++
 2 files changed, 31 insertions(+)

diff --git a/extensions/filter.c b/extensions/filter.c
index bebcbdfca..fecba7542 100644
--- a/extensions/filter.c
+++ b/extensions/filter.c
@@ -56,6 +56,7 @@ static const char filter_desc[] = "Filter messages using a precompiled Hyperscan
 static void filter_msg_user(void *data);
 static void filter_msg_channel(void *data);
 static void filter_client_quit(void *data);
+static void filter_client_nick(void *data);
 static void on_client_exit(void *data);
 
 static void mo_setfilter(struct MsgBuf *, struct Client *, struct Client *, int, const char **);
@@ -93,6 +94,7 @@ mapi_hfn_list_av1 filter_hfnlist[] = {
 	{ "privmsg_user", filter_msg_user },
 	{ "privmsg_channel", filter_msg_channel },
 	{ "client_quit", filter_client_quit },
+	{ "local_nick_change", filter_client_nick },
 	{ "client_exit", on_client_exit },
 	{ NULL, NULL }
 };
@@ -483,6 +485,29 @@ filter_client_quit(void *data_)
 	/* No point in doing anything with ACT_KILL */
 }
 
+void
+filter_client_nick(void *data_)
+{
+	hook_cdata *data = data_;
+	struct Client *s = data->client;
+	if (IsOper(s)) {
+		return;
+	}
+
+	unsigned r = match_message("0", s, "NICK", NULL, data->arg2);
+	if (r & ACT_DROP) {
+		data->arg2 = NULL;
+	}
+	if (r & ACT_ALARM) {
+		sendto_realops_snomask(SNO_GENERAL, L_ALL | L_NETWIDE,
+			"FILTER: %s!%s@%s [%s]",
+			s->name, s->username, s->host, s->sockhost);
+	}
+	if (r & ACT_KILL) {
+		exit_client(NULL, s, s, FILTER_EXIT_MSG);
+	}
+}
+
 void
 on_client_exit(void *data_)
 {
diff --git a/modules/core/m_nick.c b/modules/core/m_nick.c
index 890d0c2b3..3bce4e80d 100644
--- a/modules/core/m_nick.c
+++ b/modules/core/m_nick.c
@@ -673,6 +673,12 @@ change_local_nick(struct Client *client_p, struct Client *source_p,
 	hook_info.arg2 = nick;
 	call_hook(h_local_nick_change, &hook_info);
 
+	if (!hook_info.arg2) {
+		sendto_one(source_p, form_str(ERR_ERRONEUSNICKNAME),
+			   me.name, EmptyString(source_p->name) ? "*" : source_p->name, nick);
+		return;
+	}
+
 	sendto_realops_snomask(SNO_NCHANGE, L_ALL,
 			     "Nick change: From %s to %s [%s@%s]",
 			     source_p->name, nick, source_p->username, source_p->host);