- For #762: Interaction between DNS Cookies and source IP ratelimiting

by allowing Cookies to bypass the ratelimit, but still allowing
  ratelimit to valid DNS Cookie clients via the new
  ip-ratelimit-cookie option.

daemon/worker.c

@@ -1319,6 +1319,40 @@ deny_refuse_non_local(struct comm_point* c, enum acl_access acl,
 		worker, repinfo, acladdr, ede, check_result);
 }
 
+/* Returns 1 if the ip rate limit check can happen before EDNS parsing,
+ * else 0 */
+static int
+pre_edns_ip_ratelimit_check(enum acl_access acl)
+{
+	if(acl == acl_allow_cookie) return 0;
+	return 1;
+}
+
+/* Check if the query is blocked by source IP rate limiting.
+ * Returns 1 if it passes the check, 0 otherwise. */
+static int
+check_ip_ratelimit(struct worker* worker, struct sockaddr_storage* addr,
+	socklen_t addrlen, int has_cookie, sldns_buffer* pkt)
+{
+	if(!infra_ip_ratelimit_inc(worker->env.infra_cache, addr, addrlen,
+			*worker->env.now, has_cookie,
+			worker->env.cfg->ip_ratelimit_backoff, pkt)) {
+		/* See if we can pass through with slip factor */
+		if(!has_cookie && worker->env.cfg->ip_ratelimit_factor != 0 &&
+			ub_random_max(worker->env.rnd,
+			worker->env.cfg->ip_ratelimit_factor) == 0) {
+			char addrbuf[128];
+			addr_to_str(addr, addrlen, addrbuf, sizeof(addrbuf));
+			verbose(VERB_QUERY, "ip_ratelimit allowed through for "
+				"ip address %s because of slip in "
+				"ip_ratelimit_factor", addrbuf);
+			return 1;
+		}
+		return 0;
+	}
+	return 1;
+}
+
 int
 worker_handle_request(struct comm_point* c, void* arg, int error,
 	struct comm_reply* repinfo)
@@ -1332,6 +1366,7 @@ worker_handle_request(struct comm_point* c, void* arg, int error,
 	struct edns_option* original_edns_list = NULL;
 	enum acl_access acl;
 	struct acl_addr* acladdr;
+	int pre_edns_ip_ratelimit = 1;
 	int rc = 0;
 	int need_drop = 0;
 	int is_expired_answer = 0;
@@ -1456,33 +1491,21 @@ worker_handle_request(struct comm_point* c, void* arg, int error,
 	}
 
 	worker->stats.num_queries++;
+	pre_edns_ip_ratelimit = pre_edns_ip_ratelimit_check(acl);
 
-	/* check if this query should be dropped based on source ip rate limiting
-	 * NOTE: we always check the repinfo->client_address. IP ratelimiting is
-	 *       implicitly disabled for proxies. */
-	if(!infra_ip_ratelimit_inc(worker->env.infra_cache,
-			&repinfo->client_addr, repinfo->client_addrlen,
-			*worker->env.now,
-			worker->env.cfg->ip_ratelimit_backoff, c->buffer)) {
-		/* See if we are passed through with slip factor */
-		if(worker->env.cfg->ip_ratelimit_factor != 0 &&
-			ub_random_max(worker->env.rnd,
-			worker->env.cfg->ip_ratelimit_factor) == 0) {
-			char addrbuf[128];
-			addr_to_str(&repinfo->client_addr,
-				repinfo->client_addrlen, addrbuf,
-				sizeof(addrbuf));
-			verbose(VERB_QUERY, "ip_ratelimit allowed through for "
-				"ip address %s because of slip in "
-				"ip_ratelimit_factor", addrbuf);
-		} else {
+	/* If the IP rate limiting check needs extra EDNS information (e.g.,
+	 * DNS Cookies) postpone the check until after EDNS is parsed. */
+	if(pre_edns_ip_ratelimit) {
+		/* NOTE: we always check the repinfo->client_address.
+		 *       IP ratelimiting is implicitly disabled for proxies. */
+		if(!check_ip_ratelimit(worker, &repinfo->client_addr,
+			repinfo->client_addrlen, 0, c->buffer)) {
 			worker->stats.num_queries_ip_ratelimited++;
 			comm_point_drop_reply(repinfo);
 			return 0;
 		}
 	}
 
-	/* see if query is in the cache */
 	if(!query_info_parse(&qinfo, c->buffer)) {
 		verbose(VERB_ALGO, "worker parse request: formerror.");
 		log_addr(VERB_CLIENT, "from", &repinfo->client_addr,
@@ -1579,6 +1602,19 @@ worker_handle_request(struct comm_point* c, void* arg, int error,
 		}
 	}
 
+	/* If the IP rate limiting check was postponed, check now. */
+	if(!pre_edns_ip_ratelimit) {
+		/* NOTE: we always check the repinfo->client_address.
+		 *       IP ratelimiting is implicitly disabled for proxies. */
+		if(!check_ip_ratelimit(worker, &repinfo->client_addr,
+			repinfo->client_addrlen, edns.cookie_valid,
+			c->buffer)) {
+			worker->stats.num_queries_ip_ratelimited++;
+			comm_point_drop_reply(repinfo);
+			return 0;
+		}
+	}
+
 	/* "if, else if" sequence below deals with downstream DNS Cookies */
 	if(acl != acl_allow_cookie)
 		; /* pass; No cookie downstream processing whatsoever */

doc/unbound.conf.5.in

@@ -747,6 +747,10 @@ generated DNS Cookie, allowing clients to retry with that DNS Cookie.
 The \fIallow_cookie\fR action will also accept requests over stateful
 transports, regardless of the presence of an DNS Cookie and regardless of the
 \fBanswer\-cookie\fR setting.
+If \fBip\-ratelimit\fR is used, clients with a valid DNS Cookie will bypass the
+ratelimit.
+If a ratelimit for such clients is still needed, \fBip\-ratelimit\-cookie\fR
+can be used instead.
 .IP
 By default only localhost is \fIallow\fRed, the rest is \fIrefuse\fRd.
 The default is \fIrefuse\fRd, because that is protocol\-friendly. The DNS
@@ -1816,11 +1820,27 @@ A value of 0 will disable ratelimiting for domain names that end in this name.
 .TP 5
 .B ip\-ratelimit: \fI<number or 0>
 Enable global ratelimiting of queries accepted per IP address.
-If 0, the default, it is disabled.  This option is experimental at this time.
+This option is experimental at this time.
 The ratelimit is in queries per second that are allowed.  More queries are
 completely dropped and will not receive a reply, SERVFAIL or otherwise.
 IP ratelimiting happens before looking in the cache. This may be useful for
 mitigating amplification attacks.
+Default is 0 (disabled).
+.TP 5
+.B ip\-ratelimit\-cookie: \fI<number or 0>
+Enable global ratelimiting of queries accepted per IP address with a valid DNS
+Cookie.
+This option is experimental at this time.
+The ratelimit is in queries per second that are allowed.
+More queries are completely dropped and will not receive a reply, SERVFAIL or
+otherwise.
+IP ratelimiting happens before looking in the cache.
+This option could be useful in combination with \fIallow_cookie\fR in an
+attempt to mitigate other amplification attacks than UDP reflections (e.g.,
+attacks targeting Unbound itself) which are already handled with DNS Cookies.
+If used, the value is suggested to be higher than \fBip\-ratelimit\fR e.g.,
+tenfold.
+Default is 0 (disabled).
 .TP 5
 .B ip\-ratelimit\-size: \fI<memory size>
 Give the size of the data structure in which the current ongoing rates are

services/cache/infra.c

@@ -67,6 +67,11 @@ int infra_dp_ratelimit = 0;
  *  in queries per second. */
 int infra_ip_ratelimit = 0;
 
+/** ratelimit value for client ip addresses,
+ *  in queries per second.
+ *  For clients with a valid DNS Cookie. */
+int infra_ip_ratelimit_cookie = 0;
+
 size_t 
 infra_sizefunc(void* k, void* ATTR_UNUSED(d))
 {
@@ -1051,9 +1056,50 @@ infra_get_mem(struct infra_cache* infra)
 	return s;
 }
 
+/* Returns 1 if the limit has not been exceeded, 0 otherwise. */
+static int
+check_ip_ratelimit(struct sockaddr_storage* addr, socklen_t addrlen,
+	struct sldns_buffer* buffer, int premax, int max, int has_cookie)
+{
+	int limit;
+
+	if(has_cookie) limit = infra_ip_ratelimit_cookie;
+	else           limit = infra_ip_ratelimit;
+
+	/* Disabled */
+	if(limit == 0) return 1;
+
+	if(premax <= limit && max > limit) {
+		char client_ip[128], qnm[LDNS_MAX_DOMAINLEN+1+12+12];
+		addr_to_str(addr, addrlen, client_ip, sizeof(client_ip));
+		qnm[0]=0;
+		if(sldns_buffer_limit(buffer)>LDNS_HEADER_SIZE &&
+			LDNS_QDCOUNT(sldns_buffer_begin(buffer))!=0) {
+			(void)sldns_wire2str_rrquestion_buf(
+				sldns_buffer_at(buffer, LDNS_HEADER_SIZE),
+				sldns_buffer_limit(buffer)-LDNS_HEADER_SIZE,
+				qnm, sizeof(qnm));
+			if(strlen(qnm)>0 && qnm[strlen(qnm)-1]=='\n')
+				qnm[strlen(qnm)-1] = 0; /*remove newline*/
+			if(strchr(qnm, '\t'))
+				*strchr(qnm, '\t') = ' ';
+			if(strchr(qnm, '\t'))
+				*strchr(qnm, '\t') = ' ';
+			verbose(VERB_OPS, "ip_ratelimit exceeded %s %d%s %s",
+				client_ip, limit,
+				has_cookie?"(cookie)":"", qnm);
+		} else {
+			verbose(VERB_OPS, "ip_ratelimit exceeded %s %d%s (no query name)",
+				client_ip, limit,
+				has_cookie?"(cookie)":"");
+		}
+	}
+	return (max <= limit);
+}
+
 int infra_ip_ratelimit_inc(struct infra_cache* infra,
 	struct sockaddr_storage* addr, socklen_t addrlen, time_t timenow,
-	int backoff, struct sldns_buffer* buffer)
+	int has_cookie, int backoff, struct sldns_buffer* buffer)
 {
 	int max;
 	struct lruhash_entry* entry;
@@ -1070,31 +1116,8 @@ int infra_ip_ratelimit_inc(struct infra_cache* infra,
 		(*cur)++;
 		max = infra_rate_max(entry->data, timenow, backoff);
 		lock_rw_unlock(&entry->lock);
-
-		if(premax <= infra_ip_ratelimit && max > infra_ip_ratelimit) {
-			char client_ip[128], qnm[LDNS_MAX_DOMAINLEN+1+12+12];
-			addr_to_str(addr, addrlen, client_ip, sizeof(client_ip));
-			qnm[0]=0;
-			if(sldns_buffer_limit(buffer)>LDNS_HEADER_SIZE &&
-				LDNS_QDCOUNT(sldns_buffer_begin(buffer))!=0) {
-				(void)sldns_wire2str_rrquestion_buf(
-					sldns_buffer_at(buffer, LDNS_HEADER_SIZE),
-					sldns_buffer_limit(buffer)-LDNS_HEADER_SIZE,
-					qnm, sizeof(qnm));
-				if(strlen(qnm)>0 && qnm[strlen(qnm)-1]=='\n')
-					qnm[strlen(qnm)-1] = 0; /*remove newline*/
-				if(strchr(qnm, '\t'))
-					*strchr(qnm, '\t') = ' ';
-				if(strchr(qnm, '\t'))
-					*strchr(qnm, '\t') = ' ';
-				verbose(VERB_OPS, "ip_ratelimit exceeded %s %d %s",
-					client_ip, infra_ip_ratelimit, qnm);
-			} else {
-				verbose(VERB_OPS, "ip_ratelimit exceeded %s %d (no query name)",
-					client_ip, infra_ip_ratelimit);
-			}
-		}
-		return (max <= infra_ip_ratelimit);
+		return check_ip_ratelimit(addr, addrlen, buffer, premax, max,
+			has_cookie);
 	}
 
 	/* create */

services/cache/infra.h

@@ -153,6 +153,8 @@ struct rate_key {
 
 /** ip ratelimit, 0 is off */
 extern int infra_ip_ratelimit;
+/** ip ratelimit for DNS Cookie clients, 0 is off */
+extern int infra_ip_ratelimit_cookie;
 
 /**
  * key for ip_ratelimit lookups, a source IP.
@@ -419,13 +421,14 @@ int infra_find_ratelimit(struct infra_cache* infra, uint8_t* name,
  *  @param addr: client address
  *  @param addrlen: client address length
  *  @param timenow: what time it is now.
+ *  @param has_cookie: if the request came with a DNS Cookie.
  *  @param backoff: if backoff is enabled.
  *  @param buffer: with query for logging.
  *  @return 1 if it could be incremented. 0 if the increment overshot the
  *  ratelimit and the query should be dropped. */
 int infra_ip_ratelimit_inc(struct infra_cache* infra,
 	struct sockaddr_storage* addr, socklen_t addrlen, time_t timenow,
-	int backoff, struct sldns_buffer* buffer);
+	int has_cookie, int backoff, struct sldns_buffer* buffer);
 
 /**
  * Get memory used by the infra cache.

testdata/edns_downstream_cookies.rpl

@@ -134,7 +134,7 @@ HEX_EDNSDATA_BEGIN
 	00 0a			; Opcode 10
 	00 18			; Length 24
 	31 32 33 34 35 36 37 38	; Random bits
-	01 00 00 00		; wrong version
+	01 00 00 00		; Version/Reserved
 	00 00 00 00		; Timestamp
 	38 52 7b a8 c6 a4 ea 96	; Hash
 HEX_EDNSDATA_END

testdata/ip_ratelimit.tdir/ip_ratelimit.conf

@@ -0,0 +1,28 @@
+server:
+	verbosity: 5
+	# num-threads: 1
+	interface: 127.0.0.1
+	port: @PORT@
+	use-syslog: no
+	directory: .
+	pidfile: "unbound.pid"
+	chroot: ""
+	username: ""
+	local-data: "test. IN TXT localdata"
+
+	ip-ratelimit: 1
+	ip-ratelimit-cookie: 0
+	ip-ratelimit-factor: 0
+	ip-ratelimit-backoff: yes
+	answer-cookie: yes
+	access-control: 127.0.0.0/8 allow_cookie
+
+remote-control:
+	control-enable: yes
+	control-interface: 127.0.0.1
+	# control-interface: ::1
+	control-port: @CONTROL_PORT@
+	server-key-file: "unbound_server.key"
+	server-cert-file: "unbound_server.pem"
+	control-key-file: "unbound_control.key"
+	control-cert-file: "unbound_control.pem"

testdata/ip_ratelimit.tdir/ip_ratelimit.dsc

@@ -0,0 +1,16 @@
+BaseName: ip_ratelimit
+Version: 1.0
+Description: Test IP source ratelimit.
+CreationDate: Tue Aug 8 00:00:00 CET 2023
+Maintainer: Yorgos Thessalonikefs
+Category:
+Component:
+CmdDepends:
+Depends:
+Help:
+Pre: ip_ratelimit.pre
+Post: ip_ratelimit.post
+Test: ip_ratelimit.test
+AuxFiles:
+Passed:
+Failure:

testdata/ip_ratelimit.tdir/ip_ratelimit.post

@@ -0,0 +1,13 @@
+# #-- ip_ratelimit.post --#
+# source the master var file when it's there
+[ -f ../.tpkg.var.master ] && source ../.tpkg.var.master
+# source the test var file when it's there
+[ -f .tpkg.var.test ] && source .tpkg.var.test
+#
+# do your teardown here
+. ../common.sh
+kill_pid $UNBOUND_PID
+if test -f unbound.log; then
+	echo ">>> unbound log"
+	cat unbound.log
+fi

testdata/ip_ratelimit.tdir/ip_ratelimit.pre

@@ -0,0 +1,24 @@
+# #-- ip_ratelimit.pre--#
+# source the master var file when it's there
+[ -f ../.tpkg.var.master ] && source ../.tpkg.var.master
+# use .tpkg.var.test for in test variable passing
+[ -f .tpkg.var.test ] && source .tpkg.var.test
+
+PRE="../.."
+. ../common.sh
+get_random_port 2
+UNBOUND_PORT=$RND_PORT
+CONTROL_PORT=$(($RND_PORT + 1))
+echo "UNBOUND_PORT=$UNBOUND_PORT" >> .tpkg.var.test
+echo "CONTROL_PORT=$CONTROL_PORT" >> .tpkg.var.test
+
+# make config file
+sed -e 's/@PORT\@/'$UNBOUND_PORT'/' -e 's/@CONTROL_PORT\@/'$CONTROL_PORT'/' < ip_ratelimit.conf > ub.conf
+# start unbound in the background
+$PRE/unbound -d -c ub.conf >unbound.log 2>&1 &
+UNBOUND_PID=$!
+echo "UNBOUND_PID=$UNBOUND_PID" >> .tpkg.var.test
+
+wait_unbound_up unbound.log
+
+cat .tpkg.var.test

testdata/ip_ratelimit.tdir/ip_ratelimit.test

@@ -0,0 +1,159 @@
+# #-- ip_ratelimit.test --#
+# source the master var file when it's there
+[ -f ../.tpkg.var.master ] && source ../.tpkg.var.master
+# use .tpkg.var.test for in test variable passing
+[ -f .tpkg.var.test ] && source .tpkg.var.test
+
+PRE="../.."
+. ../common.sh
+
+get_make
+(cd $PRE; $MAKE streamtcp)
+
+# These tests rely on second time precision. To combat false negatives the
+# tests run multiple times and we allow 1/3 of the runs to fail.
+total_runs=6
+success_threshold=4  # 2/3*total_runs
+
+echo "> First get a valid cookie"
+dig @127.0.0.1 -p $UNBOUND_PORT +ednsopt=10:0102030405060708 +tcp +retry=0 +time=1 test. TXT >outfile 2>&1
+if test "$?" -ne 0; then
+	echo "exit status not OK"
+	echo "> cat logfiles"
+	cat outfile
+	cat unbound.log
+	echo "Not OK"
+	exit 1
+fi
+if test `grep "COOKIE: " outfile | wc -l` -ne 1; then
+	echo "Could not get cookie"
+	echo "> cat logfiles"
+	cat outfile
+	cat unbound.log
+	echo "Not OK"
+	exit 1
+fi
+cookie=`grep "COOKIE: " outfile | cut -d ' ' -f 3`
+
+successes=0
+echo "> Three parallel queries with backoff and cookie"
+# For this test we send three parallel queries. The ratelimit should be reached
+# for that second. We send a query to verify that there is no reply.
+# Then for the next second we again send three parallel queries and we expect
+# none of them to be allowed through because of the backoff logic that keeps
+# rolling the RATE_WINDOW based on demand.
+# Again we send another query but with a valid cookie and we expect to receive
+# an answer.
+for i in $(seq 1 $total_runs); do
+	# Try to hit limit
+	$PRE/streamtcp -nu -f 127.0.0.1@$UNBOUND_PORT test. TXT IN test. TXT IN test. TXT IN >outfile 2>&1
+	if test "$?" -ne 0; then
+		echo "exit status not OK"
+		echo "> cat logfiles"
+		cat outfile
+		cat unbound.log
+		echo "Not OK"
+		exit 1
+	fi
+	# Expect no answer because of limit
+	dig @127.0.0.1 -p $UNBOUND_PORT +retry=0 +time=1 test. TXT >outfile 2>&1
+	if test "$?" -eq 0; then
+		continue
+	fi
+	# Try to keep limit
+	$PRE/streamtcp -nu -f 127.0.0.1@$UNBOUND_PORT test. TXT IN test. TXT IN test. TXT IN >outfile 2>&1
+	if test "$?" -ne 0; then
+		echo "exit status not OK"
+		echo "> cat logfiles"
+		cat outfile
+		cat unbound.log
+		echo "Not OK"
+		exit 1
+	fi
+	# Expect answer because of DNS cookie
+	dig @127.0.0.1 -p $UNBOUND_PORT +ednsopt=10:$cookie +retry=0 +time=1 test. TXT >outfile 2>&1
+	if test "$?" -ne 0; then
+		continue
+	fi
+	((successes++))
+	# We don't have to wait for all the runs to complete if we know
+	# we passed the threshold.
+	if test $successes -ge $success_threshold; then
+		break
+	fi
+done
+
+if test $successes -ge $success_threshold; then
+	echo "Three parallel queries with backoff and cookie OK"
+else
+	echo "Three parallel queries with backoff and cookie NOT OK"
+	echo "> cat logfiles"
+	cat outfile
+	cat unbound.log
+	echo "Three parallel queries with backoff and cookie NOT OK"
+	exit 1
+fi
+
+echo "> Activating ip-ratelimit-cookie"
+echo "$PRE/unbound-control -c ub.conf set_option ip-ratelimit-cookie: 1"
+$PRE/unbound-control -c ub.conf set_option ip-ratelimit-cookie: 1
+if test $? -ne 0; then
+	echo "wrong exit value after success"
+	exit 1
+fi
+
+successes=0
+echo "> Three parallel queries with backoff and cookie with ip-ratelimit-cookie"
+# This is the exact same test as above with the exception that we don't expect
+# an answer on the last query because ip-ratelimit-cookie is now enabled.
+for i in $(seq 1 $total_runs); do
+	# Try to hit limit
+	$PRE/streamtcp -nu -f 127.0.0.1@$UNBOUND_PORT test. TXT IN test. TXT IN test. TXT IN >outfile 2>&1
+	if test "$?" -ne 0; then
+		echo "exit status not OK"
+		echo "> cat logfiles"
+		cat outfile
+		cat unbound.log
+		echo "Not OK"
+		exit 1
+	fi
+	# Expect no answer because of limit
+	dig @127.0.0.1 -p $UNBOUND_PORT +retry=0 +time=1 test. TXT >outfile 2>&1
+	if test "$?" -eq 0; then
+		continue
+	fi
+	# Try to keep limit
+	$PRE/streamtcp -nu -f 127.0.0.1@$UNBOUND_PORT test. TXT IN test. TXT IN test. TXT IN >outfile 2>&1
+	if test "$?" -ne 0; then
+		echo "exit status not OK"
+		echo "> cat logfiles"
+		cat outfile
+		cat unbound.log
+		echo "Not OK"
+		exit 1
+	fi
+	# Expect no answer because of ip-ratelimit-cookie
+	dig @127.0.0.1 -p $UNBOUND_PORT +ednsopt=10:$cookie +retry=0 +time=1 test. TXT >outfile 2>&1
+	if test "$?" -eq 0; then
+		continue
+	fi
+	((successes++))
+	# We don't have to wait for all the runs to complete if we know
+	# we passed the threshold.
+	if test $successes -ge $success_threshold; then
+		break
+	fi
+done
+
+if test $successes -ge $success_threshold; then
+	echo "Three parallel queries with backoff and cookie with ip-ratelimit-cookie OK"
+else
+	echo "Three parallel queries with backoff and cookie with ip-ratelimit-cookie NOT OK"
+	echo "> cat logfiles"
+	cat outfile
+	cat unbound.log
+	echo "Three parallel queries with backoff and cookie with ip-ratelimit-cookie NOT OK"
+	exit 1
+fi
+
+exit 0

testdata/ip_ratelimit.tdir/unbound_control.key

@@ -0,0 +1,39 @@
+-----BEGIN RSA PRIVATE KEY-----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+C1TpXebHGyXGpY9WdWXhjdE/1jPvfS+uO5WyuDpYPr339gsdq1g=
+-----END RSA PRIVATE KEY-----

testdata/ip_ratelimit.tdir/unbound_control.pem

@@ -0,0 +1,22 @@
+-----BEGIN CERTIFICATE-----
+MIIDszCCAhsCFGD5193whHQ2bVdzbaQfdf1gc4SkMA0GCSqGSIb3DQEBCwUAMBIx
+EDAOBgNVBAMMB3VuYm91bmQwHhcNMjAwNzA4MTMzMjMwWhcNNDAwMzI1MTMzMjMw
+WjAaMRgwFgYDVQQDDA91bmJvdW5kLWNvbnRyb2wwggGiMA0GCSqGSIb3DQEBAQUA
+A4IBjwAwggGKAoIBgQCy0Sn4/KHxcau1nvsDgWFiO9t4Hd0xrtDasZbGhvOUD2mv
+OEDVoKEC9S0I4C4z6sHo1M0HxhZ9kltAdrDIw2mYLvtyDq9ctgIZRAdnICqJ03Tj
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+A6a+UMdip6SMNv+85bYrFRAsbThpkwnWZZ91vAbQIpCRKMhIQNnWXvq+EzqZMzR/
+Bdsi/IVn3I88KV7WYXlpKXFLZyYa4ZVJFBrDxcX197dr0AIklOvfcd1KnJpmQpEB
+TMtwqosKXfbd1oq/c3DABPTdOPiJAzjXoBIyiLJ8Vr/YZZMpBWN127wKtqvu0Zp/
+nGuWKDgMGasG91gDeePLvb9EPvWEvCaVGgIZTt1G4Ov07ooBJSbVGL3U41n+p2My
++i/XmXa+PgZX4pdHTR0CAwEAATANBgkqhkiG9w0BAQsFAAOCAYEAd++Wen6l8Ifj
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+72tMfu+Fu55y3awdWWGc6YlaGogZiuMnJkvQphwgn+5qE/7CGEckoKEsH601rqIZ
+muaIc85+nEcHJeijd/ZlBN9zeltjFoMuqTUENgmv8+tUAdVm/UMY9Vjme6b43ydP
+uv6DS02+k9z8toxXworLiPr94BGaiGV1NxgwZKLZigYJt/Fi2Qte
+-----END CERTIFICATE-----

testdata/ip_ratelimit.tdir/unbound_server.key

@@ -0,0 +1,39 @@
+-----BEGIN RSA PRIVATE KEY-----
+MIIG5AIBAAKCAYEAvjSVSN2QMXudpzukdLCqgg/IOhCX8KYkD0FFFfWcQjgKq5wI
+0x41iG32a6wbGanre4IX7VxaSPu9kkHfnGgynCk5nwDRedE/FLFhAU78PoT0+Nqq
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+WaBe1ca4TZHr9ThL2gEMEfAQl0wXDwRWRoi3NjNMH+mw0L1rjwThI5GXqNIee7o5
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+A5UoZgRzXgzECelXSCTBFlMTnT48LfA9pMLydyjAz2UdPHs5Iv+TK5nnI+aJoeaP
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+bNh2QSoWah3FdzNGuWd0iRf9+LFxhjAAMo/FS8zFJAJKrFsBdCGTfFUMdsLC0bjr
+YjiWBuvV72uKf8XIZX5KIZruKdWBBcWukcb21R1UDyFYyXRBsly5XHaIYKZql3km
+7pV7MKWO0IYgHbHIqGUqPQlzZ/lkunS1jKECgcEA23wHffD6Ou9/x3okPx2AWpTr
+gh8rgqbyo6hQkBW5Y90Wz824cqaYebZDaBR/xlVx/YwjKkohv8Bde2lpH/ZxRZ1Z
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+kCGJ3hEHCHqT/ZRQyX85BKIDFhA0z4tYKxWVqIFiYBNq56R0X9tMMmMs36mEnF93
+7Ht6mowxTZQRa7nU0qOgeKh/P7ki4Zus3y+WJ+T9IqahLtlRAoHBAIhqMrcxSAB8
+RpB9jukJlAnidw2jCMPgrFE8tP0khhVvGrXMldxAUsMKntDIo8dGCnG1KTcWDI0O
+jepvSPHSsxVLFugL79h0eVIS5z4huW48i9xgU8VlHdgAcgEPIAOFcOw2BCu/s0Vp
+O+MM/EyUOdo3NsibB3qc/GJI6iNBYS7AljYEVo6rXo5V/MZvZUF4vClen6Obzsre
+MTTb+4sJjfqleWuvr1XNMeu2mBfXBQkWGZP1byBK0MvD/aQ2PWq92A==
+-----END RSA PRIVATE KEY-----

testdata/ip_ratelimit.tdir/unbound_server.pem

@@ -0,0 +1,22 @@
+-----BEGIN CERTIFICATE-----
+MIIDqzCCAhMCFBHWXeQ6ZIa9QcQbXLFfC6tj+KA+MA0GCSqGSIb3DQEBCwUAMBIx
+EDAOBgNVBAMMB3VuYm91bmQwHhcNMjAwNzA4MTMzMjI5WhcNNDAwMzI1MTMzMjI5
+WjASMRAwDgYDVQQDDAd1bmJvdW5kMIIBojANBgkqhkiG9w0BAQEFAAOCAY8AMIIB
+igKCAYEAvjSVSN2QMXudpzukdLCqgg/IOhCX8KYkD0FFFfWcQjgKq5wI0x41iG32
+a6wbGanre4IX7VxaSPu9kkHfnGgynCk5nwDRedE/FLFhAU78PoT0+NqqGRS7XVQ2
+4vLmIz9Hqc2Ozx1um1BXBTmIT0UfN2e22I0LWQ6a3seZlEDRj45gnk7Zuh9MDgot
+aBdm+v1JAbupSf6Zis4VEH3JNdvVGE3O1DHEIeuuz/3BDhpf6WBDH+8KWaBe1ca4
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++nypHk/DOoC7DIM3ufN0yxPBsFo5TVowxfhdjZXJbbftd2TZv7AH8+XLA5UoZgRz
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+dy1+A/bNAgMBAAEwDQYJKoZIhvcNAQELBQADggGBABunf93MKaCUHiZgnoOTinsW
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+JE0Kln9cV//wiiNoFU0O4mnzyGUIMvlaEX6QHMJJQYvL05+w/3AAcf5XmMJtR5ca
+fJ8FqvGC34b2WxX9lTQoyT52sRt+1KnQikiMEnEyAdKktMG+MwKsFDdOwDXyZhZg
+XZhRrfX3/NVJolqB6EahjWIGXDeKuSSKZVtCyib6LskyeMzN5lcRfvubKDdlqFVF
+qlD7rHBsKhQUWK/IO64mGf7y/de+CgHtED5vDvr/p2uj/9sABATfbrOQR3W/Of25
+sLBj4OEfrJ7lX8hQgFaxkMI3x6VFT3W8dTCp7xnQgb6bgROWB5fNEZ9jk/gjSRmD
+yIU+r0UbKe5kBk/CmZVFXL2TyJ92V5NYEQh8V4DGy19qZ6u/XKYyNJL4ocs35GGe
+CA8SBuyrmdhx38h1RHErR2Skzadi1S7MwGf1y431fQ==
+-----END CERTIFICATE-----

util/config_file.c

@@ -330,6 +330,7 @@ config_create(void)
 	cfg->dnstap_bidirectional = 1;
 	cfg->dnstap_tls = 1;
 	cfg->disable_dnssec_lame_check = 0;
+	cfg->ip_ratelimit_cookie = 0;
 	cfg->ip_ratelimit = 0;
 	cfg->ratelimit = 0;
 	cfg->ip_ratelimit_slabs = 4;
@@ -779,6 +780,10 @@ int config_set_option(struct config_file* cfg, const char* opt,
 	else S_POW2("dnscrypt-nonce-cache-slabs:",
 		dnscrypt_nonce_cache_slabs)
 #endif
+	else if(strcmp(opt, "ip-ratelimit-cookie:") == 0) {
+	    IS_NUMBER_OR_ZERO; cfg->ip_ratelimit_cookie = atoi(val);
+	    infra_ip_ratelimit_cookie=cfg->ip_ratelimit_cookie;
+	}
 	else if(strcmp(opt, "ip-ratelimit:") == 0) {
 	    IS_NUMBER_OR_ZERO; cfg->ip_ratelimit = atoi(val);
 	    infra_ip_ratelimit=cfg->ip_ratelimit;
@@ -1248,6 +1253,7 @@ config_get_option(struct config_file* cfg, const char* opt,
 	else O_LST(opt, "python-script", python_script)
 	else O_LST(opt, "dynlib-file", dynlib_file)
 	else O_YNO(opt, "disable-dnssec-lame-check", disable_dnssec_lame_check)
+	else O_DEC(opt, "ip-ratelimit-cookie", ip_ratelimit_cookie)
 	else O_DEC(opt, "ip-ratelimit", ip_ratelimit)
 	else O_DEC(opt, "ratelimit", ratelimit)
 	else O_MEM(opt, "ip-ratelimit-size", ip_ratelimit_size)

util/config_file.h

@@ -590,6 +590,9 @@ struct config_file {
 
 	/** ratelimit for ip addresses. 0 is off, otherwise qps (unless overridden) */
 	int ip_ratelimit;
+	/** ratelimit for ip addresses with a valid DNS Cookie. 0 is off,
+	 *  otherwise qps (unless overridden) */
+	int ip_ratelimit_cookie;
 	/** number of slabs for ip_ratelimit cache */
 	size_t ip_ratelimit_slabs;
 	/** memory size in bytes for ip_ratelimit cache */

util/configlexer.lex

@@ -507,6 +507,7 @@ dnstap-log-forwarder-response-messages{COLON}	{
 		YDVAR(1, VAR_DNSTAP_LOG_FORWARDER_RESPONSE_MESSAGES) }
 disable-dnssec-lame-check{COLON} { YDVAR(1, VAR_DISABLE_DNSSEC_LAME_CHECK) }
 ip-ratelimit{COLON}		{ YDVAR(1, VAR_IP_RATELIMIT) }
+ip-ratelimit-cookie{COLON}	{ YDVAR(1, VAR_IP_RATELIMIT_COOKIE) }
 ratelimit{COLON}		{ YDVAR(1, VAR_RATELIMIT) }
 ip-ratelimit-slabs{COLON}		{ YDVAR(1, VAR_IP_RATELIMIT_SLABS) }
 ratelimit-slabs{COLON}		{ YDVAR(1, VAR_RATELIMIT_SLABS) }

util/configparser.y

@@ -184,7 +184,7 @@ extern struct config_parser_state* cfg_parser;
 %token VAR_FALLBACK_ENABLED VAR_TLS_ADDITIONAL_PORT VAR_LOW_RTT VAR_LOW_RTT_PERMIL
 %token VAR_FAST_SERVER_PERMIL VAR_FAST_SERVER_NUM
 %token VAR_ALLOW_NOTIFY VAR_TLS_WIN_CERT VAR_TCP_CONNECTION_LIMIT
-%token VAR_ANSWER_COOKIE VAR_COOKIE_SECRET
+%token VAR_ANSWER_COOKIE VAR_COOKIE_SECRET VAR_IP_RATELIMIT_COOKIE
 %token VAR_FORWARD_NO_CACHE VAR_STUB_NO_CACHE VAR_LOG_SERVFAIL VAR_DENY_ANY
 %token VAR_UNKNOWN_SERVER_TIME_LIMIT VAR_LOG_TAG_QUERYREPLY
 %token VAR_STREAM_WAIT_SIZE VAR_TLS_CIPHERS VAR_TLS_CIPHERSUITES VAR_TLS_USE_SNI
@@ -325,7 +325,7 @@ content_server: server_num_threads | server_verbosity | server_port |
 	server_unknown_server_time_limit | server_log_tag_queryreply |
 	server_stream_wait_size | server_tls_ciphers |
 	server_tls_ciphersuites | server_tls_session_ticket_keys |
-	server_answer_cookie | server_cookie_secret |
+	server_answer_cookie | server_cookie_secret | server_ip_ratelimit_cookie |
 	server_tls_use_sni | server_edns_client_string |
 	server_edns_client_string_opcode | server_nsid |
 	server_zonemd_permissive_mode | server_max_reuse_tcp_queries |
@@ -1163,7 +1163,7 @@ server_http_nodelay: VAR_HTTP_NODELAY STRING_ARG
 			yyerror("expected yes or no.");
 		else cfg_parser->cfg->http_nodelay = (strcmp($2, "yes")==0);
 		free($2);
-	}
+	};
 server_http_notls_downstream: VAR_HTTP_NOTLS_DOWNSTREAM STRING_ARG
 	{
 		OUTYY(("P(server_http_notls_downstream:%s)\n", $2));
@@ -2210,6 +2210,7 @@ server_permit_small_holddown: VAR_PERMIT_SMALL_HOLDDOWN STRING_ARG
 			(strcmp($2, "yes")==0);
 		free($2);
 	}
+	;
 server_key_cache_size: VAR_KEY_CACHE_SIZE STRING_ARG
 	{
 		OUTYY(("P(server_key_cache_size:%s)\n", $2));
@@ -2567,6 +2568,15 @@ server_ip_ratelimit: VAR_IP_RATELIMIT STRING_ARG
 		free($2);
 	}
 	;
+server_ip_ratelimit_cookie: VAR_IP_RATELIMIT_COOKIE STRING_ARG
+	{
+		OUTYY(("P(server_ip_ratelimit_cookie:%s)\n", $2));
+		if(atoi($2) == 0 && strcmp($2, "0") != 0)
+			yyerror("number expected");
+		else cfg_parser->cfg->ip_ratelimit_cookie = atoi($2);
+		free($2);
+	}
+	;
 server_ratelimit: VAR_RATELIMIT STRING_ARG
 	{
 		OUTYY(("P(server_ratelimit:%s)\n", $2));
@@ -3520,6 +3530,7 @@ py_script: VAR_PYTHON_SCRIPT STRING_ARG
 		if(!cfg_strlist_append_ex(&cfg_parser->cfg->python_script, $2))
 			yyerror("out of memory");
 	}
+	;
 dynlibstart: VAR_DYNLIB
 	{
 		OUTYY(("\nP(dynlib:)\n"));
@@ -3536,6 +3547,7 @@ dl_file: VAR_DYNLIB_FILE STRING_ARG
 		if(!cfg_strlist_append_ex(&cfg_parser->cfg->dynlib_file, $2))
 			yyerror("out of memory");
 	}
+	;
 server_disable_dnssec_lame_check: VAR_DISABLE_DNSSEC_LAME_CHECK STRING_ARG
 	{
 		OUTYY(("P(disable_dnssec_lame_check:%s)\n", $2));
@@ -3596,7 +3608,6 @@ dnsc_dnscrypt_enable: VAR_DNSCRYPT_ENABLE STRING_ARG
 		free($2);
 	}
 	;
-
 dnsc_dnscrypt_port: VAR_DNSCRYPT_PORT STRING_ARG
 	{
 		OUTYY(("P(dnsc_dnscrypt_port:%s)\n", $2));
@@ -3828,6 +3839,7 @@ server_cookie_secret: VAR_COOKIE_SECRET STRING_ARG
 		}
 		free($2);
 	}
+	;
 	ipsetstart: VAR_IPSET
 		{
 			OUTYY(("\nP(ipset:)\n"));