From: Ondřej Surý <ondrej@isc.org>
Date: Fri, 27 Oct 2023 08:16:13 +0000 (+0200)
Subject: Call isccc_ccmsg_invalidate() when shutting down the connection
X-Git-Tag: v9.19.18~15^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2d2c249958d3f983e77bdecaf4bfc4553dacad62;p=thirdparty%2Fbind9.git

Call isccc_ccmsg_invalidate() when shutting down the connection

Previously, the isccc_ccmsg_invalidate() was called from conn_free() and
this could lead to netmgr calling control_recvmessage() after we
detached the reading controlconnection_t reference, but it wouldn't be
the last reference because controlconnection_t is also attached/detached
when sending response or running command asynchronously.

Instead, move the isccc_ccmsg_invalidate() call to control_recvmessage()
error handling path to make sure that control_recvmessage() won't be
ever called again from the netmgr.
---

diff --git a/bin/named/controlconf.c b/bin/named/controlconf.c
index 5dbc97106f3..3b8b3f5f2b4 100644
--- a/bin/named/controlconf.c
+++ b/bin/named/controlconf.c
@@ -407,9 +407,7 @@ control_recvmessage(isc_nmhandle_t *handle ISC_ATTR_UNUSED, isc_result_t result,
 	isccc_time_t exp;
 	uint32_t nonce;
 
-	if (conn->shuttingdown) {
-		return;
-	}
+	INSIST(!conn->shuttingdown);
 
 	/* Is the server shutting down? */
 	if (listener->controls->shuttingdown) {
@@ -539,6 +537,9 @@ control_recvmessage(isc_nmhandle_t *handle ISC_ATTR_UNUSED, isc_result_t result,
 	return;
 
 cleanup:
+	/* Make sure no read callbacks are called again */
+	isccc_ccmsg_invalidate(&conn->ccmsg);
+
 	conn->shuttingdown = true;
 
 	REQUIRE(isc_tid() == 0);
@@ -564,8 +565,6 @@ conn_free(controlconnection_t *conn) {
 	}
 #endif /* ifdef ENABLE_AFL */
 
-	isccc_ccmsg_invalidate(&conn->ccmsg);
-
 	isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
 		      NAMED_LOGMODULE_CONTROL, ISC_LOG_DEBUG(3),
 		      "freeing control connection");