Re-implement print_mac() to do its own buffer managment.

print_mac() used to output into caller-supplied buffer with no
length checking. The various callers supplied different
length buffers and did their own, ad-hoc, length checking before
calling print_mac(). This was an accident waiting to happen and
it had actually happened in couple of places, with buffer
overflows possible.

print_mac() now returns the address of its own buffer, which
is grown as required.

Thanks to Nicholas Carlini <npc@anthropic.com> for spotting this problem.

CHANGELOG

@@ -33,7 +33,17 @@ version 2.93
 	This means that the permissions used when creating the watches
 	are the same as used for accessing watched files, which makes
 	more sense and avoids odd and confusing error conditions.
-
+	
+	Rework storage allocation for domain names.  This fixes a security
+	bug that can cause heap-overwrite with long domain names.
+	CVE-2026-2291 covers this and a simple patch for existing
+	releases was released with the CVE. This patch reworks the whole
+	code base to make it cleaner and less liable to future
+	confusions. Either upgrading to 2.93 or applying the patch
+	to earlier versions is sufficient to close the security hole.
+	Thanks to Andrew S. Fasano for spotting this problem in the
+	first place.
+	
 	
 version 2.92
         Redesign the interaction between DNSSEC validation and per-domain

Makefile

@@ -1,4 +1,4 @@
-# dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+# dnsmasq is Copyright (c) 2000-2026 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

contrib/lease-tools/dhcp_release6.c

@@ -233,31 +233,55 @@ struct dhcp6_packet create_release_packet(const char* iaid, const char* ip, cons
   return result;
 }
 
+static void copy_option_string(char *dst, size_t dst_len, const char *src, size_t src_len)
+{
+  if (dst_len == 0)
+    return;
+
+  if (src_len >= dst_len)
+    src_len = dst_len - 1;
+
+  memcpy(dst, src, src_len);
+  dst[src_len] = '\0';
+}
+
 uint16_t parse_iana_suboption(char* buf, size_t len)
 {
   size_t current_pos = 0;
   char option_value[1024];
   while (current_pos < len)
     {
+      if (len - current_pos < 2 * sizeof(uint16_t))
+        return UNSPEC_FAIL;
+
       uint16_t option_type, option_len;
       memcpy(&option_type,buf + current_pos, sizeof(uint16_t));
       memcpy(&option_len,buf + current_pos + sizeof(uint16_t), sizeof(uint16_t));
       option_type = ntohs(option_type);
       option_len = ntohs(option_len);
       current_pos += 2 * sizeof(uint16_t);
+      if (option_len > len - current_pos)
+        return UNSPEC_FAIL;
+
       if (option_type == STATUS_CODE)
 	{
 	  uint16_t status;
+	  if (option_len < sizeof(uint16_t))
+	    return UNSPEC_FAIL;
+
 	  memcpy(&status, buf + current_pos, sizeof(uint16_t));
 	  status = ntohs(status);
 	  if (status != SUCCESS)
 	    {
-	      memcpy(option_value, buf + current_pos + sizeof(uint16_t) , option_len - sizeof(uint16_t));
-	      option_value[option_len-sizeof(uint16_t)] ='\0';
+	      copy_option_string(option_value, sizeof(option_value),
+				 buf + current_pos + sizeof(uint16_t),
+				 option_len - sizeof(uint16_t));
 	      fprintf(stderr, "Error: %s\n", option_value);
             }
 	  return status;
         }
+
+      current_pos += option_len;
     }
 
   return -2;
@@ -266,6 +290,9 @@ uint16_t parse_iana_suboption(char* buf, size_t len)
 int16_t parse_packet(char* buf, size_t len)
 {
   int16_t ret = -1;
+  if (len < 4)
+    return UNSPEC_FAIL;
+
   uint8_t type = buf[0];
   /*skipping tx id. you need it, uncomment following line
     uint16_t tx_id = ntohs((buf[1] <<16) + (buf[2] <<8) + buf[3]);
@@ -277,20 +304,31 @@ int16_t parse_packet(char* buf, size_t len)
   char option_value[1024];
   while (current_pos < len)
     {
+      if (len - current_pos < 2 * sizeof(uint16_t))
+	return UNSPEC_FAIL;
+
       uint16_t option_type, option_len;
       memcpy(&option_type,buf + current_pos, sizeof(uint16_t));
       memcpy(&option_len,buf + current_pos + sizeof(uint16_t), sizeof(uint16_t));
       option_type = ntohs(option_type);
       option_len = ntohs(option_len);
       current_pos += 2 * sizeof(uint16_t);
+      if (option_len > len - current_pos)
+	return UNSPEC_FAIL;
+
       if (option_type == STATUS_CODE)
 	{
 	  uint16_t status;
+	  if (option_len < sizeof(uint16_t))
+	    return UNSPEC_FAIL;
+
 	  memcpy(&status, buf + current_pos, sizeof(uint16_t));
 	  status = ntohs(status);
 	  if (status != SUCCESS)
 	    {
-	      memcpy(option_value, buf + current_pos +sizeof(uint16_t) , option_len -sizeof(uint16_t));
+	      copy_option_string(option_value, sizeof(option_value),
+				 buf + current_pos + sizeof(uint16_t),
+				 option_len - sizeof(uint16_t));
 	      fprintf(stderr, "Error: %d %s\n", status, option_value);
 	      return status;
 	    }
@@ -301,6 +339,9 @@ int16_t parse_packet(char* buf, size_t len)
 
       if (option_type == IA_NA )
 	{
+	  if (option_len < 24)
+	    return UNSPEC_FAIL;
+
 	  uint16_t result = parse_iana_suboption(buf + current_pos +24, option_len -24);
 	  if (result)
 	    return result;

contrib/leasequery/leasequery.c

@@ -331,9 +331,15 @@ static char *print_mac(char *buff, unsigned char *mac, int len)
   if (len == 0)
     sprintf(p, "<null>");
   else
-    for (i = 0; i < len; i++)
-      p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":");
-  
+    {
+      /* Server-controlled lengths (e.g. BOOTREPLY hlen) must not be trusted
+	 to fit the destination buffer; cap at the actual chaddr field size. */
+      if (len > DHCP_CHADDR_MAX)
+	len = DHCP_CHADDR_MAX;
+      for (i = 0; i < len; i++)
+	p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":");
+    }
+
   return buff;
 }
 

man/dnsmasq.8

@@ -1515,7 +1515,7 @@ The normal default DNS server (the same address as the DHCP server)
 will not be appropriate when there is no route bewteen the
 two, so this will have to be explicitly configured. 
 .TP
-.B \-U, --dhcp-vendorclass=set:<tag>,[enterprise:<IANA-enterprise number>,]<vendor-class>
+.B \-U, --dhcp-vendorclass=set:<tag>,[enterprise:<IANA-enterprise number>,][<vendor-class>]
 Map from a vendor-class string to a tag. Most DHCP clients provide a 
 "vendor class" which represents, in some sense, the type of host. This option 
 maps vendor classes to tags, so that DHCP options may be selectively delivered
@@ -1529,9 +1529,11 @@ allow fuzzy matching. The set: prefix is optional but allowed for
 consistency. 
 
 Note that in IPv6 only, vendorclasses are namespaced with an 
-IANA-allocated enterprise number. This is given with enterprise:
+IANA-allocated enterprise number. This may be given with an enterprise:
 keyword and specifies that only vendorclasses matching the specified
-number should be searched.
+number should be searched. Similarly, an enterprise number may be given
+with no vendor-class string. This always matches vendorclasses with
+the given enterprise number.
 .TP
 .B \-j, --dhcp-userclass=set:<tag>,<user-class>
 Map from a user-class string to a tag (with substring

src/arp.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/auth.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/blockdata.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/bpf.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -47,24 +47,20 @@ static union all_addr del_addr;
 
 #if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
 
-int arp_enumerate(void *parm, callback_t callback)
+static int arp_enumerate_family(int family, void *parm, callback_t callback)
 {
   int mib[6];
   size_t needed;
   char *next;
   struct rt_msghdr *rtm;
-  struct sockaddr_inarp *sin2;
   struct sockaddr_dl *sdl;
-  struct iovec buff;
+  static struct iovec buff = { NULL, 0 };
   int rc;
 
-  buff.iov_base = NULL;
-  buff.iov_len = 0;
-
   mib[0] = CTL_NET;
   mib[1] = PF_ROUTE;
   mib[2] = 0;
-  mib[3] = AF_INET;
+  mib[3] = family;
   mib[4] = NET_RT_FLAGS;
 #ifdef RTF_LLINFO
   mib[5] = RTF_LLINFO;
@@ -72,8 +68,8 @@ int arp_enumerate(void *parm, callback_t callback)
   mib[5] = 0;
 #endif	
   if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1 || needed == 0)
-    return 0;
-
+    return 1;  /* not a failure: unsupported or empty table */
+  
   while (1) 
     {
       if (!expand_buf(&buff, needed))
@@ -83,20 +79,50 @@ int arp_enumerate(void *parm, callback_t callback)
 	break;
       needed += needed / 8;
     }
+  
   if (rc == -1)
     return 0;
   
   for (next = buff.iov_base ; next < (char *)buff.iov_base + needed; next += rtm->rtm_msglen)
     {
       rtm = (struct rt_msghdr *)next;
-      sin2 = (struct sockaddr_inarp *)(rtm + 1);
-      sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
-      if (!callback.af_unspec(AF_INET, &sin2->sin_addr, LLADDR(sdl), sdl->sdl_alen, parm))
-	return 0;
+      if (family == AF_INET)
+	{
+	  struct sockaddr_inarp *sin2 = (struct sockaddr_inarp *)(rtm + 1);
+	  sdl = (struct sockaddr_dl *)((char *)sin2 + SA_SIZE(sin2));
+          if (!callback.af_unspec(AF_INET, &sin2->sin_addr,
+				  LLADDR(sdl), sdl->sdl_alen, parm))
+	    return 0;
+        }
+      else
+	{
+          struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)(rtm + 1);
+          sdl = (struct sockaddr_dl *)((char *)sin6 + SA_SIZE(sin6));
+          if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr))
+            {
+              /* PF_ROUTE sysctl returns raw kernel structures with the interface
+		 index embedded in bytes 2-3 of link-local addresses. Extract it
+                 into sin6_scope_id per the KAME API contract before clearing. */
+	      sin6->sin6_scope_id =
+		((uint32_t)(sin6->sin6_addr.s6_addr[2]) << 8) | sin6->sin6_addr.s6_addr[3];
+	      sin6->sin6_addr.s6_addr[2] = 0;
+              sin6->sin6_addr.s6_addr[3] = 0;
+	    }
+          if (!callback.af_unspec(AF_INET6, &sin6->sin6_addr,
+                                  LLADDR(sdl), sdl->sdl_alen, parm))
+            return 0;
+        }
     }
-
+  
   return 1;
 }
+
+static int arp_enumerate(void *parm, callback_t callback)
+{
+  if (!arp_enumerate_family(AF_INET, parm, callback))
+    return 0;
+  return arp_enumerate_family(AF_INET6, parm, callback);
+}
 #endif /* defined(HAVE_BSD_NETWORK) && !defined(__APPLE__) */
 
 

src/cache.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -22,6 +22,7 @@ static struct crec *new_chain = NULL;
 static int insert_error;
 static union bigname *big_free = NULL;
 static int bignames_left, hash_size;
+
 struct nameblock {
   struct nameblock *next;
   unsigned int last, index;
@@ -221,6 +222,9 @@ static char *store_name(unsigned int namelen, unsigned int index)
   struct nameblock *block;
   char *ret = NULL;
 
+  if (namelen > NAMEBLOCK_CHARS)
+    return NULL;
+  
   for (block = hostblocks; block; block = block->next)
     if (block->index == index && NAMEBLOCK_CHARS - block->last >= namelen)
       break;
@@ -1083,11 +1087,16 @@ int cache_recv_insert(time_t now, int fd)
 	     !read_write(fd, (unsigned char *)&validatecount, sizeof(validatecount), RW_READ) ||
 	     !read_write(fd, (unsigned char *)&validatecountp, sizeof(validatecountp), RW_READ)))
 	  return 0;
+
+	if (op == PIPE_OP_KILLED)
+	  my_syslog(LOG_INFO, _("TCP process for DNSSEC validation timed out"));
 	
-	/* There's a tiny chance that the frec may have been freed 
-	   and reused before the TCP process returns. Detect that with
-	   the uid field which is unique modulo 2^32 for each use. */
-	if (uid == forward->uid)
+	/* There's a chance that the frec may have timed-out and been
+	   freed before the TCP process returns, so check that the
+	   frec is still marked in use. Even if it is in use, there's a tiny chance
+	   that the frec may have been freed and _reused_ before the TCP process returns.
+	   Detect that with the uid field which is unique modulo 2^32 for each use. */
+	if (forward->sentto && uid == forward->uid)
 	  {
 	    if (op == PIPE_OP_RESULT)
 	      {
@@ -1400,9 +1409,10 @@ static int eatspace(FILE *f)
     }
 }
 	 
-static int gettok(FILE *f, char *token)
+static int gettok(FILE *f, char *token, size_t buffsz)
 {
-  int c, count = 0;
+  int c;
+  unsigned int count = 0;
  
   while (1)
     {
@@ -1415,7 +1425,7 @@ static int gettok(FILE *f, char *token)
 	  return eatspace(f);
 	}
       
-      if (count < (MAXDNAME - 1))
+      if (count < (buffsz - 1))
 	{
 	  token[count++] = c;
 	  token[count] = 0;
@@ -1440,7 +1450,7 @@ int read_hostsfile(char *filename, unsigned int index, int cache_size, struct cr
   
   lineno += eatspace(f);
   
-  while ((atnl = gettok(f, token)) != -1)
+  while ((atnl = gettok(f, token, MAXDNAMESTR)) != -1)
     {
       if (inet_pton(AF_INET, token, &addr) > 0)
 	{
@@ -1458,7 +1468,7 @@ int read_hostsfile(char *filename, unsigned int index, int cache_size, struct cr
 	{
 	  my_syslog(LOG_ERR, _("bad address at %s line %d"), filename, lineno); 
 	  while (atnl == 0)
-	    atnl = gettok(f, token);
+	    atnl = gettok(f, token, MAXDNAMESTR);
 	  lineno += atnl;
 	  continue;
 	}
@@ -1476,7 +1486,7 @@ int read_hostsfile(char *filename, unsigned int index, int cache_size, struct cr
 	  int fqdn, nomem;
 	  char *canon;
 	  
-	  if ((atnl = gettok(f, token)) == -1)
+	  if ((atnl = gettok(f, token, MAXDNAMESTR)) == -1)
 	    break;
 
 	  fqdn = !!strchr(token, '.');
@@ -1790,7 +1800,7 @@ void cache_add_dhcp_entry(char *host_name, int prot,
   /* Name in hosts, address doesn't match */
   if (fail_crec)
     {
-      inet_ntop(prot, &fail_crec->addr, daemon->namebuff, MAXDNAME);
+      inet_ntop(prot, &fail_crec->addr, daemon->namebuff, MAXDNAMESTR);
       my_syslog(MS_DHCP | LOG_WARNING, 
 		_("not giving name %s to the DHCP lease of %s because "
 		  "the name exists in %s with address %s"), 
@@ -2328,7 +2338,7 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
     return;
 
   /* build query type string if requested */
-  if (!(flags & (F_SERVER | F_IPSET | F_QUERY)) && type > 0)
+  if (!(flags & (F_SERVER | F_IPSET | F_QUERY | F_KEYTAG | F_RR)) && type > 0)
     arg = querystr(arg, type);
 
   dest = arg;
@@ -2344,19 +2354,25 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
     {
       dest = daemon->addrbuff;
 
-       if (flags & F_RR)
-	 {
-	   if (flags & F_KEYTAG)
-	     dest = querystr(NULL, addr->rrblock.rrtype);
-	   else
-	     dest = querystr(NULL, addr->rrdata.rrtype);
-	 }
-       else if (flags & F_KEYTAG)
-	sprintf(daemon->addrbuff, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
+      if (flags & F_RR)
+	{
+	  if (flags & F_KEYTAG)
+	    dest = querystr(NULL, addr->rrblock.rrtype);
+	  else
+	    dest = querystr(NULL, addr->rrdata.rrtype);
+	}
+#ifdef HAVE_DNSSEC
+      else if (flags & F_KEYTAG)
+	{
+	  snprintf(daemon->addrbuff, ADDRSTRLEN, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
+	  if (type)
+	    extra = " (not supported)";
+	}
+#endif
       else if (flags & F_RCODE)
 	{
 	  unsigned int rcode = addr->log.rcode;
-
+	  
 	  if (rcode == SERVFAIL)
 	    dest = "SERVFAIL";
 	  else if (rcode == REFUSED)

src/config.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -15,7 +15,7 @@
 */
 
 #define FTABSIZ 150 /* max number of outstanding requests (default) */
-#define MAX_PROCS 20 /* default max no children for TCP requests */
+#define MAX_PROCS 30 /* default max no children for TCP requests */
 #define CHILD_LIFETIME 150 /* secs 'till terminated (RFC1035 suggests > 120s) */
 #define TCP_MAX_QUERIES 100 /* Maximum number of queries per incoming TCP connection */
 #define TCP_TIMEOUT 5 /* timeout waiting to connect to an upstream server - double this for answer */
@@ -43,7 +43,7 @@
 #define PING_CACHE_TIME 30 /* Ping test assumed to be valid this long. */
 #define DECLINE_BACKOFF 600 /* disable DECLINEd static addresses for this long */
 #define DHCP_PACKET_MAX 16384 /* hard limit on DHCP packet size */
-#define SMALLDNAME 50 /* most domain names are smaller than this */
+#define SMALLDNAME 75 /* most domain names are smaller than this */
 #define CNAME_CHAIN 10 /* chains longer than this atr dropped for loop protection */
 #define DNSSEC_MIN_TTL 60 /* DNSKEY and DS records in cache last at least this long */
 #define HOSTSFILE "/etc/hosts"

src/conntrack.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/crypto.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/dbus.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -736,7 +736,7 @@ static void add_dict_entry(DBusMessageIter *container, const char *key, const ch
 
 static void add_dict_int(DBusMessageIter *container, const char *key, const unsigned int val)
 {
-  snprintf(daemon->namebuff, MAXDNAME, "%u", val);
+  snprintf(daemon->namebuff, MAXDNAMESTR, "%u", val);
   
   add_dict_entry(container, key, daemon->namebuff);
 }
@@ -1055,7 +1055,7 @@ void emit_dbus_signal(int action, struct dhcp_lease *lease, char *hostname)
   DBusConnection *connection = (DBusConnection *)daemon->dbus;
   DBusMessage* message = NULL;
   DBusMessageIter args;
-  char *action_str, *mac = daemon->namebuff;
+  char *action_str, *mac;
   unsigned char *p;
   int i;
 
@@ -1068,7 +1068,7 @@ void emit_dbus_signal(int action, struct dhcp_lease *lease, char *hostname)
 #ifdef HAVE_DHCP6
    if (lease->flags & (LEASE_TA | LEASE_NA))
      {
-       print_mac(mac, lease->clid, lease->clid_len);
+       mac = print_mac(lease->clid, lease->clid_len);
        inet_ntop(AF_INET6, &lease->addr6, daemon->addrbuff, ADDRSTRLEN);
      }
    else
@@ -1076,7 +1076,7 @@ void emit_dbus_signal(int action, struct dhcp_lease *lease, char *hostname)
      {
        p = extended_hwaddr(lease->hwaddr_type, lease->hwaddr_len,
 			   lease->hwaddr, lease->clid_len, lease->clid, &i);
-       print_mac(mac, p, i);
+       mac = print_mac(p, i);
        inet_ntop(AF_INET, &lease->addr, daemon->addrbuff, ADDRSTRLEN);
      }
 

src/dhcp-common.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -278,9 +278,9 @@ void log_tags(struct dhcp_netid *netid, u32 xid)
 	  
 	  if (!n)
 	    {
-	      strncat (s, netid->net, (MAXDNAME-1) - strlen(s));
+	      strncat (s, netid->net, MAXDNAMESTR - strlen(s));
 	      if (netid->next)
-		strncat (s, ", ", (MAXDNAME-1) - strlen(s));
+		strncat (s, ", ", MAXDNAMESTR - strlen(s));
 	    }
 	}
       my_syslog(MS_DHCP | LOG_INFO, _("%u tags: %s"), xid, s);
@@ -882,7 +882,7 @@ char *option_string(int prot, unsigned int opt, unsigned char *val, int opt_len,
 			 buf[j++] = c;
 		     }
 		    i = l;
-		    if (val[i] != 0 && j < buf_len)
+		    if (i < opt_len && val[i] != 0 && j < buf_len)
 		      buf[j++] = '.';
 		  }
 	      }
@@ -892,24 +892,23 @@ char *option_string(int prot, unsigned int opt, unsigned char *val, int opt_len,
 		unsigned char *p;
 
 		i = 0, j = 0;
-		while (1)
+		while (i + 2 <= opt_len)
 		  {
 		    p = &val[i];
 		    GETSHORT(len, p);
+		    if (i + 2 + len > opt_len)
+		      break; /* malformed: body extends beyond option */
 		    for (k = 0; k < len && j < buf_len; k++)
 		      {
 		       char c = *p++;
 		       if (isprint((unsigned char)c))
 			 buf[j++] = c;
 		     }
-		    i += len +2;
-		    if (i >= opt_len)
-		      break;
-
-		    if (j < buf_len)
+		    i += len + 2;
+		    if (i < opt_len && j < buf_len)
 		      buf[j++] = ',';
 		  }
-	      }	      
+	      }
 #endif
 	    else if ((ot[o].size & (OT_DEC | OT_TIME)) && opt_len != 0)
 	      {
@@ -937,11 +936,11 @@ char *option_string(int prot, unsigned int opt, unsigned char *val, int opt_len,
 	  trunc = 1;
 	  opt_len = 14;
 	}
-      print_mac(buf, val, opt_len);
+
+      *buf = 0;
+      strncat(buf, print_mac(val, opt_len), buf_len);
       if (trunc)
 	strncat(buf, "...", buf_len - strlen(buf));
-    
-
     }
 
   return ot[o].name ? ot[o].name : "";

src/dhcp-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/dhcp.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -925,7 +925,8 @@ void dhcp_read_ethers(void)
 {
   FILE *f = fopen(ETHERSFILE, "r");
   unsigned int flags;
-  char *buff = daemon->namebuff;
+  size_t linesz = 0;
+  char *line = NULL;
   char *ip, *cp;
   struct in_addr addr;
   unsigned char hwaddr[ETHER_ADDR_LEN];
@@ -958,22 +959,22 @@ void dhcp_read_ethers(void)
 	up = &config->next;
     }
 
-  while (fgets(buff, MAXDNAME, f))
+  while (get_line_alloc(f, &line, &linesz))
     {
       char *host = NULL;
       
       lineno++;
       
-      while (strlen(buff) > 0 && isspace((unsigned char)buff[strlen(buff)-1]))
-	buff[strlen(buff)-1] = 0;
+      while (strlen(line) > 0 && isspace((unsigned char)line[strlen(line)-1]))
+	line[strlen(line)-1] = 0;
       
-      if ((*buff == '#') || (*buff == '+') || (*buff == 0))
+      if ((*line == '#') || (*line == '+') || (*line == 0))
 	continue;
       
-      for (ip = buff; *ip && !isspace((unsigned char)*ip); ip++);
+      for (ip = line; *ip && !isspace((unsigned char)*ip); ip++);
       for(; *ip && isspace((unsigned char)*ip); ip++)
 	*ip = 0;
-      if (!*ip || parse_hex(buff, hwaddr, ETHER_ADDR_LEN, NULL, NULL) != ETHER_ADDR_LEN)
+      if (!*ip || parse_hex(line, hwaddr, ETHER_ADDR_LEN, NULL, NULL) != ETHER_ADDR_LEN)
 	{
 	  my_syslog(MS_DHCP | LOG_ERR, _("bad line at %s line %d"), ETHERSFILE, lineno); 
 	  continue;

src/dhcp6-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/dhcp6.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/dns-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -22,8 +22,34 @@
 #define IN6ADDRSZ       16
 #define INADDRSZ        4
 
+/* Dnsmasq handles domains names internally as NULL-terminated C strings.
+   The '.' characters in these strings are significant as label-seperators.
+   '.' and /0 characters _within_ labels are escaped and take up two
+   characters to allow labels to contain arbitrary characters.
+
+   The maximum length of a domain name in wire format is 255 bytes.
+   and the maximum length of this when coverted to a <label>.<label> string
+   is 253 characters. Reasoning: the wire format representation of a
+   label is one byte length followed by up to length characters so each of
+   these labels except the last takes the same space since the length is
+   replaced by the '.' seperator.
+   The last label doesn't have the "." so it takes one less character
+   and the terminating zero-length label takes no character either.
+
+   When we introduce the dnsmasq escaped format, the maximum length
+   of this representation is when there are the minimum number of labels,
+   since that gives us the maximum number of characters that may need
+   escaping. The minimum number of labels is four, so the overhead
+   is five bytes (four non-zero lengths plus the zero length terminator)
+   leaving a total of 250 characters in labels. If every one of these
+   is escaped and becomes two characters, that gives 500 characters,
+   plus the three '.' seperators between the four labels, for a total of
+   503 characters.
+*/
+#define MAXDNAME        255             /* Maximum size of a domain name in wire format */
+#define MAXDNAMESTR     503             /* Maximum size of dnsmasq c-string representaion of a domain name. */
+					   
 #define PACKETSZ	512		/* maximum packet size */
-#define MAXDNAME	1025		/* maximum presentation domain name */
 #define RRFIXEDSZ	10		/* #/bytes of fixed data in r record */
 #define MAXLABEL        63              /* maximum length of domain label */
 
@@ -185,10 +211,12 @@ 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.
+/* Escape character in our internal c-string 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
+#define IS_NAME_ESCAPE(x) ((x) == 0 || (x) == '.' || (x) == NAME_ESCAPE)
+

src/dnsmasq.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -135,13 +135,8 @@ int main (int argc, char **argv)
 #ifdef HAVE_DNSSEC
   if (option_bool(OPT_DNSSEC_VALID))
     {
-      /* 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. */
-      daemon->keyname = safe_malloc((MAXDNAME * 2) + 1);
-      daemon->cname = safe_malloc((MAXDNAME * 2) + 1);
+      daemon->keyname = safe_malloc(MAXDNAMESTR + 1);
+      daemon->cname = safe_malloc(MAXDNAMESTR + 1);
       /* one char flag per possible RR in answer section (may get extended). */
       daemon->rr_status_sz = 64;
       daemon->rr_status = safe_malloc(sizeof(*daemon->rr_status) * daemon->rr_status_sz);
@@ -1385,8 +1380,6 @@ static void sig_handler(int sig)
 		  read_write(daemon->pipe_to_parent, (unsigned char *)(&daemon->forward_to_tcp), sizeof(daemon->forward_to_tcp), RW_WRITE);
 		  read_write(daemon->pipe_to_parent, (unsigned char *)(&daemon->forward_to_tcp->uid), sizeof(daemon->forward_to_tcp->uid), RW_WRITE);
 
-		  my_syslog(LOG_INFO, _("TCP process for DNSSEC validation timed out"));
-
 		  _exit(0);
 		}
 	    }

src/dnsmasq.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -14,7 +14,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#define COPYRIGHT "Copyright (c) 2000-2025 Simon Kelley"
+#define COPYRIGHT "Copyright (c) 2000-2026 Simon Kelley"
 
 /* We do defines that influence behavior of stdio.h, so complain
    if included too early. */
@@ -486,7 +486,7 @@ struct interface_name {
 };
 
 union bigname {
-  char name[MAXDNAME];
+  char name[MAXDNAMESTR+1];
   union bigname *next; /* freelist */
 };
 
@@ -1271,10 +1271,10 @@ extern struct daemon {
   /* globally used stuff for DNS */
   char *packet; /* packet buffer */
   int packet_buff_sz; /* size of above */
-  char *namebuff; /* MAXDNAME size buffer */
+  char *namebuff; /* MAXDNAMESTR+1 size buffer */
   char *workspacename;
 #ifdef HAVE_DNSSEC
-  char *keyname, *cname; /* MAXDNAME size buffer */
+  char *keyname, *cname; /* MAXDNAMESTR+1 size buffer */
   unsigned long *rr_status; /* ceiling in TTL from DNSSEC or zero for insecure */
   int rr_status_sz;
   int dnssec_no_time_check;
@@ -1468,11 +1468,12 @@ int in_zone(struct auth_zone *zone, char *name, char **cut);
 
 /* dnssec.c */
 #ifdef HAVE_DNSSEC
-size_t dnssec_generate_query(struct dns_header *header, unsigned char *end, char *name, int class, int id, int type);
+size_t dnssec_generate_query(struct dns_header *header, size_t outlen, char *name, int class, int id, int type);
 int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, char *name,
 			  char *keyname, int class, int *validate_count);
 int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char *name,
 		       char *keyname, int class, int *validate_count);
+int cache_neg_ds(char *name, int flags, int class, time_t now, int neg_ttl);
 int dnssec_validate_reply(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int *class,
 			  int check_unsigned, int *neganswer, int *prim_ok, int *nons, int *nsec_ttl, int *validate_count);
 int dnskey_keytag(int alg, int flags, unsigned char *key, int keylen);
@@ -1499,7 +1500,7 @@ u64 rand64(void);
 int rr_on_list(struct rrlist *list, unsigned short rr);
 int legal_hostname(char *name);
 char *canonicalise(char *in, int *nomem);
-unsigned char *do_rfc1035_name(unsigned char *p, char *sval, char *limit);
+unsigned char *do_rfc1035_name(unsigned char *p, char *sval, unsigned char *limit);
 void *safe_malloc(size_t size);
 void safe_strncpy(char *dest, const char *src, size_t size);
 void safe_pipe(int *fd, int read_noblock);
@@ -1515,6 +1516,7 @@ void *whine_malloc_real(const char *func, unsigned int line, size_t size);
 void *whine_realloc_real(const char *wrapper, const char *func, unsigned int line, void *ptr, size_t size);
 int expand_buf_real(const char *func, unsigned int line, struct iovec *iov, size_t size);
 int expand_workspace_real(const char *func, unsigned int line, unsigned char ***wkspc, int *szp, int new);
+int get_line_alloc(FILE *f, char **buffp, size_t *sizep);
 int sa_len(union mysockaddr *addr);
 int sockaddr_isequal(const union mysockaddr *s1, const union mysockaddr *s2);
 int sockaddr_isnull(const union mysockaddr *s);
@@ -1536,7 +1538,7 @@ int parse_hex(char *in, unsigned char *out, int maxlen,
 	      unsigned int *wildcard_mask, int *mac_type);
 int memcmp_masked(unsigned char *a, unsigned char *b, int len, 
 		  unsigned int mask);
-char *print_mac(char *buff, unsigned char *mac, int len);
+char *print_mac(unsigned char *mac, int len);
 int read_write(int fd, unsigned char *packet, int size, int rw);
 int read_writev(int fd, struct iovec *iov, int iovcnt, int rw);
 void close_fds(long max_fd, int spare1, int spare2, int spare3);
@@ -1937,11 +1939,11 @@ void from_wire(char *name);
 /* edns0.c */
 unsigned char *find_pseudoheader(struct dns_header *header, size_t plen,
 				   size_t *len, unsigned char **p, int *is_sign, int *is_last);
-size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *limit, 
+size_t add_pseudoheader(struct dns_header *header, size_t plen, size_t out_size, 
 			int optno, unsigned char *opt, size_t optlen, int set_do, int replace);
-size_t add_do_bit(struct dns_header *header, size_t plen, unsigned char *limit);
+size_t add_do_bit(struct dns_header *header, size_t plen, size_t outlen);
 void edns0_needs_mac(union mysockaddr *addr, time_t now);
-size_t add_edns0_config(struct dns_header *header, size_t plen, unsigned char *limit, 
+size_t add_edns0_config(struct dns_header *header, size_t plen, size_t outlen, 
 			union mysockaddr *source, time_t now, int *cacheable);
 int check_source(struct dns_header *header, size_t plen, unsigned char *pseudoheader, union mysockaddr *peer);
 
@@ -1964,7 +1966,7 @@ int lookup_domain(char *qdomain, int flags, int *lowout, int *highout);
 int filter_servers(int seed, int flags, int *lowout, int *highout);
 int is_local_answer(time_t now, int first, char *name);
 size_t make_local_answer(int flags, int gotname, size_t size, struct dns_header *header,
-			 char *name, char *limit, int first, int last, int ede);
+			 char *name, size_t limit, int first, int last, int ede);
 int server_samegroup(struct server *a, struct server *b);
 #ifdef HAVE_DNSSEC
 int dnssec_server(struct server *server, char *keyname, int is_ds, int *firstp, int *lastp);

src/dnssec.c

@@ -1,5 +1,5 @@
 /* dnssec.c is Copyright (c) 2012 Giovanni Bajo <rasky@develer.com>
-           and Copyright (c) 2012-2025 Simon Kelley
+           and Copyright (c) 2012-2026 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 @@ static int is_check_date(unsigned long curtime)
    Init state->ip with the RR, and state->end with the end of same.
    Init state->op to NULL.
    Init state->desc to RR descriptor.
-   Init state->buff with a MAXDNAME * 2 buffer.
+   Init state->buff with a MAXDNAMESTR+1 buffer.
    
    After each call which returns 1, state->op points to the next byte of data.
    On returning 0, the end has been reached.
@@ -383,7 +383,7 @@ static int explore_rrset(struct dns_header *header, size_t plen, int class, int
 		     an attacker using signatures made with the key of an unrelated 
 		     zone he controls. Note that the root key is always allowed.
 		     Ignore sigs which aren't valid */
-		  if (*daemon->workspacename == 0 || hostname_issubdomain(name, daemon->workspacename) != 0)
+		  if (*daemon->workspacename == 0 || hostname_issubdomain(daemon->workspacename, name) != 0)
 		    {
 		      if (gotkey)
 			{
@@ -543,10 +543,14 @@ static int validate_rrset(time_t now, struct dns_header *header, size_t plen, in
 
 	   *ttl_out = ttl;
 	 }
-       
+
+      /* Don't trust rdlen not to be too small and give us a negative sig_len
+	 It has already been checked that it doesn't run us off the end
+	 of the packet. */
+      if ((sig_len = rdlen - (p - psav)) <= 0)
+	return STAT_BOGUS;
+
       sig = p;
-      sig_len = rdlen - (p - psav);
-              
       nsigttl = htonl(orig_ttl);
       
       hash->update(ctx, 18, psav);
@@ -950,10 +954,7 @@ int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, ch
 			   
 			   a.log.keytag = keytag;
 			   a.log.algo = algo;
-			   if (algo_digest_name(algo))
-			     log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu", 0);
-			   else
-			     log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu (not supported)", 0);
+			   log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu", !algo_digest_name(algo));
 			 }
 		     }
 				  
@@ -1027,21 +1028,21 @@ int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char
 		  (flags = in_arpa_name_2_addr(name, &a)) &&
 		  ((flags == F_IPV6 && private_net6(&a.addr6, 0)) || (flags == F_IPV4 && private_net(a.addr4, 0))))
 		{
-		  my_syslog(LOG_INFO, _("Insecure reply received for DS %s, assuming that's OK for a RFC-1918 address."), name);
+		  my_syslog(LOG_INFO, _("insecure reply received for DS %s, assuming that's OK for a RFC-1918 address"), name);
 		  neganswer = 1;
 		  nons = 0; /* If we're faking a DS, fake one with an NS. */
 		  neg_ttl = DNSSEC_ASSUMED_DS_TTL;
 		}
 	      else if (lookup_domain(name, F_DOMAINSRV, NULL, NULL))
 		{
-		  my_syslog(LOG_INFO, _("Insecure reply received for DS %s, assuming non-DNSSEC domain-specific server."), name);
+		  my_syslog(LOG_INFO, _("insecure reply received for DS %s, assuming non-DNSSEC domain-specific server"), name);
 		  neganswer = 1;
 		  nons = 0; /* If we're faking a DS, fake one with an NS. */
 		  neg_ttl = DNSSEC_ASSUMED_DS_TTL;
 		}
 	      else
 		{
-		  my_syslog(LOG_WARNING, _("Insecure DS reply received for %s, check domain configuration and upstream DNS server DNSSEC support"), name);
+		  my_syslog(LOG_WARNING, _("insecure DS reply received for %s, check domain configuration and upstream DNS server DNSSEC support"), name);
 		  log_query(F_NOEXTRA | F_UPSTREAM, name, NULL, "BOGUS DS - not secure", 0);
 		  return STAT_BOGUS | DNSSEC_FAIL_INDET; 
 		}
@@ -1101,7 +1102,7 @@ int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char
 		  a.log.keytag = keytag;
 		  a.log.algo = algo;
 		  a.log.digest = digest;
-		  log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DS for keytag %hu, algo %hu, digest %hu (not supported)", 0);
+		  log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DS for keytag %hu, algo %hu, digest %hu", 1);
 		  neg_ttl = ttl;
 		} 
 	      else if ((key = blockdata_alloc((char*)p, rdlen - 4)))
@@ -1141,44 +1142,47 @@ int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char
     }
   
   flags = F_FORWARD | F_DS | F_NEG | F_DNSSECOK;
-  
+
   if (neganswer)
     {
       if (RCODE(header) == NXDOMAIN)
 	flags |= F_NXDOMAIN;
       
-      /* We only cache validated DS records, DNSSECOK flag hijacked 
-	 to store presence/absence of NS. */
       if (nons)
 	{
 	  if (lookup_domain(name, F_DOMAINSRV, NULL, NULL))
 	    {
-	      my_syslog(LOG_WARNING, _("Negative DS reply without NS record received for %s, assuming non-DNSSEC domain-specific server."), name);
+	      my_syslog(LOG_WARNING, _("negative DS reply without NS record received for %s, assuming non-DNSSEC domain-specific server"), name);
 	      nons = 0;
+	      neg_ttl = DNSSEC_ASSUMED_DS_TTL;
 	    }
 	  else
 	    /* We only cache validated DS records, DNSSECOK flag hijacked 
 	       to store presence/absence of NS. */
 	    flags &= ~F_DNSSECOK;
 	}
+      
+      log_query(F_NOEXTRA | F_UPSTREAM, name, NULL,
+		servfail ? "SERVFAIL" : (nons ? "no DS/cut" : "no DS"), 0);
     }
-
+  
+  return cache_neg_ds(name, flags, class, now, neg_ttl);
+  
+}
+       
+int cache_neg_ds(char *name, int flags, int class, time_t now, int ttl)
+{
   cache_start_insert();
   
   /* Use TTL from NSEC for negative cache entries */
-  if (!cache_insert(name, NULL, class, now, neg_ttl, flags))
+  if (!cache_insert(name, NULL, class, now, ttl, flags))
     return STAT_ABANDONED;
   
   cache_end_insert();  
   
-  if (neganswer)
-    log_query(F_NOEXTRA | F_UPSTREAM, name, NULL,
-	      servfail ? "SERVFAIL" : (nons ? "no DS/cut" : "no DS"), 0);
-      
   return STAT_OK;
 }
 
-
 /* 4034 6.1 */
 static int hostname_cmp(const char *a, const char *b)
 {
@@ -1243,15 +1247,23 @@ static int hostname_cmp(const char *a, const char *b)
     }
 }
 
+static int check_type_bitmap(unsigned char *p, int type)
+{
+  int offset = (type & 0xff) >> 3;
+  
+  if (p[0] == type >> 8 && p[1] > offset && (p[offset + 2] & (0x80 >> (type & 0x07))))
+    return 1;
+
+  return 0;
+}
+  
 /* returns 0 on success, or DNSSEC_FAIL_* value on failure. */
 static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsigned char **nsecs, unsigned char **labels, int nsec_count,
 				    char *workspace1_in, char *workspace2, char *name, int type, int *nons)
 {
   int i, rc, rdlen;
   unsigned char *p, *psave;
-  int offset = (type & 0xff) >> 3;
-  int mask = 0x80 >> (type & 0x07);
-
+  
   if (nons)
     *nons = 1;
   
@@ -1295,17 +1307,6 @@ static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsi
       /* rdlen is now length of type map, and p points to it 
 	 packet checked to be as long as rdlen implies in prove_non_existence() */
       
-      /* check that the first typemap is complete. */
-      if (rdlen < 2 || rdlen < p[1] + 2)
-	return DNSSEC_FAIL_BADPACKET;
-
-      /* RFC 6672 5.3.4.1. */
-#define DNAME_OFFSET (T_DNAME >> 3)
-#define DNAME_MASK (0x80 >> (T_DNAME & 0x07))
-      if (p[0] == 0 && (p[1] >= DNAME_OFFSET + 1) && (p[2 + DNAME_OFFSET] & DNAME_MASK) != 0 &&
-	  hostname_issubdomain(name, workspace1) == 1)
-	return DNSSEC_FAIL_NONSEC;
-      
       rc = hostname_cmp(workspace1, name);
       
       if (rc == 0)
@@ -1314,42 +1315,37 @@ static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsi
 	  if (type == T_NSEC || type == T_RRSIG)
 	    return 0;
 
-	  /* NSEC with the same name as the RR we're testing, check
-	     that the type in question doesn't appear in the type map */
-	  if (p[0] == 0 && p[1] >= 1)
-	    {
-	      /* If we can prove that there's no NS record, return that information. */
-	      if (nons && (p[2] & (0x80 >> T_NS)) != 0)
-		*nons = 0;
-	    
-	      /* A CNAME answer would also be valid, so if there's a CNAME is should 
-		 have been returned. */
-	      if ((p[2] & (0x80 >> T_CNAME)) != 0)
-		return DNSSEC_FAIL_NONSEC;
-	      
-	      /* If the SOA bit is set for a DS record, then we have the
-		 DS from the wrong side of the delegation. For the root DS, 
-		 this is expected. */
-	      if (name_labels != 0 && type == T_DS && (p[2] & (0x80 >> T_SOA)) != 0)
-		return DNSSEC_FAIL_NONSEC;
-	    }
-	  
 	  while (rdlen > 0)
 	    {
 	      if (rdlen < 2 || rdlen < p[1] + 2)
 		return DNSSEC_FAIL_BADPACKET;
 	      
-	      if (p[0] == type >> 8)
-		{
-		  /* Does the NSEC say our type exists? */
-		  if (offset < p[1] && (p[offset+2] & mask) != 0)
-		    return DNSSEC_FAIL_NONSEC;
-		  
-		  break; /* finished checking */
-		}
+	      /* If we can prove that there's no NS record, return that information. */
+	      if (nons && check_type_bitmap(p, T_NS))
+		*nons = 0;
 	      
-	      rdlen -= p[1];
-	      p +=  p[1];
+	      /* NSEC with the same name as the RR we're testing, check
+		 that the type in question doesn't appear in the type map */
+	      if (check_type_bitmap(p, type))
+		return DNSSEC_FAIL_NONSEC;
+
+	      /* A CNAME answer would also be valid, so if there's a CNAME it should 
+		 have been returned. */
+	      if (check_type_bitmap(p, T_CNAME))
+		return DNSSEC_FAIL_NONSEC;
+		  
+	      /* If the SOA bit is set for a DS record, then we have the
+		 DS from the wrong side of the delegation. For the root DS, 
+		 this is expected. */
+	      if (name_labels != 0 && type == T_DS && check_type_bitmap(p, T_SOA))
+		return DNSSEC_FAIL_NONSEC;
+	      
+	      /* RFC 6672 5.3.4.1. */
+	      if (check_type_bitmap(p, T_DNAME) && hostname_issubdomain(name, workspace1) == 1)
+		return DNSSEC_FAIL_NONSEC;
+	      
+	      rdlen -= p[1] + 2;
+	      p +=  p[1] + 2;
 	    }
 	  
 	  return 0;
@@ -1437,6 +1433,7 @@ static int base32_decode(char *in, unsigned char *out)
   return p - out;
 }
 
+/* return 1 if we can prove record _doesn't_ exist */
 static int check_nsec3_coverage(struct dns_header *header, size_t plen, int digest_len, unsigned char *digest, int type,
 				char *workspace1, char *workspace2, unsigned char **nsecs, int nsec_count, int *nons, int name_labels)
 {
@@ -1473,50 +1470,35 @@ static int check_nsec3_coverage(struct dns_header *header, size_t plen, int dige
 		   we just need to check the type map. p points to the RR data for the record.
 		   Note we have packet length up to rdlen bytes checked. */
 		
-		int offset = (type & 0xff) >> 3;
-		int mask = 0x80 >> (type & 0x07);
-		
 		p += hash_len; /* skip next-domain hash */
 		rdlen -= p - psave;
-
-		/* check that the first typemap is complete. */
-		if (rdlen < 2 || rdlen < p[1] + 2)
-		  return DNSSEC_FAIL_BADPACKET;
 		
-		if (p[0] == 0 && p[1] >= 1)
-		  {
-		    /* If we can prove that there's no NS record, return that information. */
-		    if (nons && (p[2] & (0x80 >> T_NS)) != 0)
-		      *nons = 0;
-		    
-		    /* A CNAME answer would also be valid, so if there's a CNAME is should 
-		       have been returned. */
-		    if ((p[2] & (0x80 >> T_CNAME)) != 0)
-		      return 0;
-		    
-		    /* If the SOA bit is set for a DS record, then we have the
-		       DS from the wrong side of the delegation. For the root DS, 
-		       this is expected.  */
-		    if (name_labels != 0 && type == T_DS && (p[2] & (0x80 >> T_SOA)) != 0)
-		      return 0;
-		  }
-
 		while (rdlen > 0)
 		  {
 		    if (rdlen < 2 || rdlen < p[1] + 2)
-		      return DNSSEC_FAIL_BADPACKET;
+		      return 0;
+	      
+		    /* If we can prove that there's no NS record, return that information. */
+		    if (nons && check_type_bitmap(p, T_NS))
+		      *nons = 0;
 
-		    if (p[0] == type >> 8)
-		      {
-			/* Does the NSEC3 say our type exists? */
-			if (offset < p[1] && (p[offset+2] & mask) != 0)
-			  return 0;
-			
-			break; /* finished checking */
-		      }
-		    
-		    rdlen -= p[1];
-		    p +=  p[1];
+		    /* Does the NSEC3 say our type exists? */
+		    if (check_type_bitmap(p, type))
+		      return 0;
+
+		    /* A CNAME answer would also be valid, so if there's a CNAME it should 
+		       have been returned. */
+		    if (check_type_bitmap(p, T_CNAME))
+		      return 0;
+		  
+		    /* If the SOA bit is set for a DS record, then we have the
+		       DS from the wrong side of the delegation. For the root DS, 
+		       this is expected. */
+		    if (name_labels != 0 && type == T_DS && check_type_bitmap(p, T_SOA))
+		      return 0;
+	      
+		    rdlen -= p[1] + 2;
+		    p +=  p[1] + 2;
 		  }
 		
 		return 1;
@@ -2113,8 +2095,8 @@ int dnssec_validate_reply(time_t now, struct dns_header *header, size_t plen, ch
 		       CNAME must be <subdomain>.<dname>
 		       CNAME target must be <subdomain>.<dname_target>
 		       <subdomain>s must match for name and target. */ 
-		    if (hostname_issubdomain(daemon->cname, name) == 1 &&
-			hostname_issubdomain(daemon->workspacename, keyname) == 1 &&
+		    if (hostname_issubdomain(name, daemon->cname) == 1 &&
+			hostname_issubdomain(keyname, daemon->workspacename) == 1 &&
 			name_prefix_len == strlen(daemon->workspacename) - strlen(keyname))
 		      {
 			char save = daemon->cname[name_prefix_len];
@@ -2350,7 +2332,7 @@ int dnskey_keytag(int alg, int flags, unsigned char *key, int keylen)
     }
 }
 
-size_t dnssec_generate_query(struct dns_header *header, unsigned char *end, char *name,
+size_t dnssec_generate_query(struct dns_header *header, size_t outlen, char *name,
 			     int class, int id, int type)
 {
   unsigned char *p;
@@ -2374,7 +2356,7 @@ size_t dnssec_generate_query(struct dns_header *header, unsigned char *end, char
   PUTSHORT(type, p);
   PUTSHORT(class, p);
 
-  return add_do_bit(header, p - (unsigned char *)header, end);
+  return add_do_bit(header, p - (unsigned char *)header, outlen);
 }
 
 int errflags_to_ede(int status)

src/domain-match.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -408,12 +408,13 @@ int is_local_answer(time_t now, int first, char *name)
   return rc;
 }
 
-size_t make_local_answer(int flags, int gotname, size_t size, struct dns_header *header, char *name, char *limit, int first, int last, int ede)
+size_t make_local_answer(int flags, int gotname, size_t size, struct dns_header *header, char *name, size_t limit, int first, int last, int ede)
 {
   int trunc = 0, anscount = 0;
   unsigned char *p;
   int start;
   union all_addr addr;
+  char *out_end = ((char *)header) + limit;
   
   setup_reply(header, flags, ede);
 
@@ -443,7 +444,7 @@ size_t make_local_answer(int flags, int gotname, size_t size, struct dns_header
 	else
 	  addr.addr4 = srv->addr;
 	
-	if (add_resource_record(header, limit, &trunc, sizeof(struct dns_header), &p, daemon->local_ttl, NULL, T_A, C_IN, "4", &addr))
+	if (add_resource_record(header, out_end, &trunc, sizeof(struct dns_header), &p, daemon->local_ttl, NULL, T_A, C_IN, "4", &addr))
 	  anscount++;
 	log_query((flags | F_CONFIG | F_FORWARD) & ~F_IPV6, name, (union all_addr *)&addr, NULL, 0);
       }
@@ -458,7 +459,7 @@ size_t make_local_answer(int flags, int gotname, size_t size, struct dns_header
 	else
 	  addr.addr6 = srv->addr;
 	
-	if (add_resource_record(header, limit, &trunc, sizeof(struct dns_header), &p, daemon->local_ttl, NULL, T_AAAA, C_IN, "6", &addr))
+	if (add_resource_record(header, out_end, &trunc, sizeof(struct dns_header), &p, daemon->local_ttl, NULL, T_AAAA, C_IN, "6", &addr))
 	  anscount++;
 	log_query((flags | F_CONFIG | F_FORWARD) & ~F_IPV4, name, (union all_addr *)&addr, NULL, 0);
       }

src/domain.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -162,12 +162,12 @@ int is_rev_synth(int flag, union all_addr *addr, char *name)
        if (c->indexed)
 	 {
 	   unsigned int index = ntohl(addr->addr4.s_addr) - ntohl(c->start.s_addr);
-	   snprintf(name, MAXDNAME, "%s%u", c->prefix ? c->prefix : "", index);
+	   snprintf(name, MAXDNAMESTR, "%s%u", c->prefix ? c->prefix : "", index);
 	 }
        else
 	 {
 	   if (c->prefix)
-	     strncpy(name, c->prefix, MAXDNAME - ADDRSTRLEN);
+	     strncpy(name, c->prefix, MAXDNAMESTR - ADDRSTRLEN);
        
        	   inet_ntop(AF_INET, &addr->addr4, name + strlen(name), ADDRSTRLEN);
 	   for (p = name; *p; p++)
@@ -175,8 +175,8 @@ int is_rev_synth(int flag, union all_addr *addr, char *name)
 	       *p = '-';
 	 }
        
-       strncat(name, ".", MAXDNAME);
-       strncat(name, c->domain, MAXDNAME);
+       strncat(name, ".", MAXDNAMESTR - strlen(name) - 1);
+       strncat(name, c->domain, MAXDNAMESTR - strlen(name) - 1);
 
        return 1;
      }
@@ -188,7 +188,7 @@ int is_rev_synth(int flag, union all_addr *addr, char *name)
        if (c->indexed)
 	 {
 	   u64 index = addr6part(&addr->addr6) - addr6part(&c->start6);
-	   snprintf(name, MAXDNAME, "%s%llu", c->prefix ? c->prefix : "", index);
+	   snprintf(name, MAXDNAMESTR, "%s%llu", c->prefix ? c->prefix : "", index);
 	 }
        else
 	 {
@@ -196,21 +196,21 @@ int is_rev_synth(int flag, union all_addr *addr, char *name)
 	   char frag[6];
 
 	   if (c->prefix)
-	     strncpy(name, c->prefix, MAXDNAME);
+	     strncpy(name, c->prefix, MAXDNAMESTR);
 	   
 	   for (i = 0; i < 16; i += 2)
 	     {
 	       sprintf(frag, "%s%02x%02x",  i == 0 ? "" : "-", addr->addr6.s6_addr[i], addr->addr6.s6_addr[i+1]);
-	       strncat(name, frag, MAXDNAME);
+	       strncat(name, frag, MAXDNAMESTR - strlen(name) - 1);
 	     }
 	 }
 
-       strncat(name, ".", MAXDNAME);
-       strncat(name, c->domain, MAXDNAME);
-       
+       strncat(name, ".", MAXDNAMESTR - strlen(name) - 1);
+       strncat(name, c->domain, MAXDNAMESTR - strlen(name) - 1);
+
        return 1;
      }
-   
+
    return 0;
 }
 

src/dump.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -85,7 +85,8 @@ void dump_init(void)
       /* count existing records */
       while (read_write(daemon->dumpfd, (void *)&pcap_header, sizeof(pcap_header), RW_READ))
 	{
-	  lseek(daemon->dumpfd, pcap_header.incl_len, SEEK_CUR);
+	  if (lseek(daemon->dumpfd, pcap_header.incl_len, SEEK_CUR) == (off_t)-1)
+	    break;
 	  packet_count++;
 	}
     }

src/edns0.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -100,13 +100,14 @@ unsigned char *find_pseudoheader(struct dns_header *header, size_t plen, size_t
    replace == 1 ->replace existing or add option
    replace == 2 ->relpace existing option only.
 */
-size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *limit, 
+size_t add_pseudoheader(struct dns_header *header, size_t plen, size_t out_size, 
 			int optno, unsigned char *opt, size_t optlen, int set_do, int replace)
 { 
   unsigned char *lenp = NULL, *datap = NULL, *p, *udp_len, *buff = NULL;
   int rdlen = 0, is_sign, is_last;
   unsigned short flags = set_do ? 0x8000 : 0, rcode = 0;
-
+  unsigned char *limit = ((unsigned char *)header) + out_size;
+  
   p = find_pseudoheader(header, plen, NULL, &udp_len, &is_sign, &is_last);
   
   if (is_sign)
@@ -247,9 +248,9 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
   return p - (unsigned char *)header;
 }
 
-size_t add_do_bit(struct dns_header *header, size_t plen, unsigned char *limit)
+size_t add_do_bit(struct dns_header *header, size_t plen, size_t outlen)
 {
-  return add_pseudoheader(header, plen, (unsigned char *)limit, 0, NULL, 0, 1, 0);
+  return add_pseudoheader(header, plen, outlen, 0, NULL, 0, 1, 0);
 }
 
 static unsigned char char64(unsigned char c)
@@ -276,14 +277,16 @@ void edns0_needs_mac(union mysockaddr *addr, time_t now)
 
 /* OPT_ADD_MAC = MAC is added (if available)
    OPT_ADD_MAC + OPT_STRIP_MAC = MAC is replaced, if not available, it is only removed
-   OPT_STRIP_MAC = MAC is removed */
-static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned char *limit,
+   OPT_STRIP_MAC = MAC is removed
+   Handle only six byte MACs. */
+static size_t add_dns_client(struct dns_header *header, size_t plen, size_t outlen,
 			     union mysockaddr *l3, time_t now, int *cacheablep)
 {
   int replace = 0, maclen = 0;
   unsigned char mac[DHCP_CHADDR_MAX];
-  char encode[18]; /* handle 6 byte MACs ONLY */
-
+  char encode[9] = { 0 };
+  char *encoded = encode;
+  
   if ((option_bool(OPT_MAC_B64) || option_bool(OPT_MAC_HEX)) && (maclen = find_mac(l3, mac, 1, now)) == 6)
     {
       if (option_bool(OPT_STRIP_MAC))
@@ -291,7 +294,7 @@ static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned ch
        *cacheablep = 0;
     
        if (option_bool(OPT_MAC_HEX))
-	 print_mac(encode, mac, maclen);
+	 encoded = print_mac(mac, maclen);
        else
 	 {
 	   encoder(mac, encode);
@@ -303,7 +306,7 @@ static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned ch
     replace = 2;
 
   if (replace != 0 || maclen == 6)
-    plen = add_pseudoheader(header, plen, limit, EDNS0_OPTION_NOMDEVICEID, (unsigned char *)encode, strlen(encode), 0, replace);
+    plen = add_pseudoheader(header, plen, outlen, EDNS0_OPTION_NOMDEVICEID, (unsigned char *)encoded, strlen(encoded), 0, replace);
 
   return plen;
 }
@@ -312,7 +315,7 @@ static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned ch
 /* OPT_ADD_MAC = MAC is added (if available)
    OPT_ADD_MAC + OPT_STRIP_MAC = MAC is replaced, if not available, it is only removed
    OPT_STRIP_MAC = MAC is removed */
-static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *limit,
+static size_t add_mac(struct dns_header *header, size_t plen, size_t outlen,
 		      union mysockaddr *l3, time_t now, int *cacheablep)
 {
   int maclen = 0, replace = 0;
@@ -328,7 +331,7 @@ static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *lim
     replace = 2;
   
   if (replace != 0 || maclen != 0)
-    plen = add_pseudoheader(header, plen, limit, EDNS0_OPTION_MAC, mac, maclen, 0, replace);
+    plen = add_pseudoheader(header, plen, outlen, EDNS0_OPTION_MAC, mac, maclen, 0, replace);
 
   return plen; 
 }
@@ -409,7 +412,7 @@ static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source,
 /* OPT_CLIENT_SUBNET = client subnet is added
    OPT_CLIENT_SUBNET + OPT_STRIP_ECS = client subnet is replaced
    OPT_STRIP_ECS = client subnet is removed */
-static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned char *limit,
+static size_t add_source_addr(struct dns_header *header, size_t plen, size_t outlen,
 			      union mysockaddr *source, int *cacheable)
 {
   /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
@@ -439,7 +442,7 @@ static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned c
       return plen;
     }
   
-  return add_pseudoheader(header, plen, (unsigned char *)limit, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len, 0, replace);
+  return add_pseudoheader(header, plen, outlen, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len, 0, replace);
 }
 
 int check_source(struct dns_header *header, size_t plen, unsigned char *pseudoheader, union mysockaddr *peer)
@@ -469,6 +472,8 @@ int check_source(struct dns_header *header, size_t plen, unsigned char *pseudohe
      {
        GETSHORT(code, p);
        GETSHORT(len, p);
+       if (i + 4 + len > rdlen)
+	 break; /* malformed: option body extends beyond RDATA */
        if (code == EDNS0_OPTION_CLIENT_SUBNET)
 	 {
 	   if (peer)
@@ -514,7 +519,7 @@ struct umbrella_opt {
   u8 fields[4 * UMBRELLA_TYPESZ + UMBRELLA_ORGSZ + IN6ADDRSZ + UMBRELLA_DEVICESZ + UMBRELLA_ASSETSZ];
 };
 
-static size_t add_umbrella_opt(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *source, int *cacheable)
+static size_t add_umbrella_opt(struct dns_header *header, size_t plen, size_t outlen, union mysockaddr *source, int *cacheable)
 {
   *cacheable = 0;
 
@@ -546,28 +551,28 @@ static size_t add_umbrella_opt(struct dns_header *header, size_t plen, unsigned
       PUTLONG(daemon->umbrella_asset, u);
     }
   
-  return add_pseudoheader(header, plen, (unsigned char *)limit, EDNS0_OPTION_UMBRELLA, (unsigned char *)&opt, u - (u8 *)&opt, 0, 1);
+  return add_pseudoheader(header, plen, outlen, EDNS0_OPTION_UMBRELLA, (unsigned char *)&opt, u - (u8 *)&opt, 0, 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, 
+size_t add_edns0_config(struct dns_header *header, size_t plen, size_t outlen, 
 			union mysockaddr *source, time_t now, int *cacheable)    
 {
   *cacheable = 1;
   
-  plen  = add_mac(header, plen, limit, source, now, cacheable);
-  plen = add_dns_client(header, plen, limit, source, now, cacheable);
+  plen  = add_mac(header, plen, outlen, source, now, cacheable);
+  plen = add_dns_client(header, plen, outlen, source, now, cacheable);
   
   if (daemon->dns_client_id)
-    plen = add_pseudoheader(header, plen, limit, EDNS0_OPTION_NOMCPEID, 
+    plen = add_pseudoheader(header, plen, outlen, EDNS0_OPTION_NOMCPEID, 
 			    (unsigned char *)daemon->dns_client_id, strlen(daemon->dns_client_id), 0, 1);
 
   if (option_bool(OPT_UMBRELLA))
-    plen = add_umbrella_opt(header, plen, limit, source, cacheable);
+    plen = add_umbrella_opt(header, plen, outlen, source, cacheable);
   
-  plen = add_source_addr(header, plen, limit, source, cacheable);
+  plen = add_source_addr(header, plen, outlen, source, cacheable);
 
   return plen;
 }

src/forward.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -375,7 +375,7 @@ static void forward_query(int udpfd, union mysockaddr *udpaddr,
 #ifdef HAVE_DNSSEC
       if (option_bool(OPT_DNSSEC_VALID))
 	{
-	  plen = add_do_bit(header, plen, ((unsigned char *) header) + daemon->edns_pktsz);
+	  plen = add_do_bit(header, plen, daemon->edns_pktsz);
 	  
 	  /* For debugging, set Checking Disabled, otherwise, have the upstream check too,
 	     this allows it to select auth servers when one is returning bad data. */
@@ -514,7 +514,7 @@ static void forward_query(int udpfd, union mysockaddr *udpaddr,
   forwarded = 0;
 
   /* Advertise the size of UDP reply we can accept. */
-  plen = add_pseudoheader(header, plen, (unsigned char *)(header + daemon->edns_pktsz), 0, NULL, 0, 0, 0);
+  plen = add_pseudoheader(header, plen, daemon->edns_pktsz, 0, NULL, 0, 0, 0);
 
   /* check for send errors here (no route to host) 
      if we fail to send to all nameservers, send back an error
@@ -589,7 +589,7 @@ static void forward_query(int udpfd, union mysockaddr *udpaddr,
  reply:
   if (udpfd != -1)
     {
-      if (!(plen = make_local_answer(flags, gotname, plen, header, daemon->namebuff, (char *)(header + replylimit), first, last, ede)))
+      if (!(plen = make_local_answer(flags, gotname, plen, header, daemon->namebuff, replylimit, first, last, ede)))
 	return;
       
       if (fwd_flags & FREC_HAS_PHEADER)
@@ -597,9 +597,9 @@ static void forward_query(int udpfd, union mysockaddr *udpaddr,
 	  u16 swap = htons((u16)ede);
 
 	  if (ede != EDE_UNSET)
-	    plen = add_pseudoheader(header, plen, (unsigned char *)(header + replylimit), EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, 0, 0);
+	    plen = add_pseudoheader(header, plen, replylimit, EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, 0, 0);
 	  else
-	    plen = add_pseudoheader(header, plen, (unsigned char *)(header + replylimit), 0, NULL, 0, 0, 0);
+	    plen = add_pseudoheader(header, plen, replylimit, 0, NULL, 0, 0, 0);
 	}
       
 #if defined(HAVE_CONNTRACK) && defined(HAVE_UBUS)
@@ -695,7 +695,7 @@ static struct ipsets *domain_find_sets(struct ipsets *setlist, const char *domai
 
 static size_t process_reply(struct dns_header *header, time_t now, struct server *server, size_t n, int check_rebind, 
 			    int no_cache, int cache_secure, int bogusanswer, int ad_reqd, int do_bit, int added_pheader, 
-			    union mysockaddr *query_source, unsigned char *limit, int ede)
+			    union mysockaddr *query_source, size_t outlen, int ede)
 {
   unsigned char *pheader, *sizep;
   struct ipsets *ipsets = NULL, *nftsets = NULL;
@@ -724,7 +724,7 @@ static size_t process_reply(struct dns_header *header, time_t now, struct server
       /* Get extended RCODE. */
       rcode |= sizep[2] << 4;
       
-      if (option_bool(OPT_CLIENT_SUBNET) && !check_source(header, plen, pheader, query_source))
+      if (option_bool(OPT_CLIENT_SUBNET) && !check_source(header, n, pheader, query_source))
 	{
 	  my_syslog(LOG_WARNING, _("discarding DNS reply: subnet option mismatch"));
 	  return 0;
@@ -879,7 +879,7 @@ static size_t process_reply(struct dns_header *header, time_t now, struct server
   if (pheader && ede != EDE_UNSET)
     {
       u16 swap = htons((u16)ede);
-      n = add_pseudoheader(header, n, limit, EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, do_bit, 1);
+      n = add_pseudoheader(header, n, outlen, EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, do_bit, 1);
     }
 
   if (RCODE(header) == NXDOMAIN)
@@ -954,6 +954,7 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
 	  /* As soon as anything returns BOGUS, we stop and unwind, to do otherwise
 	     would invite infinite loops, since the answers to DNSKEY and DS queries
 	     will not be cached, so they'll be repeated. */
+	ds_retry:
 	  if (forward->flags & FREC_DNSKEY_QUERY)
 	    status = dnssec_validate_by_ds(now, header, plen, daemon->namebuff, daemon->keyname, forward->class, &orig->validate_counter);
 	  else if (forward->flags & FREC_DS_QUERY)
@@ -1026,7 +1027,7 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
 		 allocation of a new one: third arg of get_new_frec() does that. */
 	      if ((serverind = dnssec_server(forward->sentto, daemon->keyname, STAT_ISEQUAL(status, STAT_NEED_DS), NULL, NULL)) != -1 &&
 		  (server = daemon->serverarray[serverind]) &&
-		  (nn = dnssec_generate_query(header, ((unsigned char *) header) + daemon->edns_pktsz,
+		  (nn = dnssec_generate_query(header, daemon->edns_pktsz,
 					      daemon->keyname, forward->class, get_id(),
 					      STAT_ISEQUAL(status, STAT_NEED_KEY) ? T_DNSKEY : T_DS)) && 
 		  (fd = allocate_rfd(&rfds, server)) != -1 &&
@@ -1083,6 +1084,18 @@ static void dnssec_validate(struct frec *forward, struct dns_header *header,
 				       STAT_ISEQUAL(status, STAT_NEED_KEY) ? "dnssec-query[DNSKEY]" : "dnssec-query[DS]", 0);
 		  return;
 		}
+
+	      /* If there's no server for the parent of a domain-specific server's domain,
+		 assume that said server's contents it legitimately unsigned, as if the parent
+		 contained a negative DS record. This is part of the same logic that's found
+		 in dnssec_validate_ds() when it gets a negative DS repsonse. */
+	      if (STAT_ISEQUAL(status, STAT_NEED_DS) && serverind == -1 && lookup_domain(daemon->keyname, F_DOMAINSRV, NULL, NULL) &&
+		  cache_neg_ds(daemon->keyname, F_FORWARD | F_DS | F_NEG | F_DNSSECOK, forward->class, now, DNSSEC_ASSUMED_DS_TTL) == STAT_OK)
+		{
+		  my_syslog(LOG_WARNING, _("no server for parent domain of %s, assuming unsigned domain"), daemon->keyname);
+		  blockdata_free(stash);
+		  goto ds_retry;
+		}
 	      
 	      /* error unwind */
 	      free_rfds(&rfds);
@@ -1192,10 +1205,10 @@ void reply_query(int fd, time_t now)
 	  server = daemon->serverarray[serv];
 	  if (server->sfd && server->sfd->fd == fd)
 	    break;
-
-	  if (serv == last)
-	    return;
 	}
+
+      if (serv == last)
+	return;
     }
   
   /* spoof check: answer must come from known server, also
@@ -1429,7 +1442,7 @@ void return_reply(time_t now, struct frec *forward, struct dns_header *header, s
   if ((nn = process_reply(header, now, forward->sentto, (size_t)n, check_rebind, no_cache_dnssec, cache_secure, bogusanswer, 
 			  forward->flags & FREC_AD_QUESTION, forward->flags & FREC_DO_QUESTION, 
 			  !(forward->flags & FREC_HAS_PHEADER), &forward->frec_src.source,
-			  ((unsigned char *)header) + daemon->edns_pktsz, ede)))
+			  daemon->edns_pktsz, ede)))
     {
       struct frec_src *src, *prev;
       int do_trunc;
@@ -1932,7 +1945,7 @@ void receive_query(struct listener *listen, time_t now)
     {
       int cacheable;
 
-      n = add_edns0_config(header, n, ((unsigned char *)header) + daemon->edns_pktsz, &source_addr, now, &cacheable);
+      n = add_edns0_config(header, n, daemon->edns_pktsz, &source_addr, now, &cacheable);
       saved_question = blockdata_alloc((char *) header, (size_t)n);
 
       if (!cacheable)
@@ -1966,12 +1979,12 @@ void receive_query(struct listener *listen, time_t now)
 	    {
 	      u16 swap = htons(ede);
 	      
-	      m = add_pseudoheader(header,  m,  ((unsigned char *) header) + daemon->edns_pktsz,
-				   EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, do_bit, 0);
+	      m = add_pseudoheader(header, m, daemon->edns_pktsz, EDNS0_OPTION_EDE,
+				   (unsigned char *)&swap, 2, do_bit, 0);
 	    }
 	  else
-	    m = add_pseudoheader(header,  m,  ((unsigned char *) header) + daemon->edns_pktsz,
-				 0, NULL, 0, do_bit, 0);
+	    m = add_pseudoheader(header, m, daemon->edns_pktsz, 0, 
+				 NULL, 0, do_bit, 0);
 	}
   
 #ifdef HAVE_DUMPFILE
@@ -2162,9 +2175,12 @@ static ssize_t tcp_talk(int first, int last, int start, struct dns_header *heade
 	     someone might be attempting to insert bogus values into the cache by 
 	     sending replies containing questions and bogus answers.
 	     Try another server, or give up */
-	  p = (unsigned char *)(((struct dns_header *)recvbuff->iov_base)+1);
-	  if (extract_name(((struct dns_header *)recvbuff->iov_base), rsize, &p, daemon->namebuff, EXTR_NAME_COMPARE, 4) != 1)
+	  struct dns_header *header = (struct dns_header *)recvbuff->iov_base;
+	  p = (unsigned char *)(header+1);
+	  if (rsize < (unsigned int)sizeof(struct dns_header) || !(header->hb3 & HB3_QR) || ntohs(header->qdcount) != 1 ||
+	      extract_name(header, rsize, &p, daemon->namebuff, EXTR_NAME_COMPARE, 4) != 1)
 	    continue;
+	  
 	  GETSHORT(rtype, p); 
 	  GETSHORT(rclass, p);
       
@@ -2310,7 +2326,7 @@ static int tcp_key_recurse(time_t now, int status, struct dns_header *header, si
       query_header = (struct dns_header *)daemon->packet;
       daemon->srv_save = NULL;
 
-      m = dnssec_generate_query(query_header, ((unsigned char *)query_header) + daemon->edns_pktsz, keyname, class, 0,
+      m = dnssec_generate_query(query_header, daemon->edns_pktsz, keyname, class, 0,
 				STAT_ISEQUAL(new_status, STAT_NEED_KEY) ? T_DNSKEY : T_DS);
       
       if ((start = dnssec_server(server, keyname, STAT_ISEQUAL(new_status, STAT_NEED_DS), &first, &last)) == -1 ||
@@ -2452,18 +2468,18 @@ void tcp_request(int confd, time_t now, struct iovec *bigbuff,
 	      !read_write(confd, (unsigned char *)daemon->packet, size, RW_READ))
 	    break;
 	  
-	  if (size < (int)sizeof(struct dns_header))
+	  /* header == query */
+	  header = (struct dns_header *)daemon->packet;
+
+	  if (size < (int)sizeof(struct dns_header) || (header->hb3 & HB3_QR))
 	    continue;
 	  
 	  /* Make sure we have a buffer big enough for the largest answer. */
 	  expand_buf(bigbuff, 65536 + MAXDNAME + RRFIXEDSZ);
 	  out_header = bigbuff->iov_base;
 	  
-	  /* header == query */
-	  header = (struct dns_header *)daemon->packet;
-
 	  /* Add edns0 pheader to query */
-	  size = add_edns0_config(header, size, ((unsigned char *) header) + daemon->edns_pktsz, &peer_addr, now, &cacheable);
+	  size = add_edns0_config(header, size, daemon->packet_buff_sz, &peer_addr, now, &cacheable);
 
 	  /* Clear buffer to avoid risk of information disclosure. */
 	  memset(bigbuff->iov_base, 0, bigbuff->iov_len);
@@ -2604,7 +2620,7 @@ void tcp_request(int confd, time_t now, struct iovec *bigbuff,
 #ifdef HAVE_DNSSEC
 		  if (option_bool(OPT_DNSSEC_VALID))
 		    {
-		      size = add_do_bit(header, size, ((unsigned char *) header) + daemon->edns_pktsz);
+		      size = add_do_bit(header, size, daemon->edns_pktsz);
 		      
 		      /* For debugging, set Checking Disabled, otherwise, have the upstream check too,
 			 this allows it to select auth servers when one is returning bad data. */
@@ -2699,7 +2715,7 @@ void tcp_request(int confd, time_t now, struct iovec *bigbuff,
 		      
 		      m = process_reply(out_header, now, serv, (unsigned int)m, 
 					option_bool(OPT_NO_REBIND) && !norebind, no_cache_dnssec, cache_secure, bogusanswer,
-					ad_reqd, do_bit, !have_pseudoheader, &peer_addr, ((unsigned char *)out_header) + 65536, ede);
+					ad_reqd, do_bit, !have_pseudoheader, &peer_addr, 65536, ede);
 
 		      /* process_reply() adds pheader itself */
 		      have_pseudoheader = 0; 
@@ -2715,7 +2731,7 @@ void tcp_request(int confd, time_t now, struct iovec *bigbuff,
       if (m == 0)
 	{
 	  if (!(m = make_local_answer(flags, gotname, size, out_header, daemon->namebuff,
-				      ((char *) out_header) + 65536, first, last, ede)))
+				      65536, first, last, ede)))
 	    break;
 	}
       else if (ede == EDE_UNSET)
@@ -2731,9 +2747,9 @@ void tcp_request(int confd, time_t now, struct iovec *bigbuff,
 	  u16 swap = htons((u16)ede);
 	  
 	  if (ede != EDE_UNSET)
-	    m = add_pseudoheader(out_header, m, ((unsigned char *) out_header) + 65536, EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, do_bit, 0);
+	    m = add_pseudoheader(out_header, m, 65536, EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, do_bit, 0);
 	  else
-	    m = add_pseudoheader(out_header, m, ((unsigned char *) out_header) + 65536, 0, NULL, 0, do_bit, 0);
+	    m = add_pseudoheader(out_header, m, 65536, 0, NULL, 0, do_bit, 0);
 	}
       
       check_log_writer(1);

src/helper.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -253,7 +253,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 	}
       
       /* supplied data may just exceed normal buffer (unlikely) */
-      if ((data.hostname_len + data.ed_len + data.clid_len) > MAXDNAME && 
+      if ((data.hostname_len + data.ed_len + data.clid_len) > MAXDNAMESTR && 
 	  !(alloc_buff = buf = malloc(data.hostname_len + data.ed_len + data.clid_len)))
 	continue;
       
@@ -261,8 +261,8 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 		      data.hostname_len + data.ed_len + data.clid_len, RW_READ))
 	continue;
 
-      /* CLID into packet */
-      for (p = daemon->packet, i = 0; i < data.clid_len; i++)
+      /* CLID into packet: limit to 100 bytes to avoid overflowing buffer. */
+      for (p = daemon->packet, i = 0; i < data.clid_len && i < 100; i++)
 	{
 	  p += sprintf(p, "%.2x", buf[i]);
 	  if (i != data.clid_len - 1) 
@@ -533,18 +533,12 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 		close(pipeout[0]);
 	      else
 		{
-		  while (fgets(daemon->packet, daemon->packet_buff_sz, fp))
-		    {
-		      /* do not include new lines, log will append them */
-		      size_t len = strlen(daemon->packet);
-		      if (len > 0)
-			{
-			  --len;
-			  if (daemon->packet[len] == '\n')
-			    daemon->packet[len] = 0;
-			}
-		      send_event(event_fd, EVENT_SCRIPT_LOG, 0, daemon->packet);
-		    }
+		  char *line = NULL;
+		  size_t linesz = 0;
+		  
+		  while (get_line_alloc(fp, &line, &linesz))
+		    send_event(event_fd, EVENT_SCRIPT_LOG, 0, line);
+		    
 		  fclose(fp);
 		}
 	    }
@@ -740,9 +734,11 @@ static unsigned char *grab_extradata_lua(unsigned char *buf, unsigned char *end,
   if (!buf || (buf == end))
     return NULL;
 
-  for (next = buf; *next != 0; next++)
+  for (next = buf; ; next++)
     if (next == end)
       return NULL;
+    else if (*next == 0)
+      break;
   
   if (next != buf)
     {

src/inotify.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/ip6addr.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/lease.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -35,7 +35,7 @@ static int read_leases(time_t now, FILE *leasestream)
 
      Check various buffers are big enough for the code below */
 
-#if (DHCP_BUFF_SZ < 255) || (MAXDNAME < 64) || (PACKETSZ+MAXDNAME+RRFIXEDSZ  < 764)
+#if (DHCP_BUFF_SZ < 255) || (MAXDNAMESTR < 64) || (PACKETSZ+MAXDNAME+RRFIXEDSZ  < 764)
 # error Buffer size breakage in leasefile parsing.
 #endif
 
@@ -73,7 +73,9 @@ static int read_leases(time_t now, FILE *leasestream)
 		if (lease)
 		  {
 		    opt_len = parse_hex(daemon->packet, (unsigned char *)daemon->packet, 255, NULL, NULL);
-		    
+		    if (opt_len < 0)
+		      continue;
+
 		    if (strcmp(daemon->dhcp_buff3, "vendorclass") == 0)
 		      lease_set_vendorclass(lease, (unsigned char *)daemon->packet, opt_len);
 		    else if (strcmp(daemon->dhcp_buff3, "agent-info") == 0)
@@ -99,6 +101,8 @@ static int read_leases(time_t now, FILE *leasestream)
 	    
 	    
 	    hw_len = parse_hex(daemon->dhcp_buff2, (unsigned char *)daemon->dhcp_buff2, DHCP_CHADDR_MAX, NULL, &hw_type);
+	    if (hw_len < 0)
+	      hw_len = 0;
 	    /* For backwards compatibility, no explicit MAC address type means ether. */
 	    if (hw_type == 0 && hw_len != 0)
 	      hw_type = ARPHRD_ETHER; 
@@ -131,7 +135,11 @@ static int read_leases(time_t now, FILE *leasestream)
 	  die (_("too many stored leases"), NULL, EC_MISC);
 
 	if (strcmp(daemon->packet, "*") != 0)
-	  clid_len = parse_hex(daemon->packet, (unsigned char *)daemon->packet, 255, NULL, NULL);
+	  {
+	    clid_len = parse_hex(daemon->packet, (unsigned char *)daemon->packet, 255, NULL, NULL);
+	    if (clid_len < 0)
+	      clid_len = 0;
+	  }
 	
 	lease_set_hwaddr(lease, (unsigned char *)daemon->dhcp_buff2, (unsigned char *)daemon->packet, 
 			 hw_len, hw_type, clid_len, now, 0);

src/log.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -113,7 +113,7 @@ int log_start(struct passwd *ent_pw, int errfd)
       struct stat ls;
       if (getgid() == 0 && fstat(log_fd, &ls) == 0 && ls.st_gid == 0 &&
 	  (ls.st_mode & S_IWGRP) == 0)
-	(void)fchmod(log_fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
+	(void)fchmod(log_fd, ls.st_mode | S_IWGRP);
       if (fchown(log_fd, ent_pw->pw_uid, -1) != 0)
 	ret = errno;
     }

src/loop.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/metrics.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/metrics.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/netlink.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/network.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -1699,19 +1699,19 @@ void check_servers(int no_loop_check)
 int reload_servers(char *fname)
 {
   FILE *f;
-  char *line;
+  char *line = NULL;
+  size_t linesz = 0;
   int gotone = 0;
 
-  /* buff happens to be MAXDNAME long... */
   if (!(f = fopen(fname, "r")))
     {
       my_syslog(LOG_ERR, _("failed to read %s: %s"), fname, strerror(errno));
       return 0;
     }
-   
+  
   mark_servers(SERV_FROM_RESOLV);
-    
-  while ((line = fgets(daemon->namebuff, MAXDNAME, f)))
+  
+  while (get_line_alloc(f, &line, &linesz))
     {
       union mysockaddr addr, source_addr;
       char *token = strtok(line, " \t\n\r");

src/nftset.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/option.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -4580,39 +4580,41 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    only allowed for agent-options. */
 	 
 	 arg = comma;
-	 if ((comma = split(arg)))
+	 if (option  == 'U' && strstr(arg, "enterprise:") == arg)
 	   {
-	     if (option  != 'U' || strstr(arg, "enterprise:") != arg)
+	     comma = split(arg);
+	     new->enterprise = atoi(arg+11);
+	     arg = comma;
+	   }
+	 
+	 if (arg)
+	   {
+	     for (dig = 0, colon = 0, p = (unsigned char *)arg; *p; p++)
+	       if (isxdigit(*p))
+		 dig = 1;
+	       else if (*p == ':')
+		 colon = 1;
+	       else
+		 break;
+	     
+	     unhide_metas(arg);
+	     if (option == 'U' || option == 'j' || *p || !dig || !colon)
 	       {
-	         free(new->netid.net);
-	         ret_err_free(gen_err, new);
+		 new->len = strlen(arg);  
+		 new->data = opt_malloc(new->len);
+		 memcpy(new->data, arg, new->len);
 	       }
 	     else
-	       new->enterprise = atoi(arg+11);
+	       {
+		 new->len = parse_hex(comma, (unsigned char *)arg, strlen(arg), NULL, NULL);
+		 new->data = opt_malloc(new->len);
+		 memcpy(new->data, arg, new->len);
+	       }
 	   }
-	 else
-	   comma = arg;
-	 
-	 for (dig = 0, colon = 0, p = (unsigned char *)comma; *p; p++)
-	   if (isxdigit(*p))
-	     dig = 1;
-	   else if (*p == ':')
-	     colon = 1;
-	   else
-	     break;
-	 
-	 unhide_metas(comma);
-	 if (option == 'U' || option == 'j' || *p || !dig || !colon)
+	 else if (option != 'U' || new->enterprise == 0)
 	   {
-	     new->len = strlen(comma);  
-	     new->data = opt_malloc(new->len);
-	     memcpy(new->data, comma, new->len);
-	   }
-	 else
-	   {
-	     new->len = parse_hex(comma, (unsigned char *)comma, strlen(comma), NULL, NULL);
-	     new->data = opt_malloc(new->len);
-	     memcpy(new->data, comma, new->len);
+	     free(new->netid.net);
+	     ret_err_free(gen_err, new);
 	   }
 	 
 	 switch (option)
@@ -4635,7 +4637,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	   }
 	 new->next = daemon->dhcp_vendors;
 	 daemon->dhcp_vendors = new;
-
+	 
 	 break;
       }
       
@@ -4958,7 +4960,8 @@ err:
 	      arg = NULL; /* provoke error below */
 	  }
 	
-	if (!domain || !arg || !(new->name = canonicalise_opt(domain)))
+	if (!domain || !arg || !new->intr ||
+	    !(new->name = canonicalise_opt(domain)))
 	  ret_err(option == LOPT_DYNHOST ?
 		  _("bad dynamic host") : _("bad interface name"));
 	
@@ -5468,9 +5471,20 @@ err:
 static void read_file(char *file, FILE *f, int hard_opt, int from_script)	
 {
   volatile int lineno = 0;
-  char *buff = daemon->namebuff;
+  char *buff;
+  size_t buffsz;
+
+  /* Memory allocation failure longjmps here if mem_recover == 1 */ 
+  if (hard_opt != 0)
+    {
+      setjmp(mem_jmp);
+      mem_recover = 1;
+    }
   
-  while (fgets(buff, MAXDNAME, f))
+  buff = NULL;
+  buffsz = 0;
+
+  while (get_line_alloc(f, &buff, &buffsz))
     {
       int white, i;
       volatile int option;
@@ -5478,15 +5492,7 @@ static void read_file(char *file, FILE *f, int hard_opt, int from_script)
       size_t len;
 
       option = (hard_opt == LOPT_REV_SERV) ? 0 : hard_opt;
-
-      /* Memory allocation failure longjmps here if mem_recover == 1 */ 
-      if (option != 0 || hard_opt == LOPT_REV_SERV)
-	{
-	  if (setjmp(mem_jmp))
-	    continue;
-	  mem_recover = 1;
-	}
-
+      
       arg = NULL;
       lineno++;
       errmess = NULL;
@@ -5945,23 +5951,17 @@ void reread_dhcp(void)
 
 void read_opts(int argc, char **argv, char *compile_opts)
 {
-  size_t argbuf_size = MAXDNAME;
-  char *argbuf = opt_malloc(argbuf_size);
-  /* 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. */
-  char *buff = opt_malloc((MAXDNAME * 2) + 1);
+  size_t argbuf_size = 300;
+  char *argbuf = safe_malloc(argbuf_size);
   int option, testmode = 0;
   char *arg, *conffile = NULL;
   
   opterr = 0;
-
+  
   daemon = opt_malloc(sizeof(struct daemon));
   memset(daemon, 0, sizeof(struct daemon));
-  daemon->namebuff = buff;
-  daemon->workspacename = safe_malloc((MAXDNAME * 2) + 1);
+  daemon->namebuff = safe_malloc(MAXDNAMESTR+1);
+  daemon->workspacename = safe_malloc(MAXDNAMESTR+1);
   daemon->addrbuff = safe_malloc(ADDRSTRLEN);
   
   /* Set defaults - everything else is zero or NULL */
@@ -6199,9 +6199,9 @@ void read_opts(int argc, char **argv, char *compile_opts)
   /* create default, if not specified */
   if (daemon->authserver && !daemon->hostmaster)
     {
-      strcpy(buff, "hostmaster.");
-      strcat(buff, daemon->authserver);
-      daemon->hostmaster = opt_string_alloc(buff);
+      strcpy(daemon->namebuff, "hostmaster.");
+      strncat(daemon->namebuff, daemon->authserver, MAXDNAMESTR - strlen(daemon->namebuff));
+      daemon->hostmaster = opt_string_alloc(daemon->namebuff);
     }
 
   if (!daemon->dhcp_pxe_vendors)
@@ -6216,11 +6216,11 @@ void read_opts(int argc, char **argv, char *compile_opts)
     {
       struct mx_srv_record *mx;
       
-      if (gethostname(buff, MAXDNAME) == -1)
+      if (gethostname(daemon->namebuff, MAXDNAMESTR) == -1)
 	die(_("cannot get host-name: %s"), NULL, EC_MISC);
       
       for (mx = daemon->mxnames; mx; mx = mx->next)
-	if (!mx->issrv && hostname_isequal(mx->name, buff))
+	if (!mx->issrv && hostname_isequal(mx->name, daemon->namebuff))
 	  break;
       
       if ((daemon->mxtarget || option_bool(OPT_LOCALMX)) && !mx)
@@ -6229,12 +6229,12 @@ void read_opts(int argc, char **argv, char *compile_opts)
 	  mx->next = daemon->mxnames;
 	  mx->issrv = 0;
 	  mx->target = NULL;
-	  mx->name = opt_string_alloc(buff);
+	  mx->name = opt_string_alloc(daemon->namebuff);
 	  daemon->mxnames = mx;
 	}
       
       if (!daemon->mxtarget)
-	daemon->mxtarget = opt_string_alloc(buff);
+	daemon->mxtarget = opt_string_alloc(daemon->namebuff);
 
       for (mx = daemon->mxnames; mx; mx = mx->next)
 	if (!mx->issrv && !mx->target)
@@ -6249,7 +6249,8 @@ void read_opts(int argc, char **argv, char *compile_opts)
   
   if (option_bool(OPT_RESOLV_DOMAIN))
     {
-      char *line;
+      char *line = NULL;
+      size_t linesz = 0;
       FILE *f;
 
       if (option_bool(OPT_NO_RESOLV) ||
@@ -6260,7 +6261,7 @@ void read_opts(int argc, char **argv, char *compile_opts)
       if (!(f = fopen((daemon->resolv_files)->name, "r")))
 	die(_("failed to read %s: %s"), (daemon->resolv_files)->name, EC_FILE);
       
-      while ((line = fgets(buff, MAXDNAME, f)))
+      while (get_line_alloc(f, &line, &linesz))
 	{
 	  char *token = strtok(line, " \t\n\r");
 	  
@@ -6280,7 +6281,7 @@ void read_opts(int argc, char **argv, char *compile_opts)
 
   if (daemon->domain_suffix)
     {
-       /* add domain for any srv record without one. */
+      /* add domain for any srv record without one. */
       struct mx_srv_record *srv;
       
       for (srv = daemon->mxnames; srv; srv = srv->next)
@@ -6288,13 +6289,14 @@ void read_opts(int argc, char **argv, char *compile_opts)
 	    strchr(srv->name, '.') && 
 	    strchr(srv->name, '.') == strrchr(srv->name, '.'))
 	  {
-	    if (strlen(srv->name) + 1 + strlen(daemon->domain_suffix) > MAXDNAME)
+	    if (strlen(srv->name) + 1 + strlen(daemon->domain_suffix) > MAXDNAMESTR)
 	      die(_("srv-host name %s too long after domain appended"), srv->name, EC_MISC);
-	    strcpy(buff, srv->name);
-	    strcat(buff, ".");
-	    strcat(buff, daemon->domain_suffix);
+	    strcpy(daemon->namebuff, srv->name);
+	    strcat(daemon->namebuff, ".");
+	    strcat(daemon->namebuff, daemon->domain_suffix);
 	    free(srv->name);
-	    srv->name = opt_string_alloc(buff);
+	    if (!(srv->name = canonicalise_opt(daemon->namebuff)))
+	      die(_("bad srv-host name %s after domain appended"), srv->name, EC_MISC); 
 	  }
     }
   else if (option_bool(OPT_DHCP_FQDN))

src/outpacket.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/pattern.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/poll.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/radv-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/radv.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -215,11 +215,8 @@ void icmp6_packet(time_t now)
 	  if (opt_sz == 0 || opt_sz > rem)
 	    return; /* Bad packet */
 	  
-	  if (p[0] == ICMP6_OPT_SOURCE_MAC && ((opt_sz - 2) * 3 - 1 < MAXDNAME))
-	    {
-	      print_mac(daemon->namebuff, &p[2], opt_sz - 2);
-	      mac = daemon->namebuff;
-	    }
+	  if (p[0] == ICMP6_OPT_SOURCE_MAC)
+	    mac = print_mac(&p[2], opt_sz - 2);
 	}
       
       if (!option_bool(OPT_QUIET_RA))
@@ -435,7 +432,7 @@ static void send_ra_alias(time_t now, int iface, char *iface_name, struct in6_ad
       sprintf(daemon->namebuff, "/proc/sys/net/ipv6/conf/%s/mtu", mtu_name ? mtu_name : iface_name);
       if ((f = fopen(daemon->namebuff, "r")))
         {
-          if (fgets(daemon->namebuff, MAXDNAME, f))
+          if (fgets(daemon->namebuff, MAXDNAMESTR, f))
             mtu = atoi(daemon->namebuff);
           fclose(f);
         }

src/rfc1035.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -106,11 +106,16 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 	  
 	  p = l + (unsigned char *)header;
 	}
-      else if (label_type == 0x00)
-	{ /* label_type = 0 -> label. */
-	  namelen += l + 1; /* include period */
+      else if (label_type == 0x00) /* label_type = 0 -> label. */
+	{
+	  /* reject wire-format names > MAXDNAME bytes
+	     This also ensures that internal-format
+	     names don't exceed MAXDNAMESTR characters. */
+	  namelen += l + 1; 
+	  /* namelen == MAXDNAME means terminator will overflow. */
 	  if (namelen >= MAXDNAME)
 	    return 0;
+
 	  if (!CHECK_LEN(header, p, plen, l))
 	    return 0;
 	  
@@ -119,13 +124,13 @@ int extract_name(struct dns_header *header, size_t plen, unsigned char **pp,
 	      {
 		unsigned char c = *p;
 
-		if (c == 0 || c == '.' || c == NAME_ESCAPE)
+		if (IS_NAME_ESCAPE(c))
 		  {
 		    *cp++ = NAME_ESCAPE;
 		    *cp++ = c+1;
 		  }
 		else
-		  *cp++ = c; 
+		  *cp++ = c;
 	      }
 	    else if (flip)
 	      {
@@ -317,7 +322,7 @@ unsigned char *skip_name(unsigned char *ansp, struct dns_header *header, size_t
       else if (label_type == 0x40)
 	{
 	  /* Extended label type */
-	  unsigned int count;
+	  unsigned int count, llen;
 	  
 	  if (!CHECK_LEN(header, ansp, plen, 2))
 	    return NULL;
@@ -328,9 +333,12 @@ unsigned char *skip_name(unsigned char *ansp, struct dns_header *header, size_t
 	  count = *(ansp++); /* Bits in bitstring */
 	  
 	  if (count == 0) /* count == 0 means 256 bits */
-	    ansp += 32;
+	    llen = 32;
 	  else
-	    ansp += ((count-1)>>3)+1;
+	    llen = ((count-1)>>3)+1;
+
+	  if (!ADD_RDLEN(header, ansp, plen, llen))
+	    return NULL;
 	}
       else
 	{ /* label type == 0 Bottom six bits is length */
@@ -440,7 +448,7 @@ int private_net6(struct in6_addr *a, int ban_localhost)
     (IN6_IS_ADDR_LOOPBACK(a) && ban_localhost) ||    /* RFC 6303 4.3 */
     IN6_IS_ADDR_LINKLOCAL(a) ||   /* RFC 6303 4.5 */
     IN6_IS_ADDR_SITELOCAL(a) ||
-    ((unsigned char *)a)[0] == 0xfd ||   /* RFC 6303 4.4 */
+    (((unsigned char *)a)[0] & 0xfe) == 0xfc || /* RFC 4196 3.1 */
     ((u32 *)a)[0] == htonl(0x20010db8); /* RFC 6303 4.6 */
 }
 
@@ -495,7 +503,7 @@ int do_doctor(struct dns_header *header, size_t qlen, char *namebuff)
 	      header->hb3 &= ~HB3_AA;
 #ifdef HAVE_DNSSEC
 	      /* remove validated flag from this RR, since we changed it! */
-	      if (option_bool(OPT_DNSSEC_VALID) && i <  ntohs(header->ancount))
+	      if (option_bool(OPT_DNSSEC_VALID) && i < daemon->rr_status_sz && i <  ntohs(header->ancount))
 		daemon->rr_status[i] = 0;
 #endif
 	      done = 1;
@@ -537,7 +545,7 @@ static int find_soa(struct dns_header *header, size_t qlen, char *name, int *sub
 
   for (i = 0; i < ntohs(header->nscount); i++)
     {
-      if (!extract_name(header, qlen, &p, daemon->workspacename, EXTR_NAME_EXTRACT, 0))
+      if (!extract_name(header, qlen, &p, daemon->workspacename, EXTR_NAME_EXTRACT, 10))
 	return 0; /* bad packet */
       
       GETSHORT(qtype, p); 
@@ -607,7 +615,9 @@ static int find_soa(struct dns_header *header, size_t qlen, char *name, int *sub
 		  addr.rrblock.datalen += 20;
 		  
 #ifdef HAVE_DNSSEC
-		  if (option_bool(OPT_DNSSEC_VALID) && daemon->rr_status[i + ntohs(header->ancount)] != 0)
+		  if (option_bool(OPT_DNSSEC_VALID) &&
+		      i + ntohs(header->ancount) < daemon->rr_status_sz &&
+		      daemon->rr_status[i + ntohs(header->ancount)] != 0)
 		    {
 		      secflag = F_DNSSECOK; 
 		  
@@ -943,7 +953,8 @@ int extract_addresses(struct dns_header *header, size_t qlen, char *name, time_t
 			      /* Name, extract it then re-encode. */
 			      int len;
 			      
-			      if (!extract_name(header, qlen, &p1, name, EXTR_NAME_EXTRACT, 0))
+			      /* rdlen may lie, and extract_name() advances p1 past where it says the record ends. */
+			      if (!extract_name(header, qlen, &p1, name, EXTR_NAME_EXTRACT, 0) || (p1 > endrr))
 				{
 				  blockdata_free(addr.rrblock.rrdata);
 				  return 2;
@@ -1458,7 +1469,7 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
   else
     {
       char *name = va_arg(ap, char *);
-      if (name && !(p = do_rfc1035_name(p, name, limit)))
+      if (name && !(p = do_rfc1035_name(p, name, (unsigned char *)limit)))
 	goto truncated;
       
       if (nameoffset < 0)
@@ -1522,7 +1533,7 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
         /* get domain-name answer arg and store it in RDATA field */
         if (offset)
           *offset = p - (unsigned char *)header;
-        if (!(p = do_rfc1035_name(p, va_arg(ap, char *), limit)))
+        if (!(p = do_rfc1035_name(p, va_arg(ap, char *), (unsigned char *)limit)))
 	  goto truncated;
 	CHECK_LIMIT(1);
         *p++ = 0;

src/rfc2131.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -413,7 +413,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 	  struct dhcp_context *context_tmp;
 	  for (context_tmp = context; context_tmp; context_tmp = context_tmp->current)
 	    {
-	      inet_ntop(AF_INET, &context_tmp->start, daemon->namebuff, MAXDNAME);
+	      inet_ntop(AF_INET, &context_tmp->start, daemon->namebuff, MAXDNAMESTR);
 	      if (context_tmp->flags & (CONTEXT_STATIC | CONTEXT_PROXY))
 		{
 		  inet_ntop(AF_INET, &context_tmp->netmask, daemon->addrbuff, ADDRSTRLEN);
@@ -597,7 +597,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
       if (mess->file[0])
 	{
 	  memcpy(daemon->dhcp_buff2, mess->file, sizeof(mess->file));
-	  daemon->dhcp_buff2[sizeof(mess->file) + 1] = 0; /* ensure zero term. */
+	  daemon->dhcp_buff2[sizeof(mess->file)] = 0; /* ensure zero term. */
 	  id.net = (char *)daemon->dhcp_buff2;
 	  id.next = netid;
 	  netid = &id;
@@ -1313,7 +1313,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 		  unsigned char *mac = extended_hwaddr(ltmp->hwaddr_type, ltmp->hwaddr_len,
 						       ltmp->hwaddr, ltmp->clid_len, ltmp->clid, &len);
 		  my_syslog(MS_DHCP | LOG_WARNING, _("not using configured address %s because it is leased to %s"),
-			    daemon->addrbuff, print_mac(daemon->namebuff, mac, len));
+			    daemon->addrbuff, print_mac(mac, len));
 		}
 	      else
 		{
@@ -1537,7 +1537,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 		{
 		  inet_ntop(AF_INET, &ltmp->addr, daemon->addrbuff, ADDRSTRLEN);
 		  my_syslog(MS_DHCP | LOG_INFO, _("abandoning lease to %s of %s"),
-			    print_mac(daemon->namebuff, ltmp->hwaddr, ltmp->hwaddr_len), 
+			    print_mac(ltmp->hwaddr, ltmp->hwaddr_len), 
 			    daemon->addrbuff);
 		  lease = ltmp;
 		}
@@ -1918,16 +1918,18 @@ static void add_extradata_opt(struct dhcp_lease *lease, unsigned char *opt)
 static void log_packet(char *type, void *addr, unsigned char *ext_mac, 
 		       int mac_len, char *interface, char *string, char *err, u32 xid)
 {
+  char *mac = "";
+
   if (!err && !option_bool(OPT_LOG_OPTS) && option_bool(OPT_QUIET_DHCP))
     return;
   
-  daemon->addrbuff[0] = daemon->namebuff[0] = 0;
+  daemon->addrbuff[0] = 0;
   
   if (addr)
     inet_ntop(AF_INET, addr, daemon->addrbuff, ADDRSTRLEN);
   
   if (ext_mac)
-    print_mac(daemon->namebuff, ext_mac, mac_len);
+    mac = print_mac(ext_mac, mac_len);
   
   if (option_bool(OPT_LOG_OPTS))
     my_syslog(MS_DHCP | LOG_INFO, "%u %s(%s) %s%s%s%s%s%s",
@@ -1936,7 +1938,7 @@ static void log_packet(char *type, void *addr, unsigned char *ext_mac,
 	      interface, 
 	      daemon->addrbuff,
 	      addr ? " " : "",
-	      daemon->namebuff,
+	      mac,
 	      ext_mac ? " " : "",
 	      string ? string : "",
 	      err ? err : "");
@@ -1946,16 +1948,16 @@ static void log_packet(char *type, void *addr, unsigned char *ext_mac,
 	      interface, 
 	      daemon->addrbuff,
 	      addr ? " " : "",
-	      daemon->namebuff,
+	      mac,
 	      ext_mac ? " " : "",
 	      string ? string : "",
 	      err ? err : "");
   
 #ifdef HAVE_UBUS
   if (!strcmp(type, "DHCPACK"))
-    ubus_event_bcast("dhcp.ack", daemon->namebuff, addr ? daemon->addrbuff : NULL, string, interface);
+    ubus_event_bcast("dhcp.ack", mac, addr ? daemon->addrbuff : NULL, string, interface);
   else if (!strcmp(type, "DHCPRELEASE"))
-    ubus_event_bcast("dhcp.release", daemon->namebuff, addr ? daemon->addrbuff : NULL, string, interface);
+    ubus_event_bcast("dhcp.release", mac, addr ? daemon->addrbuff : NULL, string, interface);
 #endif
 }
 
@@ -1963,7 +1965,7 @@ static void log_options(unsigned char *start, u32 xid)
 {
   while (*start != OPTION_END)
     {
-      char *optname = option_string(AF_INET, start[0], option_ptr(start, 0), option_len(start), daemon->namebuff, MAXDNAME);
+      char *optname = option_string(AF_INET, start[0], option_ptr(start, 0), option_len(start), daemon->namebuff, MAXDNAMESTR);
       
       my_syslog(MS_DHCP | LOG_INFO, "%u sent size:%3d option:%3d %s  %s", 
 		ntohl(xid), option_len(start), start[0], optname, daemon->namebuff);
@@ -2642,7 +2644,7 @@ static void do_options(struct dhcp_context *context,
       for (i = 0; req_options[i] != OPTION_END; i++)
 	{
 	  char *s = option_string(AF_INET, req_options[i], NULL, 0, NULL, 0);
-	  q += snprintf(q, MAXDNAME - (q - daemon->namebuff),
+	  q += snprintf(q, MAXDNAMESTR - (q - daemon->namebuff),
 			"%d%s%s%s", 
 			req_options[i],
 			strlen(s) != 0 ? ":" : "",
@@ -3248,7 +3250,7 @@ unsigned int relay_reply4(struct dhcp_packet *mess, size_t sz, char *arrival_int
 
 	      /* delete agent info before return RFC 3046 para 2.1 */
 	      *opt = OPTION_END;
-	      memset(opt + 1, 0, option_len(opt) + 2);
+	      memset(opt + 1, 0, option_len(opt) + 1);
 	    }
 	}
       else if (mess->giaddr.s_addr == relay->local.addr4.s_addr)

src/rfc3315.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -24,7 +24,7 @@ struct state {
   int clid_len, ia_type, interface, hostname_auth, lease_allocate;
   char *client_hostname, *hostname, *domain, *send_domain;
   struct dhcp_context *context;
-  struct in6_addr *link_address, *fallback, *ll_addr, *ula_addr;
+  struct in6_addr *relay_address, *fallback, *ll_addr, *ula_addr;
   unsigned int xid, fqdn_flags, iaid;
   char *iface_name;
   void *packet_options, *end;
@@ -34,14 +34,14 @@ struct state {
 };
 
 static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz, 
-			     struct in6_addr *client_addr, time_t now);
+			     struct in6_addr *client_addr, struct in6_addr *link_address, time_t now);
 static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, time_t now);
 static void log6_opts(int nest, unsigned int xid, void *start_opts, void *end_opts);
 static void log6_packet(struct state *state, char *type, struct in6_addr *addr, char *string);
 static void log6_quiet(struct state *state, char *type, struct in6_addr *addr, char *string);
-static void *opt6_find (uint8_t *opts, uint8_t *end, unsigned int search, unsigned int minsize);
+static void *opt6_find (uint8_t *opts, uint8_t *end, unsigned int search, int minsize);
 static void *opt6_first(uint8_t *opt, uint8_t *end);
-static void *opt6_next(uint8_t *opts, uint8_t *end);
+static void *opt6_user_vendor_first(uint8_t *opt, uint8_t *end);
 static unsigned int opt6_uint(unsigned char *opt, int offset, int size);
 static void get_context_tag(struct state *state, struct dhcp_context *context);
 static int check_ia(struct state *state, void *opt, void **endp, void **ia_option);
@@ -63,11 +63,12 @@ static void calculate_times(struct dhcp_context *context, unsigned int *min_time
 #define opt6_len(opt) ((int)(opt6_uint(opt, -2, 2)))
 #define opt6_type(opt) (opt6_uint(opt, -4, 2))
 #define opt6_ptr(opt, i) ((void *)&(((uint8_t *)(opt))[4+(i)]))
+#define opt6_next(opt, end) (opt6_first(opt6_ptr((opt), opt6_len((opt))), (end)))
 
 #define opt6_user_vendor_ptr(opt, i) ((void *)&(((uint8_t *)(opt))[2+(i)]))
-#define opt6_user_vendor_len(opt) ((int)(opt6_uint(opt, -4, 2)))
-#define opt6_user_vendor_next(opt, end) (opt6_next(((uint8_t *) opt) - 2, end))
- 
+#define opt6_user_vendor_len(opt) ((int)(opt6_uint((opt), -4, 2)))
+#define opt6_user_vendor_next(opt, end) (opt6_user_vendor_first(opt6_user_vendor_ptr((opt), opt6_user_vendor_len((opt))), (end)))
+
 
 unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int interface, char *iface_name,
 			   struct in6_addr *fallback,  struct in6_addr *ll_addr, struct in6_addr *ula_addr,
@@ -99,9 +100,8 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
   state.ula_addr = ula_addr;
   state.mac_len = 0;
   state.tags = NULL;
-  state.link_address = NULL;
-
-  if (dhcp6_maybe_relay(&state, daemon->dhcp_packet.iov_base, sz, client_addr, now))
+  
+  if (dhcp6_maybe_relay(&state, daemon->dhcp_packet.iov_base, sz, client_addr, NULL, now))
     return msg_type == DHCP6RELAYFORW ? DHCPV6_SERVER_PORT : DHCPV6_CLIENT_PORT;
 
   return 0;
@@ -109,7 +109,7 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
 
 /* This cost me blood to write, it will probably cost you blood to understand - srk. */
 static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz, 
-			     struct in6_addr *client_addr, time_t now)
+			     struct in6_addr *client_addr, struct in6_addr *link_address, time_t now)
 {
   uint8_t *end = inbuff + sz;
   uint8_t *opts = inbuff + 34;
@@ -136,7 +136,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
       link_address == NULL means there's no relay in use, so we try and find the client's 
       MAC address from the local ND cache. */
       
-      if (!state->link_address)
+      if (!link_address)
 	get_client_mac(client_addr, state->interface, state->mac, &state->mac_len, &state->mac_type, now);
       else
 	{
@@ -144,9 +144,9 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  struct shared_network *share = NULL;
 	  state->context = NULL;
 
-	  if (!IN6_IS_ADDR_LOOPBACK(state->link_address) &&
-	      !IN6_IS_ADDR_LINKLOCAL(state->link_address) &&
-	      !IN6_IS_ADDR_MULTICAST(state->link_address))
+	  if (!IN6_IS_ADDR_LOOPBACK(link_address) &&
+	      !IN6_IS_ADDR_LINKLOCAL(link_address) &&
+	      !IN6_IS_ADDR_MULTICAST(link_address))
 	    for (c = daemon->dhcp6; c; c = c->next)
 	      {
 		for (share = daemon->shared_networks; share; share = share->next)
@@ -155,7 +155,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 		      continue;
 		    
 		    if (share->if_index != 0 ||
-			!IN6_ARE_ADDR_EQUAL(state->link_address, &share->match_addr6))
+			!IN6_ARE_ADDR_EQUAL(link_address, &share->match_addr6))
 		      continue;
 		    
 		    if ((c->flags & CONTEXT_DHCP) &&
@@ -168,8 +168,8 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 		if (share ||
 		    ((c->flags & CONTEXT_DHCP) &&
 		     !(c->flags & (CONTEXT_TEMPLATE | CONTEXT_OLD)) &&
-		     is_same_net6(state->link_address, &c->start6, c->prefix) &&
-		     is_same_net6(state->link_address, &c->end6, c->prefix)))
+		     is_same_net6(link_address, &c->start6, c->prefix) &&
+		     is_same_net6(link_address, &c->end6, c->prefix)))
 		  {
 		    c->preferred = c->valid = 0xffffffff;
 		    c->current = state->context;
@@ -179,7 +179,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  
 	  if (!state->context)
 	    {
-	      inet_ntop(AF_INET6, state->link_address, daemon->addrbuff, ADDRSTRLEN); 
+	      inet_ntop(AF_INET6, link_address, daemon->addrbuff, ADDRSTRLEN); 
 	      my_syslog(MS_DHCP | LOG_WARNING, 
 			_("no address range available for DHCPv6 request from relay at %s"),
 			daemon->addrbuff);
@@ -194,6 +194,8 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  return 0;
 	}
 
+      state->relay_address = link_address;
+
       return dhcp6_no_relay(state, msg_type, inbuff, sz, now);
     }
 
@@ -253,11 +255,12 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	      /* the packet data is unaligned, copy to aligned storage */
 	      memcpy(&align, inbuff + 2, IN6ADDRSZ); 
 
-
-	      /* RFC6221 para 4 */
-	      if (!IN6_IS_ADDR_UNSPECIFIED(&align))
-		state->link_address = &align;
-	      if (!dhcp6_maybe_relay(state, opt6_ptr(opt, 0), opt6_len(opt), client_addr, now))
+	      /* RFC6221 para 4 says if link_address in encapulation
+		 is zero, ignore it, and, by implication, use the link
+		 address of any enclosing encapsulation or, failing that
+		 of the arrival interface on the the server. */
+	      if (!dhcp6_maybe_relay(state, opt6_ptr(opt, 0), opt6_len(opt), client_addr,
+				     IN6_IS_ADDR_UNSPECIFIED(&align) ? link_address : &align, now))
 		return 0;
 	    }
 	  else
@@ -392,14 +395,28 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 	      if (opt6_len(opt) < 4)
 		continue;
 	      
-	      if (vendor->enterprise != opt6_uint(opt, 0, 4))
+	      if (vendor->enterprise != 0 && vendor->enterprise != opt6_uint(opt, 0, 4))
 		continue;
-	    
+
+	      /* matching enterprise, no string match. */
+	      if (vendor->enterprise != 0 && vendor->len == 0)
+		{
+		  vendor->netid.next = state->tags;
+		  state->tags = &vendor->netid;
+		  break;
+		}
+	      
 	      offset = 4;
+
+	      /* If we're going to search the strings below, there must be at least one empty string to search
+		 I think a vendor_class option with just the enterprise number is valid. */
+	      if (opt6_len(opt) < 6)
+		continue;
 	    }
- 
-	  /* Note that format if user/vendor classes is different to DHCP options - no option types. */
-	  for (enc_opt = opt6_ptr(opt, offset); enc_opt; enc_opt = opt6_user_vendor_next(enc_opt, enc_end))
+
+       	  /* Note that format if user/vendor classes is different to DHCP options - no option types. */
+	  for (enc_opt = opt6_user_vendor_first(opt6_ptr(opt, offset), enc_end);
+	       enc_opt; enc_opt = opt6_user_vendor_next(enc_opt, enc_end))
 	    for (i = 0; i <= (opt6_user_vendor_len(enc_opt) - vendor->len); i++)
 	      if (memcmp(vendor->data, opt6_user_vendor_ptr(enc_opt, i), vendor->len) == 0)
 		{
@@ -457,10 +474,8 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
   if (state->mac_len != 0)
     {
       if (option_bool(OPT_LOG_OPTS))
-	{
-	  print_mac(daemon->dhcp_buff, state->mac, state->mac_len);
-	  my_syslog(MS_DHCP | LOG_INFO, _("%u client MAC address: %s"), state->xid, daemon->dhcp_buff);
-	}
+	my_syslog(MS_DHCP | LOG_INFO, _("%u client MAC address: %s"), state->xid,
+		  print_mac(state->mac, state->mac_len));
 
       for (mac_opt = daemon->dhcp_macs; mac_opt; mac_opt = mac_opt->next)
 	if ((unsigned)mac_opt->hwaddr_len == state->mac_len &&
@@ -662,7 +677,7 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 	for (c = state->context; c; c = c->current)
 	  c->flags &= ~CONTEXT_CONF_USED;
 
-	for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
+	for (opt = opt6_first(state->packet_options, state->end); opt; opt = opt6_next(opt, state->end))
 	  {   
 	    void *ia_option, *ia_end;
 	    unsigned int min_time = 0xffffffff;
@@ -826,7 +841,7 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 	if (ignore)
 	  return 0;
 	
-	for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
+	for (opt = opt6_first(state->packet_options, state->end); opt; opt = opt6_next(opt, state->end))
 	  {   
 	    void *ia_option, *ia_end;
 	    unsigned int min_time = 0xffffffff;
@@ -937,7 +952,7 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 	
 	log6_quiet(state, msg_type == DHCP6RENEW ? "DHCPRENEW" : "DHCPREBIND", NULL, NULL);
 
-	for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
+	for (opt = opt6_first(state->packet_options, state->end); opt; opt = opt6_next(opt, state->end))
 	  {
 	    void *ia_option, *ia_end;
 	    unsigned int min_time = 0xffffffff;
@@ -1072,7 +1087,7 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 	
 	log6_quiet(state, "DHCPCONFIRM", NULL, NULL);
 	
-	for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
+	for (opt = opt6_first(state->packet_options, state->end); opt; opt = opt6_next(opt, state->end))
 	  {
 	    void *ia_option, *ia_end;
 	    
@@ -1148,7 +1163,7 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 
 	log6_quiet(state, "DHCPRELEASE", NULL, NULL);
 
-	for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
+	for (opt = opt6_first(state->packet_options, state->end); opt; opt = opt6_next(opt, state->end))
 	  {
 	    void *ia_option, *ia_end;
 	    int made_ia = 0;
@@ -1213,7 +1228,7 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 	
 	log6_quiet(state, "DHCPDECLINE", NULL, NULL);
 
-	for (opt = state->packet_options; opt; opt = opt6_next(opt, state->end))
+	for (opt = opt6_first(state->packet_options, state->end); opt; opt = opt6_next(opt, state->end))
 	  {
 	    void *ia_option, *ia_end;
 	    int made_ia = 0;
@@ -1519,7 +1534,7 @@ static struct dhcp_netid *add_options(struct state *state, int do_refresh)
       for (i = 0; i <  opt6_len(oro) - 1; i += 2)
 	{
 	  char *s = option_string(AF_INET6, opt6_uint(oro, i, 2), NULL, 0, NULL, 0);
-	  q += snprintf(q, MAXDNAME - (q - daemon->namebuff),
+	  q += snprintf(q, MAXDNAMESTR - (q - daemon->namebuff),
 			"%d%s%s%s", 
 			opt6_uint(oro, i, 2),
 			strlen(s) != 0 ? ":" : "",
@@ -1585,10 +1600,7 @@ static int check_ia(struct state *state, void *opt, void **endp, void **ia_optio
 {
   *ia_option = NULL;
 
-  /* must be a minimal option to check without stepping outside received packet. */
-  if (opt6_ptr(opt, 4) > state->end)
-    return 0;
-  
+  /* callee ensures packet is long enough for opt6_len(opt) to be valid and believe-able. */
   state->ia_type = opt6_type(opt);
   
   if (state->ia_type != OPTION6_IA_NA && state->ia_type != OPTION6_IA_TA)
@@ -1600,10 +1612,7 @@ static int check_ia(struct state *state, void *opt, void **endp, void **ia_optio
   if (state->ia_type == OPTION6_IA_TA && opt6_len(opt) < 4)
     return 0;
   
-  /* Check we don't overflow the received packet. */
-  if ((*endp = opt6_ptr(opt, opt6_len(opt))) > state->end)
-    return 0;
-  
+  *endp = opt6_ptr(opt, opt6_len(opt));
   state->iaid = opt6_uint(opt, 0, 4);
   *ia_option = opt6_find(opt6_ptr(opt, state->ia_type == OPTION6_IA_NA ? 12 : 4), *endp, OPTION6_IAADDR, 24);
 
@@ -1918,10 +1927,11 @@ static void update_leases(struct state *state, struct dhcp_context *context, str
 	      lease_add_extradata(lease, (unsigned char *)daemon->dhcp_buff2, strlen(daemon->dhcp_buff2), 0);
 	      
 	      if (opt6_len(opt) >= 6) 
-		for (enc_opt = opt6_ptr(opt, 4); enc_opt; enc_opt = opt6_next(enc_opt, enc_end))
+		for (enc_opt = opt6_user_vendor_first(opt6_ptr(opt, 4), enc_end);
+		     enc_opt; enc_opt = opt6_user_vendor_next(enc_opt, enc_end))
 		  {
 		    lease->vendorclass_count++;
-		    lease_add_extradata(lease, opt6_ptr(enc_opt, 0), opt6_len(enc_opt), 0);
+		    lease_add_extradata(lease, opt6_user_vendor_ptr(enc_opt, 0), opt6_user_vendor_len(enc_opt), 0);
 		  }
 	    }
 	  
@@ -1970,16 +1980,17 @@ static void update_leases(struct state *state, struct dhcp_context *context, str
 		}
 	    }
 	  
-	  if (state->link_address)
-	    inet_ntop(AF_INET6, state->link_address, daemon->addrbuff, ADDRSTRLEN);
+	  if (state->relay_address)
+	    inet_ntop(AF_INET6, state->relay_address, daemon->addrbuff, ADDRSTRLEN);
 	  
-	  lease_add_extradata(lease, (unsigned char *)daemon->addrbuff, state->link_address ? strlen(daemon->addrbuff) : 0, 0);
+	  lease_add_extradata(lease, (unsigned char *)daemon->addrbuff, state->relay_address ? strlen(daemon->addrbuff) : 0, 0);
 	  
 	  if ((opt = opt6_find(state->packet_options, state->end, OPTION6_USER_CLASS, 2)))
 	    {
 	      void *enc_opt, *enc_end = opt6_ptr(opt, opt6_len(opt));
-	      for (enc_opt = opt6_ptr(opt, 0); enc_opt; enc_opt = opt6_next(enc_opt, enc_end))
-		lease_add_extradata(lease, opt6_ptr(enc_opt, 0), opt6_len(enc_opt), 0);
+	      for (enc_opt = opt6_user_vendor_first(opt6_ptr(opt, 0), enc_end);
+		   enc_opt; enc_opt = opt6_user_vendor_next(enc_opt, enc_end))
+		lease_add_extradata(lease, opt6_user_vendor_ptr(enc_opt, 0), opt6_user_vendor_len(enc_opt), 0);
 	    }
 	}
 #endif	
@@ -1994,10 +2005,10 @@ static void log6_opts(int nest, unsigned int xid, void *start_opts, void *end_op
   void *opt;
   char *desc = nest ? "nest" : "sent";
   
-  if (!option_bool(OPT_LOG_OPTS) || start_opts == end_opts)
+  if (!option_bool(OPT_LOG_OPTS))
     return;
   
-  for (opt = start_opts; opt; opt = opt6_next(opt, end_opts))
+  for (opt = opt6_first(start_opts, end_opts); opt; opt = opt6_next(opt, end_opts))
     {
       int type = opt6_type(opt);
       void *ia_options = NULL;
@@ -2030,16 +2041,22 @@ static void log6_opts(int nest, unsigned int xid, void *start_opts, void *end_op
 	}
       else if (type == OPTION6_STATUS_CODE)
 	{
-	  int len = sprintf(daemon->namebuff, "%u ", opt6_uint(opt, 0, 2));
-	  memcpy(daemon->namebuff + len, opt6_ptr(opt, 2), opt6_len(opt)-2);
-	  daemon->namebuff[len + opt6_len(opt) - 2] = 0;
+	  if (opt6_len(opt) >= 2)
+	    {
+	      int slen = opt6_len(opt) - 2;
+	      int len = sprintf(daemon->namebuff, "%u ", opt6_uint(opt, 0, 2));
+	      if (slen > (MAXDNAMESTR) - len - 1)
+		slen = (MAXDNAMESTR) - len - 1;
+	      memcpy(daemon->namebuff + len, opt6_ptr(opt, 2), slen);
+	      daemon->namebuff[len + slen] = 0;
+	    }
 	  optname = "status";
 	}
       else
 	{
 	  /* account for flag byte on FQDN */
 	  int offset = type == OPTION6_FQDN ? 1 : 0;
-	  optname = option_string(AF_INET6, type, opt6_ptr(opt, offset), opt6_len(opt) - offset, daemon->namebuff, MAXDNAME);
+	  optname = option_string(AF_INET6, type, opt6_ptr(opt, offset), opt6_len(opt) - offset, daemon->namebuff, MAXDNAMESTR);
 	}
       
       my_syslog(MS_DHCP | LOG_INFO, "%u %s size:%3d option:%3d %s  %s", 
@@ -2058,14 +2075,6 @@ static void log6_quiet(struct state *state, char *type, struct in6_addr *addr, c
 
 static void log6_packet(struct state *state, char *type, struct in6_addr *addr, char *string)
 {
-  int clid_len = state->clid_len;
-
-  /* avoid buffer overflow */
-  if (clid_len > 100)
-    clid_len = 100;
-  
-  print_mac(daemon->namebuff, state->clid, clid_len);
-
   if (addr)
     {
       inet_ntop(AF_INET6, addr, daemon->dhcp_buff2, DHCP_BUFF_SZ - 1);
@@ -2080,46 +2089,31 @@ static void log6_packet(struct state *state, char *type, struct in6_addr *addr,
 	      type,
 	      state->iface_name, 
 	      daemon->dhcp_buff2,
-	      daemon->namebuff,
+	      print_mac(state->clid, state->clid_len),
 	      string ? string : "");
   else
     my_syslog(MS_DHCP | LOG_INFO, "%s(%s) %s%s %s",
 	      type,
 	      state->iface_name, 
 	      daemon->dhcp_buff2,
-	      daemon->namebuff,
+	      print_mac(state->clid, state->clid_len),
 	      string ? string : "");
 }
 
-static void *opt6_find (uint8_t *opts, uint8_t *end, unsigned int search, unsigned int minsize)
+static void *opt6_find(uint8_t *opts, uint8_t *end, unsigned int search, int minsize)
 {
-  u16 opt, opt_len;
-  void *start;
-  
-  if (!opts)
-    return NULL;
-    
-  while (1)
-    {
-      if (end - opts < 4) 
-	return NULL;
-      
-      start = opts;
-      GETSHORT(opt, opts);
-      GETSHORT(opt_len, opts);
-      
-      if (opt_len > (end - opts))
-	return NULL;
-      
-      if (opt == search && (opt_len >= minsize))
-	return start;
-      
-      opts += opt_len;
-    }
+  for (opts = opt6_first(opts, end); opts; opts = opt6_next(opts, end))
+    if (opt6_type(opts) == search && opt6_len(opts) >= minsize)
+      return opts;
+
+  return NULL;
 }
 
 static void *opt6_first(uint8_t *opt, uint8_t *end)
 {
+  if (!opt)
+    return NULL;
+
   /* make sure we have option number and length. */
   if ((uint8_t *)opt6_ptr(opt, 0) > end)
     return NULL;
@@ -2130,21 +2124,21 @@ static void *opt6_first(uint8_t *opt, uint8_t *end)
 
   return opt;
 }
-  
-static void *opt6_next(uint8_t *opts, uint8_t *end)
+
+static void *opt6_user_vendor_first(uint8_t *opt, uint8_t *end)
 {
-  u16 opt_len;
-  
-  if (end - opts < 4) 
+  if (!opt)
     return NULL;
-  
-  opts += 2;
-  GETSHORT(opt_len, opts);
-  
-  if (opt_len >= (end - opts))
+
+  /* make sure we have length. */
+  if ((uint8_t *)opt6_user_vendor_ptr(opt, 0) > end)
     return NULL;
-  
-  return opts + opt_len;
+
+  /* make sure we have bytes promised by length. */
+  if ((uint8_t *)opt6_user_vendor_ptr(opt, opt6_user_vendor_len(opt)) > end)
+    return NULL;
+
+  return opt;
 }
 
 static unsigned int opt6_uint(unsigned char *opt, int offset, int size)
@@ -2160,12 +2154,12 @@ static unsigned int opt6_uint(unsigned char *opt, int offset, int size)
   return ret;
 } 
 
+/* return 0 if we're not configured to relay. */
 int relay_upstream6(int iface_index, ssize_t sz, 
 		    struct in6_addr *peer_address, u32 scope_id, time_t now)
 {
   unsigned char *header;
   unsigned char *inbuff = daemon->dhcp_packet.iov_base;
-  int msg_type = *inbuff;
   int hopcount, o;
   struct in6_addr multicast;
   unsigned int maclen, mactype;
@@ -2182,10 +2176,22 @@ int relay_upstream6(int iface_index, ssize_t sz,
   
   inet_pton(AF_INET6, ALL_SERVERS, &multicast);
   get_client_mac(peer_address, scope_id, mac, &maclen, &mactype, now);
+
+  /* We need at least four bytes for valid client/server message
+     (type, and transaction ID) A relay-originated message needs more. */
+  if (sz < 4)
+    return 1;
   
-  /* Get hop count from nested relayed message */ 
-  if (msg_type == DHCP6RELAYFORW)
-    hopcount = *((unsigned char *)inbuff+1) + 1;
+  if (inbuff[0] == DHCP6RELAYFORW)
+    {
+      /* must have at least msg_type+hopcount+link_address+peer_address+minimal size option
+	 which is               1   +    1   +    16      +     16     + 2 + 2 = 38 */
+      if (sz < 38)
+	return 1;
+      
+      /* Get hop count from nested relayed message. */
+      hopcount = inbuff[1] + 1;
+    }
   else
     hopcount = 0;
 
@@ -2251,7 +2257,7 @@ int relay_upstream6(int iface_index, ssize_t sz,
 	  {
 	    inet_ntop(AF_INET6, &relay->local, daemon->addrbuff, ADDRSTRLEN);
 	    if (IN6_ARE_ADDR_EQUAL(&relay->server.addr6, &multicast))
-	      snprintf(daemon->namebuff, MAXDNAME, _("multicast via %s"), relay->interface);
+	      snprintf(daemon->namebuff, MAXDNAMESTR, _("multicast via %s"), relay->interface);
 	    else
 	      inet_ntop(AF_INET6, &relay->server, daemon->namebuff, ADDRSTRLEN);
 	    my_syslog(MS_DHCP | LOG_INFO, _("DHCP relay at %s -> %s"), daemon->addrbuff, daemon->namebuff);

src/rrfilter.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -344,14 +344,6 @@ short *rrfilter_desc(int type)
    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 declared as 2049 (allowing for the trailing zero) 
-   for this reason.
 */
 int to_wire(char *name)
 {
@@ -397,14 +389,17 @@ void from_wire(char *name)
       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)++;
-	  }
-	
+	{
+	  unsigned char c = *p;
+	  if (IS_NAME_ESCAPE(c))
+	    {
+	      memmove(p+1, p, 1 + last - p);
+	      last++;
+	      len++;
+	      *p++ = NAME_ESCAPE; 
+	      (*p)++;
+	    }
+	}
       l[len] = '.';
     }
 

src/slaac.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/tftp.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -434,17 +434,17 @@ static void tftp_request(char *packet, ssize_t plen, struct listener *listen, ti
 	    {
 	      if (prefix[0] == '/')
 		daemon->namebuff[0] = 0;
-	      strncat(daemon->namebuff, prefix, (MAXDNAME-1) - strlen(daemon->namebuff));
+	      strncat(daemon->namebuff, prefix, MAXDNAMESTR - strlen(daemon->namebuff));
 	      if (prefix[strlen(prefix)-1] != '/')
-		strncat(daemon->namebuff, "/", (MAXDNAME-1) - strlen(daemon->namebuff));
+		strncat(daemon->namebuff, "/", MAXDNAMESTR - strlen(daemon->namebuff));
 	      
 	      if (option_bool(OPT_TFTP_APREF_IP))
 		{
 		  size_t oldlen = strlen(daemon->namebuff);
 		  struct stat statbuf;
 		  
-		  strncat(daemon->namebuff, daemon->addrbuff, (MAXDNAME-1) - strlen(daemon->namebuff));
-		  strncat(daemon->namebuff, "/", (MAXDNAME-1) - strlen(daemon->namebuff));
+		  strncat(daemon->namebuff, daemon->addrbuff, MAXDNAMESTR - strlen(daemon->namebuff));
+		  strncat(daemon->namebuff, "/", MAXDNAMESTR - strlen(daemon->namebuff));
 		  
 		  /* remove unique-directory if it doesn't exist */
 		  if (stat(daemon->namebuff, &statbuf) == -1 || !S_ISDIR(statbuf.st_mode))
@@ -475,7 +475,7 @@ static void tftp_request(char *packet, ssize_t plen, struct listener *listen, ti
 		      size_t oldlen = strlen(daemon->namebuff);
 		      struct stat statbuf;
 		      
-		      snprintf(daemon->namebuff + oldlen, (MAXDNAME-1) - oldlen, "%.2x-%.2x-%.2x-%.2x-%.2x-%.2x/",
+		      snprintf(daemon->namebuff + oldlen, MAXDNAMESTR - oldlen, "%.2x-%.2x-%.2x-%.2x-%.2x-%.2x/",
 			       macaddr[0], macaddr[1], macaddr[2], macaddr[3], macaddr[4], macaddr[5]);
 		      
 		      /* remove unique-directory if it doesn't exist */
@@ -495,7 +495,7 @@ static void tftp_request(char *packet, ssize_t plen, struct listener *listen, ti
 	    }
 	  else if (filename[0] == '/')
 	    daemon->namebuff[0] = 0;
-	  strncat(daemon->namebuff, filename, (MAXDNAME-1) - strlen(daemon->namebuff));
+	  strncat(daemon->namebuff, filename, MAXDNAMESTR - strlen(daemon->namebuff));
 	  
 	  /* check permissions and open file */
 	  if ((transfer->file = check_tftp_fileperm(packet, &len, prefix, daemon->addrbuff)))
@@ -545,8 +545,13 @@ static struct tftp_file *check_tftp_fileperm(char *packet, ssize_t *len, char *p
   int fd = -1;
 
   /* trick to ban moving out of the subtree */
-  if (prefix && strstr(namebuff, "/../"))
-    goto perm;
+  if (prefix)
+    {
+      char *suspect = strstr(namebuff, "/..");
+
+      if (suspect && (suspect[3] == '/' || suspect[3] == 0))
+        goto perm;
+    }
   
   if ((fd = open(namebuff, O_RDONLY)) == -1)
     {
@@ -622,7 +627,7 @@ void check_tftp_listeners(time_t now)
 {
   /* Use workspace to receive (small) request/ACK, to avoid overwriting precomputed reply */
   char *packet = daemon->workspacename;
-  ssize_t plen = MAXDNAME * 2;
+  ssize_t plen = MAXDNAMESTR;
   struct listener *listener;
   struct tftp_transfer *transfer, *tmp, **up;
   

src/ubus.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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

src/util.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 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
@@ -105,8 +105,6 @@ u32 rand32(void)
 
 u64 rand64(void)
 {
-  static int outleft = 0;
-
   if (outleft < 2)
     {
       if (!++in[0]) if (!++in[1]) if (!++in[2]) ++in[3];
@@ -138,14 +136,15 @@ static int check_name(char *in)
 {
   /* remove trailing . 
      also fail empty string and label > 63 chars */
-  size_t dotgap = 0, l = strlen(in);
+  size_t dotgap = 0, wiresize = 0, l = strlen(in);
   char c;
   int nowhite = 0;
   int idn_encode = 0;
   int hasuscore = 0;
   int hasucase = 0;
   
-  if (l == 0 || l > MAXDNAME) return 0;
+  if (l == 0)
+    return 0;
   
   if (in[l-1] == '.')
     {
@@ -156,7 +155,10 @@ static int check_name(char *in)
   for (; (c = *in); in++)
     {
       if (c == '.')
-        dotgap = 0;
+        {
+	  wiresize += dotgap + 1;
+	  dotgap = 0;
+	}
       else if (++dotgap > MAXLABEL)
         return 0;
       else if (isascii((unsigned char)c) && iscntrl((unsigned char)c)) 
@@ -198,6 +200,10 @@ static int check_name(char *in)
   idn_encode = idn_encode || hasucase;
 #endif
 
+ /* length of final label and terminaton added */
+  if (!idn_encode && wiresize + dotgap + 2 >  MAXDNAME)
+    return 0; /* wire representation too long */
+
   return (idn_encode) ? 2 : 1;
 }
 
@@ -285,20 +291,24 @@ char *canonicalise(char *in, int *nomem)
   return ret;
 }
 
-unsigned char *do_rfc1035_name(unsigned char *p, char *sval, char *limit)
+unsigned char *do_rfc1035_name(unsigned char *p, char *sval, unsigned char *limit)
 {
   int j;
+
+  /* Never make a name larger than the RFC limit */
+  if (!limit || (limit - p > MAXDNAME))
+    limit = p + MAXDNAME;
   
   while (sval && *sval)
     {
       unsigned char *cp = p++;
 
-      if (limit && p > (unsigned char*)limit)
+      if (p > limit)
         return NULL;
 
       for (j = 0; *sval && (*sval != '.'); sval++, j++)
 	{
-          if (limit && p + 1 > (unsigned char*)limit)
+          if (p + 1 > limit)
             return NULL;
 
 	  if (*sval == NAME_ESCAPE)
@@ -429,10 +439,14 @@ int hostname_issubdomain(char *a, char *b)
   for (ap = a; *ap; ap++); 
   for (bp = b; *bp; bp++);
 
-  /* a shorter than b */
-  if ((ap - a) < (bp - b))
+  /* anything is a subdomain of the root domain. */
+  if (ap == a)
+    return (bp == b) ? 2 : 1;
+  
+  /* b shorter than a */
+  if ((bp - b) < (ap - a))
     return 0;
-
+  
   do
     {
       c1 = (unsigned char) *(--ap);
@@ -445,18 +459,17 @@ int hostname_issubdomain(char *a, char *b)
 
        if (c1 != c2)
 	 return 0;
-    } while (bp != b);
+    } while (ap != a);
 
-  if (ap == a)
+  if (bp == b)
     return 2;
 
-  if (*(--ap) == '.')
+  if (*(--bp) == '.')
     return 1;
 
   return 0;
 }
  
-  
 time_t dnsmasq_time(void)
 {
 #ifdef HAVE_BROKEN_RTC
@@ -581,6 +594,7 @@ void prettyprint_time(char *buf, unsigned int t)
   else
     {
       unsigned int x, p = 0;
+      buf[0] = '\0';
        if ((x = t/86400))
 	p += sprintf(&buf[p], "%ud", x);
        if ((x = (t/3600)%24))
@@ -678,18 +692,24 @@ int memcmp_masked(unsigned char *a, unsigned char *b, int len, unsigned int mask
   return count;
 }
 
-char *print_mac(char *buff, unsigned char *mac, int len)
+char *print_mac(unsigned char *mac, int len)
 {
-  char *p = buff;
-  int i;
-   
-  if (len == 0)
-    sprintf(p, "<null>");
-  else
-    for (i = 0; i < len; i++)
-      p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":");
+  static struct iovec buff = { NULL, 0 };
   
-  return buff;
+  /* each byte is two digits plus ':' except that last
+     which is two digits plus terminator. */
+  if (len == 0 || !expand_buf(&buff, len*3))
+    return "<null>";
+  else
+    {
+      char *p =  buff.iov_base;
+      int i;
+
+      for (i = 0; i < len; i++)
+	p += sprintf(p, "%.2x%s", mac[i], (i == len - 1) ? "" : ":");
+    }
+  
+  return buff.iov_base;
 }
 
 /* rc is return from sendto and friends.
@@ -991,7 +1011,7 @@ int expand_workspace_real(const char *func, unsigned int line, unsigned char ***
   if (!(p = whine_realloc_real("expand_workspace", func, line, *wkspc, new * sizeof(unsigned char *))))
     return 0;
 
-  memset(p+old, 0, new-old);
+  memset(p+old, 0, (new-old) * sizeof(unsigned char *));
   
   *wkspc = p;
   *szp = new;
@@ -1016,3 +1036,54 @@ void free_real(const char *func, unsigned int line, void *ptr)
       free(ptr);
     }
 }
+
+/* get lines from f, expand buffer as required. Buffer is freed when
+   EOF reached and we return zero. */
+int get_line_alloc(FILE *f, char **buffp, size_t *sizep)
+{
+  char c;
+  size_t cnt = 0;
+  char *buff = *buffp;
+  
+  while (1) {
+    c = getc(f);
+
+    if (cnt == *sizep)
+      {
+	void *new;
+	
+	if ((new = whine_realloc(buff, cnt + 1024)))
+	  {
+	    buff = *buffp = new;
+	    *sizep = cnt + 1024; 
+	  }
+	else
+	  {
+	    /* allocation failed, ignore line.
+	       Whine_realloc will have complained. */
+	    while (c != '\n' && c != EOF) 
+	      c = getc(f);
+	    
+	    cnt = 0;
+	    continue;
+	  }
+      }
+
+    buff[cnt] = 0;
+
+    if (c == '\n')
+      return 1;
+    
+    if (c == EOF)
+      {
+	/* handle last line without '\n' */
+	if (cnt != 0)
+	  return 1;
+
+	free(buff);
+	return 0;
+      }
+	
+    buff[cnt++] = c;
+  }
+}