added unbound to external deps

1 files changed, 754 insertions, 0 deletions

diff --git a/external/unbound/iterator/iter_scrub.c b/external/unbound/iterator/iter_scrub.c
new file mode 100644
index 000000000..b2248bc0c
--- /dev/null
+++ b/external/unbound/iterator/iter_scrub.c
@@ -0,0 +1,754 @@
+/*
+ * iterator/iter_scrub.c - scrubbing, normalization, sanitization of DNS msgs.
+ *
+ * Copyright (c) 2007, NLnet Labs. All rights reserved.
+ *
+ * This software is open source.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 
+ * Neither the name of the NLNET LABS nor the names of its contributors may
+ * be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * \file
+ *
+ * This file has routine(s) for cleaning up incoming DNS messages from 
+ * possible useless or malicious junk in it.
+ */
+#include "config.h"
+#include "iterator/iter_scrub.h"
+#include "iterator/iterator.h"
+#include "iterator/iter_priv.h"
+#include "services/cache/rrset.h"
+#include "util/log.h"
+#include "util/net_help.h"
+#include "util/regional.h"
+#include "util/config_file.h"
+#include "util/module.h"
+#include "util/data/msgparse.h"
+#include "util/data/dname.h"
+#include "util/data/msgreply.h"
+#include "util/alloc.h"
+#include "ldns/sbuffer.h"
+
+/** RRset flag used during scrubbing. The RRset is OK. */
+#define RRSET_SCRUB_OK	0x80
+
+/** remove rrset, update loop variables */
+static void
+remove_rrset(const char* str, sldns_buffer* pkt, struct msg_parse* msg, 
+	struct rrset_parse* prev, struct rrset_parse** rrset)
+{
+	if(verbosity >= VERB_QUERY && str
+		&& (*rrset)->dname_len <= LDNS_MAX_DOMAINLEN) {
+		uint8_t buf[LDNS_MAX_DOMAINLEN+1];
+		dname_pkt_copy(pkt, buf, (*rrset)->dname);
+		log_nametypeclass(VERB_QUERY, str, buf, 
+			(*rrset)->type, ntohs((*rrset)->rrset_class));
+	}
+	if(prev)
+		prev->rrset_all_next = (*rrset)->rrset_all_next;
+	else	msg->rrset_first = (*rrset)->rrset_all_next;
+	if(msg->rrset_last == *rrset)
+		msg->rrset_last = prev;
+	msg->rrset_count --;
+	switch((*rrset)->section) {
+		case LDNS_SECTION_ANSWER: msg->an_rrsets--; break;
+		case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break;
+		case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break;
+		default: log_assert(0);
+	}
+	msgparse_bucket_remove(msg, *rrset);
+	*rrset = (*rrset)->rrset_all_next;
+}
+
+/** return true if rr type has additional names in it */
+static int
+has_additional(uint16_t t)
+{
+	switch(t) {
+		case LDNS_RR_TYPE_MB:
+		case LDNS_RR_TYPE_MD:
+		case LDNS_RR_TYPE_MF:
+		case LDNS_RR_TYPE_NS:
+		case LDNS_RR_TYPE_MX:
+		case LDNS_RR_TYPE_KX:
+		case LDNS_RR_TYPE_SRV:
+			return 1;
+		case LDNS_RR_TYPE_NAPTR:
+			/* TODO: NAPTR not supported, glue stripped off */
+			return 0;
+	}
+	return 0;
+}
+
+/** get additional name from rrset RR, return false if no name present */
+static int
+get_additional_name(struct rrset_parse* rrset, struct rr_parse* rr, 
+	uint8_t** nm, size_t* nmlen, sldns_buffer* pkt) 
+{
+	size_t offset = 0;
+	size_t len, oldpos;
+	switch(rrset->type) {
+		case LDNS_RR_TYPE_MB:
+		case LDNS_RR_TYPE_MD:
+		case LDNS_RR_TYPE_MF:
+		case LDNS_RR_TYPE_NS:
+			offset = 0;
+			break;
+		case LDNS_RR_TYPE_MX:
+		case LDNS_RR_TYPE_KX:
+			offset = 2;
+			break;
+		case LDNS_RR_TYPE_SRV:
+			offset = 6;
+			break;
+		case LDNS_RR_TYPE_NAPTR:
+			/* TODO: NAPTR not supported, glue stripped off */
+			return 0;
+		default:
+			return 0;
+	}
+	len = sldns_read_uint16(rr->ttl_data+sizeof(uint32_t));
+	if(len < offset+1)
+		return 0; /* rdata field too small */
+	*nm = rr->ttl_data+sizeof(uint32_t)+sizeof(uint16_t)+offset;
+	oldpos = sldns_buffer_position(pkt);
+	sldns_buffer_set_position(pkt, (size_t)(*nm - sldns_buffer_begin(pkt)));
+	*nmlen = pkt_dname_len(pkt);
+	sldns_buffer_set_position(pkt, oldpos);
+	if(*nmlen == 0)
+		return 0;
+	return 1;
+}
+
+/** Place mark on rrsets in additional section they are OK */
+static void
+mark_additional_rrset(sldns_buffer* pkt, struct msg_parse* msg, 
+	struct rrset_parse* rrset)
+{
+	/* Mark A and AAAA for NS as appropriate additional section info. */
+	uint8_t* nm = NULL;
+	size_t nmlen = 0;
+	struct rr_parse* rr;
+
+	if(!has_additional(rrset->type))
+		return;
+	for(rr = rrset->rr_first; rr; rr = rr->next) {
+		if(get_additional_name(rrset, rr, &nm, &nmlen, pkt)) {
+			/* mark A */
+			hashvalue_t h = pkt_hash_rrset(pkt, nm, LDNS_RR_TYPE_A, 
+				rrset->rrset_class, 0);
+			struct rrset_parse* r = msgparse_hashtable_lookup(
+				msg, pkt, h, 0, nm, nmlen, 
+				LDNS_RR_TYPE_A, rrset->rrset_class);
+			if(r && r->section == LDNS_SECTION_ADDITIONAL) {
+				r->flags |= RRSET_SCRUB_OK;
+			}
+			
+			/* mark AAAA */
+			h = pkt_hash_rrset(pkt, nm, LDNS_RR_TYPE_AAAA, 
+				rrset->rrset_class, 0);
+			r = msgparse_hashtable_lookup(msg, pkt, h, 0, nm, 
+				nmlen, LDNS_RR_TYPE_AAAA, rrset->rrset_class);
+			if(r && r->section == LDNS_SECTION_ADDITIONAL) {
+				r->flags |= RRSET_SCRUB_OK;
+			}
+		}
+	}
+}
+
+/** Get target name of a CNAME */
+static int
+parse_get_cname_target(struct rrset_parse* rrset, uint8_t** sname, 
+	size_t* snamelen)
+{
+	if(rrset->rr_count != 1) {
+		struct rr_parse* sig;
+		verbose(VERB_ALGO, "Found CNAME rrset with "
+			"size > 1: %u", (unsigned)rrset->rr_count);
+		/* use the first CNAME! */
+		rrset->rr_count = 1;
+		rrset->size = rrset->rr_first->size;
+		for(sig=rrset->rrsig_first; sig; sig=sig->next)
+			rrset->size += sig->size;
+		rrset->rr_last = rrset->rr_first;
+		rrset->rr_first->next = NULL;
+	}
+	if(rrset->rr_first->size < sizeof(uint16_t)+1)
+		return 0; /* CNAME rdata too small */
+	*sname = rrset->rr_first->ttl_data + sizeof(uint32_t)
+		+ sizeof(uint16_t); /* skip ttl, rdatalen */
+	*snamelen = rrset->rr_first->size - sizeof(uint16_t);
+	return 1;
+}
+
+/** Synthesize CNAME from DNAME, false if too long */
+static int 
+synth_cname(uint8_t* qname, size_t qnamelen, struct rrset_parse* dname_rrset, 
+	uint8_t* alias, size_t* aliaslen, sldns_buffer* pkt)
+{
+	/* we already know that sname is a strict subdomain of DNAME owner */
+	uint8_t* dtarg = NULL;
+	size_t dtarglen;
+	if(!parse_get_cname_target(dname_rrset, &dtarg, &dtarglen))
+		return 0; 
+	log_assert(qnamelen > dname_rrset->dname_len);
+	/* DNAME from com. to net. with qname example.com. -> example.net. */
+	/* so: \3com\0 to \3net\0 and qname \7example\3com\0 */
+	*aliaslen = qnamelen + dtarglen - dname_rrset->dname_len;
+	if(*aliaslen > LDNS_MAX_DOMAINLEN)
+		return 0; /* should have been RCODE YXDOMAIN */
+	/* decompress dnames into buffer, we know it fits */
+	dname_pkt_copy(pkt, alias, qname);
+	dname_pkt_copy(pkt, alias+(qnamelen-dname_rrset->dname_len), dtarg);
+	return 1;
+}
+
+/** synthesize a CNAME rrset */
+static struct rrset_parse*
+synth_cname_rrset(uint8_t** sname, size_t* snamelen, uint8_t* alias, 
+	size_t aliaslen, struct regional* region, struct msg_parse* msg, 
+	struct rrset_parse* rrset, struct rrset_parse* prev,
+	struct rrset_parse* nx, sldns_buffer* pkt)
+{
+	struct rrset_parse* cn = (struct rrset_parse*)regional_alloc(region,
+		sizeof(struct rrset_parse));
+	if(!cn)
+		return NULL;
+	memset(cn, 0, sizeof(*cn));
+	cn->rr_first = (struct rr_parse*)regional_alloc(region, 
+		sizeof(struct rr_parse));
+	if(!cn->rr_first)
+		return NULL;
+	cn->rr_last = cn->rr_first;
+	/* CNAME from sname to alias */
+	cn->dname = (uint8_t*)regional_alloc(region, *snamelen);
+	if(!cn->dname)
+		return NULL;
+	dname_pkt_copy(pkt, cn->dname, *sname);
+	cn->dname_len = *snamelen;
+	cn->type = LDNS_RR_TYPE_CNAME;
+	cn->section = rrset->section;
+	cn->rrset_class = rrset->rrset_class;
+	cn->rr_count = 1;
+	cn->size = sizeof(uint16_t) + aliaslen;
+	cn->hash=pkt_hash_rrset(pkt, cn->dname, cn->type, cn->rrset_class, 0);
+	/* allocate TTL + rdatalen + uncompressed dname */
+	memset(cn->rr_first, 0, sizeof(struct rr_parse));
+	cn->rr_first->outside_packet = 1;
+	cn->rr_first->ttl_data = (uint8_t*)regional_alloc(region, 
+		sizeof(uint32_t)+sizeof(uint16_t)+aliaslen);
+	if(!cn->rr_first->ttl_data)
+		return NULL;
+	sldns_write_uint32(cn->rr_first->ttl_data, 0); /* TTL = 0 */
+	sldns_write_uint16(cn->rr_first->ttl_data+4, aliaslen);
+	memmove(cn->rr_first->ttl_data+6, alias, aliaslen);
+	cn->rr_first->size = sizeof(uint16_t)+aliaslen;
+
+	/* link it in */
+	cn->rrset_all_next = nx;
+	if(prev)
+		prev->rrset_all_next = cn;
+	else	msg->rrset_first = cn;
+	if(nx == NULL)
+		msg->rrset_last = cn;
+	msg->rrset_count ++;
+	msg->an_rrsets++;
+	/* it is not inserted in the msg hashtable. */
+
+	*sname = cn->rr_first->ttl_data + sizeof(uint32_t)+sizeof(uint16_t);
+	*snamelen = aliaslen;
+	return cn;
+}
+
+/** check if DNAME applies to a name */
+static int
+pkt_strict_sub(sldns_buffer* pkt, uint8_t* sname, uint8_t* dr)
+{
+	uint8_t buf1[LDNS_MAX_DOMAINLEN+1];
+	uint8_t buf2[LDNS_MAX_DOMAINLEN+1];
+	/* decompress names */
+	dname_pkt_copy(pkt, buf1, sname);
+	dname_pkt_copy(pkt, buf2, dr);
+	return dname_strict_subdomain_c(buf1, buf2);
+}
+
+/** check subdomain with decompression */
+static int
+pkt_sub(sldns_buffer* pkt, uint8_t* comprname, uint8_t* zone)
+{
+	uint8_t buf[LDNS_MAX_DOMAINLEN+1];
+	dname_pkt_copy(pkt, buf, comprname);
+	return dname_subdomain_c(buf, zone);
+}
+
+/** check subdomain with decompression, compressed is parent */
+static int
+sub_of_pkt(sldns_buffer* pkt, uint8_t* zone, uint8_t* comprname)
+{
+	uint8_t buf[LDNS_MAX_DOMAINLEN+1];
+	dname_pkt_copy(pkt, buf, comprname);
+	return dname_subdomain_c(zone, buf);
+}
+
+/**
+ * This routine normalizes a response. This includes removing "irrelevant"
+ * records from the answer and additional sections and (re)synthesizing
+ * CNAMEs from DNAMEs, if present.
+ *
+ * @param pkt: packet.
+ * @param msg: msg to normalize.
+ * @param qinfo: original query.
+ * @param region: where to allocate synthesized CNAMEs.
+ * @return 0 on error.
+ */
+static int
+scrub_normalize(sldns_buffer* pkt, struct msg_parse* msg, 
+	struct query_info* qinfo, struct regional* region)
+{
+	uint8_t* sname = qinfo->qname;
+	size_t snamelen = qinfo->qname_len;
+	struct rrset_parse* rrset, *prev, *nsset=NULL;
+
+	if(FLAGS_GET_RCODE(msg->flags) != LDNS_RCODE_NOERROR &&
+		FLAGS_GET_RCODE(msg->flags) != LDNS_RCODE_NXDOMAIN)
+		return 1;
+
+	/* For the ANSWER section, remove all "irrelevant" records and add
+	 * synthesized CNAMEs from DNAMEs
+	 * This will strip out-of-order CNAMEs as well. */
+
+	/* walk through the parse packet rrset list, keep track of previous
+	 * for insert and delete ease, and examine every RRset */
+	prev = NULL;
+	rrset = msg->rrset_first;
+	while(rrset && rrset->section == LDNS_SECTION_ANSWER) {
+		if(rrset->type == LDNS_RR_TYPE_DNAME && 
+			pkt_strict_sub(pkt, sname, rrset->dname)) {
+			/* check if next rrset is correct CNAME. else,
+			 * synthesize a CNAME */
+			struct rrset_parse* nx = rrset->rrset_all_next;
+			uint8_t alias[LDNS_MAX_DOMAINLEN+1];
+			size_t aliaslen = 0;
+			if(rrset->rr_count != 1) {
+				verbose(VERB_ALGO, "Found DNAME rrset with "
+					"size > 1: %u", 
+					(unsigned)rrset->rr_count);
+				return 0;
+			}
+			if(!synth_cname(sname, snamelen, rrset, alias, 
+				&aliaslen, pkt)) {
+				verbose(VERB_ALGO, "synthesized CNAME "
+					"too long");
+				return 0;
+			}
+			if(nx && nx->type == LDNS_RR_TYPE_CNAME && 
+			   dname_pkt_compare(pkt, sname, nx->dname) == 0) {
+				/* check next cname */
+				uint8_t* t = NULL;
+				size_t tlen = 0;
+				if(!parse_get_cname_target(rrset, &t, &tlen))
+					return 0;
+				if(dname_pkt_compare(pkt, alias, t) == 0) {
+					/* it's OK and better capitalized */
+					prev = rrset;
+					rrset = nx;
+					continue;
+				}
+				/* synth ourselves */
+			}
+			/* synth a CNAME rrset */
+			prev = synth_cname_rrset(&sname, &snamelen, alias, 
+				aliaslen, region, msg, rrset, rrset, nx, pkt);
+			if(!prev) {
+				log_err("out of memory synthesizing CNAME");
+				return 0;
+			}
+			/* FIXME: resolve the conflict between synthesized 
+			 * CNAME ttls and the cache. */
+			rrset = nx;
+			continue;
+
+		}
+
+		/* The only records in the ANSWER section not allowed to */
+		if(dname_pkt_compare(pkt, sname, rrset->dname) != 0) {
+			remove_rrset("normalize: removing irrelevant RRset:", 
+				pkt, msg, prev, &rrset);
+			continue;
+		}
+
+		/* Follow the CNAME chain. */
+		if(rrset->type == LDNS_RR_TYPE_CNAME) {
+			uint8_t* oldsname = sname;
+			if(!parse_get_cname_target(rrset, &sname, &snamelen))
+				return 0;
+			prev = rrset;
+			rrset = rrset->rrset_all_next;
+			/* in CNAME ANY response, can have data after CNAME */
+			if(qinfo->qtype == LDNS_RR_TYPE_ANY) {
+				while(rrset && rrset->section ==
+					LDNS_SECTION_ANSWER &&
+					dname_pkt_compare(pkt, oldsname,
+					rrset->dname) == 0) {
+					prev = rrset;
+					rrset = rrset->rrset_all_next;
+				}
+			}
+			continue;
+		}
+
+		/* Otherwise, make sure that the RRset matches the qtype. */
+		if(qinfo->qtype != LDNS_RR_TYPE_ANY && 
+			qinfo->qtype != rrset->type) {
+			remove_rrset("normalize: removing irrelevant RRset:", 
+				pkt, msg, prev, &rrset);
+			continue;
+		}
+
+		/* Mark the additional names from relevant rrset as OK. */
+		/* only for RRsets that match the query name, other ones
+		 * will be removed by sanitize, so no additional for them */
+		if(dname_pkt_compare(pkt, qinfo->qname, rrset->dname) == 0)
+			mark_additional_rrset(pkt, msg, rrset);
+		
+		prev = rrset;
+		rrset = rrset->rrset_all_next;
+	}
+
+	/* Mark additional names from AUTHORITY */
+	while(rrset && rrset->section == LDNS_SECTION_AUTHORITY) {
+		if(rrset->type==LDNS_RR_TYPE_DNAME ||
+			rrset->type==LDNS_RR_TYPE_CNAME ||
+			rrset->type==LDNS_RR_TYPE_A ||
+			rrset->type==LDNS_RR_TYPE_AAAA) {
+			remove_rrset("normalize: removing irrelevant "
+				"RRset:", pkt, msg, prev, &rrset);
+			continue;
+		}
+		/* only one NS set allowed in authority section */
+		if(rrset->type==LDNS_RR_TYPE_NS) {
+			/* NS set must be pertinent to the query */
+			if(!sub_of_pkt(pkt, qinfo->qname, rrset->dname)) {
+				remove_rrset("normalize: removing irrelevant "
+					"RRset:", pkt, msg, prev, &rrset);
+				continue;
+			}
+			if(nsset == NULL) {
+				nsset = rrset;
+			} else {
+				remove_rrset("normalize: removing irrelevant "
+					"RRset:", pkt, msg, prev, &rrset);
+				continue;
+			}
+		}
+		mark_additional_rrset(pkt, msg, rrset);
+		prev = rrset;
+		rrset = rrset->rrset_all_next;
+	}
+
+	/* For each record in the additional section, remove it if it is an
+	 * address record and not in the collection of additional names 
+	 * found in ANSWER and AUTHORITY. */
+	/* These records have not been marked OK previously */
+	while(rrset && rrset->section == LDNS_SECTION_ADDITIONAL) {
+		/* FIXME: what about other types? */
+		if(rrset->type==LDNS_RR_TYPE_A || 
+			rrset->type==LDNS_RR_TYPE_AAAA) 
+		{
+			if((rrset->flags & RRSET_SCRUB_OK)) {
+				/* remove flag to clean up flags variable */
+				rrset->flags &= ~RRSET_SCRUB_OK;
+			} else {
+				remove_rrset("normalize: removing irrelevant "
+					"RRset:", pkt, msg, prev, &rrset);
+				continue;
+			}
+		}
+		if(rrset->type==LDNS_RR_TYPE_DNAME || 
+			rrset->type==LDNS_RR_TYPE_CNAME ||
+			rrset->type==LDNS_RR_TYPE_NS) {
+			remove_rrset("normalize: removing irrelevant "
+				"RRset:", pkt, msg, prev, &rrset);
+			continue;
+		}
+		prev = rrset;
+		rrset = rrset->rrset_all_next;
+	}
+	
+	return 1;
+}
+
+/**
+ * Store potential poison in the cache (only if hardening disabled).
+ * The rrset is stored in the cache but removed from the message.
+ * So that it will be used for infrastructure purposes, but not be 
+ * returned to the client.
+ * @param pkt: packet
+ * @param msg: message parsed
+ * @param env: environment with cache
+ * @param rrset: to store.
+ */
+static void
+store_rrset(sldns_buffer* pkt, struct msg_parse* msg, struct module_env* env,
+	struct rrset_parse* rrset)
+{
+	struct ub_packed_rrset_key* k;
+	struct packed_rrset_data* d;
+	struct rrset_ref ref;
+	time_t now = *env->now;
+
+	k = alloc_special_obtain(env->alloc);
+	if(!k)
+		return;
+	k->entry.data = NULL;
+	if(!parse_copy_decompress_rrset(pkt, msg, rrset, NULL, k)) {
+		alloc_special_release(env->alloc, k);
+		return;
+	}
+	d = (struct packed_rrset_data*)k->entry.data;
+	packed_rrset_ttl_add(d, now);
+	ref.key = k;
+	ref.id = k->id;
+	/*ignore ret: it was in the cache, ref updated */
+	(void)rrset_cache_update(env->rrset_cache, &ref, env->alloc, now);
+}
+
+/** Check if there are SOA records in the authority section (negative) */
+static int
+soa_in_auth(struct msg_parse* msg)
+{
+	struct rrset_parse* rrset;
+	for(rrset = msg->rrset_first; rrset; rrset = rrset->rrset_all_next)
+		if(rrset->type == LDNS_RR_TYPE_SOA &&
+			rrset->section == LDNS_SECTION_AUTHORITY) 
+			return 1;
+	return 0;
+}
+ 
+/**
+ * Check if right hand name in NSEC is within zone
+ * @param rrset: the NSEC rrset
+ * @param zonename: the zone name.
+ * @return true if BAD.
+ */
+static int sanitize_nsec_is_overreach(struct rrset_parse* rrset, 
+	uint8_t* zonename)
+{
+	struct rr_parse* rr;
+	uint8_t* rhs;
+	size_t len;
+	log_assert(rrset->type == LDNS_RR_TYPE_NSEC);
+	for(rr = rrset->rr_first; rr; rr = rr->next) {
+		rhs = rr->ttl_data+4+2;
+		len = sldns_read_uint16(rr->ttl_data+4);
+		if(!dname_valid(rhs, len)) {
+			/* malformed domain name in rdata */
+			return 1;
+		}
+		if(!dname_subdomain_c(rhs, zonename)) {
+			/* overreaching */
+			return 1;
+		}
+	}
+	/* all NSEC RRs OK */
+	return 0;
+}
+
+/**
+ * Given a response event, remove suspect RRsets from the response.
+ * "Suspect" rrsets are potentially poison. Note that this routine expects
+ * the response to be in a "normalized" state -- that is, all "irrelevant"
+ * RRsets have already been removed, CNAMEs are in order, etc.
+ *
+ * @param pkt: packet.
+ * @param msg: msg to normalize.
+ * @param qinfo: the question originally asked.
+ * @param zonename: name of server zone.
+ * @param env: module environment with config and cache.
+ * @param ie: iterator environment with private address data.
+ * @return 0 on error.
+ */
+static int
+scrub_sanitize(sldns_buffer* pkt, struct msg_parse* msg, 
+	struct query_info* qinfo, uint8_t* zonename, struct module_env* env,
+	struct iter_env* ie)
+{
+	int del_addi = 0; /* if additional-holding rrsets are deleted, we
+		do not trust the normalized additional-A-AAAA any more */
+	struct rrset_parse* rrset, *prev;
+	prev = NULL;
+	rrset = msg->rrset_first;
+
+	/* the first DNAME is allowed to stay. It needs checking before
+	 * it can be used from the cache. After normalization, an initial 
+	 * DNAME will have a correctly synthesized CNAME after it. */
+	if(rrset && rrset->type == LDNS_RR_TYPE_DNAME && 
+		rrset->section == LDNS_SECTION_ANSWER &&
+		pkt_strict_sub(pkt, qinfo->qname, rrset->dname) &&
+		pkt_sub(pkt, rrset->dname, zonename)) {
+		prev = rrset; /* DNAME allowed to stay in answer section */
+		rrset = rrset->rrset_all_next;
+	}
+	
+	/* remove all records from the answer section that are 
+	 * not the same domain name as the query domain name.
+	 * The answer section should contain rrsets with the same name
+	 * as the question. For DNAMEs a CNAME has been synthesized.
+	 * Wildcards have the query name in answer section.
+	 * ANY queries get query name in answer section.
+	 * Remainders of CNAME chains are cut off and resolved by iterator. */
+	while(rrset && rrset->section == LDNS_SECTION_ANSWER) {
+		if(dname_pkt_compare(pkt, qinfo->qname, rrset->dname) != 0) {
+			if(has_additional(rrset->type)) del_addi = 1;
+			remove_rrset("sanitize: removing extraneous answer "
+				"RRset:", pkt, msg, prev, &rrset);
+			continue;
+		}
+		prev = rrset;
+		rrset = rrset->rrset_all_next;
+	}
+
+	/* At this point, we brutally remove ALL rrsets that aren't 
+	 * children of the originating zone. The idea here is that, 
+	 * as far as we know, the server that we contacted is ONLY 
+	 * authoritative for the originating zone. It, of course, MAY 
+	 * be authoriative for any other zones, and of course, MAY 
+	 * NOT be authoritative for some subdomains of the originating 
+	 * zone. */
+	prev = NULL;
+	rrset = msg->rrset_first;
+	while(rrset) {
+
+		/* remove private addresses */
+		if( (rrset->type == LDNS_RR_TYPE_A || 
+			rrset->type == LDNS_RR_TYPE_AAAA)) {
+
+			/* do not set servfail since this leads to too
+			 * many drops of other people using rfc1918 space */
+			/* also do not remove entire rrset, unless all records
+			 * in it are bad */
+			if(priv_rrset_bad(ie->priv, pkt, rrset)) {
+				remove_rrset(NULL, pkt, msg, prev, &rrset);
+				continue;
+			}
+		}
+		
+		/* skip DNAME records -- they will always be followed by a 
+		 * synthesized CNAME, which will be relevant.
+		 * FIXME: should this do something differently with DNAME 
+		 * rrsets NOT in Section.ANSWER? */
+		/* But since DNAME records are also subdomains of the zone,
+		 * same check can be used */
+
+		if(!pkt_sub(pkt, rrset->dname, zonename)) {
+			if(msg->an_rrsets == 0 && 
+				rrset->type == LDNS_RR_TYPE_NS && 
+				rrset->section == LDNS_SECTION_AUTHORITY &&
+				FLAGS_GET_RCODE(msg->flags) == 
+				LDNS_RCODE_NOERROR && !soa_in_auth(msg) &&
+				sub_of_pkt(pkt, zonename, rrset->dname)) {
+				/* noerror, nodata and this NS rrset is above
+				 * the zone. This is LAME! 
+				 * Leave in the NS for lame classification. */
+				/* remove everything from the additional
+				 * (we dont want its glue that was approved
+				 * during the normalize action) */
+				del_addi = 1;
+			} else if(!env->cfg->harden_glue) {
+				/* store in cache! Since it is relevant
+				 * (from normalize) it will be picked up 
+				 * from the cache to be used later */
+				store_rrset(pkt, msg, env, rrset);
+				remove_rrset("sanitize: storing potential "
+				"poison RRset:", pkt, msg, prev, &rrset);
+				continue;
+			} else {
+				if(has_additional(rrset->type)) del_addi = 1;
+				remove_rrset("sanitize: removing potential "
+				"poison RRset:", pkt, msg, prev, &rrset);
+				continue;
+			}
+		}
+		if(del_addi && rrset->section == LDNS_SECTION_ADDITIONAL) {
+			remove_rrset("sanitize: removing potential "
+			"poison reference RRset:", pkt, msg, prev, &rrset);
+			continue;
+		}
+		/* check if right hand side of NSEC is within zone */
+		if(rrset->type == LDNS_RR_TYPE_NSEC &&
+			sanitize_nsec_is_overreach(rrset, zonename)) {
+			remove_rrset("sanitize: removing overreaching NSEC "
+				"RRset:", pkt, msg, prev, &rrset);
+			continue;
+		}
+		prev = rrset;
+		rrset = rrset->rrset_all_next;
+	}
+	return 1;
+}
+
+int 
+scrub_message(sldns_buffer* pkt, struct msg_parse* msg, 
+	struct query_info* qinfo, uint8_t* zonename, struct regional* region,
+	struct module_env* env, struct iter_env* ie)
+{
+	/* basic sanity checks */
+	log_nametypeclass(VERB_ALGO, "scrub for", zonename, LDNS_RR_TYPE_NS, 
+		qinfo->qclass);
+	if(msg->qdcount > 1)
+		return 0;
+	if( !(msg->flags&BIT_QR) )
+		return 0;
+	msg->flags &= ~(BIT_AD|BIT_Z); /* force off bit AD and Z */
+	
+	/* make sure that a query is echoed back when NOERROR or NXDOMAIN */
+	/* this is not required for basic operation but is a forgery 
+	 * resistance (security) feature */
+	if((FLAGS_GET_RCODE(msg->flags) == LDNS_RCODE_NOERROR ||
+		FLAGS_GET_RCODE(msg->flags) == LDNS_RCODE_NXDOMAIN) &&
+		msg->qdcount == 0)
+		return 0;
+
+	/* if a query is echoed back, make sure it is correct. Otherwise,
+	 * this may be not a reply to our query. */
+	if(msg->qdcount == 1) {
+		if(dname_pkt_compare(pkt, msg->qname, qinfo->qname) != 0)
+			return 0;
+		if(msg->qtype != qinfo->qtype || msg->qclass != qinfo->qclass)
+			return 0;
+	}
+
+	/* normalize the response, this cleans up the additional.  */
+	if(!scrub_normalize(pkt, msg, qinfo, region))
+		return 0;
+	/* delete all out-of-zone information */
+	if(!scrub_sanitize(pkt, msg, qinfo, zonename, env, ie))
+		return 0;
+	return 1;
+}