From: Colin Vidal <colin@isc.org>
Date: Tue, 18 Nov 2025 09:31:24 +0000 (+0100)
Subject: attach socket before async streamdns_resume_processing
X-Git-Tag: v9.21.16~40^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7c8b517d563141271625605ddc35559f22f613bd;p=thirdparty%2Fbind9.git

attach socket before async streamdns_resume_processing

Call to `streamdns_resume_processing` is asynchronous but the socket
passed as argument is not attached when scheduling the call.

While there is no reproducible way (so far) to make the socket reference
number down to 0 before `streamdns_resume_processing` is called, attach
the socket before scheduling the call. This guard against an hypothetic
case where, for some reasons, the socket refcount would reach 0, and be
freed from memory when `streamdns_resume_processing` is called.
---

diff --git a/lib/isc/netmgr/streamdns.c b/lib/isc/netmgr/streamdns.c
index 2da8a63a0aa..9dd8b0aeab6 100644
--- a/lib/isc/netmgr/streamdns.c
+++ b/lib/isc/netmgr/streamdns.c
@@ -93,6 +93,8 @@ streamdns_closing(isc_nmsocket_t *sock);
 
 static void
 streamdns_resume_processing(void *arg);
+static void
+async_streamdns_resume_processing(void *arg);
 
 static void
 streamdns_resumeread(isc_nmsocket_t *sock, isc_nmhandle_t *transphandle) {
@@ -193,8 +195,9 @@ streamdns_on_complete_dnsmessage(isc_dnsstream_assembler_t *dnsasm,
 		 * Process more DNS messages in the next loop tick.
 		 */
 		streamdns_pauseread(sock, transphandle);
-		isc_async_run(sock->worker->loop, streamdns_resume_processing,
-			      sock);
+		isc__nmsocket_attach(sock, &(isc_nmsocket_t *){ NULL });
+		isc_async_run(sock->worker->loop,
+			      async_streamdns_resume_processing, sock);
 	}
 
 	return false;
@@ -690,6 +693,15 @@ streamdns_resume_processing(void *arg) {
 	streamdns_handle_incoming_data(sock, sock->outerhandle, NULL, 0);
 }
 
+static void
+async_streamdns_resume_processing(void *arg) {
+	isc_nmsocket_t *sock = (isc_nmsocket_t *)arg;
+
+	streamdns_resume_processing(sock);
+
+	isc__nmsocket_detach(&sock);
+}
+
 static isc_result_t
 streamdns_accept_cb(isc_nmhandle_t *handle, isc_result_t result, void *cbarg) {
 	isc_nmsocket_t *listensock = (isc_nmsocket_t *)cbarg;