--- embedaddon/dnsmasq/src/edns0.c	2016/11/02 09:57:01	1.1.1.1
+++ embedaddon/dnsmasq/src/edns0.c	2021/03/17 00:56:46	1.1.1.2
@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2016 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2021 Simon Kelley
 
    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
@@ -144,7 +144,7 @@ size_t add_pseudoheader(struct dns_header *header, siz
 	  GETSHORT(len, p);
 	  
 	  /* malformed option, delete the whole OPT RR and start again. */
-	  if (i + len > rdlen)
+	  if (i + 4 + len > rdlen)
 	    {
 	      rdlen = 0;
 	      is_last = 0;
@@ -159,7 +159,7 @@ size_t add_pseudoheader(struct dns_header *header, siz
 	      /* delete option if we're to replace it. */
 	      p -= 4;
 	      rdlen -= len + 4;
-	      memcpy(p, p+len+4, rdlen - i);
+	      memmove(p, p+len+4, rdlen - i);
 	      PUTSHORT(rdlen, lenp);
 	      lenp -= 2;
 	    }
@@ -192,7 +192,15 @@ size_t add_pseudoheader(struct dns_header *header, siz
 	  !(p = skip_section(p, 
 			     ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount), 
 			     header, plen)))
+      {
+	free(buff);
 	return plen;
+      }
+      if (p + 11 > limit)
+      {
+        free(buff);
+        return plen; /* Too big */
+      }
       *p++ = 0; /* empty name */
       PUTSHORT(T_OPT, p);
       PUTSHORT(udp_sz, p); /* max packet length, 512 if not given in EDNS0 header */
@@ -204,11 +212,19 @@ size_t add_pseudoheader(struct dns_header *header, siz
       /* Copy back any options */
       if (buff)
 	{
+          if (p + rdlen > limit)
+          {
+            free(buff);
+            return plen; /* Too big */
+          }
 	  memcpy(p, buff, rdlen);
 	  free(buff);
 	  p += rdlen;
 	}
-      header->arcount = htons(ntohs(header->arcount) + 1);
+      
+      /* Only bump arcount if RR is going to fit */ 
+      if (((ssize_t)optlen) <= (limit - (p + 4)))
+	header->arcount = htons(ntohs(header->arcount) + 1);
     }
   
   if (((ssize_t)optlen) > (limit - (p + 4)))
@@ -217,8 +233,12 @@ size_t add_pseudoheader(struct dns_header *header, siz
   /* Add new option */
   if (optno != 0 && replace != 2)
     {
+      if (p + 4 > limit)
+       return plen; /* Too big */
       PUTSHORT(optno, p);
       PUTSHORT(optlen, p);
+      if (p + optlen > limit)
+       return plen; /* Too big */
       memcpy(p, opt, optlen);
       p += optlen;  
       PUTSHORT(p - datap, lenp);
@@ -244,7 +264,8 @@ static void encoder(unsigned char *in, char *out)
   out[3] = char64(in[2]);
 }
 
-static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *l3, time_t now)
+static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned char *limit,
+			     union mysockaddr *l3, time_t now, int *cacheablep)
 {
   int maclen, replace = 2; /* can't get mac address, just delete any incoming. */
   unsigned char mac[DHCP_CHADDR_MAX];
@@ -253,6 +274,7 @@ static size_t add_dns_client(struct dns_header *header
   if ((maclen = find_mac(l3, mac, 1, now)) == 6)
     {
       replace = 1;
+      *cacheablep = 0;
 
       if (option_bool(OPT_MAC_HEX))
 	print_mac(encode, mac, maclen);
@@ -268,49 +290,47 @@ static size_t add_dns_client(struct dns_header *header
 }
 
 
-static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *l3, time_t now)
+static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *limit,
+		      union mysockaddr *l3, time_t now, int *cacheablep)
 {
   int maclen;
   unsigned char mac[DHCP_CHADDR_MAX];
 
   if ((maclen = find_mac(l3, mac, 1, now)) != 0)
-    plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_MAC, mac, maclen, 0, 0); 
-    
+    {
+      *cacheablep = 0;
+      plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_MAC, mac, maclen, 0, 0); 
+    }
+  
   return plen; 
 }
 
 struct subnet_opt {
   u16 family;
-  u8 source_netmask, scope_netmask;
-#ifdef HAVE_IPV6 
+  u8 source_netmask, scope_netmask; 
   u8 addr[IN6ADDRSZ];
-#else
-  u8 addr[INADDRSZ];
-#endif
 };
 
 static void *get_addrp(union mysockaddr *addr, const short family) 
 {
-#ifdef HAVE_IPV6
   if (family == AF_INET6)
     return &addr->in6.sin6_addr;
-#endif
 
   return &addr->in.sin_addr;
 }
 
-static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source)
+static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source, int *cacheablep)
 {
   /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
   
   int len;
-  void *addrp;
+  void *addrp = NULL;
   int sa_family = source->sa.sa_family;
-
+  int cacheable = 0;
+  
   opt->source_netmask = 0;
   opt->scope_netmask = 0;
-
-#ifdef HAVE_IPV6
+    
   if (source->sa.sa_family == AF_INET6 && daemon->add_subnet6)
     {
       opt->source_netmask = daemon->add_subnet6->mask;
@@ -318,11 +338,11 @@ static size_t calc_subnet_opt(struct subnet_opt *opt, 
 	{
 	  sa_family = daemon->add_subnet6->addr.sa.sa_family;
 	  addrp = get_addrp(&daemon->add_subnet6->addr, sa_family);
+	  cacheable = 1;
 	} 
       else 
 	addrp = &source->in6.sin6_addr;
     }
-#endif
 
   if (source->sa.sa_family == AF_INET && daemon->add_subnet4)
     {
@@ -331,38 +351,41 @@ static size_t calc_subnet_opt(struct subnet_opt *opt, 
 	{
 	  sa_family = daemon->add_subnet4->addr.sa.sa_family;
 	  addrp = get_addrp(&daemon->add_subnet4->addr, sa_family);
+	  cacheable = 1; /* Address is constant */
 	} 
 	else 
 	  addrp = &source->in.sin_addr;
     }
   
-#ifdef HAVE_IPV6
   opt->family = htons(sa_family == AF_INET6 ? 2 : 1);
-#else
-  opt->family = htons(1);
-#endif
   
-  len = 0;
-  
-  if (opt->source_netmask != 0)
+  if (addrp && opt->source_netmask != 0)
     {
       len = ((opt->source_netmask - 1) >> 3) + 1;
       memcpy(opt->addr, addrp, len);
       if (opt->source_netmask & 7)
 	opt->addr[len-1] &= 0xff << (8 - (opt->source_netmask & 7));
     }
+  else
+    {
+      cacheable = 1; /* No address ever supplied. */
+      len = 0;
+    }
+
+  if (cacheablep)
+    *cacheablep = cacheable;
   
   return len + 4;
 }
  
-static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *source)
+static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *source, int *cacheable)
 {
   /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
   
   int len;
   struct subnet_opt opt;
   
-  len = calc_subnet_opt(&opt, source);
+  len = calc_subnet_opt(&opt, source, cacheable);
   return add_pseudoheader(header, plen, (unsigned char *)limit, PACKETSZ, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len, 0, 0);
 }
 
@@ -375,18 +398,18 @@ int check_source(struct dns_header *header, size_t ple
   unsigned char *p;
   int code, i, rdlen;
   
-   calc_len = calc_subnet_opt(&opt, peer);
+  calc_len = calc_subnet_opt(&opt, peer, NULL);
    
-   if (!(p = skip_name(pseudoheader, header, plen, 10)))
-     return 1;
-   
-   p += 8; /* skip UDP length and RCODE */
-   
-   GETSHORT(rdlen, p);
-   if (!CHECK_LEN(header, p, plen, rdlen))
-     return 1; /* bad packet */
-   
-   /* check if option there */
+  if (!(p = skip_name(pseudoheader, header, plen, 10)))
+    return 1;
+  
+  p += 8; /* skip UDP length and RCODE */
+  
+  GETSHORT(rdlen, p);
+  if (!CHECK_LEN(header, p, plen, rdlen))
+    return 1; /* bad packet */
+  
+  /* check if option there */
    for (i = 0; i + 4 < rdlen; i += len + 4)
      {
        GETSHORT(code, p);
@@ -404,24 +427,28 @@ int check_source(struct dns_header *header, size_t ple
    return 1;
 }
 
+/* Set *check_subnet if we add a client subnet option, which needs to checked 
+   in the reply. Set *cacheable to zero if we add an option which the answer
+   may depend on. */
 size_t add_edns0_config(struct dns_header *header, size_t plen, unsigned char *limit, 
-			union mysockaddr *source, time_t now, int *check_subnet)    
+			union mysockaddr *source, time_t now, int *check_subnet, int *cacheable)    
 {
   *check_subnet = 0;
-
+  *cacheable = 1;
+  
   if (option_bool(OPT_ADD_MAC))
-    plen  = add_mac(header, plen, limit, source, now);
+    plen  = add_mac(header, plen, limit, source, now, cacheable);
   
   if (option_bool(OPT_MAC_B64) || option_bool(OPT_MAC_HEX))
-    plen = add_dns_client(header, plen, limit, source, now);
-
+    plen = add_dns_client(header, plen, limit, source, now, cacheable);
+  
   if (daemon->dns_client_id)
     plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_NOMCPEID, 
 			    (unsigned char *)daemon->dns_client_id, strlen(daemon->dns_client_id), 0, 1);
   
   if (option_bool(OPT_CLIENT_SUBNET))
     {
-      plen = add_source_addr(header, plen, limit, source); 
+      plen = add_source_addr(header, plen, limit, source, cacheable); 
       *check_subnet = 1;
     }