From 603a0e2637b35a2da820bc807f69bcf09c682dce Mon Sep 17 00:00:00 2001 From: Evan Hunt Date: Mon, 17 Nov 2014 23:49:07 -0800 Subject: [PATCH] [v9_9] limit recursion depth and iterative queries 4006. [security] A flaw in delegation handling could be exploited to put named into an infinite loop. This has been addressed by placing limits on the number of levels of recursion named will allow (default 7), and the number of iterative queries that it will send (default 50) before terminating a recursive query (CVE-2014-8500). The recursion depth limit is configured via the "max-recursion-depth" option. [RT #35780] Upstream-Status: Backport Signed-off-by: Sona Sarmadi --- bin/named/config.c | 3 +- bin/named/include/named/query.h | 2 - bin/named/query.c | 7 ++- bin/named/server.c | 5 ++ bin/tests/system/many/clean.sh | 7 +++ bin/tests/system/many/ns1/named.conf | 33 +++++++++++++ bin/tests/system/many/ns2/named.conf | 30 ++++++++++++ bin/tests/system/many/ns3/named.conf | 32 +++++++++++++ bin/tests/system/many/ns4/named.conf | 30 ++++++++++++ bin/tests/system/many/ns5/hints.db | 2 + bin/tests/system/many/ns5/named.conf | 29 ++++++++++++ bin/tests/system/many/setup.sh | 75 ++++++++++++++++++++++++++++++ bin/tests/system/many/tests.sh | 48 +++++++++++++++++++ doc/arm/Bv9ARM-book.xml | 12 +++++ lib/dns/adb.c | 58 ++++++++++++++++------- lib/dns/include/dns/adb.h | 8 ++++ lib/dns/include/dns/resolver.h | 25 ++++++++++ lib/dns/resolver.c | 90 ++++++++++++++++++++++++++++++------ lib/isccfg/namedconf.c | 1 + 20 files changed, 471 insertions(+), 37 deletions(-) create mode 100644 bin/tests/system/many/clean.sh create mode 100644 bin/tests/system/many/ns1/named.conf create mode 100644 bin/tests/system/many/ns2/named.conf create mode 100644 bin/tests/system/many/ns3/named.conf create mode 100644 bin/tests/system/many/ns4/named.conf create mode 100644 bin/tests/system/many/ns5/hints.db create mode 100644 bin/tests/system/many/ns5/named.conf create mode 100644 bin/tests/system/many/setup.sh create mode 100644 bin/tests/system/many/tests.sh diff --git a/bin/named/config.c b/bin/named/config.c index 2782720..5ee8c4e 100644 --- a/bin/named/config.c +++ b/bin/named/config.c @@ -15,8 +15,6 @@ * PERFORMANCE OF THIS SOFTWARE. */ -/* $Id: config.c,v 1.123 2012/01/06 23:46:41 tbox Exp $ */ - /*! \file */ #include @@ -160,6 +158,7 @@ options {\n\ dnssec-accept-expired no;\n\ clients-per-query 10;\n\ max-clients-per-query 100;\n\ + max-recursion-depth 7;\n\ zero-no-soa-ttl-cache no;\n\ nsec3-test-zone no;\n\ allow-new-zones no;\n\ diff --git a/bin/named/include/named/query.h b/bin/named/include/named/query.h index 3beabb8..b5e3900 100644 --- a/bin/named/include/named/query.h +++ b/bin/named/include/named/query.h @@ -15,8 +15,6 @@ * PERFORMANCE OF THIS SOFTWARE. */ -/* $Id: query.h,v 1.45 2011/01/13 04:59:24 tbox Exp $ */ - #ifndef NAMED_QUERY_H #define NAMED_QUERY_H 1 diff --git a/bin/named/query.c b/bin/named/query.c index 982f76d..47bfc6a 100644 --- a/bin/named/query.c +++ b/bin/named/query.c @@ -3877,12 +3877,11 @@ query_recurse(ns_client_t *client, dns_rdatatype_t qtype, dns_name_t *qname, peeraddr = &client->peeraddr; else peeraddr = NULL; - result = dns_resolver_createfetch2(client->view->resolver, + result = dns_resolver_createfetch3(client->view->resolver, qname, qtype, qdomain, nameservers, NULL, peeraddr, client->message->id, - client->query.fetchoptions, - client->task, - query_resume, client, + client->query.fetchoptions, 0, + client->task, query_resume, client, rdataset, sigrdataset, &client->query.fetch); diff --git a/bin/named/server.c b/bin/named/server.c index ac015a4..0559977 100644 --- a/bin/named/server.c +++ b/bin/named/server.c @@ -3161,6 +3161,11 @@ configure_view(dns_view_t *view, cfg_obj_t *config, cfg_obj_t *vconfig, cfg_obj_asuint32(obj), max_clients_per_query); + obj = NULL; + result = ns_config_get(maps, "max-recursion-depth", &obj); + INSIST(result == ISC_R_SUCCESS); + dns_resolver_setmaxdepth(view->resolver, cfg_obj_asuint32(obj)); + #ifdef ALLOW_FILTER_AAAA_ON_V4 obj = NULL; result = ns_config_get(maps, "filter-aaaa-on-v4", &obj); diff --git a/bin/tests/system/many/clean.sh b/bin/tests/system/many/clean.sh new file mode 100644 index 0000000..119b1f5 --- /dev/null +++ b/bin/tests/system/many/clean.sh @@ -0,0 +1,7 @@ +rm -f ns1/[1-9]*example.tld?.db +rm -f ns2/[1-9]*example.tld?.db +rm -f ns1/zones.conf +rm -f ns2/zones.conf +rm -f */root.db +rm -f ns3/tld1.db +rm -f ns4/tld2.db diff --git a/bin/tests/system/many/ns1/named.conf b/bin/tests/system/many/ns1/named.conf new file mode 100644 index 0000000..abc9dca --- /dev/null +++ b/bin/tests/system/many/ns1/named.conf @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC") + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +controls { /* empty */ }; + +options { + query-source address 10.53.0.1; + notify-source 10.53.0.1; + transfer-source 10.53.0.1; + port 5300; + pid-file "named.pid"; + listen-on { 10.53.0.1; }; + listen-on-v6 { none; }; + recursion no; +}; + +include "zones.conf"; + +// zone "tld1" { type master; file "tld1.db"; }; +// zone "tld2" { type master; file "tld2.db"; }; diff --git a/bin/tests/system/many/ns2/named.conf b/bin/tests/system/many/ns2/named.conf new file mode 100644 index 0000000..16266e2 --- /dev/null +++ b/bin/tests/system/many/ns2/named.conf @@ -0,0 +1,30 @@ +/* + * Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC") + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +controls { /* empty */ }; + +options { + query-source address 10.53.0.2; + notify-source 10.53.0.2; + transfer-source 10.53.0.2; + port 5300; + pid-file "named.pid"; + listen-on { 10.53.0.2; }; + listen-on-v6 { none; }; + recursion no; +}; + +include "zones.conf"; diff --git a/bin/tests/system/many/ns3/named.conf b/bin/tests/system/many/ns3/named.conf new file mode 100644 index 0000000..b950afe --- /dev/null +++ b/bin/tests/system/many/ns3/named.conf @@ -0,0 +1,32 @@ +/* + * Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC") + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +controls { /* empty */ }; + +options { + query-source address 10.53.0.3; + notify-source 10.53.0.3; + transfer-source 10.53.0.3; + port 5300; + pid-file "named.pid"; + listen-on { 10.53.0.3; }; + listen-on-v6 { none; }; + recursion no; +}; + +zone "." { type master; file "root.db"; }; + +zone "tld1" { type master; file "tld1.db"; }; diff --git a/bin/tests/system/many/ns4/named.conf b/bin/tests/system/many/ns4/named.conf new file mode 100644 index 0000000..ca9aa6a --- /dev/null +++ b/bin/tests/system/many/ns4/named.conf @@ -0,0 +1,30 @@ +/* + * Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC") + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +controls { /* empty */ }; + +options { + query-source address 10.53.0.4; + notify-source 10.53.0.4; + transfer-source 10.53.0.4; + port 5300; + pid-file "named.pid"; + listen-on { 10.53.0.4; }; + listen-on-v6 { none; }; + recursion no; +}; + +zone "tld2" { type master; file "tld2.db"; }; diff --git a/bin/tests/system/many/ns5/hints.db b/bin/tests/system/many/ns5/hints.db new file mode 100644 index 0000000..c05809b --- /dev/null +++ b/bin/tests/system/many/ns5/hints.db @@ -0,0 +1,2 @@ +. 60 in ns ns.nil. +ns.nil. 60 in A 10.53.0.3 diff --git a/bin/tests/system/many/ns5/named.conf b/bin/tests/system/many/ns5/named.conf new file mode 100644 index 0000000..fce7d59 --- /dev/null +++ b/bin/tests/system/many/ns5/named.conf @@ -0,0 +1,29 @@ +/* + * Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC") + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH + * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, + * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE + * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR + * PERFORMANCE OF THIS SOFTWARE. + */ + +controls { /* empty */ }; + +options { + query-source address 10.53.0.5; + notify-source 10.53.0.5; + transfer-source 10.53.0.5; + port 5300; + pid-file "named.pid"; + listen-on { 10.53.0.5; }; + listen-on-v6 { none; }; +}; + +zone "." { type hint; file "hints.db"; }; diff --git a/bin/tests/system/many/setup.sh b/bin/tests/system/many/setup.sh new file mode 100644 index 0000000..80695b5 --- /dev/null +++ b/bin/tests/system/many/setup.sh @@ -0,0 +1,75 @@ +i=1 + +cat > ns3/root.db << EOF +. 60 in soa ns.nil. hostmaster.ns.nil. 1 0 0 0 0 +. 60 in ns ns.nil. +ns.nil. 60 in a 10.53.0.3 +tld1. 60 in ns ns.tld1. +ns.tld1. 60 in a 10.53.0.3 +tld2. 60 in ns ns.tld2. +ns.tld2. 60 in a 10.53.0.4 +EOF + +cat > ns3/tld1.db << EOF +tld1. 60 in soa ns.tld1. hostmaster.ns.tld1. 1 0 0 0 0 +tld1. 60 in ns ns.tld1. +ns.tld1. 60 in a 10.53.0.1 +EOF + +cat > ns4/tld2.db << EOF +tld2. 60 in soa ns.tld2. hostmaster.ns.tld4. 1 0 0 0 0 +tld2. 60 in ns ns.tld2. +ns.tld2. 60 in a 10.53.0.1 +EOF + +: > ns1/zones.conf +: > ns2/zones.conf + +while [ $i -lt 1000 ] +do +j=`expr $i + 1` +s=`expr $j % 2 + 1` +n=`expr $i % 2 + 1` +t=`expr $s + 2` + +# i=1 j=2 s=1 n=2 +# i=2 j=3 s=1 n=2 +# i=3 j=4 s=1 n=2 + +cat > ns1/${i}example.tld${s}.db << EOF +${i}example.tld${s}. 60 in soa ns.${j}example.tld${n}. hostmaster 1 0 0 0 0 +${i}example.tld${s}. 60 in ns ns.${j}example.tld${n}. +ns.${i}example.tld${s}. 60 in a 10.53.0.1 +EOF + +cat >> ns1/zones.conf << EOF +zone "${i}example.tld${s}" { type master; file "${i}example.tld${s}.db"; }; +EOF + +cat >> ns${t}/tld${s}.db << EOF +${i}example.tld${s}. 60 in ns ns.${j}example.tld${n}. +EOF + +i=$j + +done + +j=`expr $i + 1` +s=`expr $j % 2 + 1` +n=`expr $s % 2 + 1` +t=`expr $s + 2` + +cat > ns1/${i}example.tld${s}.db << EOF +${i}example.tld${s}. 60 in soa ns.${i}example.tld${s}. hostmaster 1 0 0 0 0 +${i}example.tld${s}. 60 in ns ns.${i}example.tld${s}. +ns.${i}example.tld${s}. 60 in a 10.53.0.1 +EOF + +cat >> ns1/zones.conf << EOF +zone "${i}example.tld${s}" { type master; file "${i}example.tld${s}.db"; }; +EOF + +cat >> ns${t}/tld${s}.db << EOF +${i}example.tld${s}. 60 in ns ns.${i}example.tld${s}. +ns.${i}example.tld${s}. 60 in a 10.53.0.1 +EOF diff --git a/bin/tests/system/many/tests.sh b/bin/tests/system/many/tests.sh new file mode 100644 index 0000000..37964e2 --- /dev/null +++ b/bin/tests/system/many/tests.sh @@ -0,0 +1,48 @@ +#!/bin/sh +# +# Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC") +# +# Permission to use, copy, modify, and/or distribute this software for any +# purpose with or without fee is hereby granted, provided that the above +# copyright notice and this permission notice appear in all copies. +# +# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH +# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY +# AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, +# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM +# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE +# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR +# PERFORMANCE OF THIS SOFTWARE. + +SYSTEMTESTTOP=.. +. $SYSTEMTESTTOP/conf.sh + +status=0 +n=0 + +n=`expr $n + 1` +echo "I: attempt lookup 1example.tld2 soa ($n)" +ret=0 +$DIG +tcp 1example.tld1 soa @10.53.0.5 -p 5300 > dig.out.test$n +grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1 +if [ $ret != 0 ]; then echo "I:failed"; fi +status=`expr $status + $ret` + +n=`expr $n + 1` +echo "I: attempt lookup 992example.tld2 soa ($n)" +ret=0 +$DIG +tcp 992example.tld2 soa @10.53.0.5 -p 5300 > dig.out.test$n +grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1 +if [ $ret != 0 ]; then echo "I:failed"; fi +status=`expr $status + $ret` + +n=`expr $n + 1` +echo "I: attempt lookup 993example.tld1 soa ($n)" +ret=0 +$DIG +tcp 993example.tld1 soa @10.53.0.5 -p 5300 > dig.out.test$n +grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1 +if [ $ret != 0 ]; then echo "I:failed"; fi +status=`expr $status + $ret` + +echo "I:exit status: $status" +exit $status diff --git a/doc/arm/Bv9ARM-book.xml b/doc/arm/Bv9ARM-book.xml index 9f7bd38..fff4249 100644 --- a/doc/arm/Bv9ARM-book.xml +++ b/doc/arm/Bv9ARM-book.xml @@ -4861,6 +4861,7 @@ badresp:1,adberr:0,findfail:0,valfail:0] max-acache-size size_spec ; clients-per-query number ; max-clients-per-query number ; + max-recursion-depth number ; masterfile-format (text|raw) ; empty-server name ; empty-contact name ; @@ -8680,6 +8681,17 @@ avoid-v6-udp-ports { 40000; range 50000 60000; }; + + max-recursion-depth + + + Sets the maximum number of levels of recursion + permitted at any one time while resolving a name. + The default is 7. + + + + notify-delay diff --git a/lib/dns/adb.c b/lib/dns/adb.c index 2ccb51e..fe9b3f7 100644 --- a/lib/dns/adb.c +++ b/lib/dns/adb.c @@ -199,6 +199,7 @@ struct dns_adbfetch { unsigned int magic; dns_fetch_t *fetch; dns_rdataset_t rdataset; + unsigned int depth; }; /*% @@ -300,7 +301,7 @@ static inline void violate_locking_hierarchy(isc_mutex_t *, isc_mutex_t *); static isc_boolean_t clean_namehooks(dns_adb_t *, dns_adbnamehooklist_t *); static void clean_target(dns_adb_t *, dns_name_t *); static void clean_finds_at_name(dns_adbname_t *, isc_eventtype_t, - unsigned int); + isc_uint32_t, unsigned int); static isc_boolean_t check_expire_namehooks(dns_adbname_t *, isc_stdtime_t); static isc_boolean_t check_expire_entry(dns_adb_t *, dns_adbentry_t **, isc_stdtime_t); @@ -308,7 +309,7 @@ static void cancel_fetches_at_name(dns_adbname_t *); static isc_result_t dbfind_name(dns_adbname_t *, isc_stdtime_t, dns_rdatatype_t); static isc_result_t fetch_name(dns_adbname_t *, isc_boolean_t, - dns_rdatatype_t); + unsigned int, dns_rdatatype_t); static inline void check_exit(dns_adb_t *); static void destroy(dns_adb_t *); static isc_boolean_t shutdown_names(dns_adb_t *); @@ -984,7 +985,7 @@ kill_name(dns_adbname_t **n, isc_eventtype_t ev) { * Clean up the name's various lists. These two are destructive * in that they will always empty the list. */ - clean_finds_at_name(name, ev, DNS_ADBFIND_ADDRESSMASK); + clean_finds_at_name(name, ev, 0, DNS_ADBFIND_ADDRESSMASK); result4 = clean_namehooks(adb, &name->v4); result6 = clean_namehooks(adb, &name->v6); clean_target(adb, &name->target); @@ -1409,7 +1410,7 @@ event_free(isc_event_t *event) { */ static void clean_finds_at_name(dns_adbname_t *name, isc_eventtype_t evtype, - unsigned int addrs) + isc_uint32_t qtotal, unsigned int addrs) { isc_event_t *ev; isc_task_t *task; @@ -1469,6 +1470,7 @@ clean_finds_at_name(dns_adbname_t *name, isc_eventtype_t evtype, ev->ev_sender = find; find->result_v4 = find_err_map[name->fetch_err]; find->result_v6 = find_err_map[name->fetch6_err]; + find->qtotal += qtotal; ev->ev_type = evtype; ev->ev_destroy = event_free; ev->ev_destroy_arg = find; @@ -1827,6 +1829,7 @@ new_adbfind(dns_adb_t *adb) { h->flags = 0; h->result_v4 = ISC_R_UNEXPECTED; h->result_v6 = ISC_R_UNEXPECTED; + h->qtotal = 0; ISC_LINK_INIT(h, publink); ISC_LINK_INIT(h, plink); ISC_LIST_INIT(h->list); @@ -2799,6 +2802,19 @@ dns_adb_createfind(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, isc_stdtime_t now, dns_name_t *target, in_port_t port, dns_adbfind_t **findp) { + return (dns_adb_createfind2(adb, task, action, arg, name, + qname, qtype, options, now, + target, port, 0, findp)); +} + +isc_result_t +dns_adb_createfind2(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, + void *arg, dns_name_t *name, dns_name_t *qname, + dns_rdatatype_t qtype, unsigned int options, + isc_stdtime_t now, dns_name_t *target, + in_port_t port, unsigned int depth, + dns_adbfind_t **findp) +{ dns_adbfind_t *find; dns_adbname_t *adbname; int bucket; @@ -3029,7 +3045,7 @@ dns_adb_createfind(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, * Start V4. */ if (WANT_INET(wanted_fetches) && - fetch_name(adbname, start_at_zone, + fetch_name(adbname, start_at_zone, depth, dns_rdatatype_a) == ISC_R_SUCCESS) { DP(DEF_LEVEL, "dns_adb_createfind: started A fetch for name %p", @@ -3040,7 +3056,7 @@ dns_adb_createfind(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, * Start V6. */ if (WANT_INET6(wanted_fetches) && - fetch_name(adbname, start_at_zone, + fetch_name(adbname, start_at_zone, depth, dns_rdatatype_aaaa) == ISC_R_SUCCESS) { DP(DEF_LEVEL, "dns_adb_createfind: " @@ -3656,6 +3672,7 @@ fetch_callback(isc_task_t *task, isc_event_t *ev) { isc_result_t result; unsigned int address_type; isc_boolean_t want_check_exit = ISC_FALSE; + isc_uint32_t qtotal = 0; UNUSED(task); @@ -3666,6 +3683,8 @@ fetch_callback(isc_task_t *task, isc_event_t *ev) { adb = name->adb; INSIST(DNS_ADB_VALID(adb)); + qtotal = dev->qtotal; + bucket = name->lock_bucket; LOCK(&adb->namelocks[bucket]); @@ -3783,6 +3802,12 @@ fetch_callback(isc_task_t *task, isc_event_t *ev) { DP(DEF_LEVEL, "adb: fetch of '%s' %s failed: %s", buf, address_type == DNS_ADBFIND_INET ? "A" : "AAAA", dns_result_totext(dev->result)); + /* + * Don't record a failure unless this is the initial + * fetch of a chain. + */ + if (fetch->depth > 1) + goto out; /* XXXMLG Don't pound on bad servers. */ if (address_type == DNS_ADBFIND_INET) { name->expire_v4 = ISC_MIN(name->expire_v4, now + 300); @@ -3814,15 +3839,14 @@ fetch_callback(isc_task_t *task, isc_event_t *ev) { free_adbfetch(adb, &fetch); isc_event_free(&ev); - clean_finds_at_name(name, ev_status, address_type); + clean_finds_at_name(name, ev_status, qtotal, address_type); UNLOCK(&adb->namelocks[bucket]); } static isc_result_t -fetch_name(dns_adbname_t *adbname, - isc_boolean_t start_at_zone, - dns_rdatatype_t type) +fetch_name(dns_adbname_t *adbname, isc_boolean_t start_at_zone, + unsigned int depth, dns_rdatatype_t type) { isc_result_t result; dns_adbfetch_t *fetch = NULL; @@ -3867,12 +3891,14 @@ fetch_name(dns_adbname_t *adbname, result = ISC_R_NOMEMORY; goto cleanup; } - - result = dns_resolver_createfetch(adb->view->resolver, &adbname->name, - type, name, nameservers, NULL, - options, adb->task, fetch_callback, - adbname, &fetch->rdataset, NULL, - &fetch->fetch); + fetch->depth = depth; + + result = dns_resolver_createfetch3(adb->view->resolver, &adbname->name, + type, name, nameservers, NULL, + NULL, 0, options, depth, adb->task, + fetch_callback, adbname, + &fetch->rdataset, NULL, + &fetch->fetch); if (result != ISC_R_SUCCESS) goto cleanup; diff --git a/lib/dns/include/dns/adb.h b/lib/dns/include/dns/adb.h index 35350ff..7501f01 100644 --- a/lib/dns/include/dns/adb.h +++ b/lib/dns/include/dns/adb.h @@ -118,6 +118,8 @@ struct dns_adbfind { isc_result_t result_v6; /*%< RO: v6 result */ ISC_LINK(dns_adbfind_t) publink; /*%< RW: client use */ + isc_uint32_t qtotal; + /* Private */ isc_mutex_t lock; /* locks all below */ in_port_t port; @@ -334,6 +336,12 @@ dns_adb_createfind(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, dns_rdatatype_t qtype, unsigned int options, isc_stdtime_t now, dns_name_t *target, in_port_t port, dns_adbfind_t **find); +isc_result_t +dns_adb_createfind2(dns_adb_t *adb, isc_task_t *task, isc_taskaction_t action, + void *arg, dns_name_t *name, dns_name_t *qname, + dns_rdatatype_t qtype, unsigned int options, + isc_stdtime_t now, dns_name_t *target, in_port_t port, + unsigned int depth, dns_adbfind_t **find); /*%< * Main interface for clients. The adb will look up the name given in * "name" and will build up a list of found addresses, and perhaps start diff --git a/lib/dns/include/dns/resolver.h b/lib/dns/include/dns/resolver.h index 4e20eb6..c256049 100644 --- a/lib/dns/include/dns/resolver.h +++ b/lib/dns/include/dns/resolver.h @@ -82,6 +82,7 @@ typedef struct dns_fetchevent { isc_sockaddr_t * client; dns_messageid_t id; isc_result_t vresult; + isc_uint32_t qtotal; } dns_fetchevent_t; /* @@ -275,6 +276,18 @@ dns_resolver_createfetch2(dns_resolver_t *res, dns_name_t *name, dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset, dns_fetch_t **fetchp); +isc_result_t +dns_resolver_createfetch3(dns_resolver_t *res, dns_name_t *name, + dns_rdatatype_t type, + dns_name_t *domain, dns_rdataset_t *nameservers, + dns_forwarders_t *forwarders, + isc_sockaddr_t *client, isc_uint16_t id, + unsigned int options, unsigned int depth, + isc_task_t *task, + isc_taskaction_t action, void *arg, + dns_rdataset_t *rdataset, + dns_rdataset_t *sigrdataset, + dns_fetch_t **fetchp); /*%< * Recurse to answer a question. * @@ -576,6 +589,18 @@ dns_resolver_printbadcache(dns_resolver_t *resolver, FILE *fp); * \li resolver to be valid. */ +void +dns_resolver_setmaxdepth(dns_resolver_t *resolver, unsigned int maxdepth); +unsigned int +dns_resolver_getmaxdepth(dns_resolver_t *resolver); +/*% + * Get and set how many NS indirections will be followed when looking for + * nameserver addresses. + * + * Requires: + * \li resolver to be valid. + */ + ISC_LANG_ENDDECLS #endif /* DNS_RESOLVER_H */ diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c index e517dad..6a635b2 100644 --- a/lib/dns/resolver.c +++ b/lib/dns/resolver.c @@ -131,6 +131,16 @@ #define MAXIMUM_QUERY_TIMEOUT 30 /* The maximum time in seconds for the whole query to live. */ #endif +/* The default maximum number of recursions to follow before giving up. */ +#ifndef DEFAULT_RECURSION_DEPTH +#define DEFAULT_RECURSION_DEPTH 7 +#endif + +/* The default maximum number of iterative queries to allow before giving up. */ +#ifndef DEFAULT_MAX_QUERIES +#define DEFAULT_MAX_QUERIES 50 +#endif + /*% * Maximum EDNS0 input packet size. */ @@ -297,6 +307,7 @@ struct fetchctx { isc_uint64_t duration; isc_boolean_t logged; unsigned int querysent; + unsigned int totalqueries; unsigned int referrals; unsigned int lamecount; unsigned int neterr; @@ -307,6 +318,7 @@ struct fetchctx { isc_boolean_t timeout; dns_adbaddrinfo_t *addrinfo; isc_sockaddr_t *client; + unsigned int depth; }; #define FCTX_MAGIC ISC_MAGIC('F', '!', '!', '!') @@ -419,6 +431,7 @@ struct dns_resolver { isc_timer_t * spillattimer; isc_boolean_t zero_no_soa_ttl; unsigned int query_timeout; + unsigned int maxdepth; /* Locked by lock. */ unsigned int references; @@ -1097,6 +1110,7 @@ fctx_sendevents(fetchctx_t *fctx, isc_result_t result, int line) { event->result == DNS_R_NCACHENXRRSET); } + event->qtotal = fctx->totalqueries; isc_task_sendanddetach(&task, ISC_EVENT_PTR(&event)); count++; } @@ -1537,7 +1551,9 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo, if (result != ISC_R_SUCCESS) goto cleanup_dispatch; } + fctx->querysent++; + fctx->totalqueries++; ISC_LIST_APPEND(fctx->queries, query, link); query->fctx->nqueries++; @@ -2194,9 +2210,10 @@ fctx_finddone(isc_task_t *task, isc_event_t *event) { */ INSIST(!SHUTTINGDOWN(fctx)); fctx->attributes &= ~FCTX_ATTR_ADDRWAIT; - if (event->ev_type == DNS_EVENT_ADBMOREADDRESSES) + if (event->ev_type == DNS_EVENT_ADBMOREADDRESSES) { want_try = ISC_TRUE; - else { + fctx->totalqueries += find->qtotal; + } else { fctx->findfail++; if (fctx->pending == 0) { /* @@ -2479,12 +2496,13 @@ findname(fetchctx_t *fctx, dns_name_t *name, in_port_t port, * See what we know about this address. */ find = NULL; - result = dns_adb_createfind(fctx->adb, - res->buckets[fctx->bucketnum].task, - fctx_finddone, fctx, name, - &fctx->name, fctx->type, - options, now, NULL, - res->view->dstport, &find); + result = dns_adb_createfind2(fctx->adb, + res->buckets[fctx->bucketnum].task, + fctx_finddone, fctx, name, + &fctx->name, fctx->type, + options, now, NULL, + res->view->dstport, + fctx->depth + 1, &find); if (result != ISC_R_SUCCESS) { if (result == DNS_R_ALIAS) { /* @@ -2592,6 +2610,11 @@ fctx_getaddresses(fetchctx_t *fctx, isc_boolean_t badcache) { res = fctx->res; + if (fctx->depth > res->maxdepth) { + FCTXTRACE("too much NS indirection"); + return (DNS_R_SERVFAIL); + } + /* * Forwarders. */ @@ -3030,6 +3053,9 @@ fctx_try(fetchctx_t *fctx, isc_boolean_t retrying, isc_boolean_t badcache) { REQUIRE(!ADDRWAIT(fctx)); + if (fctx->totalqueries > DEFAULT_MAX_QUERIES) + fctx_done(fctx, DNS_R_SERVFAIL, __LINE__); + addrinfo = fctx_nextaddress(fctx); if (addrinfo == NULL) { /* @@ -3388,6 +3414,7 @@ fctx_start(isc_task_t *task, isc_event_t *event) { * Normal fctx startup. */ fctx->state = fetchstate_active; + fctx->totalqueries = 0; /* * Reset the control event for later use in shutting down * the fctx. @@ -3457,6 +3484,7 @@ fctx_join(fetchctx_t *fctx, isc_task_t *task, isc_sockaddr_t *client, event->fetch = fetch; event->client = client; event->id = id; + event->qtotal = 0; dns_fixedname_init(&event->foundname); /* @@ -3493,7 +3521,8 @@ log_ns_ttl(fetchctx_t *fctx, const char *where) { static isc_result_t fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type, dns_name_t *domain, dns_rdataset_t *nameservers, - unsigned int options, unsigned int bucketnum, fetchctx_t **fctxp) + unsigned int options, unsigned int bucketnum, unsigned int depth, + fetchctx_t **fctxp) { fetchctx_t *fctx; isc_result_t result; @@ -3545,6 +3574,7 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type, fctx->state = fetchstate_init; fctx->want_shutdown = ISC_FALSE; fctx->cloned = ISC_FALSE; + fctx->depth = depth; ISC_LIST_INIT(fctx->queries); ISC_LIST_INIT(fctx->finds); ISC_LIST_INIT(fctx->altfinds); @@ -3563,6 +3593,7 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type, fctx->pending = 0; fctx->restarts = 0; fctx->querysent = 0; + fctx->totalqueries = 0; fctx->referrals = 0; TIME_NOW(&fctx->start); fctx->timeouts = 0; @@ -7781,6 +7812,7 @@ dns_resolver_create(dns_view_t *view, res->spillattimer = NULL; res->zero_no_soa_ttl = ISC_FALSE; res->query_timeout = DEFAULT_QUERY_TIMEOUT; + res->maxdepth = DEFAULT_RECURSION_DEPTH; res->nbuckets = ntasks; res->activebuckets = ntasks; res->buckets = isc_mem_get(view->mctx, @@ -8219,9 +8251,9 @@ dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name, dns_rdataset_t *sigrdataset, dns_fetch_t **fetchp) { - return (dns_resolver_createfetch2(res, name, type, domain, + return (dns_resolver_createfetch3(res, name, type, domain, nameservers, forwarders, NULL, 0, - options, task, action, arg, + options, 0, task, action, arg, rdataset, sigrdataset, fetchp)); } @@ -8237,6 +8269,25 @@ dns_resolver_createfetch2(dns_resolver_t *res, dns_name_t *name, dns_rdataset_t *sigrdataset, dns_fetch_t **fetchp) { + return (dns_resolver_createfetch3(res, name, type, domain, + nameservers, forwarders, client, id, + options, 0, task, action, arg, + rdataset, sigrdataset, fetchp)); +} + +isc_result_t +dns_resolver_createfetch3(dns_resolver_t *res, dns_name_t *name, + dns_rdatatype_t type, + dns_name_t *domain, dns_rdataset_t *nameservers, + dns_forwarders_t *forwarders, + isc_sockaddr_t *client, dns_messageid_t id, + unsigned int options, unsigned int depth, + isc_task_t *task, + isc_taskaction_t action, void *arg, + dns_rdataset_t *rdataset, + dns_rdataset_t *sigrdataset, + dns_fetch_t **fetchp) +{ dns_fetch_t *fetch; fetchctx_t *fctx = NULL; isc_result_t result = ISC_R_SUCCESS; @@ -8325,11 +8376,12 @@ dns_resolver_createfetch2(dns_resolver_t *res, dns_name_t *name, if (fctx == NULL) { result = fctx_create(res, name, type, domain, nameservers, - options, bucketnum, &fctx); + options, bucketnum, depth, &fctx); if (result != ISC_R_SUCCESS) goto unlock; new_fctx = ISC_TRUE; - } + } else if (fctx->depth > depth) + fctx->depth = depth; result = fctx_join(fctx, task, client, id, action, arg, rdataset, sigrdataset, fetch); @@ -9101,3 +9153,15 @@ dns_resolver_settimeout(dns_resolver_t *resolver, unsigned int seconds) { resolver->query_timeout = seconds; } + +void +dns_resolver_setmaxdepth(dns_resolver_t *resolver, unsigned int maxdepth) { + REQUIRE(VALID_RESOLVER(resolver)); + resolver->maxdepth = maxdepth; +} + +unsigned int +dns_resolver_getmaxdepth(dns_resolver_t *resolver) { + REQUIRE(VALID_RESOLVER(resolver)); + return (resolver->maxdepth); +} diff --git a/lib/isccfg/namedconf.c b/lib/isccfg/namedconf.c index bfd4bab..5f8b037 100644 --- a/lib/isccfg/namedconf.c +++ b/lib/isccfg/namedconf.c @@ -1393,6 +1393,7 @@ view_clauses[] = { { "max-cache-ttl", &cfg_type_uint32, 0 }, { "max-clients-per-query", &cfg_type_uint32, 0 }, { "max-ncache-ttl", &cfg_type_uint32, 0 }, + { "max-recursion-depth", &cfg_type_uint32, 0 }, { "max-udp-size", &cfg_type_uint32, 0 }, { "min-roots", &cfg_type_uint32, CFG_CLAUSEFLAG_NOTIMP }, { "minimal-responses", &cfg_type_boolean, 0 }, -- 1.9.1