new: dev: Implement -T cookiealwaysvalid

When `-T cookiealwaysvalid` is passed to `named`, DNS cookie checks for
the incoming queries always pass, given they are structurally correct.

Merge branch 'aram/new-named-minus-T-option-of-cookiealwaysvalid' into 'main'

See merge request isc-projects/bind9!10232

bin/named/main.c

@@ -129,6 +129,7 @@ static int maxudp = 0;
 /*
  * -T options:
  */
+static bool cookiealwaysvalid = false;
 static bool dropedns = false;
 static bool ednsformerr = false;
 static bool ednsnotimp = false;
@@ -652,7 +653,9 @@ parse_T_opt(char *option) {
 	 * force the server to behave (or misbehave) in
 	 * specified ways for testing purposes.
 	 */
-	if (!strcmp(option, "dropedns")) {
+	if (!strcmp(option, "cookiealwaysvalid")) {
+		cookiealwaysvalid = true;
+	} else if (!strcmp(option, "dropedns")) {
 		dropedns = true;
 	} else if (!strcmp(option, "ednsformerr")) {
 		ednsformerr = true;
@@ -1220,6 +1223,9 @@ setup(void) {
 	/*
 	 * Modify server context according to command line options
 	 */
+	if (cookiealwaysvalid) {
+		ns_server_setoption(sctx, NS_SERVER_COOKIEALWAYSVALID, true);
+	}
 	if (disable4) {
 		ns_server_setoption(sctx, NS_SERVER_DISABLE4, true);
 	}

bin/tests/system/cookie/tests.sh

@@ -361,6 +361,23 @@ grep "status: NOERROR," dig.out.test$n >/dev/null || ret=1
 if [ $ret != 0 ]; then echo_i "failed"; fi
 status=$((status + ret))
 
+n=$((n + 1))
+echo_i "Restart NS4 with -T cookiealwaysvalid ($n)"
+stop_server ns4
+touch ns4/named.cookiealwaysvalid
+start_server --noclean --restart --port ${PORT} ns4 || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=$((status + ret))
+
+n=$((n + 1))
+echo_i "test NS6 cookie on NS4 with -T cookiealwaysvalid (expect success) ($n)"
+ret=0
+$DIG $DIGOPTS +cookie=$ns6cookie -b 10.53.0.4 +nobadcookie soa . @10.53.0.4 >dig.out.test$n || ret=1
+grep "; COOKIE:.*(good)" dig.out.test$n >/dev/null || ret=1
+grep "status: NOERROR," dig.out.test$n >/dev/null || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=$((status + ret))
+
 n=$((n + 1))
 echo_i "check that test server is correctly configured ($n)"
 ret=0

bin/tests/system/cookie/tests_sh_cookie.py

@@ -19,6 +19,7 @@ pytestmark = pytest.mark.extra_artifacts(
         "ans*/ans.run",
         "ans*/query.log",
         "ns1/named_dump.db*",
+        "ns4/named.cookiealwaysvalid",
     ]
 )
 

bin/tests/system/start.pl

@@ -264,7 +264,8 @@ sub construct_ns_command {
 
 		foreach my $t_option(
 			"dropedns", "ednsformerr", "ednsnotimp", "ednsrefused",
-			"noaa", "noedns", "nosoa", "maxudp512", "maxudp1460",
+			"cookiealwaysvalid", "noaa", "noedns", "nosoa",
+			"maxudp512", "maxudp1460",
 		    ) {
 			if (-e "$testdir/$server/named.$t_option") {
 				$command .= "-T $t_option "

lib/ns/client.c

@@ -1290,6 +1290,7 @@ process_cookie(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
 	isc_stdtime_t now;
 	uint32_t when;
 	isc_buffer_t db;
+	bool alwaysvalid;
 
 	/*
 	 * If we have already seen a cookie option skip this cookie option.
@@ -1335,11 +1336,22 @@ process_cookie(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
 	when = isc_buffer_getuint32(buf);
 	isc_buffer_forward(buf, 8);
 
+	/*
+	 * For '-T cookiealwaysvalid' still process everything to not skew any
+	 * performance tests involving cookies, but make sure that the cookie
+	 * check passes in the end, given the cookie was structurally correct.
+	 */
+	alwaysvalid = ns_server_getoption(client->manager->sctx,
+					  NS_SERVER_COOKIEALWAYSVALID);
+
 	/*
 	 * Allow for a 5 minute clock skew between servers sharing a secret.
 	 * Only accept COOKIE if we have talked to the client in the last hour.
 	 */
 	now = isc_stdtime_now();
+	if (alwaysvalid) {
+		now = when;
+	}
 	if (isc_serial_gt(when, (now + 300)) /* In the future. */ ||
 	    isc_serial_lt(when, (now - 3600)) /* In the past. */)
 	{
@@ -1352,7 +1364,7 @@ process_cookie(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
 	isc_buffer_init(&db, dbuf, sizeof(dbuf));
 	compute_cookie(client, when, client->manager->sctx->secret, &db);
 
-	if (isc_safe_memequal(old, dbuf, COOKIE_SIZE)) {
+	if (isc_safe_memequal(old, dbuf, COOKIE_SIZE) || alwaysvalid) {
 		ns_stats_increment(client->manager->sctx->nsstats,
 				   ns_statscounter_cookiematch);
 		client->attributes |= NS_CLIENTATTR_HAVECOOKIE;

lib/ns/include/ns/server.h

@@ -50,6 +50,7 @@
 #define NS_SERVER_TRANSFERSLOWLY    0x00010000U /*%< -T transferslowly */
 #define NS_SERVER_TRANSFERSTUCK	    0x00020000U /*%< -T transferstuck */
 #define NS_SERVER_LOGRESPONSES	    0x00040000U /*%< log responses */
+#define NS_SERVER_COOKIEALWAYSVALID 0x00080000U /*%< -T cookiealwaysvalid */
 
 /*%
  * Type for callback function to get hostname.