1 files changed, 112 insertions, 77 deletions

diff --git a/src/lease.c b/src/lease.c
index 8adb605..5c33df7 100644
--- a/src/lease.c
+++ b/src/lease.c
@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2015 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2018 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
@@ -21,94 +21,62 @@
 static struct dhcp_lease *leases = NULL, *old_leases = NULL;
 static int dns_dirty, file_dirty, leases_left;
 
-void lease_init(time_t now)
+static int read_leases(time_t now, FILE *leasestream)
 {
   unsigned long ei;
   struct all_addr addr;
   struct dhcp_lease *lease;
   int clid_len, hw_len, hw_type;
-  FILE *leasestream;
-  
-  leases_left = daemon->dhcp_max;
-  
-  if (option_bool(OPT_LEASE_RO))
-    {
-      /* run "<lease_change_script> init" once to get the
-	 initial state of the database. If leasefile-ro is
-	 set without a script, we just do without any 
-	 lease database. */
-#ifdef HAVE_SCRIPT
-      if (daemon->lease_change_command)
-	{
-	  strcpy(daemon->dhcp_buff, daemon->lease_change_command);
-	  strcat(daemon->dhcp_buff, " init");
-	  leasestream = popen(daemon->dhcp_buff, "r");
-	}
-      else
+  int items;
+  char *domain = NULL;
+
+  *daemon->dhcp_buff3 = *daemon->dhcp_buff2 = '\0';
+
+  /* client-id max length is 255 which is 255*2 digits + 254 colons
+     borrow DNS packet buffer which is always larger than 1000 bytes
+
+     Check various buffers are big enough for the code below */
+
+#if (DHCP_BUFF_SZ < 255) || (MAXDNAME < 64) || (PACKETSZ+MAXDNAME+RRFIXEDSZ  < 764)
+# error Buffer size breakage in leasefile parsing.
 #endif
-	{
-          file_dirty = dns_dirty = 0;
-          return;
-        }
 
-    }
-  else
-    {
-      /* NOTE: need a+ mode to create file if it doesn't exist */
-      leasestream = daemon->lease_stream = fopen(daemon->lease_file, "a+");
-      
-      if (!leasestream)
-	die(_("cannot open or create lease file %s: %s"), daemon->lease_file, EC_FILE);
-      
-      /* a+ mode leaves pointer at end. */
-      rewind(leasestream);
-    }
-  
-  /* client-id max length is 255 which is 255*2 digits + 254 colons 
-     borrow DNS packet buffer which is always larger than 1000 bytes */
-  if (leasestream)
-    while (fscanf(leasestream, "%255s %255s", daemon->dhcp_buff3, daemon->dhcp_buff2) == 2)
+    while ((items=fscanf(leasestream, "%255s %255s", daemon->dhcp_buff3, daemon->dhcp_buff2)) == 2)
       {
+	*daemon->namebuff = *daemon->dhcp_buff = *daemon->packet = '\0';
+	hw_len = hw_type = clid_len = 0;
+	
 #ifdef HAVE_DHCP6
 	if (strcmp(daemon->dhcp_buff3, "duid") == 0)
 	  {
 	    daemon->duid_len = parse_hex(daemon->dhcp_buff2, (unsigned char *)daemon->dhcp_buff2, 130, NULL, NULL);
+	    if (daemon->duid_len < 0)
+	      return 0;
 	    daemon->duid = safe_malloc(daemon->duid_len);
 	    memcpy(daemon->duid, daemon->dhcp_buff2, daemon->duid_len);
 	    continue;
 	  }
 #endif
-
-	ei = atol(daemon->dhcp_buff3);
 	
 	if (fscanf(leasestream, " %64s %255s %764s",
 		   daemon->namebuff, daemon->dhcp_buff, daemon->packet) != 3)
-	  break;
+	  return 0;
 	
-	clid_len = 0;
-	if (strcmp(daemon->packet, "*") != 0)
-	  clid_len = parse_hex(daemon->packet, (unsigned char *)daemon->packet, 255, NULL, NULL);
-	
-	if (inet_pton(AF_INET, daemon->namebuff, &addr.addr.addr4) &&
-	    (lease = lease4_allocate(addr.addr.addr4)))
+	if (inet_pton(AF_INET, daemon->namebuff, &addr.addr.addr4))
 	  {
+	    if ((lease = lease4_allocate(addr.addr.addr4)))
+	      domain = get_domain(lease->addr);
+	    
 	    hw_len = parse_hex(daemon->dhcp_buff2, (unsigned char *)daemon->dhcp_buff2, DHCP_CHADDR_MAX, NULL, &hw_type);
-	    /* For backwards compatibility, no explict MAC address type means ether. */
+	    /* For backwards compatibility, no explicit MAC address type means ether. */
 	    if (hw_type == 0 && hw_len != 0)
 	      hw_type = ARPHRD_ETHER; 
-
-	    lease_set_hwaddr(lease, (unsigned char *)daemon->dhcp_buff2, (unsigned char *)daemon->packet, 
-			     hw_len, hw_type, clid_len, now, 0);
-	    
-	    if (strcmp(daemon->dhcp_buff, "*") !=  0)
-	      lease_set_hostname(lease, daemon->dhcp_buff, 0, get_domain(lease->addr), NULL);
 	  }
 #ifdef HAVE_DHCP6
 	else if (inet_pton(AF_INET6, daemon->namebuff, &addr.addr.addr6))
 	  {
 	    char *s = daemon->dhcp_buff2;
 	    int lease_type = LEASE_NA;
-	    int iaid;
 
 	    if (s[0] == 'T')
 	      {
@@ -116,23 +84,30 @@ void lease_init(time_t now)
 		s++;
 	      }
 	    
-	    iaid = strtoul(s, NULL, 10);
-	    
 	    if ((lease = lease6_allocate(&addr.addr.addr6, lease_type)))
 	      {
-		lease_set_hwaddr(lease, NULL, (unsigned char *)daemon->packet, 0, 0, clid_len, now, 0);
-		lease_set_iaid(lease, iaid);
-		if (strcmp(daemon->dhcp_buff, "*") !=  0)
-		  lease_set_hostname(lease, daemon->dhcp_buff, 0, get_domain6((struct in6_addr *)lease->hwaddr), NULL);
+		lease_set_iaid(lease, strtoul(s, NULL, 10));
+		domain = get_domain6((struct in6_addr *)lease->hwaddr);
 	      }
 	  }
 #endif
 	else
-	  break;
+	  return 0;
 
 	if (!lease)
 	  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);
+	
+	lease_set_hwaddr(lease, (unsigned char *)daemon->dhcp_buff2, (unsigned char *)daemon->packet, 
+			 hw_len, hw_type, clid_len, now, 0);
+	
+	if (strcmp(daemon->dhcp_buff, "*") !=  0)
+	  lease_set_hostname(lease, daemon->dhcp_buff, 0, domain, NULL);
+
+	ei = atol(daemon->dhcp_buff3);
+
 #ifdef HAVE_BROKEN_RTC
 	if (ei != 0)
 	  lease->expires = (time_t)ei + now;
@@ -148,7 +123,62 @@ void lease_init(time_t now)
 	/* set these correctly: the "old" events are generated later from
 	   the startup synthesised SIGHUP. */
 	lease->flags &= ~(LEASE_NEW | LEASE_CHANGED);
+	
+	*daemon->dhcp_buff3 = *daemon->dhcp_buff2 = '\0';
       }
+    
+    return (items == 0 || items == EOF);
+}
+
+void lease_init(time_t now)
+{
+  FILE *leasestream;
+
+  leases_left = daemon->dhcp_max;
+
+  if (option_bool(OPT_LEASE_RO))
+    {
+      /* run "<lease_change_script> init" once to get the
+	 initial state of the database. If leasefile-ro is
+	 set without a script, we just do without any
+	 lease database. */
+#ifdef HAVE_SCRIPT
+      if (daemon->lease_change_command)
+	{
+	  strcpy(daemon->dhcp_buff, daemon->lease_change_command);
+	  strcat(daemon->dhcp_buff, " init");
+	  leasestream = popen(daemon->dhcp_buff, "r");
+	}
+      else
+#endif
+	{
+          file_dirty = dns_dirty = 0;
+          return;
+        }
+
+    }
+  else
+    {
+      /* NOTE: need a+ mode to create file if it doesn't exist */
+      leasestream = daemon->lease_stream = fopen(daemon->lease_file, "a+");
+
+      if (!leasestream)
+	die(_("cannot open or create lease file %s: %s"), daemon->lease_file, EC_FILE);
+
+      /* a+ mode leaves pointer at end. */
+      rewind(leasestream);
+    }
+
+  if (leasestream)
+    {
+      if (!read_leases(now, leasestream))
+	my_syslog(MS_DHCP | LOG_ERR, _("failed to parse lease database, invalid line: %s %s %s %s ..."),
+		  daemon->dhcp_buff3, daemon->dhcp_buff2,
+		  daemon->namebuff, daemon->dhcp_buff);
+
+      if (ferror(leasestream))
+	die(_("failed to read lease file %s: %s"), daemon->lease_file, EC_FILE);
+    }
   
 #ifdef HAVE_SCRIPT
   if (!daemon->lease_stream)
@@ -162,6 +192,7 @@ void lease_init(time_t now)
 	    errno = ENOENT;
 	  else if (WEXITSTATUS(rc) == 126)
 	    errno = EACCES;
+
 	  die(_("cannot run lease-init script %s: %s"), daemon->lease_change_command, EC_FILE);
 	}
       
@@ -198,7 +229,7 @@ void lease_update_from_configs(void)
     else if ((name = host_from_dns(lease->addr)))
       lease_set_hostname(lease, name, 1, get_domain(lease->addr), NULL); /* updates auth flag only */
 }
- 
+
 static void ourprintf(int *errp, char *format, ...)
 {
   va_list ap;
@@ -406,7 +437,7 @@ void lease_ping_reply(struct in6_addr *sender, unsigned char *packet, char *inte
 
 void lease_update_slaac(time_t now)
 {
-  /* Called when we contruct a new RA-names context, to add putative
+  /* Called when we construct a new RA-names context, to add putative
      new SLAAC addresses to existing leases. */
 
   struct dhcp_lease *lease;
@@ -776,7 +807,7 @@ void lease_set_expires(struct dhcp_lease *lease, unsigned int len, time_t now)
     {
       exp = now + (time_t)len;
       /* Check for 2038 overflow. Make the lease
-	 inifinite in that case, as the least disruptive
+	 infinite in that case, as the least disruptive
 	 thing we can do. */
       if (difftime(exp, now) <= 0.0)
 	exp = 0;
@@ -1110,18 +1141,22 @@ int do_script_run(time_t now)
 }
 
 #ifdef HAVE_SCRIPT
+/* delim == -1 -> delim = 0, but embedded 0s, creating extra records, are OK. */
 void lease_add_extradata(struct dhcp_lease *lease, unsigned char *data, unsigned int len, int delim)
 {
   unsigned int i;
   
-  /* check for embeded NULLs */
-  for (i = 0; i < len; i++)
-    if (data[i] == 0)
-      {
-	len = i;
-	break;
-      }
-
+  if (delim == -1)
+    delim = 0;
+  else
+    /* check for embedded NULLs */
+    for (i = 0; i < len; i++)
+      if (data[i] == 0)
+	{
+	  len = i;
+	  break;
+	}
+  
   if ((lease->extradata_size - lease->extradata_len) < (len + 1))
     {
       size_t newsz = lease->extradata_len + len + 100;