From fff2960981a3294ac641968a17558c8d7eecf74d Mon Sep 17 00:00:00 2001

From: Mark Andrews <marka@isc.org>

Date: Wed, 24 Aug 2022 12:21:50 +1000

Subject: [PATCH] Have dns_zt_apply lock the zone table

There where a number of places where the zone table should have

been locked, but wasn't, when dns_zt_apply was called.

Added a isc_rwlocktype_t type parameter to dns_zt_apply and adjusted

all calls to using it.  Removed locks in callers.

Modified upstream commit for v9_11

---

 bin/named/server.c       | 11 ++++++-----

 bin/named/statschannel.c |  8 ++++----

 lib/dns/include/dns/zt.h |  4 ++--

 lib/dns/tests/zt_test.c  |  3 ++-

 lib/dns/view.c           |  3 ++-

 lib/dns/zt.c             | 34 +++++++++++++++++++---------------

 6 files changed, 35 insertions(+), 28 deletions(-)

diff --git a/bin/named/server.c b/bin/named/server.c

index 9826588e6d..0b4b309461 100644

--- a/bin/named/server.c

+++ b/bin/named/server.c

@@ -8723,8 +8723,8 @@ load_configuration(const char *filename, ns_server_t *server,

 		    strcmp(view->name, "_bind") != 0)

 		{

 			dns_view_setviewrevert(view);

-			(void)dns_zt_apply(view->zonetable, false,

-					   removed, view);

+			(void)dns_zt_apply(view->zonetable, isc_rwlocktype_read,

+					   false, removed, view);

 		}

 		dns_view_detach(&view);

 	}

@@ -10090,8 +10090,8 @@ add_view_tolist(struct dumpcontext *dctx, dns_view_t *view) {

 	ISC_LIST_INIT(vle->zonelist);

 	ISC_LIST_APPEND(dctx->viewlist, vle, link);

 	if (dctx->dumpzones)

-		result = dns_zt_apply(view->zonetable, true,

-				      add_zone_tolist, dctx);

+		result = dns_zt_apply(view->zonetable, isc_rwlocktype_read,

+				      true, add_zone_tolist, dctx);

 	return (result);

 }

@@ -11367,7 +11367,8 @@ ns_server_sync(ns_server_t *server, isc_lex_t *lex, isc_buffer_t **text) {

 		for (view = ISC_LIST_HEAD(server->viewlist);

 		     view != NULL;

 		     view = ISC_LIST_NEXT(view, link)) {

-			result = dns_zt_apply(view->zonetable, false,

+			result = dns_zt_apply(view->zonetable,

+					      isc_rwlocktype_none, false,

 					      synczone, &cleanup);

 			if (result != ISC_R_SUCCESS &&

 			    tresult == ISC_R_SUCCESS)

diff --git a/bin/named/statschannel.c b/bin/named/statschannel.c

index 12ab048469..9828df0f4e 100644

--- a/bin/named/statschannel.c

+++ b/bin/named/statschannel.c

@@ -1833,8 +1833,8 @@ generatexml(ns_server_t *server, uint32_t flags,

 		if ((flags & STATS_XML_ZONES) != 0) {

 			TRY0(xmlTextWriterStartElement(writer,

 						       ISC_XMLCHAR "zones"));

-			result = dns_zt_apply(view->zonetable, true,

-					      zone_xmlrender, writer);

+			result = dns_zt_apply(view->zonetable, isc_rwlocktype_read,

+					      true, zone_xmlrender, writer);

 			if (result != ISC_R_SUCCESS)

 				goto error;

 			TRY0(xmlTextWriterEndElement(writer)); /* /zones */

@@ -2489,8 +2489,8 @@ generatejson(ns_server_t *server, size_t *msglen,

 			CHECKMEM(za);

 			if ((flags & STATS_JSON_ZONES) != 0) {

-				result = dns_zt_apply(view->zonetable, true,

-						      zone_jsonrender, za);

+				result = dns_zt_apply(view->zonetable, isc_rwlocktype_read,

+						      true, zone_jsonrender, za);

 				if (result != ISC_R_SUCCESS) {

 					goto error;

 				}

diff --git a/lib/dns/include/dns/zt.h b/lib/dns/include/dns/zt.h

index e658e5bb67..94212250da 100644

--- a/lib/dns/include/dns/zt.h

+++ b/lib/dns/include/dns/zt.h

@@ -177,11 +177,11 @@ dns_zt_freezezones(dns_zt_t *zt, bool freeze);

  */

 isc_result_t

-dns_zt_apply(dns_zt_t *zt, bool stop,

+dns_zt_apply(dns_zt_t *zt, isc_rwlocktype_t lock, bool stop,

 	     isc_result_t (*action)(dns_zone_t *, void *), void *uap);

 isc_result_t

-dns_zt_apply2(dns_zt_t *zt, bool stop, isc_result_t *sub,

+dns_zt_apply2(dns_zt_t *zt, isc_rwlocktype_t lock, bool stop, isc_result_t *sub,

 	      isc_result_t (*action)(dns_zone_t *, void *), void *uap);

 /*%<

  * Apply a given 'action' to all zone zones in the table.

diff --git a/lib/dns/tests/zt_test.c b/lib/dns/tests/zt_test.c

index 3f1e812d60..ee75303a50 100644

--- a/lib/dns/tests/zt_test.c

+++ b/lib/dns/tests/zt_test.c

@@ -145,7 +145,8 @@ apply(void **state) {

 	assert_non_null(view->zonetable);

 	assert_int_equal(nzones, 0);

-	result = dns_zt_apply(view->zonetable, false, count_zone, &nzones);

+	result = dns_zt_apply2(view->zonetable, isc_rwlocktype_read, false, NULL,

+			      count_zone, &nzones);

 	assert_int_equal(result, ISC_R_SUCCESS);

 	assert_int_equal(nzones, 1);

diff --git a/lib/dns/view.c b/lib/dns/view.c

index f01b4dea0f..bd1ced2863 100644

--- a/lib/dns/view.c

+++ b/lib/dns/view.c

@@ -676,7 +676,8 @@ dns_view_dialup(dns_view_t *view) {

 	REQUIRE(DNS_VIEW_VALID(view));

 	REQUIRE(view->zonetable != NULL);

-	(void)dns_zt_apply(view->zonetable, false, dialup, NULL);

+	(void)dns_zt_apply2(view->zonetable, isc_rwlocktype_read, false, NULL,

+			   dialup, NULL);

 }

 void

diff --git a/lib/dns/zt.c b/lib/dns/zt.c

index 3f12e247e0..af65740325 100644

--- a/lib/dns/zt.c

+++ b/lib/dns/zt.c

@@ -202,7 +202,8 @@ flush(dns_zone_t *zone, void *uap) {

 static void

 zt_destroy(dns_zt_t *zt) {

 	if (zt->flush) {

-		(void)dns_zt_apply(zt, false, flush, NULL);

+		(void)dns_zt_apply(zt, isc_rwlocktype_none,

+				   false, flush, NULL);

 	}

 	isc_refcount_destroy(&zt->references);

 	dns_rbt_destroy(&zt->table);

@@ -249,9 +250,7 @@ dns_zt_load(dns_zt_t *zt, bool stop) {

 	REQUIRE(VALID_ZT(zt));

-	RWLOCK(&zt->rwlock, isc_rwlocktype_read);

-	result = dns_zt_apply(zt, stop, load, NULL);

-	RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);

+	result = dns_zt_apply2(zt, isc_rwlocktype_read, stop, NULL, load, NULL);

 	return (result);

 }

@@ -293,7 +292,7 @@ dns_zt_asyncload2(dns_zt_t *zt, dns_zt_allloaded_t alldone, void *arg,

 	 * Prevent loads_pending going to zero while kicking off the loads.

 	 */

 	zt->loads_pending++;

-	result = dns_zt_apply2(zt, false, NULL, asyncload, &params);

+	result = dns_zt_apply2(zt, isc_rwlocktype_none, false, NULL, asyncload, &params);

 	pending = --zt->loads_pending;

 	if (pending != 0) {

 		zt->loaddone = alldone;

@@ -342,9 +341,7 @@ dns_zt_loadnew(dns_zt_t *zt, bool stop) {

 	REQUIRE(VALID_ZT(zt));

-	RWLOCK(&zt->rwlock, isc_rwlocktype_read);

-	result = dns_zt_apply(zt, stop, loadnew, NULL);

-	RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);

+	result = dns_zt_apply(zt, isc_rwlocktype_read, stop, loadnew, NULL);

 	return (result);

 }

@@ -366,9 +363,7 @@ dns_zt_freezezones(dns_zt_t *zt, bool freeze) {

 	REQUIRE(VALID_ZT(zt));

-	RWLOCK(&zt->rwlock, isc_rwlocktype_read);

-	result = dns_zt_apply2(zt, false, &tresult, freezezones, &freeze);

-	RWUNLOCK(&zt->rwlock, isc_rwlocktype_read);

+	result = dns_zt_apply2(zt, isc_rwlocktype_read, false, &tresult, freezezones, &freeze);

 	if (tresult == ISC_R_NOTFOUND)

 		tresult = ISC_R_SUCCESS;

 	return ((result == ISC_R_SUCCESS) ? tresult : result);

@@ -490,14 +485,14 @@ dns_zt_setviewrevert(dns_zt_t *zt) {

 }

 isc_result_t

-dns_zt_apply(dns_zt_t *zt, bool stop,

+dns_zt_apply(dns_zt_t *zt, isc_rwlocktype_t lock, bool stop,

 	     isc_result_t (*action)(dns_zone_t *, void *), void *uap)

 {

-	return (dns_zt_apply2(zt, stop, NULL, action, uap));

+	return (dns_zt_apply2(zt, lock, stop, NULL, action, uap));

 }

 isc_result_t

-dns_zt_apply2(dns_zt_t *zt, bool stop, isc_result_t *sub,

+dns_zt_apply2(dns_zt_t *zt, isc_rwlocktype_t lock, bool stop, isc_result_t *sub,

 	      isc_result_t (*action)(dns_zone_t *, void *), void *uap)

 {

 	dns_rbtnode_t *node;

@@ -508,6 +503,10 @@ dns_zt_apply2(dns_zt_t *zt, bool stop, isc_result_t *sub,

 	REQUIRE(VALID_ZT(zt));

 	REQUIRE(action != NULL);

+	if (lock != isc_rwlocktype_none) {

+		RWLOCK(&zt->rwlock, lock);

+	}

+

 	dns_rbtnodechain_init(&chain, zt->mctx);

 	result = dns_rbtnodechain_first(&chain, zt->table, NULL, NULL);

 	if (result == ISC_R_NOTFOUND) {

@@ -538,8 +537,13 @@ dns_zt_apply2(dns_zt_t *zt, bool stop, isc_result_t *sub,

  cleanup:

 	dns_rbtnodechain_invalidate(&chain);

-	if (sub != NULL)

+	if (sub != NULL) {

 		*sub = tresult;

+	}

+

+	if (lock != isc_rwlocktype_none) {

+		RWUNLOCK(&zt->rwlock, lock);

+	}

 	return (result);

 }

-- 

2.37.2