SECURITY: Ignore apparent answers before first RR we found the first time

[adns.git] / src / reply.c

diff --git a/src/reply.c b/src/reply.c
index 199746cd7797de682f9c8ee4da28cc2ae239061c..0379ca441ff52f90feefdce6cf3dc333c7b808a7 100644 (file)
--- a/src/reply.c
+++ b/src/reply.c
@@ -3,16 +3,16 @@
  * - main handling and parsing routine for received datagrams
  */
 /*
- *  This file is
- *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
- *
- *  It is part of adns, which is
- *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
- *    Copyright (C) 1999-2000 Tony Finch <dot@dotat.at>
+ *  This file is part of adns, which is
+ *    Copyright (C) 1997-2000,2003,2006,2014-2016  Ian Jackson
+ *    Copyright (C) 2014  Mark Wooding
+ *    Copyright (C) 1999-2000,2003,2006  Tony Finch
+ *    Copyright (C) 1991 Massachusetts Institute of Technology
+ *  (See the file INSTALL for full details.)
  *  
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2, or (at your option)
+ *  the Free Software Foundation; either version 3, or (at your option)
  *  any later version.
  *  
  *  This program is distributed in the hope that it will be useful,
@@ -21,8 +21,7 @@
  *  GNU General Public License for more details.
  *  
  *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software Foundation,
- *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
+ *  along with this program; if not, write to the Free Software Foundation.
  */
 
 #include <stdlib.h>
@@ -35,8 +34,8 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
   int id, f1, f2, qdcount, ancount, nscount, arcount;
   int flg_ra, flg_rd, flg_tc, flg_qr, opcode;
   int rrtype, rrclass, rdlength, rdstart;
-  int anstart, nsstart, arstart;
-  int ownermatched, l, nrrs;
+  int anstart, nsstart;
+  int ownermatched, l, nrrs, restartfrom;
   unsigned long ttl, soattl;
   const typeinfo *typei;
   adns_query qu, nqu;
@@ -158,12 +157,12 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
    * query now. */
   
   anstart= qu->query_dglen;
-  arstart= -1;
 
   /* Now, take a look at the answer section, and see if it is complete.
    * If it has any CNAMEs we stuff them in the answer.
    */
   wantedrrs= 0;
+  restartfrom= -1;
   cbyte= anstart;
   for (rri= 0; rri<ancount; rri++) {
     rrstart= cbyte;
@@ -231,6 +230,7 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
         */
       }
     } else if (rrtype == (qu->answer->type & adns_rrt_typemask)) {
+      if (restartfrom==-1) restartfrom= rri;
       wantedrrs++;
     } else {
       adns__debug(ads,serv,qu,"ignoring answer RR"
@@ -313,7 +313,7 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
 
   /* Now, we have some RRs which we wanted. */
 
-  qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->typei->rrsz*wantedrrs);
+  qu->answer->rrs.untyped= adns__alloc_interim(qu,qu->answer->rrsz*wantedrrs);
   if (!qu->answer->rrs.untyped) {
     adns__query_fail(qu,adns_s_nomemory);
     return;
@@ -333,17 +333,20 @@ void adns__procdgram(adns_state ads, const byte *dgram, int dglen,
   pai.arcount= arcount;
   pai.now= now;
 
+  assert(restartfrom>=0);
   for (rri=0, nrrs=0; rri<ancount; rri++) {
     st= adns__findrr(qu,serv, dgram,dglen,&cbyte,
                     &rrtype,&rrclass,&ttl, &rdlength,&rdstart,
                     &ownermatched);
     assert(!st); assert(rrtype != -1);
-    if (rrclass != DNS_CLASS_IN ||
+    if (rri < restartfrom ||
+       rrclass != DNS_CLASS_IN ||
        rrtype != (qu->answer->type & adns_rrt_typemask) ||
        !ownermatched)
       continue;
     adns__update_expires(qu,ttl,now);
-    st= typei->parse(&pai, rdstart,rdstart+rdlength, rrsdata+nrrs*typei->rrsz);
+    st= typei->parse(&pai, rdstart,rdstart+rdlength,
+                    rrsdata+nrrs*qu->answer->rrsz);
     if (st) { adns__query_fail(qu,st); return; }
     if (rdstart==-1) goto x_truncated;
     nrrs++;