- Fix #3397: Fix that cachedb could return a partial CNAME chain.

git-svn-id: file:///svn/unbound/trunk@4445 be551aaa-1e26-0410-a405-d3ace91eadb9

cachedb/cachedb.c

@@ -568,7 +568,9 @@ cachedb_intcache_lookup(struct module_qstate* qstate)
 	msg = dns_cache_lookup(qstate->env, qstate->qinfo.qname,
 		qstate->qinfo.qname_len, qstate->qinfo.qtype,
 		qstate->qinfo.qclass, qstate->query_flags,
-		qstate->region, qstate->env->scratch);
+		qstate->region, qstate->env->scratch,
+		1 /* no partial messages with only a CNAME */
+		);
 	if(!msg && qstate->env->neg_cache) {
 		/* lookup in negative cache; may result in 
 		 * NOERROR/NODATA or NXDOMAIN answers that need validation */

doc/Changelog

@@ -3,6 +3,7 @@
 	  also recognized and means the same.  Also for tls-port,
 	  tls-service-key, tls-service-pem, stub-tls-upstream and
 	  forward-tls-upstream.
+	- Fix #3397: Fix that cachedb could return a partial CNAME chain.
 
 19 January 2018: Wouter
 	- tag 1.6.8 for release with CVE fix.

iterator/iterator.c

@@ -1109,7 +1109,7 @@ processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq,
 		msg = dns_cache_lookup(qstate->env, iq->qchase.qname, 
 			iq->qchase.qname_len, iq->qchase.qtype, 
 			iq->qchase.qclass, qstate->query_flags,
-			qstate->region, qstate->env->scratch);
+			qstate->region, qstate->env->scratch, 0);
 		if(!msg && qstate->env->neg_cache) {
 			/* lookup in negative cache; may result in
 			 * NOERROR/NODATA or NXDOMAIN answers that need validation */
@@ -2170,7 +2170,7 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
 				iq->qinfo_out.qname, iq->qinfo_out.qname_len, 
 				iq->qinfo_out.qtype, iq->qinfo_out.qclass, 
 				qstate->query_flags, qstate->region, 
-				qstate->env->scratch);
+				qstate->env->scratch, 0);
 			if(msg && msg->rep->an_numrrsets == 0
 				&& FLAGS_GET_RCODE(msg->rep->flags) == 
 				LDNS_RCODE_NOERROR)

services/cache/dns.c

@@ -711,7 +711,8 @@ fill_any(struct module_env* env,
 struct dns_msg* 
 dns_cache_lookup(struct module_env* env,
 	uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
-	uint16_t flags, struct regional* region, struct regional* scratch)
+	uint16_t flags, struct regional* region, struct regional* scratch,
+	int no_partial)
 {
 	struct lruhash_entry* e;
 	struct query_info k;
@@ -743,7 +744,8 @@ dns_cache_lookup(struct module_env* env,
 	/* see if a DNAME exists. Checked for first, to enforce that DNAMEs
 	 * are more important, the CNAME is resynthesized and thus 
 	 * consistent with the DNAME */
-	if( (rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
+	if(!no_partial &&
+		(rrset=find_closest_of_type(env, qname, qnamelen, qclass, now,
 		LDNS_RR_TYPE_DNAME, 1))) {
 		/* synthesize a DNAME+CNAME message based on this */
 		struct dns_msg* msg = synth_dname_msg(rrset, region, now, &k);
@@ -756,7 +758,7 @@ dns_cache_lookup(struct module_env* env,
 
 	/* see if we have CNAME for this domain,
 	 * but not for DS records (which are part of the parent) */
-	if( qtype != LDNS_RR_TYPE_DS &&
+	if(!no_partial && qtype != LDNS_RR_TYPE_DS &&
 	   (rrset=rrset_cache_lookup(env->rrset_cache, qname, qnamelen, 
 		LDNS_RR_TYPE_CNAME, qclass, 0, now, 0))) {
 		uint8_t* wc = NULL;

services/cache/dns.h

@@ -159,13 +159,16 @@ struct dns_msg* tomsg(struct module_env* env, struct query_info* q,
  * @param flags: flags with BIT_CD for AAAA queries in dns64 translation.
  * @param region: where to allocate result.
  * @param scratch: where to allocate temporary data.
+ * @param no_partial: if true, only complete messages and not a partial
+ *   one (with only the start of the CNAME chain and not the rest).
  * @return new response message (alloced in region, rrsets do not have IDs).
  * 	or NULL on error or if not found in cache.
  *	TTLs are made relative to the current time.
  */
 struct dns_msg* dns_cache_lookup(struct module_env* env,
 	uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass,
-	uint16_t flags, struct regional* region, struct regional* scratch);
+	uint16_t flags, struct regional* region, struct regional* scratch,
+	int no_partial);
 
 /** 
  * find and add A and AAAA records for missing nameservers in delegpt