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From cba333b262b7ee0034a66cc93cf27f6c4918eea2 Mon Sep 17 00:00:00 2001
From: Evan Hunt <each@isc.org>
Date: Tue, 8 Nov 2022 17:32:41 -0800
Subject: [PATCH] move update ACL and update-policy checks before quota
check allow-update, update-policy, and allow-update-forwarding before
consuming quota slots, so that unauthorized clients can't fill the
quota.
(this moves the access check before the prerequisite check, which
violates the precise wording of RFC 2136. however, RFC co-author Paul
Vixie has stated that the RFC is mistaken on this point; it should have
said that access checking must happen *no later than* the completion of
prerequisite checks, not that it must happen exactly then.)
(cherry picked from commit 964f559edb5036880b8e463b8f190b9007ee055d)
---
bin/named/update.c | 440 ++++++++++++++++++++++++++++++---------------
1 file changed, 298 insertions(+), 142 deletions(-)
diff --git a/bin/named/update.c b/bin/named/update.c
index 8853ee7..4d1fe78 100644
--- a/bin/named/update.c
+++ b/bin/named/update.c
@@ -251,6 +251,9 @@ static void updatedone_action(isc_task_t *task, isc_event_t *event);
static isc_result_t send_forward_event(ns_client_t *client, dns_zone_t *zone);
static void forward_done(isc_task_t *task, isc_event_t *event);
static isc_result_t add_rr_prepare_action(void *data, rr_t *rr);
+static isc_result_t
+rr_exists(dns_db_t *db, dns_dbversion_t *ver, dns_name_t *name,
+ const dns_rdata_t *rdata, bool *flag);
/**************************************************************************/
@@ -328,23 +331,24 @@ checkqueryacl(ns_client_t *client, dns_acl_t *queryacl, dns_name_t *zonename,
{
char namebuf[DNS_NAME_FORMATSIZE];
char classbuf[DNS_RDATACLASS_FORMATSIZE];
- int level;
isc_result_t result;
+ bool update_possible =
+ ((updateacl != NULL && !dns_acl_isnone(updateacl)) ||
+ ssutable != NULL);
result = ns_client_checkaclsilent(client, NULL, queryacl, true);
if (result != ISC_R_SUCCESS) {
+ int level = update_possible ? ISC_LOG_ERROR : ISC_LOG_INFO;
+
dns_name_format(zonename, namebuf, sizeof(namebuf));
dns_rdataclass_format(client->view->rdclass, classbuf,
sizeof(classbuf));
- level = (updateacl == NULL && ssutable == NULL) ?
- ISC_LOG_INFO : ISC_LOG_ERROR;
-
ns_client_log(client, NS_LOGCATEGORY_UPDATE_SECURITY,
NS_LOGMODULE_UPDATE, level,
"update '%s/%s' denied due to allow-query",
namebuf, classbuf);
- } else if (updateacl == NULL && ssutable == NULL) {
+ } else if (!update_possible) {
dns_name_format(zonename, namebuf, sizeof(namebuf));
dns_rdataclass_format(client->view->rdclass, classbuf,
sizeof(classbuf));
@@ -1525,6 +1529,277 @@ send_update_event(ns_client_t *client, dns_zone_t *zone) {
update_event_t *event = NULL;
isc_task_t *zonetask = NULL;
ns_client_t *evclient;
+#if 1
+ dns_ssutable_t *ssutable = NULL;
+ dns_message_t *request = client->message;
+ dns_rdataclass_t zoneclass;
+ dns_rdatatype_t covers;
+ dns_name_t *zonename = NULL;
+ dns_db_t *db = NULL;
+ dns_dbversion_t *ver = NULL;
+
+ CHECK(dns_zone_getdb(zone, &db));
+ zonename = dns_db_origin(db);
+ zoneclass = dns_db_class(db);
+ dns_zone_getssutable(zone, &ssutable);
+ dns_db_currentversion(db, &ver);
+
+ /*
+ * Update message processing can leak record existence information
+ * so check that we are allowed to query this zone. Additionally,
+ * if we would refuse all updates for this zone, we bail out here.
+ */
+ CHECK(checkqueryacl(client, dns_zone_getqueryacl(zone),
+ dns_zone_getorigin(zone),
+ dns_zone_getupdateacl(zone), ssutable));
+
+ /*
+ * Check requestor's permissions.
+ */
+ if (ssutable == NULL)
+ CHECK(checkupdateacl(client, dns_zone_getupdateacl(zone),
+ "update", zonename, false, false));
+ else if (client->signer == NULL && !TCPCLIENT(client))
+ CHECK(checkupdateacl(client, NULL, "update", zonename,
+ false, true));
+
+ if (dns_zone_getupdatedisabled(zone))
+ FAILC(DNS_R_REFUSED, "dynamic update temporarily disabled "
+ "because the zone is frozen. Use "
+ "'rndc thaw' to re-enable updates.");
+
+ /*
+ * Perform the Update Section Prescan.
+ */
+
+ for (result = dns_message_firstname(request, DNS_SECTION_UPDATE);
+ result == ISC_R_SUCCESS;
+ result = dns_message_nextname(request, DNS_SECTION_UPDATE))
+ {
+ dns_name_t *name = NULL;
+ dns_rdata_t rdata = DNS_RDATA_INIT;
+ dns_ttl_t ttl;
+ dns_rdataclass_t update_class;
+ get_current_rr(request, DNS_SECTION_UPDATE, zoneclass,
+ &name, &rdata, &covers, &ttl, &update_class);
+
+ if (! dns_name_issubdomain(name, zonename))
+ FAILC(DNS_R_NOTZONE,
+ "update RR is outside zone");
+ if (update_class == zoneclass) {
+ /*
+ * Check for meta-RRs. The RFC2136 pseudocode says
+ * check for ANY|AXFR|MAILA|MAILB, but the text adds
+ * "or any other QUERY metatype"
+ */
+ if (dns_rdatatype_ismeta(rdata.type)) {
+ FAILC(DNS_R_FORMERR,
+ "meta-RR in update");
+ }
+ result = dns_zone_checknames(zone, name, &rdata);
+ if (result != ISC_R_SUCCESS)
+ FAIL(DNS_R_REFUSED);
+ } else if (update_class == dns_rdataclass_any) {
+ if (ttl != 0 || rdata.length != 0 ||
+ (dns_rdatatype_ismeta(rdata.type) &&
+ rdata.type != dns_rdatatype_any))
+ FAILC(DNS_R_FORMERR,
+ "meta-RR in update");
+ } else if (update_class == dns_rdataclass_none) {
+ if (ttl != 0 ||
+ dns_rdatatype_ismeta(rdata.type))
+ FAILC(DNS_R_FORMERR,
+ "meta-RR in update");
+ } else {
+ update_log(client, zone, ISC_LOG_WARNING,
+ "update RR has incorrect class %d",
+ update_class);
+ FAIL(DNS_R_FORMERR);
+ }
+
+ /*
+ * draft-ietf-dnsind-simple-secure-update-01 says
+ * "Unlike traditional dynamic update, the client
+ * is forbidden from updating NSEC records."
+ */
+ if (rdata.type == dns_rdatatype_nsec3) {
+ FAILC(DNS_R_REFUSED,
+ "explicit NSEC3 updates are not allowed "
+ "in secure zones");
+ } else if (rdata.type == dns_rdatatype_nsec) {
+ FAILC(DNS_R_REFUSED,
+ "explicit NSEC updates are not allowed "
+ "in secure zones");
+ } else if (rdata.type == dns_rdatatype_rrsig &&
+ !dns_name_equal(name, zonename)) {
+ FAILC(DNS_R_REFUSED,
+ "explicit RRSIG updates are currently "
+ "not supported in secure zones except "
+ "at the apex");
+ }
+
+ if (ssutable != NULL) {
+ isc_netaddr_t netaddr;
+ dst_key_t *tsigkey = NULL;
+ isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+
+ if (client->message->tsigkey != NULL)
+ tsigkey = client->message->tsigkey->key;
+
+ if (rdata.type != dns_rdatatype_any) {
+ if (!dns_ssutable_checkrules2
+ (ssutable, client->signer, name, &netaddr,
+ TCPCLIENT(client),
+ &ns_g_server->aclenv,
+ rdata.type, tsigkey))
+ {
+ FAILC(DNS_R_REFUSED,
+ "rejected by secure update");
+ }
+ } else {
+ if (!ssu_checkall(db, ver, name, ssutable,
+ client->signer,
+ &netaddr,
+ TCPCLIENT(client),
+ tsigkey))
+ {
+ FAILC(DNS_R_REFUSED,
+ "rejected by secure update");
+ }
+ }
+ }
+ }
+ if (result != ISC_R_NOMORE)
+ FAIL(result);
+
+ update_log(client, zone, LOGLEVEL_DEBUG,
+ "update section prescan OK");
+#if 0
+ if (ssutable == NULL) {
+ CHECK(checkupdateacl(client, dns_zone_getupdateacl(zone),
+ // zonename
+ "update", dns_zone_getorigin(zone), false,
+ false));
+ } else if (client->signer == NULL && !TCPCLIENT(client)) {
+ CHECK(checkupdateacl(client, NULL, "update",
+ dns_zone_getorigin(zone), false, true));
+ }
+
+ if (dns_zone_getupdatedisabled(zone)) {
+ FAILC(DNS_R_REFUSED, "dynamic update temporarily disabled "
+ "because the zone is frozen. Use "
+ "'rndc thaw' to re-enable updates.");
+ }
+
+ /*
+ * Prescan the update section, checking for updates that
+ * are illegal or violate policy.
+ */
+ for (result = dns_message_firstname(request, DNS_SECTION_UPDATE);
+ result == ISC_R_SUCCESS;
+ result = dns_message_nextname(request, DNS_SECTION_UPDATE))
+ {
+ dns_name_t *name = NULL;
+ dns_rdata_t rdata = DNS_RDATA_INIT;
+ dns_ttl_t ttl;
+ dns_rdataclass_t update_class;
+
+ get_current_rr(request, DNS_SECTION_UPDATE, zoneclass, &name,
+ &rdata, &covers, &ttl, &update_class);
+
+ if (!dns_name_issubdomain(name, zonename)) {
+ FAILC(DNS_R_NOTZONE, "update RR is outside zone");
+ }
+ if (update_class == zoneclass) {
+ /*
+ * Check for meta-RRs. The RFC2136 pseudocode says
+ * check for ANY|AXFR|MAILA|MAILB, but the text adds
+ * "or any other QUERY metatype"
+ */
+ if (dns_rdatatype_ismeta(rdata.type)) {
+ FAILC(DNS_R_FORMERR, "meta-RR in update");
+ }
+ result = dns_zone_checknames(zone, name, &rdata);
+ if (result != ISC_R_SUCCESS) {
+ FAIL(DNS_R_REFUSED);
+ }
+ } else if (update_class == dns_rdataclass_any) {
+ if (ttl != 0 || rdata.length != 0 ||
+ (dns_rdatatype_ismeta(rdata.type) &&
+ rdata.type != dns_rdatatype_any))
+ {
+ FAILC(DNS_R_FORMERR, "meta-RR in update");
+ }
+ } else if (update_class == dns_rdataclass_none) {
+ if (ttl != 0 || dns_rdatatype_ismeta(rdata.type)) {
+ FAILC(DNS_R_FORMERR, "meta-RR in update");
+ }
+ } else {
+ update_log(client, zone, ISC_LOG_WARNING,
+ "update RR has incorrect class %d",
+ update_class);
+ FAIL(DNS_R_FORMERR);
+ }
+
+ /*
+ * draft-ietf-dnsind-simple-secure-update-01 says
+ * "Unlike traditional dynamic update, the client
+ * is forbidden from updating NSEC records."
+ */
+ if (rdata.type == dns_rdatatype_nsec3) {
+ FAILC(DNS_R_REFUSED, "explicit NSEC3 updates are not "
+ "allowed "
+ "in secure zones");
+ } else if (rdata.type == dns_rdatatype_nsec) {
+ FAILC(DNS_R_REFUSED, "explicit NSEC updates are not "
+ "allowed "
+ "in secure zones");
+ } else if (rdata.type == dns_rdatatype_rrsig &&
+ !dns_name_equal(name, zonename))
+ {
+ FAILC(DNS_R_REFUSED, "explicit RRSIG updates are "
+ "currently "
+ "not supported in secure zones "
+ "except "
+ "at the apex");
+ }
+
+ if (ssutable != NULL) {
+ isc_netaddr_t netaddr;
+ dst_key_t *tsigkey = NULL;
+ isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
+
+ if (client->message->tsigkey != NULL) {
+ tsigkey = client->message->tsigkey->key;
+ }
+
+ if (rdata.type != dns_rdatatype_any) {
+ if (!dns_ssutable_checkrules(
+ ssutable, client->signer, name,
+ &netaddr, TCPCLIENT(client), env,
+ rdata.type, tsigkey))
+ {
+ FAILC(DNS_R_REFUSED, "rejected by "
+ "secure update");
+ }
+ } else {
+ if (!ssu_checkall(db, ver, name, ssutable,
+ client->signer, &netaddr, env,
+ TCPCLIENT(client), tsigkey))
+ {
+ FAILC(DNS_R_REFUSED, "rejected by "
+ "secure update");
+ }
+ }
+ }
+ }
+ if (result != ISC_R_NOMORE) {
+ FAIL(result);
+ }
+
+ update_log(client, zone, LOGLEVEL_DEBUG, "update section prescan OK");
+#endif
+#endif
result = isc_quota_attach(&ns_g_server->updquota,
&(isc_quota_t *){ NULL });
@@ -1558,6 +1833,15 @@ send_update_event(ns_client_t *client, dns_zone_t *zone) {
failure:
if (event != NULL)
isc_event_free(ISC_EVENT_PTR(&event));
+ if (db != NULL) {
+ dns_db_closeversion(db, &ver, false);
+ dns_db_detach(&db);
+ }
+
+ if (ssutable != NULL) {
+ dns_ssutable_detach(&ssutable);
+ }
+
return (result);
}
@@ -1644,9 +1928,6 @@ ns_update_start(ns_client_t *client, isc_result_t sigresult) {
CHECK(send_update_event(client, zone));
break;
case dns_zone_slave:
- CHECK(checkupdateacl(client, dns_zone_getforwardacl(zone),
- "update forwarding", zonename, true,
- false));
CHECK(send_forward_event(client, zone));
break;
default:
@@ -1656,7 +1937,6 @@ ns_update_start(ns_client_t *client, isc_result_t sigresult) {
failure:
if (result == DNS_R_REFUSED) {
- INSIST(dns_zone_gettype(zone) == dns_zone_slave);
inc_stats(zone, dns_nsstatscounter_updaterej);
}
/*
@@ -2520,7 +2800,7 @@ update_action(isc_task_t *task, isc_event_t *event) {
dns_rdatatype_t covers;
dns_message_t *request = client->message;
dns_rdataclass_t zoneclass;
- dns_name_t *zonename;
+ dns_name_t *zonename = NULL;
dns_ssutable_t *ssutable = NULL;
dns_fixedname_t tmpnamefixed;
dns_name_t *tmpname = NULL;
@@ -2542,14 +2822,7 @@ update_action(isc_task_t *task, isc_event_t *event) {
zonename = dns_db_origin(db);
zoneclass = dns_db_class(db);
dns_zone_getssutable(zone, &ssutable);
-
- /*
- * Update message processing can leak record existence information
- * so check that we are allowed to query this zone. Additionally
- * if we would refuse all updates for this zone we bail out here.
- */
- CHECK(checkqueryacl(client, dns_zone_getqueryacl(zone), zonename,
- dns_zone_getupdateacl(zone), ssutable));
+ options = dns_zone_getoptions(zone);
/*
* Get old and new versions now that queryacl has been checked.
@@ -2673,134 +2946,10 @@ update_action(isc_task_t *task, isc_event_t *event) {
update_log(client, zone, LOGLEVEL_DEBUG,
"prerequisites are OK");
- /*
- * Check Requestor's Permissions. It seems a bit silly to do this
- * only after prerequisite testing, but that is what RFC2136 says.
- */
- if (ssutable == NULL)
- CHECK(checkupdateacl(client, dns_zone_getupdateacl(zone),
- "update", zonename, false, false));
- else if (client->signer == NULL && !TCPCLIENT(client))
- CHECK(checkupdateacl(client, NULL, "update", zonename,
- false, true));
-
- if (dns_zone_getupdatedisabled(zone))
- FAILC(DNS_R_REFUSED, "dynamic update temporarily disabled "
- "because the zone is frozen. Use "
- "'rndc thaw' to re-enable updates.");
-
- /*
- * Perform the Update Section Prescan.
- */
-
- for (result = dns_message_firstname(request, DNS_SECTION_UPDATE);
- result == ISC_R_SUCCESS;
- result = dns_message_nextname(request, DNS_SECTION_UPDATE))
- {
- dns_name_t *name = NULL;
- dns_rdata_t rdata = DNS_RDATA_INIT;
- dns_ttl_t ttl;
- dns_rdataclass_t update_class;
- get_current_rr(request, DNS_SECTION_UPDATE, zoneclass,
- &name, &rdata, &covers, &ttl, &update_class);
-
- if (! dns_name_issubdomain(name, zonename))
- FAILC(DNS_R_NOTZONE,
- "update RR is outside zone");
- if (update_class == zoneclass) {
- /*
- * Check for meta-RRs. The RFC2136 pseudocode says
- * check for ANY|AXFR|MAILA|MAILB, but the text adds
- * "or any other QUERY metatype"
- */
- if (dns_rdatatype_ismeta(rdata.type)) {
- FAILC(DNS_R_FORMERR,
- "meta-RR in update");
- }
- result = dns_zone_checknames(zone, name, &rdata);
- if (result != ISC_R_SUCCESS)
- FAIL(DNS_R_REFUSED);
- } else if (update_class == dns_rdataclass_any) {
- if (ttl != 0 || rdata.length != 0 ||
- (dns_rdatatype_ismeta(rdata.type) &&
- rdata.type != dns_rdatatype_any))
- FAILC(DNS_R_FORMERR,
- "meta-RR in update");
- } else if (update_class == dns_rdataclass_none) {
- if (ttl != 0 ||
- dns_rdatatype_ismeta(rdata.type))
- FAILC(DNS_R_FORMERR,
- "meta-RR in update");
- } else {
- update_log(client, zone, ISC_LOG_WARNING,
- "update RR has incorrect class %d",
- update_class);
- FAIL(DNS_R_FORMERR);
- }
-
- /*
- * draft-ietf-dnsind-simple-secure-update-01 says
- * "Unlike traditional dynamic update, the client
- * is forbidden from updating NSEC records."
- */
- if (rdata.type == dns_rdatatype_nsec3) {
- FAILC(DNS_R_REFUSED,
- "explicit NSEC3 updates are not allowed "
- "in secure zones");
- } else if (rdata.type == dns_rdatatype_nsec) {
- FAILC(DNS_R_REFUSED,
- "explicit NSEC updates are not allowed "
- "in secure zones");
- } else if (rdata.type == dns_rdatatype_rrsig &&
- !dns_name_equal(name, zonename)) {
- FAILC(DNS_R_REFUSED,
- "explicit RRSIG updates are currently "
- "not supported in secure zones except "
- "at the apex");
- }
-
- if (ssutable != NULL) {
- isc_netaddr_t netaddr;
- dst_key_t *tsigkey = NULL;
- isc_netaddr_fromsockaddr(&netaddr, &client->peeraddr);
-
- if (client->message->tsigkey != NULL)
- tsigkey = client->message->tsigkey->key;
-
- if (rdata.type != dns_rdatatype_any) {
- if (!dns_ssutable_checkrules2
- (ssutable, client->signer, name, &netaddr,
- TCPCLIENT(client),
- &ns_g_server->aclenv,
- rdata.type, tsigkey))
- {
- FAILC(DNS_R_REFUSED,
- "rejected by secure update");
- }
- } else {
- if (!ssu_checkall(db, ver, name, ssutable,
- client->signer,
- &netaddr,
- TCPCLIENT(client),
- tsigkey))
- {
- FAILC(DNS_R_REFUSED,
- "rejected by secure update");
- }
- }
- }
- }
- if (result != ISC_R_NOMORE)
- FAIL(result);
-
- update_log(client, zone, LOGLEVEL_DEBUG,
- "update section prescan OK");
-
/*
* Process the Update Section.
*/
- options = dns_zone_getoptions(zone);
options2 = dns_zone_getoptions2(zone);
for (result = dns_message_firstname(request, DNS_SECTION_UPDATE);
result == ISC_R_SUCCESS;
@@ -3494,6 +3643,13 @@ send_forward_event(ns_client_t *client, dns_zone_t *zone) {
isc_task_t *zonetask = NULL;
ns_client_t *evclient;
+ result = checkupdateacl(client, dns_zone_getforwardacl(zone),
+ "update forwarding", dns_zone_getorigin(zone),
+ true, false);
+ if (result != ISC_R_SUCCESS) {
+ return (result);
+ }
+
result = isc_quota_attach(&ns_g_server->updquota,
&(isc_quota_t *){ NULL });
if (result != ISC_R_SUCCESS) {
--
2.39.2
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