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Fix shutdown races in catzs

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The dns__catz_update_cb() does not expect that 'catzs->zones'
can become NULL during shutdown.

Add similar checks in the dns__catz_update_cb() and dns_catz_zone_get()
functions to protect from such a case. Also add an INSIST in the
dns_catz_zone_add() function to explicitly state that such a case
is not expected there, because that function is called only during a
reconfiguration.
This commit is contained in:
Aram Sargsyan 2023-10-20 10:45:35 +00:00 committed by Arаm Sаrgsyаn
parent cddd9dcb53
commit 4eb4fa288c
2 changed files with 18 additions and 1 deletions
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16
lib/dns/catz.c
View file

@ -897,6 +897,13 @@ dns_catz_zone_add(dns_catz_zones_t *catzs, const dns_name_t *name,
LOCK(&catzs->lock);
/*
* This function is called only during a (re)configuration, while
* 'catzs->zones' can become NULL only during shutdown.
*/
INSIST(catzs->zones != NULL);
INSIST(!atomic_load(&catzs->shuttingdown));
result = isc_ht_find(catzs->zones, name->ndata, name->length,
(void **)&catz);
switch (result) {
@ -932,6 +939,10 @@ dns_catz_zone_get(dns_catz_zones_t *catzs, const dns_name_t *name) {
REQUIRE(ISC_MAGIC_VALID(name, DNS_NAME_MAGIC));
LOCK(&catzs->lock);
if (catzs->zones == NULL) {
UNLOCK(&catzs->lock);
return (NULL);
}
result = isc_ht_find(catzs->zones, name->ndata, name->length,
(void **)&found);
UNLOCK(&catzs->lock);
@ -2241,6 +2252,11 @@ dns__catz_update_cb(void *data) {
*/
dns_name_toregion(&updb->origin, &r);
LOCK(&catzs->lock);
if (catzs->zones == NULL) {
UNLOCK(&catzs->lock);
result = ISC_R_SHUTTINGDOWN;
goto exit;
}
result = isc_ht_find(catzs->zones, r.base, r.length, (void **)&oldcatz);
is_active = (result == ISC_R_SUCCESS && oldcatz->active);
UNLOCK(&catzs->lock);

3
lib/dns/include/dns/catz.h
View file

@ -302,7 +302,8 @@ isc_result_t
dns_catz_zone_add(dns_catz_zones_t *catzs, const dns_name_t *name,
dns_catz_zone_t **catzp);
/*%<
* Allocate a new catz named 'name' and put it in 'catzs' collection.
* Allocate a new catz named 'name' and put it in 'catzs' collection. This
* function is safe to call only during a (re)configuration.
*
* Requires:
* \li 'catzs' is a valid dns_catz_zones_t.