Segfault with some CNAMEs. Also memory leak on reload of /etc/hosts.

CHANGELOG

@@ -32,6 +32,12 @@ version 2.68
 	    the prefix is deleted (rather than replaced), it doesn't
 	    get advertised with zero preferred time. Thanks to Tsachi
 	    for the bug report. 
+
+	    Fix segfault with some locally configured CNAMEs. Thanks
+	    to Andrew Childs for spotting the problem.
+
+	    Fix memory leak on re-reading /etc/hosts and friends,
+	    introduced in 2.67.
  
 
 version 2.67

man/dnsmasq.8

@@ -199,7 +199,12 @@ or
 .B --listen-address
 configuration, indeed
 .B --auth-server
-will overide these and provide a different DNS service on the specified interface. The <domain> is the "glue record". It should resolve in the global DNS to a A and/or AAAA record which points to the address dnsmasq is listening on.
+will overide these and provide a different DNS service on the
+specified interface. The <domain> is the "glue record". It should
+resolve in the global DNS to a A and/or AAAA record which points to
+the address dnsmasq is listening on. When an interface is specified,
+it may be qualified with "/4" or "/6" to specify only the IPv4 or IPv6
+addresses associated with the interface.
 .TP 
 .B \-2, --no-dhcp-interface=<interface name>
 Do not provide DHCP or TFTP on the specified interface, but do provide DNS service.
@@ -509,11 +514,13 @@ record (which is always in the C_IN class). The value of the record is
 given by the hex data, which may be of the form 01:23:45 or 01 23 45 or
 012345 or any mixture of these.
 .TP
-.B --interface-name=<name>,<interface>
+.B --interface-name=<name>,<interface>[/4|/6]
 Return a DNS record associating the name with the primary address on
-the given interface. This flag specifies an A record for the given
+the given interface. This flag specifies an A or AAAA record for the given
 name in the same way as an /etc/hosts line, except that the address is
-not constant, but taken from the given interface. If the interface is
+not constant, but taken from the given interface. The interface may be
+followed by "/4" or "/6" to specify that only IPv4 or IPv6 addresses
+of the interface should be used. If the interface is
 down, not configured or non-existent, an empty record is returned. The
 matching PTR record is also created, mapping the interface address to
 the name. More than one name may be associated with an interface
@@ -588,8 +595,10 @@ needed for a client to do validation itself.
 .TP
 .B --auth-zone=<domain>[,<subnet>[/<prefix length>][,<subnet>[/<prefix length>].....]]
 Define a DNS zone for which dnsmasq acts as authoritative server. Locally defined DNS records which are in the domain
-will be served. A and AAAA records must be in one of the
-specified subnets. As alternative to directly specifying the subnets, it's possible to
+will be served. If subnet(s) are given, A and AAAA records must be in one of the
+specified subnets.
+
+As alternative to directly specifying the subnets, it's possible to
 give the name of an interface, in which case the subnets implied by
 that interface's configured addresses and netmask/prefix-length are
 used; this is useful when using constructed DHCP ranges as the actual
@@ -606,7 +615,8 @@ ipv6.arpa domains which are served for reverse-DNS queries. If not
 specified, the prefix length defaults to 24 for IPv4 and 64 for IPv6.
 For IPv4 subnets, the prefix length should be have the value 8, 16 or 24
 unless you are familiar with RFC 2317 and have arranged the
-in-addr.arpa delegation accordingly. 
+in-addr.arpa delegation accordingly. Note that if no subnets are
+specified, then no reverse queries are answered.
 .TP
 .B --auth-soa=<serial>[,<hostmaster>[,<refresh>[,<retry>[,<expiry>]]]]
 Specify fields in the SOA record associated with authoritative

src/auth.c

@@ -18,7 +18,7 @@
 
 #ifdef HAVE_AUTH
 
-static struct addrlist *filter_zone(struct auth_zone *zone, int flag, struct all_addr *addr_u)
+static struct addrlist *find_subnet(struct auth_zone *zone, int flag, struct all_addr *addr_u)
 {
   struct addrlist *subnet;
 
@@ -45,6 +45,15 @@ static struct addrlist *filter_zone(struct auth_zone *zone, int flag, struct all
   return NULL;
 }
 
+static int filter_zone(struct auth_zone *zone, int flag, struct all_addr *addr_u)
+{
+  /* No zones specified, no filter */
+  if (!zone->subnet)
+    return 1;
+  
+  return find_subnet(zone, flag, addr_u) != NULL;
+}
+
 int in_zone(struct auth_zone *zone, char *name, char **cut)
 {
   size_t namelen = strlen(name);
@@ -130,7 +139,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 	  if (!local_query)
 	    {
 	      for (zone = daemon->auth_zones; zone; zone = zone->next)
-		if ((subnet = filter_zone(zone, flag, &addr)))
+		if ((subnet = find_subnet(zone, flag, &addr)))
 		  break;
 	      
 	      if (!zone)
@@ -660,16 +669,16 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 		  *cut = 0;
 		
 		for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) 
-		  if (!(subnet->flags & ADDRLIST_IPV6) &&
-		      (local_query || filter_zone(zone, F_IPV4,  &addrlist->addr)) && 
+		  if (!(addrlist->flags & ADDRLIST_IPV6) &&
+		      (local_query || filter_zone(zone, F_IPV4, &addrlist->addr)) && 
 		      add_resource_record(header, limit, &trunc, -axfroffset, &ansp, 
 					  daemon->auth_ttl, NULL, T_A, C_IN, "4", cut ? intr->name : NULL, &addrlist->addr))
 		    anscount++;
 		
 #ifdef HAVE_IPV6
 		for (addrlist = intr->addr; addrlist; addrlist = addrlist->next) 
-		  if ((subnet->flags & ADDRLIST_IPV6) && 
-		      (local_query || filter_zone(zone, F_IPV6,  &addrlist->addr)) &&
+		  if ((addrlist->flags & ADDRLIST_IPV6) && 
+		      (local_query || filter_zone(zone, F_IPV6, &addrlist->addr)) &&
 		      add_resource_record(header, limit, &trunc, -axfroffset, &ansp, 
 					  daemon->auth_ttl, NULL, T_AAAA, C_IN, "6", cut ? intr->name : NULL, &addrlist->addr))
 		    anscount++;

src/cache.c

@@ -320,7 +320,7 @@ static int cache_scan_free(char *name, struct all_addr *addr, time_t now, unsign
 	if (is_expired(now, crecp) || is_outdated_cname_pointer(crecp))
 	  { 
 	    *up = crecp->hash_next;
-	    if (!(crecp->flags & (F_HOSTS | F_DHCP)))
+	    if (!(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)))
 	      {
 		cache_unlink(crecp);
 		cache_free(crecp);
@@ -354,13 +354,13 @@ static int cache_scan_free(char *name, struct all_addr *addr, time_t now, unsign
 	  if (is_expired(now, crecp))
 	    {
 	      *up = crecp->hash_next;
-	      if (!(crecp->flags & (F_HOSTS | F_DHCP)))
+	      if (!(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)))
 		{ 
 		  cache_unlink(crecp);
 		  cache_free(crecp);
 		}
 	    }
-	  else if (!(crecp->flags & (F_HOSTS | F_DHCP)) &&
+	  else if (!(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) &&
 		   (flags & crecp->flags & F_REVERSE) && 
 		   (flags & crecp->flags & (F_IPV4 | F_IPV6)) &&
 		   memcmp(&crecp->addr.addr, addr, addrlen) == 0)
@@ -558,7 +558,7 @@ struct crec *cache_find_by_name(struct crec *crecp, char *name, time_t now, unsi
 		  (crecp->flags & prot) &&
 		  hostname_isequal(cache_get_name(crecp), name))
 		{
-		  if (crecp->flags & (F_HOSTS | F_DHCP))
+		  if (crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG))
 		    {
 		      *chainp = crecp;
 		      chainp = &crecp->next;
@@ -599,7 +599,7 @@ struct crec *cache_find_by_name(struct crec *crecp, char *name, time_t now, unsi
 	    {
 	      /* expired entry, free it */
 	      *up = crecp->hash_next;
-	      if (!(crecp->flags & (F_HOSTS | F_DHCP)))
+	      if (!(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)))
 		{ 
 		  cache_unlink(crecp);
 		  cache_free(crecp);
@@ -649,7 +649,7 @@ struct crec *cache_find_by_addr(struct crec *crecp, struct all_addr *addr,
 	       if ((crecp->flags & prot) &&
 		   memcmp(&crecp->addr.addr, addr, addrlen) == 0)
 		 {	    
-		   if (crecp->flags & (F_HOSTS | F_DHCP))
+		   if (crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG))
 		     {
 		       *chainp = crecp;
 		       chainp = &crecp->next;
@@ -665,7 +665,7 @@ struct crec *cache_find_by_addr(struct crec *crecp, struct all_addr *addr,
 	   else
 	     {
 	       *up = crecp->hash_next;
-	       if (!(crecp->flags & (F_HOSTS | F_DHCP)))
+	       if (!(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)))
 		 {
 		   cache_unlink(crecp);
 		   cache_free(crecp);
@@ -923,7 +923,7 @@ void cache_reload(void)
     for (cache = hash_table[i], up = &hash_table[i]; cache; cache = tmp)
       {
 	tmp = cache->hash_next;
-	if (cache->flags & F_HOSTS)
+	if (cache->flags & (F_HOSTS | F_CONFIG))
 	  {
 	    *up = cache->hash_next;
 	    free(cache);
@@ -947,7 +947,7 @@ void cache_reload(void)
     for (intr = daemon->int_names; intr; intr = intr->next)
       if (hostname_isequal(a->target, intr->name))
 	{
-	  struct crec *aliasc = safe_malloc(sizeof(struct crec));
+	  struct crec *aliasc = whine_malloc(sizeof(struct crec));
 	  aliasc->flags = F_FORWARD | F_NAMEP | F_CNAME | F_IMMORTAL | F_CONFIG;
 	  aliasc->name.namep = a->alias;
 	  aliasc->addr.cname.target.int_name = intr;
@@ -1083,7 +1083,7 @@ void cache_add_dhcp_entry(char *host_name, int prot,
   while ((crec = cache_find_by_name(crec, host_name, 0, flags | F_CNAME)))
     {
       /* check all addresses associated with name */
-      if (crec->flags & F_HOSTS)
+      if (crec->flags & (F_HOSTS | F_CONFIG))
 	{
 	  if (crec->flags & F_CNAME)
 	    my_syslog(MS_DHCP | LOG_WARNING, 

src/config.h

@@ -189,10 +189,6 @@ HAVE_SOLARIS_NETWORK
 HAVE_GETOPT_LONG
    defined when GNU-style getopt_long available. 
 
-HAVE_ARC4RANDOM
-   defined if arc4random() available to get better security from DNS spoofs
-   by using really random ids (OpenBSD) 
-
 HAVE_SOCKADDR_SA_LEN
    defined if struct sockaddr has sa_len field (*BSD) 
 */
@@ -201,7 +197,6 @@ HAVE_SOCKADDR_SA_LEN
 #if defined(__uClinux__)
 #define HAVE_LINUX_NETWORK
 #define HAVE_GETOPT_LONG
-#undef HAVE_ARC4RANDOM
 #undef HAVE_SOCKADDR_SA_LEN
 /* Never use fork() on uClinux. Note that this is subtly different from the
    --keep-in-foreground option, since it also  suppresses forking new 
@@ -215,7 +210,6 @@ HAVE_SOCKADDR_SA_LEN
    ((__UCLIBC_MAJOR__==0) && (__UCLIBC_MINOR__==9) && (__UCLIBC_SUBLEVEL__<21))
 #    define HAVE_GETOPT_LONG
 #endif
-#undef HAVE_ARC4RANDOM
 #undef HAVE_SOCKADDR_SA_LEN
 #if !defined(__ARCH_HAS_MMU__) && !defined(__UCLIBC_HAS_MMU__)
 #  define NO_FORK
@@ -230,7 +224,6 @@ HAVE_SOCKADDR_SA_LEN
 #elif defined(__linux__)
 #define HAVE_LINUX_NETWORK
 #define HAVE_GETOPT_LONG
-#undef HAVE_ARC4RANDOM
 #undef HAVE_SOCKADDR_SA_LEN
 
 #elif defined(__FreeBSD__) || \
@@ -242,15 +235,11 @@ HAVE_SOCKADDR_SA_LEN
 #if defined(optional_argument) && defined(required_argument)
 #   define HAVE_GETOPT_LONG
 #endif
-#if !defined(__FreeBSD_kernel__)
-#   define HAVE_ARC4RANDOM
-#endif
 #define HAVE_SOCKADDR_SA_LEN
 
 #elif defined(__APPLE__)
 #define HAVE_BSD_NETWORK
 #define HAVE_GETOPT_LONG
-#define HAVE_ARC4RANDOM
 #define HAVE_SOCKADDR_SA_LEN
 /* Define before sys/socket.h is included so we get socklen_t */
 #define _BSD_SOCKLEN_T_
@@ -261,13 +250,11 @@ HAVE_SOCKADDR_SA_LEN
 #elif defined(__NetBSD__)
 #define HAVE_BSD_NETWORK
 #define HAVE_GETOPT_LONG
-#undef HAVE_ARC4RANDOM
 #define HAVE_SOCKADDR_SA_LEN
 
 #elif defined(__sun) || defined(__sun__)
 #define HAVE_SOLARIS_NETWORK
 #define HAVE_GETOPT_LONG
-#undef HAVE_ARC4RANDOM
 #undef HAVE_SOCKADDR_SA_LEN
 #define ETHER_ADDR_LEN 6 
  

src/dnsmasq.c

@@ -636,7 +636,10 @@ int main (int argc, char **argv)
   if (bind_fallback)
     my_syslog(LOG_WARNING, _("setting --bind-interfaces option because of OS limitations"));
 
-  warn_bound_listeners();
+  if (option_bool(OPT_NOWILD))
+    warn_bound_listeners();
+
+  warn_int_names();
   
   if (!option_bool(OPT_NOWILD)) 
     for (if_tmp = daemon->if_names; if_tmp; if_tmp = if_tmp->next)

src/dnsmasq.h

@@ -321,6 +321,7 @@ struct host_record {
 struct interface_name {
   char *name; /* domain name */
   char *intr; /* interface name */
+  int family; /* AF_INET, AF_INET6 or zero for both */
   struct addrlist *addr;
   struct interface_name *next;
 };
@@ -1076,6 +1077,7 @@ int enumerate_interfaces(int reset);
 void create_wildcard_listeners(void);
 void create_bound_listeners(int die);
 void warn_bound_listeners(void);
+void warn_int_names(void);
 int is_dad_listeners(void);
 int iface_check(int family, struct all_addr *addr, char *name, int *auth_dns);
 int loopback_exception(int fd, int family, struct all_addr *addr, char *name);

src/network.c

@@ -159,7 +159,8 @@ int iface_check(int family, struct all_addr *addr, char *name, int *auth)
   for (tmp = daemon->authinterface; tmp; tmp = tmp->next)
     if (tmp->name)
       {
-	if (strcmp(tmp->name, name) == 0)
+	if (strcmp(tmp->name, name) == 0 &&
+	    (tmp->addr.sa.sa_family == 0 || tmp->addr.sa.sa_family == family))
 	  break;
       }
     else if (addr && tmp->addr.sa.sa_family == AF_INET && family == AF_INET &&
@@ -329,7 +330,8 @@ static int iface_allowed(struct iface_param *param, int if_index, char *label,
       /* Update addresses from interface_names. These are a set independent
 	 of the set we're listening on. */  
       for (int_name = daemon->int_names; int_name; int_name = int_name->next)
-	if (strncmp(label, int_name->intr, IF_NAMESIZE) == 0)
+	if (strncmp(label, int_name->intr, IF_NAMESIZE) == 0 && 
+	    (addr->sa.sa_family == int_name->family || int_name->family == 0))
 	  {
 	    if (param->spare)
 	      {
@@ -914,7 +916,7 @@ void warn_bound_listeners(void)
   int advice = 0;
 
   for (iface = daemon->interfaces; iface; iface = iface->next)
-    if (option_bool(OPT_NOWILD) && !iface->dns_auth)
+    if (!iface->dns_auth)
       {
 	int warn = 0;
 	if (iface->addr.sa.sa_family == AF_INET)
@@ -942,15 +944,24 @@ void warn_bound_listeners(void)
 	  {
 	    iface->warned = advice = 1;
 	    my_syslog(LOG_WARNING, 
-		      _("LOUD WARNING: listening on %s may accept requests via interfaces other than %s. "),
+		      _("LOUD WARNING: listening on %s may accept requests via interfaces other than %s"),
 		      daemon->addrbuff, iface->name);
 	  }
       }
   
   if (advice)
-    my_syslog(LOG_WARNING, _("LOUD WARNING: use --bind-dynamic rather than --bind-interfaces to avoid DNS amplification attacks via these interface(s).")); 
+    my_syslog(LOG_WARNING, _("LOUD WARNING: use --bind-dynamic rather than --bind-interfaces to avoid DNS amplification attacks via these interface(s)")); 
 }
 
+void warn_int_names(void)
+{
+  struct interface_name *intname;
+ 
+  for (intname = daemon->int_names; intname; intname = intname->next)
+    if (!intname->addr)
+      my_syslog(LOG_WARNING, _("warning: no addresses found for interface %s"), intname->intr);
+}
+ 
 int is_dad_listeners(void)
 {
   struct irec *iface;

src/option.c

@@ -1615,8 +1615,22 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	  new->addr.sa.sa_family = AF_INET6;
 #endif
 	else
-	  new->name = opt_string_alloc(arg);
-	
+	  {
+	    char *fam = split_chr(arg, '/');
+	    new->name = opt_string_alloc(arg);
+	    new->addr.sa.sa_family = 0;
+	    if (fam)
+	      {
+		if (strcmp(fam, "4") == 0)
+		  new->addr.sa.sa_family = AF_INET;
+#ifdef HAVE_IPV6
+		else if (strcmp(fam, "6") == 0)
+		  new->addr.sa.sa_family = AF_INET6;
+#endif
+		else
+		  ret_err(gen_err);
+	      } 
+	  }
 	new->next = daemon->authinterface;
 	daemon->authinterface = new;
 	
@@ -3362,6 +3376,19 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	for (up = &daemon->int_names; *up; up = &((*up)->next));
 	*up = new;
 	new->name = domain;
+	new->family = 0;
+	arg = split_chr(comma, '/');
+	if (arg)
+	  {
+	    if (strcmp(arg, "4") == 0)
+	      new->family = AF_INET;
+#ifdef HAVE_IPV6
+	    else if (strcmp(arg, "6") == 0)
+	      new->family = AF_INET6;
+#endif
+	    else
+	      ret_err(gen_err);
+	  } 
 	new->intr = opt_string_alloc(comma);
 	break;
       }

src/radv.c

@@ -205,7 +205,7 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
   struct dhcp_netid iface_id;
   struct dhcp_opt *opt_cfg;
   struct ra_interface *ra_param = find_iface_param(iface_name);
-  int done_dns = 0;
+  int done_dns = 0, old_prefix = 0;
 #ifdef HAVE_LINUX_NETWORK
   FILE *f;
 #endif
@@ -267,7 +267,7 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
 	      struct in6_addr local = context->start6;
 	      int do_slaac = 0;
 
-	      parm.found_context = 1;
+	      old_prefix = 1;
 
 	      /* zero net part of address */
 	      setaddr6part(&local, addr6part(&local) & ~((context->prefix == 64) ? (u64)-1LL : (1LLU << (128 - context->prefix)) - 1LLU));
@@ -300,9 +300,14 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
 	up = &context->next;
     }
     
-  if (!parm.found_context)
-    return;
-    
+  /* If we're advertising only old prefixes, set router lifetime to zero. */
+  if (old_prefix && !parm.found_context)
+    ra->lifetime = htons(0);
+
+  /* No prefixes to advertise. */
+  if (!old_prefix && !parm.found_context)
+    return; 
+  
 #ifdef HAVE_LINUX_NETWORK
   /* Note that IPv6 MTU is not necessarilly the same as the IPv4 MTU
      available from SIOCGIFMTU */

src/util.c

@@ -28,28 +28,6 @@
 #include <idna.h>
 #endif
 
-#ifdef HAVE_ARC4RANDOM
-void rand_init(void)
-{
-  return;
-}
-
-unsigned short rand16(void)
-{
-   return (unsigned short) (arc4random() >> 15);
-}
-
-u64 rand64(void)
-{
-  u64 ret;
-
-  arc4random_buf(&ret, sizeof(ret));
-
-  return ret;
-}
-
-#else
-
 /* SURF random number generator */
 
 static u32 seed[32];
@@ -119,8 +97,6 @@ u64 rand64(void)
   return (u64)out[outleft+1] + (((u64)out[outleft]) << 32);
 }
 
-#endif
-
 static int check_name(char *in)
 {
   /* remove trailing .