Better fix than f2266d9678

Spotted by Max Julian Hofmann and the Advanced Research Team at CrowdStrike

CHANGELOG

@@ -76,6 +76,12 @@ version 2.86
 	Disallowed queries are not forwarded; they are rejected
 	with a REFUSED error code.
 
+	Allow smaller then 64 prefix lengths in synth-domain, with caveats.
+	--synth-domain=1234:4567::/56,example.com is now valid.
+
+	Make domains generated by --synth-domain appear in replies
+	when in authoritative mode.
+
 	
 version 2.85
         Fix problem with DNS retries in 2.83/2.84.

man/dnsmasq.8

@@ -705,7 +705,8 @@ configured a zero is added in front of the label. ::1 becomes 0--1.
 V4 mapped IPv6 addresses, which have a representation like ::ffff:1.2.3.4 are handled specially, and become like 0--ffff-1-2-3-4
 
 The address range can be of the form
-<ip address>,<ip address> or <ip address>/<netmask> in both forms of the option.
+<start address>,<end address> or <ip address>/<prefix-length> in both forms of the option. For IPv6 the start and end addresses
+must fall in the same /64 network, or prefix-length must be greater than or equal to 64 except that shorter prefix lengths than 64 are allowed only if non-sequential names are in use.
 .TP
 .B --dumpfile=<path/to/file>
 Specify the location of a pcap-format file which dnsmasq uses to dump copies of network packets for debugging purposes. If the file exists when dnsmasq starts, it is not deleted; new packets are added to the end.
@@ -1612,10 +1613,11 @@ tried. This flag disables this check. Use with caution.
 Extra logging for DHCP: log all the options sent to DHCP clients and
 the tags used to determine them.
 .TP
-.B --quiet-dhcp, --quiet-dhcp6, --quiet-ra
+.B --quiet-dhcp, --quiet-dhcp6, --quiet-ra, --quiet-tftp
 Suppress logging of the routine operation of these protocols. Errors and
-problems will still be logged. \fB--quiet-dhcp\fP and quiet-dhcp6 are
-over-ridden by \fB--log-dhcp\fP.
+problems will still be logged. \fB--quiet-tftp\fP does not consider file not
+found to be an error. \fB--quiet-dhcp\fP and quiet-dhcp6 are over-ridden by
+\fB--log-dhcp\fP.
 .TP
 .B \-l, --dhcp-leasefile=<path>
 Use the specified file to store DHCP lease information.
@@ -2417,6 +2419,10 @@ following data is used to populate the authoritative zone.
 .B --mx-host, --srv-host, --dns-rr, --txt-record, --naptr-record, --caa-record,
 as long as the record names are in the authoritative domain.
 .PP
+.B --synth-domain
+as long as the domain is in the authoritative zone and, for
+reverse (PTR) queries, the address is in the relevant subnet.
+.PP
 .B --cname
 as long as the record name is in  the authoritative domain. If the
 target of the CNAME is unqualified, then it  is qualified with the

src/auth.c

@@ -105,7 +105,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
   int nameoffset, axfroffset = 0;
   int q, anscount = 0, authcount = 0;
   struct crec *crecp;
-  int  auth = !local_query, trunc = 0, nxdomain = 1, soa = 0, ns = 0, axfr = 0;
+  int  auth = !local_query, trunc = 0, nxdomain = 1, soa = 0, ns = 0, axfr = 0, out_of_zone = 0;
   struct auth_zone *zone = NULL;
   struct addrlist *subnet = NULL;
   char *cut;
@@ -146,6 +146,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
       if (qclass != C_IN)
 	{
 	  auth = 0;
+	  out_of_zone = 1;
 	  continue;
 	}
 
@@ -159,6 +160,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 	  
 	  if (!zone)
 	    {
+	      out_of_zone = 1;
 	      auth = 0;
 	      continue;
 	    }
@@ -253,6 +255,17 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 		    
 	    } while ((crecp = cache_find_by_addr(crecp, &addr, now, flag)));
 
+	  if (!found && is_rev_synth(flag, &addr, name) && (local_query || in_zone(zone, name, NULL)))
+	    {
+	      log_query(F_CONFIG | F_REVERSE | flag, name, &addr, NULL); 
+	      found = 1;
+	      
+	      if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
+				      daemon->auth_ttl, NULL,
+				      T_PTR, C_IN, "d", name))
+		anscount++;
+	    }
+
 	  if (found)
 	    nxdomain = 0;
 	  else
@@ -273,6 +286,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 	  
 	  if (!zone)
 	    {
+	      out_of_zone = 1;
 	      auth = 0;
 	      continue;
 	    }
@@ -400,6 +414,17 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 		       anscount++;
 		   }
 	     }
+
+       if (!found && is_name_synthetic(flag, name, &addr) )
+	 {
+	   found = 1;
+	   nxdomain = 0;
+	   
+	   log_query(F_FORWARD | F_CONFIG | flag, name, &addr, NULL);
+	   if (add_resource_record(header, limit, &trunc, nameoffset, &ansp, 
+				   daemon->auth_ttl, NULL, qtype, C_IN, qtype == T_A ? "4" : "6", &addr))
+	     anscount++;
+	 }
        
       if (!cut)
 	{
@@ -855,10 +880,22 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
     SET_RCODE(header, NXDOMAIN);
   else
     SET_RCODE(header, NOERROR); /* no error */
+  
   header->ancount = htons(anscount);
   header->nscount = htons(authcount);
   header->arcount = htons(0);
 
+  if (!local_query && out_of_zone)
+    {
+      SET_RCODE(header, REFUSED); 
+      header->ancount = htons(0);
+      header->nscount = htons(0);
+      addr.log.rcode = REFUSED;
+      addr.log.ede = EDE_NOT_AUTH;
+      log_query(F_UPSTREAM | F_RCODE, "error", &addr, NULL);
+      return resize_packet(header,  ansp - (unsigned char *)header, NULL, 0);
+    }
+  
   /* Advertise our packet size limit in our reply */
   if (have_pseudoheader)
     return add_pseudoheader(header,  ansp - (unsigned char *)header, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit, 0);

src/cache.c

@@ -1974,7 +1974,7 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg)
     source = "reply";
   else if (flags & F_SECSTAT)
     {
-      if (addr && addr->log.ede != EDE_UNSET)
+      if (addr && addr->log.ede != EDE_UNSET && option_bool(OPT_EXTRALOG))
 	{
 	  extra = daemon->addrbuff;
 	  sprintf(extra, " (EDE: %s)", edestr(addr->log.ede));
@@ -2023,5 +2023,5 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg)
 	}
     }
   else
-    my_syslog(LOG_INFO, "%s %s %s %s", source, name, verb, dest);
+    my_syslog(LOG_INFO, "%s %s %s %s%s", source, name, verb, dest, extra);
 }

src/dnsmasq.h

@@ -107,6 +107,7 @@ typedef unsigned long long u64;
 #endif
 #include <unistd.h>
 #include <stdio.h>
+#include <stdint.h>
 #include <string.h>
 #include <stdlib.h>
 #include <fcntl.h>
@@ -273,7 +274,8 @@ struct event_desc {
 #define OPT_UMBRELLA       63
 #define OPT_UMBRELLA_DEVID 64
 #define OPT_CMARK_ALST_EN  65
-#define OPT_LAST           66
+#define OPT_QUIET_TFTP     66
+#define OPT_LAST           67
 
 #define OPTION_BITS (sizeof(unsigned int)*8)
 #define OPTION_SIZE ( (OPT_LAST/OPTION_BITS)+((OPT_LAST%OPTION_BITS)!=0) )
@@ -959,10 +961,10 @@ struct dhcp_bridge {
 };
 
 struct cond_domain {
-  char *domain, *prefix;
+  char *domain, *prefix; /* prefix is text-prefix on domain name */
   struct in_addr start, end;
   struct in6_addr start6, end6;
-  int is6, indexed;
+  int is6, indexed, prefixlen;
   struct cond_domain *next;
 }; 
 

src/domain.c

@@ -18,8 +18,9 @@
 
 
 static struct cond_domain *search_domain(struct in_addr addr, struct cond_domain *c);
+static int match_domain(struct in_addr addr, struct cond_domain *c);
 static struct cond_domain *search_domain6(struct in6_addr *addr, struct cond_domain *c);
-
+static int match_domain6(struct in6_addr *addr, struct cond_domain *c);
 
 int is_name_synthetic(int flags, char *name, union all_addr *addr)
 {
@@ -135,28 +136,9 @@ int is_name_synthetic(int flags, char *name, union all_addr *addr)
 	    }
 	  
 	  if (hostname_isequal(c->domain, p+1) && inet_pton(prot, tail, addr))
-	    {
-	      if (prot == AF_INET)
-		{
-		  if (!c->is6 &&
-		      ntohl(addr->addr4.s_addr) >= ntohl(c->start.s_addr) &&
-		      ntohl(addr->addr4.s_addr) <= ntohl(c->end.s_addr))
-		    found = 1;
-		}
-	      else
-		{
-		  u64 addrpart = addr6part(&addr->addr6);
-		  
-		  if (c->is6 &&
-		      is_same_net6(&addr->addr6, &c->start6, 64) &&
-		      addrpart >= addr6part(&c->start6) &&
-		      addrpart <= addr6part(&c->end6))
-		    found = 1;
-		}
-	    }
-
+	    found = (prot == AF_INET) ? match_domain(addr->addr4, c) : match_domain6(&addr->addr6, c);
 	}
-
+      
       /* restore name */
       for (p = tail; *p; p++)
 	if (*p == '.' || *p == ':')
@@ -246,14 +228,22 @@ int is_rev_synth(int flag, union all_addr *addr, char *name)
 }
 
 
+static int match_domain(struct in_addr addr, struct cond_domain *c)
+{
+  if (!c->is6 &&
+      ntohl(addr.s_addr) >= ntohl(c->start.s_addr) &&
+      ntohl(addr.s_addr) <= ntohl(c->end.s_addr))
+    return 1;
+
+  return 0;
+}
+
 static struct cond_domain *search_domain(struct in_addr addr, struct cond_domain *c)
 {
   for (; c; c = c->next)
-    if (!c->is6 &&
-	ntohl(addr.s_addr) >= ntohl(c->start.s_addr) &&
-        ntohl(addr.s_addr) <= ntohl(c->end.s_addr))
+    if (match_domain(addr, c))
       return c;
-
+  
   return NULL;
 }
 
@@ -267,16 +257,30 @@ char *get_domain(struct in_addr addr)
   return daemon->domain_suffix;
 } 
 
-
-static struct cond_domain *search_domain6(struct in6_addr *addr, struct cond_domain *c)
+static int match_domain6(struct in6_addr *addr, struct cond_domain *c)
 {
   u64 addrpart = addr6part(addr);
   
+  if (c->is6)
+    {
+      if (c->prefixlen >= 64)
+	{
+	  if (is_same_net6(addr, &c->start6, 64) &&
+	      addrpart >= addr6part(&c->start6) &&
+	      addrpart <= addr6part(&c->end6))
+	    return 1;
+	}
+      else if (is_same_net6(addr, &c->start6, c->prefixlen))
+	return 1;
+    }
+
+  return 0;
+}
+
+static struct cond_domain *search_domain6(struct in6_addr *addr, struct cond_domain *c)
+{
   for (; c; c = c->next)
-    if (c->is6 &&
-	is_same_net6(addr, &c->start6, 64) &&
-	addrpart >= addr6part(&c->start6) &&
-        addrpart <= addr6part(&c->end6))
+    if (match_domain6(addr, c))
       return c;
   
   return NULL;

src/forward.c

@@ -537,7 +537,7 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 	{
 	  u16 swap = htons((u16)ede);
 
-	  if (ede != -EDE_UNSET)
+	  if (ede != EDE_UNSET)
 	    plen = add_pseudoheader(header, plen, (unsigned char *)limit, daemon->edns_pktsz, EDNS0_OPTION_EDE, (unsigned char *)&swap, 2, do_bit, 0);
 	  else
 	    plen = add_pseudoheader(header, plen, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit, 0);

src/option.c

@@ -173,6 +173,7 @@ struct myoption {
 #define LOPT_UMBRELLA	   364
 #define LOPT_CMARK_ALST_EN 365
 #define LOPT_CMARK_ALST    366
+#define LOPT_QUIET_TFTP    367
  
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
@@ -351,6 +352,7 @@ static const struct myoption opts[] =
     { "dynamic-host", 1, 0, LOPT_DYNHOST },
     { "log-debug", 0, 0, LOPT_LOG_DEBUG },
 	{ "umbrella", 2, 0, LOPT_UMBRELLA },
+    { "quiet-tftp", 0, 0, LOPT_QUIET_TFTP },
     { NULL, 0, 0, 0 }
   };
 
@@ -536,6 +538,7 @@ static struct {
   { LOPT_DUMPMASK, ARG_ONE, "<hex>", gettext_noop("Mask which packets to dump"), NULL },
   { LOPT_SCRIPT_TIME, OPT_LEASE_RENEW, NULL, gettext_noop("Call dhcp-script when lease expiry changes."), NULL },
   { LOPT_UMBRELLA, ARG_ONE, "[=<optspec>]", gettext_noop("Send Cisco Umbrella identifiers including remote IP."), NULL },
+  { LOPT_QUIET_TFTP, OPT_QUIET_TFTP, NULL, gettext_noop("Do not log routine TFTP."), NULL },
   { 0, 0, NULL, NULL, NULL }
 }; 
 
@@ -651,7 +654,7 @@ static char *canonicalise_opt(char *s)
     return 0;
 
   if (strlen(s) == 0)
-    return "";
+    return opt_string_alloc("");
 
   unhide_metas(s);
   if (!(ret = canonicalise(s, &nomem)) && nomem)
@@ -965,7 +968,7 @@ static int domain_rev6(char *domain, struct in6_addr *addr, int msize)
 {
   int i;
 
-  if (msize%4)
+  if (msize > 128 || msize%4)
     return 0;
   
   *domain = 0;
@@ -1185,11 +1188,15 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)
 	{
 	  new->u.vendor_class = (unsigned char *)opt_string_alloc(arg+7);
 	  new->flags |= DHOPT_VENDOR;
+	  if ((new->flags & DHOPT_ENCAPSULATE) || flags == DHOPT_MATCH)
+	    goto_err(_("inappropriate vendor:"));
 	}
       else if (strstr(arg, "encap:") == arg)
 	{
 	  new->u.encap = atoi(arg+6);
 	  new->flags |= DHOPT_ENCAPSULATE;
+	  if ((new->flags & DHOPT_VENDOR) || flags == DHOPT_MATCH)
+	    goto_err(_("inappropriate encap:"));
 	}
       else if (strstr(arg, "vi-encap:") == arg)
 	{
@@ -2224,7 +2231,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	  arg = comma;
 	  comma = split(arg);
 	  daemon->hostmaster = opt_string_alloc(arg);
-	  for (cp = daemon->hostmaster; *cp; cp++)
+	  for (cp = daemon->hostmaster; cp && *cp; cp++)
 	    if (*cp == '@')
 	      *cp = '.';
 
@@ -2254,10 +2261,11 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	{
 	  char *d, *d_raw = arg;
 	  comma = split(arg);
-	  if (!(d = canonicalise_opt(arg)))
+	  if (!(d = canonicalise_opt(d_raw)))
 	    ret_err(gen_err);
 	  else
 	    {
+	      free(d); /* allocate this again below. */
 	      if (comma)
 		{
 		  struct cond_domain *new = opt_malloc(sizeof(struct cond_domain));
@@ -2265,6 +2273,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		  
 		  new->prefix = NULL;
 		  new->indexed = 0;
+		  new->prefixlen = 0;
 		  
 		  unhide_metas(comma);
 		  if ((netpart = split_chr(comma, '/')))
@@ -2276,7 +2285,12 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			ret_err_free(gen_err, new);
 		      else if (inet_pton(AF_INET, comma, &new->start))
 			{
-			  int mask = (1 << (32 - msize)) - 1;
+			  int mask;
+
+			  if (msize > 32)
+			     ret_err_free(_("bad prefix length"), new);
+			  
+			  mask = (1 << (32 - msize)) - 1;
 			  new->is6 = 0; 			  
 			  new->start.s_addr = ntohl(htonl(new->start.s_addr) & ~mask);
 			  new->end.s_addr = new->start.s_addr | htonl(mask);
@@ -2307,21 +2321,25 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			}
 		      else if (inet_pton(AF_INET6, comma, &new->start6))
 			{
-			  u64 mask = (1LLU << (128 - msize)) - 1LLU;
-			  u64 addrpart = addr6part(&new->start6);
+			  u64 mask, addrpart = addr6part(&new->start6);
+
+			  if (msize > 128)
+			    ret_err_free(_("bad prefix length"), new);
+
+			  mask = (1LLU << (128 - msize)) - 1LLU;
+
 			  new->is6 = 1;
+			  new->prefixlen = msize;
 			  
 			  /* prefix==64 overflows the mask calculation above */
-			  if (msize == 64)
+			  if (msize <= 64)
 			    mask = (u64)-1LL;
 			  
 			  new->end6 = new->start6;
 			  setaddr6part(&new->start6, addrpart & ~mask);
 			  setaddr6part(&new->end6, addrpart | mask);
 			  
-			  if (msize < 64)
-			    ret_err_free(gen_err, new);
-			  else if (arg)
+			  if (arg)
 			    {
 			      if (option != 's')
 				{
@@ -2381,7 +2399,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			}
 		    }
 
-		  new->domain = d;
+		  new->domain = canonicalise_opt(d_raw);
 		  if (option  == 's')
 		    {
 		      new->next = daemon->cond_domain;
@@ -2390,19 +2408,21 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		  else
 		    {
 		      char *star;
-		      new->next = daemon->synth_domains;
-		      daemon->synth_domains = new;
 		      if (new->prefix &&
 			  (star = strrchr(new->prefix, '*'))
 			  && *(star+1) == 0)
 			{
 			  *star = 0;
 			  new->indexed = 1;
+			  if (new->is6 && new->prefixlen < 64)
+			    ret_err_free(_("prefix length too small"), new);
 			}
+		      new->next = daemon->synth_domains;
+		      daemon->synth_domains = new;
 		    }
 		}
 	      else if (option == 's')
-		daemon->domain_suffix = d;
+		daemon->domain_suffix = canonicalise_opt(d_raw);
 	      else 
 		ret_err(gen_err);
 	    }
@@ -4163,13 +4183,13 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	comma = split(arg);
 	new->interface = opt_string_alloc(split(comma));
 	new->iface_index = 0;
-	if (inet_pton(AF_INET, arg, &new->local) && inet_pton(AF_INET, comma, &new->server))
+	if (comma && inet_pton(AF_INET, arg, &new->local) && inet_pton(AF_INET, comma, &new->server))
 	  {
 	    new->next = daemon->relay4;
 	    daemon->relay4 = new;
 	  }
 #ifdef HAVE_DHCP6
-	else if (inet_pton(AF_INET6, arg, &new->local) && inet_pton(AF_INET6, comma, &new->server))
+	else if (comma && inet_pton(AF_INET6, arg, &new->local) && inet_pton(AF_INET6, comma, &new->server))
 	  {
 	    new->next = daemon->relay6;
 	    daemon->relay6 = new;

src/tftp.c

@@ -761,7 +761,8 @@ static ssize_t tftp_err(int err, char *packet, char *message, char *file)
   len = snprintf(mess->message, MAXMESSAGE,  message, file, errstr);
   ret += (len < MAXMESSAGE) ? len + 1 : MAXMESSAGE; /* include terminating zero */
   
-  my_syslog(MS_TFTP | LOG_ERR, "%s", mess->message);
+  if (err != ERR_FNF || !option_bool(OPT_QUIET_TFTP))
+    my_syslog(MS_TFTP | LOG_ERR, "%s", mess->message);
   
   return  ret;
 }