Tweaks to previous, DNS label charset commit.

Only in DNSSEC mode, where we might need to validate or store
such names. In none-DNSSEC mode, simply don't cache these, as before.

CHANGELOG

@@ -68,18 +68,42 @@ version 2.73
 	    Fix broken DNSSEC validation of ECDSA signatures.
 
 	    Add --dnssec-timestamp option, which provides an automatic
-	    way to detect when the system time becomes valid after boot
+	    way to detect when the system time becomes valid after 
-	    on systems without an RTC, whilst allowing DNS queries before the
+	    boot on systems without an RTC, whilst allowing DNS 
-	    clock is valid so that NTP can run. Thanks to
+	    queries before the clock is valid so that NTP can run. 
-	    Kevin Darbyshire-Bryant for developing this idea.
+	    Thanks to Kevin Darbyshire-Bryant for developing this idea.
 
 	    Add --tftp-no-fail option. Thanks to Stefan Tomanek for
 	    the patch.
 
-	    Fix crash caused by looking up servers.bind, CHAOS text record,
+	    Fix crash caused by looking up servers.bind, CHAOS text 
-	    when more than about five --servers= lines are in the dnsmasq
+	    record, when more than about five --servers= lines are 
-	    config. This causes memory corruption which causes a crash later.
+	    in the dnsmasq config. This causes memory corruption 
-	    Thanks to Matt Coddington for sterling work chasing this down.
+	    which causes a crash later. Thanks to Matt Coddington for 
+	    sterling work chasing this down.
+
+	    Fix crash on receipt of certain malformed DNS requests.
+	    Thanks to Nick Sampanis for spotting the problem.
+	    Note that this is could allow the dnsmasq process's
+	    memory to be read by an attacker under certain
+	    circumstances, so it has a CVE, CVE-2015-3294 
+
+            Fix crash in authoritative DNS code, if a .arpa zone 
+	    is declared as authoritative, and then a PTR query which
+	    is not to be treated as authoritative arrived. Normally, 
+	    directly declaring .arpa zone as authoritative is not 
+	    done, so this crash wouldn't be seen. Instead the 
+	    relevant .arpa zone should be specified as a subnet
+	    in the auth-zone declaration. Thanks to Johnny S. Lee
+	    for the bugreport and initial patch.
+
+	    Fix authoritative DNS code to correctly reply to NS 
+	    and SOA queries for .arpa zones for which we are 
+	    declared authoritative by means of a subnet in auth-zone.
+	    Previously we provided correct answers to PTR queries
+	    in such zones (including NS and SOA) but not direct
+	    NS and SOA queries. Thanks to Johnny S. Lee for 
+	    pointing out the problem.
 
 	
 version 2.72
@@ -125,9 +149,6 @@ version 2.72
             Fix problem with --local-service option on big-endian platforms
 	    Thanks to Richard Genoud for the patch.
 
-	    Fix crash on receipt of certain malformed DNS requests. Thanks
-	    to Nick Sampanis for spotting the problem.
-	
 	
 version 2.71
             Subtle change to error handling to help DNSSEC validation 

contrib/wrt/dhcp_release.c

@@ -277,6 +277,11 @@ int main(int argc, char **argv)
       exit(1);
     }
   
+  if (inet_addr(argv[2]) == INADDR_NONE)
+    {
+      perror("invalid ip address");
+      exit(1);
+    }
   
   lease.s_addr = inet_addr(argv[2]);
   server = find_interface(lease, nl, if_nametoindex(argv[1]));

src/auth.c

@@ -131,24 +131,27 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 	  continue;
 	}
 
-      if (qtype == T_PTR)
+      if ((qtype == T_PTR || qtype == T_SOA || qtype == T_NS) &&
+	  (flag = in_arpa_name_2_addr(name, &addr)) &&
+	  !local_query)
 	{
-	  if (!(flag = in_arpa_name_2_addr(name, &addr)))
+	  for (zone = daemon->auth_zones; zone; zone = zone->next)
-	    continue;
+	    if ((subnet = find_subnet(zone, flag, &addr)))
+	      break;
 	  
-	  if (!local_query)
+	  if (!zone)
 	    {
-	      for (zone = daemon->auth_zones; zone; zone = zone->next)
+	      auth = 0;
-		if ((subnet = find_subnet(zone, flag, &addr)))
+	      continue;
-		  break;
-	      
-	      if (!zone)
-		{
-		  auth = 0;
-		  continue;
-		}
 	    }
+	  else if (qtype == T_SOA)
+	    soa = 1, found = 1;
+	  else if (qtype == T_NS)
+	    ns = 1, found = 1;
+	}
 
+      if (qtype == T_PTR && flag)
+	{
 	  intr = NULL;
 
 	  if (flag == F_IPV4)
@@ -186,7 +189,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 	  
 	  if (intr)
 	    {
-	      if (in_zone(zone, intr->name, NULL))
+	      if (local_query || in_zone(zone, intr->name, NULL))
 		{	
 		  found = 1;
 		  log_query(flag | F_REVERSE | F_CONFIG, intr->name, &addr, NULL);
@@ -208,8 +211,11 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 		    *p = 0; /* must be bare name */
 		  
 		  /* add  external domain */
-		  strcat(name, ".");
+		  if (zone)
-		  strcat(name, zone->domain);
+		    {
+		      strcat(name, ".");
+		      strcat(name, zone->domain);
+		    }
 		  log_query(flag | F_DHCP | F_REVERSE, name, &addr, record_source(crecp->uid));
 		  found = 1;
 		  if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
@@ -217,7 +223,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 					  T_PTR, C_IN, "d", name))
 		    anscount++;
 		}
-	      else if (crecp->flags & (F_DHCP | F_HOSTS) && in_zone(zone, name, NULL))
+	      else if (crecp->flags & (F_DHCP | F_HOSTS) && (local_query || in_zone(zone, name, NULL)))
 		{
 		  log_query(crecp->flags & ~F_FORWARD, name, &addr, record_source(crecp->uid));
 		  found = 1;
@@ -240,14 +246,20 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 	}
       
     cname_restart:
-      for (zone = daemon->auth_zones; zone; zone = zone->next)
+      if (found)
-	if (in_zone(zone, name, &cut))
+	/* NS and SOA .arpa requests have set found above. */
-	  break;
+	cut = NULL;
-      
+      else
-      if (!zone)
 	{
-	  auth = 0;
+	  for (zone = daemon->auth_zones; zone; zone = zone->next)
-	  continue;
+	    if (in_zone(zone, name, &cut))
+	      break;
+	  
+	  if (!zone)
+	    {
+	      auth = 0;
+	      continue;
+	    }
 	}
 
       for (rec = daemon->mxnames; rec; rec = rec->next)

src/dns-protocol.h

@@ -142,3 +142,11 @@ struct dns_header {
 
 #define ADD_RDLEN(header, pp, plen, len) \
   (!CHECK_LEN(header, pp, plen, len) ? 0 : (((pp) += (len)), 1))
+
+/* Escape character in our presentation format for names.
+   Cannot be '.' or /000 and must be !isprint().
+   Note that escaped chars are stored as
+   <NAME_ESCAPE> <orig-char+1>
+   to ensure that the escaped form of /000 doesn't include /000
+*/
+#define NAME_ESCAPE 1

src/dnsmasq.c

@@ -102,8 +102,19 @@ int main (int argc, char **argv)
 #ifdef HAVE_DNSSEC
   if (option_bool(OPT_DNSSEC_VALID))
     {
-      daemon->keyname = safe_malloc(MAXDNAME);
+      /* Note that both /000 and '.' are allowed within labels. These get
-      daemon->workspacename = safe_malloc(MAXDNAME);
+	 represented in presentation format using NAME_ESCAPE as an escape
+	 character when in DNSSEC mode. 
+	 In theory, if all the characters in a name were /000 or
+	 '.' or NAME_ESCAPE then all would have to be escaped, so the 
+	 presentation format would be twice as long as the spec.
+
+	 daemon->namebuff was previously allocated by the option-reading
+	 code before we knew if we're in DNSSEC mode, so reallocate here. */
+      free(daemon->namebuff);
+      daemon->namebuff = safe_malloc(MAXDNAME * 2);
+      daemon->keyname = safe_malloc(MAXDNAME * 2);
+      daemon->workspacename = safe_malloc(MAXDNAME * 2);
     }
 #endif
 
@@ -655,7 +666,8 @@ int main (int argc, char **argv)
 	          _exit(0);
 	        }
 	    }
-	  closedir(dir);
+	  else
+	    closedir(dir);
 	}
 
       for (p = daemon->if_prefix; p; p = p->next)
@@ -670,7 +682,8 @@ int main (int argc, char **argv)
 		  _exit(0);
 		}
 	    }
-	  closedir(dir);
+	  else
+	    closedir(dir);
 	}
     }
 #endif

src/dnssec.c

@@ -321,10 +321,18 @@ static int verify(struct blockdata *key_data, unsigned int key_len, unsigned cha
    thus generating names in canonical form.
    Calling to_wire followed by from_wire is almost an identity,
    except that the UC remains mapped to LC. 
+
+   Note that both /000 and '.' are allowed within labels. These get
+   represented in presentation format using NAME_ESCAPE as an escape
+   character. In theory, if all the characters in a name were /000 or
+   '.' or NAME_ESCAPE then all would have to be escaped, so the 
+   presentation format would be twice as long as the spec (1024). 
+   The buffers are all delcared as 2049 (allowing for the trailing zero) 
+   for this reason.
 */
 static int to_wire(char *name)
 {
-  unsigned char *l, *p, term;
+  unsigned char *l, *p, *q, term;
   int len;
 
   for (l = (unsigned char*)name; *l != 0; l = p)
@@ -332,7 +340,12 @@ static int to_wire(char *name)
       for (p = l; *p != '.' && *p != 0; p++)
 	if (*p >= 'A' && *p <= 'Z')
 	  *p = *p - 'A' + 'a';
-      
+	else if (*p == NAME_ESCAPE)
+	  {
+	    for (q = p; *q; q++)
+	      *q = *(q+1);
+	    (*p)--;
+	  }
       term = *p;
       
       if ((len = p - l) != 0)
@@ -351,13 +364,24 @@ static int to_wire(char *name)
 /* Note: no compression  allowed in input. */
 static void from_wire(char *name)
 {
-  unsigned char *l;
+  unsigned char *l, *p, *last;
   int len;
   
+  for (last = (unsigned char *)name; *last != 0; last += *last+1);
+  
   for (l = (unsigned char *)name; *l != 0; l += len+1)
     {
       len = *l;
       memmove(l, l+1, len);
+      for (p = l; p < l + len; p++)
+	if (*p == '.' || *p == 0 || *p == NAME_ESCAPE)
+	  {
+	    memmove(p+1, p, 1 + last - p);
+	    len++;
+	    *p++ = NAME_ESCAPE; 
+	    (*p)++;
+	  }
+	
       l[len] = '.';
     }
 
@@ -645,7 +669,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
 	      if (left1 != 0)
 		memmove(buff1, buff1 + len1 - left1, left1);
 	      
-	      if ((len1 = get_rdata(header, plen, end1, buff1 + left1, MAXDNAME - left1, &p1, &dp1)) == 0)
+	      if ((len1 = get_rdata(header, plen, end1, buff1 + left1, (MAXDNAME * 2) - left1, &p1, &dp1)) == 0)
 		{
 		  quit = 1;
 		  len1 = end1 - p1;
@@ -656,7 +680,7 @@ static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int
 	      if (left2 != 0)
 		memmove(buff2, buff2 + len2 - left2, left2);
 	      
-	      if ((len2 = get_rdata(header, plen, end2, buff2 + left2, MAXDNAME - left2, &p2, &dp2)) == 0)
+	      if ((len2 = get_rdata(header, plen, end2, buff2 + left2, (MAXDNAME *2) - left2, &p2, &dp2)) == 0)
 		{
 		  quit = 1;
 		  len2 = end2 - p2;
@@ -902,10 +926,11 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
 	  
 	  end = p + rdlen;
 	  
-	  /* canonicalise rdata and calculate length of same, use name buffer as workspace */
+	  /* canonicalise rdata and calculate length of same, use name buffer as workspace.
+	     Note that name buffer is twice MAXDNAME long in DNSSEC mode. */
 	  cp = p;
 	  dp = rr_desc;
-	  for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)) != 0; len += seg);
+	  for (len = 0; (seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)) != 0; len += seg);
 	  len += end - cp;
 	  len = htons(len);
 	  hash->update(ctx, 2, (unsigned char *)&len); 
@@ -913,7 +938,7 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
 	  /* Now canonicalise again and digest. */
 	  cp = p;
 	  dp = rr_desc;
-	  while ((seg = get_rdata(header, plen, end, name, MAXDNAME, &cp, &dp)))
+	  while ((seg = get_rdata(header, plen, end, name, MAXDNAME * 2, &cp, &dp)))
 	    hash->update(ctx, seg, (unsigned char *)name);
 	  if (cp != end)
 	    hash->update(ctx, end - cp, cp);

src/forward.c

@@ -1014,7 +1014,7 @@ void reply_query(int fd, int family, time_t now)
 	    header->hb3 |= HB3_TC;
 	  else
 	    {
-	      char *result;
+	      char *result, *domain = "result";
 	      
 	      if (forward->work_counter == 0)
 		{
@@ -1024,7 +1024,10 @@ void reply_query(int fd, int family, time_t now)
 	      else
 		result = (status == STAT_SECURE ? "SECURE" : (status == STAT_INSECURE ? "INSECURE" : "BOGUS"));
 	      
-	      log_query(F_KEYTAG | F_SECSTAT, "result", NULL, result);
+	      if (status == STAT_BOGUS && extract_request(header, n, daemon->namebuff, NULL))
+		domain = daemon->namebuff;
+
+	      log_query(F_KEYTAG | F_SECSTAT, domain, NULL, result);
 	    }
 	  
 	  if (status == STAT_SECURE)
@@ -1975,7 +1978,7 @@ unsigned char *tcp_request(int confd, time_t now,
 			{
 			  int keycount = DNSSEC_WORK; /* Limit to number of DNSSEC questions, to catch loops and avoid filling cache. */
 			  int status = tcp_key_recurse(now, STAT_TRUNCATED, header, m, 0, daemon->namebuff, daemon->keyname, last_server, &keycount);
-			  char *result;
+			  char *result, *domain = "result";
 
 			  if (status == STAT_INSECURE_DS)
 			    {
@@ -1993,8 +1996,10 @@ unsigned char *tcp_request(int confd, time_t now,
 			    }
 			  else
 			    result = (status == STAT_SECURE ? "SECURE" : (status == STAT_INSECURE ? "INSECURE" : "BOGUS"));
+			   if (status == STAT_BOGUS && extract_request(header, m, daemon->namebuff, NULL))
+			     domain = daemon->namebuff;
 
-			  log_query(F_KEYTAG | F_SECSTAT, "result", NULL, result);
+			  log_query(F_KEYTAG | F_SECSTAT, domain, NULL, result);
 			  
 			  if (status == STAT_BOGUS)
 			    {

src/rfc1035.c

@@ -20,7 +20,7 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 		 char *name, int isExtract, int extrabytes)
 {
   unsigned char *cp = (unsigned char *)name, *p = *pp, *p1 = NULL;
-  unsigned int j, l, hops = 0;
+  unsigned int j, l, namelen = 0, hops = 0;
   int retvalue = 1;
   
   if (isExtract)
@@ -94,9 +94,15 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 	    count = 256;
 	  digs = ((count-1)>>2)+1;
 	  
-	  /* output is \[x<hex>/siz]. which is digs+9 chars */
+	  /* output is \[x<hex>/siz]. which is digs+6/7/8 chars */
-	  if (cp - (unsigned char *)name + digs + 9 >= MAXDNAME)
+	  namelen += digs+6;
+	  if (count > 9)
+	    namelen++;
+	  if (count > 99)
+	    namelen++;
+	  if (namelen+1 >= MAXDNAME)
 	    return 0;
+
 	  if (!CHECK_LEN(header, p, plen, (count-1)>>3))
 	    return 0;
 
@@ -119,7 +125,8 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 	}
       else 
 	{ /* label_type = 0 -> label. */
-	  if (cp - (unsigned char *)name + l + 1 >= MAXDNAME)
+	  namelen += l;
+	  if (namelen+1 >= MAXDNAME)
 	    return 0;
 	  if (!CHECK_LEN(header, p, plen, l))
 	    return 0;
@@ -128,6 +135,19 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 	    if (isExtract)
 	      {
 		unsigned char c = *p;
+#ifdef HAVE_DNSSEC
+		if (option_bool(OPT_DNSSEC_VALID))
+		  {
+		    if (c == 0 || c == '.' || c == NAME_ESCAPE)
+		      {
+			*cp++ = NAME_ESCAPE;
+			*cp++ = c+1;
+		      }
+		    else
+		      *cp++ = c; 
+		  }
+		else
+#endif
 		if (c != 0 && c != '.')
 		  *cp++ = c;
 		else
@@ -144,6 +164,11 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 		    cp++;
 		    if (c1 >= 'A' && c1 <= 'Z')
 		      c1 += 'a' - 'A';
+#ifdef HAVE_DNSSEC
+		    if (option_bool(OPT_DNSSEC_VALID) && c1 == NAME_ESCAPE)
+		      c1 = (*cp++)-1;
+#endif
+		    
 		    if (c2 >= 'A' && c2 <= 'Z')
 		      c2 += 'a' - 'A';
 		     

src/rfc3315.c

@@ -824,25 +824,21 @@ static int dhcp6_no_relay(struct state *state, int msg_type, void *inbuff, size_
 	  }
 	else
 	  { 
-	    /* Windows 8 always requests an address even if the Managed bit
-	       in RA is 0 and it keeps retrying if it receives a reply
-	       stating that no addresses are available. We solve this 
-	       by not replying at all if we're not configured to give any 
-	       addresses by DHCPv6. RFC 3315 17.2.1. appears to allow this. */
-	    
-	    for (c = state->context; c; c = c->current)
-	      if (!(c->flags & CONTEXT_RA_STATELESS))
-		break;
-	    
-	    if (!c)
-	      return 0;
-	    
 	    /* no address, return error */
 	    o1 = new_opt6(OPTION6_STATUS_CODE);
 	    put_opt6_short(DHCP6NOADDRS);
 	    put_opt6_string(_("no addresses available"));
 	    end_opt6(o1);
-	    log6_packet(state, state->lease_allocate ? "DHCPREPLY" : "DHCPADVERTISE", NULL, _("no addresses available"));
+
+	    /* Some clients will ask repeatedly when we're not giving
+	       out addresses because we're in stateless mode. Avoid spamming
+	       the log in that case. */
+	    for (c = state->context; c; c = c->current)
+	      if (!(c->flags & CONTEXT_RA_STATELESS))
+		{
+		  log6_packet(state, state->lease_allocate ? "DHCPREPLY" : "DHCPADVERTISE", NULL, _("no addresses available"));
+		  break;
+		}
 	  }
 
 	break;

src/util.c

@@ -226,7 +226,14 @@ unsigned char *do_rfc1035_name(unsigned char *p, char *sval)
     {
       unsigned char *cp = p++;
       for (j = 0; *sval && (*sval != '.'); sval++, j++)
-	*p++ = *sval;
+	{
+#ifdef HAVE_DNSSEC
+	  if (option_bool(OPT_DNSSEC_VALID) && *sval == NAME_ESCAPE)
+	    *p++ = (*(++sval))-1;
+	  else
+#endif		
+	    *p++ = *sval;
+	}
       *cp  = j;
       if (*sval)
 	sval++;