From: Aram Sargsyan <aram@isc.org>
Date: Thu, 11 May 2023 12:08:13 +0000 (+0000)
Subject: Check whether zone->db is a valid pointer before attaching
X-Git-Tag: v9.19.14~54^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fae0930eb84063fc03d711a0c772c58e5b470377;p=thirdparty%2Fbind9.git

Check whether zone->db is a valid pointer before attaching

The zone_resigninc() function does not check the validity of
'zone->db', which can crash named if the zone was unloaded earlier,
for example with "rndc delete".

Check that 'zone->db' is not 'NULL' before attaching to it, like
it is done in zone_sign() and zone_nsec3chain() functions, which
can similarly be called by zone maintenance.
---

diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index d943295588b..7481d3b12f1 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -6825,8 +6825,14 @@ zone_resigninc(dns_zone_t *zone) {
 	}
 
 	ZONEDB_LOCK(&zone->dblock, isc_rwlocktype_read);
-	dns_db_attach(zone->db, &db);
+	if (zone->db != NULL) {
+		dns_db_attach(zone->db, &db);
+	}
 	ZONEDB_UNLOCK(&zone->dblock, isc_rwlocktype_read);
+	if (db == NULL) {
+		result = ISC_R_FAILURE;
+		goto failure;
+	}
 
 	result = dns_db_newversion(db, &version);
 	if (result != ISC_R_SUCCESS) {