Tidy and fix cache->uid handling.

Some CNAMES left the value of ->uid undefined.

Since there are now special values if this, for CNAMES
to interface names, that could cause a crash
if the undefined value hit the special value.

Also ensure that the special value can't arise
when the uid is encoding the source of an F_CONFIG
record, in case there's a CNAME to it.

src/cache.c

@@ -79,7 +79,7 @@ static unsigned int next_uid(void)
   uid++;
   
   /* uid == 0 used to indicate CNAME to interface name. */
-  if (uid == 0)
+  if (uid == SRC_INTERFACE)
     uid++;
   
   return uid;
@@ -265,7 +265,7 @@ char *cache_get_name(struct crec *crecp)
 
 char *cache_get_cname_target(struct crec *crecp)
 {
-  if (crecp->addr.cname.uid != 0)
+  if (crecp->addr.cname.uid != SRC_INTERFACE)
     return cache_get_name(crecp->addr.cname.target.cache);
 
   return crecp->addr.cname.target.int_name->name;
@@ -783,13 +783,14 @@ static void add_hosts_cname(struct crec *target)
 	crec->name.namep = a->alias;
 	crec->addr.cname.target.cache = target;
 	crec->addr.cname.uid = target->uid;
+	crec->uid = next_uid();
 	cache_hash(crec);
 	add_hosts_cname(crec); /* handle chains */
       }
 }
   
 static void add_hosts_entry(struct crec *cache, struct all_addr *addr, int addrlen, 
-			    int index, struct crec **rhash, int hashsz)
+			    unsigned int index, struct crec **rhash, int hashsz)
 {
   struct crec *lookup = cache_find_by_name(NULL, cache_get_name(cache), 0, cache->flags & (F_IPV4 | F_IPV6));
   int i, nameexists = 0;
@@ -893,7 +894,7 @@ static int gettok(FILE *f, char *token)
     }
 }
 
-static int read_hostsfile(char *filename, int index, int cache_size, struct crec **rhash, int hashsz)
+static int read_hostsfile(char *filename, unsigned int index, int cache_size, struct crec **rhash, int hashsz)
 {  
   FILE *f = fopen(filename, "r");
   char *token = daemon->namebuff, *domain_suffix = NULL;
@@ -1043,7 +1044,8 @@ void cache_reload(void)
 	  cache->flags = F_FORWARD | F_NAMEP | F_CNAME | F_IMMORTAL | F_CONFIG;
 	  cache->name.namep = a->alias;
 	  cache->addr.cname.target.int_name = intr;
-	  cache->addr.cname.uid = 0;
+	  cache->addr.cname.uid = SRC_INTERFACE;
+	  cache->uid = next_uid();
 	  cache_hash(cache);
 	  add_hosts_cname(cache); /* handle chains */
 	}
@@ -1079,7 +1081,7 @@ void cache_reload(void)
 	  {
 	    cache->name.namep = nl->name;
 	    cache->flags = F_HOSTS | F_IMMORTAL | F_FORWARD | F_REVERSE | F_IPV4 | F_NAMEP | F_CONFIG;
-	    add_hosts_entry(cache, (struct all_addr *)&hr->addr, INADDRSZ, 0, (struct crec **)daemon->packet, revhashsz);
+	    add_hosts_entry(cache, (struct all_addr *)&hr->addr, INADDRSZ, SRC_CONFIG, (struct crec **)daemon->packet, revhashsz);
 	  }
 #ifdef HAVE_IPV6
 	if (!IN6_IS_ADDR_UNSPECIFIED(&hr->addr6) &&
@@ -1087,7 +1089,7 @@ void cache_reload(void)
 	  {
 	    cache->name.namep = nl->name;
 	    cache->flags = F_HOSTS | F_IMMORTAL | F_FORWARD | F_REVERSE | F_IPV6 | F_NAMEP | F_CONFIG;
-	    add_hosts_entry(cache, (struct all_addr *)&hr->addr6, IN6ADDRSZ, 0, (struct crec **)daemon->packet, revhashsz);
+	    add_hosts_entry(cache, (struct all_addr *)&hr->addr6, IN6ADDRSZ, SRC_CONFIG, (struct crec **)daemon->packet, revhashsz);
 	  }
 #endif
       }
@@ -1100,7 +1102,7 @@ void cache_reload(void)
     }
     
   if (!option_bool(OPT_NO_HOSTS))
-    total_size = read_hostsfile(HOSTSFILE, 0, total_size, (struct crec **)daemon->packet, revhashsz);
+    total_size = read_hostsfile(HOSTSFILE, SRC_HOSTS, total_size, (struct crec **)daemon->packet, revhashsz);
   	   
   daemon->addn_hosts = expand_filelist(daemon->addn_hosts);
   for (ah = daemon->addn_hosts; ah; ah = ah->next)
@@ -1164,6 +1166,7 @@ static void add_dhcp_cname(struct crec *target, time_t ttd)
 	    aliasc->name.namep = a->alias;
 	    aliasc->addr.cname.target.cache = target;
 	    aliasc->addr.cname.uid = target->uid;
+	    aliasc->uid = next_uid();
 	    cache_hash(aliasc);
 	    add_dhcp_cname(aliasc, ttd);
 	  }
@@ -1377,11 +1380,13 @@ void dump_cache(time_t now)
     }
 }
 
-char *record_source(int index)
+char *record_source(unsigned int index)
 {
   struct hostsfile *ah;
 
-  if (index == 0)
+  if (index == SRC_CONFIG)
+    return "config";
+  else if (index == SRC_HOSTS)
     return HOSTSFILE;
 
   for (ah = daemon->addn_hosts; ah; ah = ah->next)

src/dnsmasq.h

@@ -427,6 +427,12 @@ struct crec {
 #define F_SECSTAT   (1u<<24)
 #define F_NO_RR     (1u<<25)
 
+/* Values of uid in crecs with F_CONFIG bit set. */
+#define SRC_INTERFACE 0
+#define SRC_CONFIG    1
+#define SRC_HOSTS     2
+#define SRC_AH        3
+
 
 /* struct sockaddr is not large enough to hold any address,
    and specifically not big enough to hold an IPv6 address.
@@ -525,7 +531,7 @@ struct hostsfile {
   struct hostsfile *next;
   int flags;
   char *fname;
-  int index; /* matches to cache entries for logging */
+  unsigned int index; /* matches to cache entries for logging */
 };
 
 
@@ -1005,7 +1011,7 @@ extern struct daemon {
 /* cache.c */
 void cache_init(void);
 void log_query(unsigned int flags, char *name, struct all_addr *addr, char *arg); 
-char *record_source(int index);
+char *record_source(unsigned int index);
 char *querystr(char *desc, unsigned short type);
 struct crec *cache_find_by_addr(struct crec *crecp,
 				struct all_addr *addr, time_t now, 

src/option.c

@@ -1664,7 +1664,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
     case 'H': /* --addn-hosts */
       {
 	struct hostsfile *new = opt_malloc(sizeof(struct hostsfile));
-	static int hosts_index = 1;
+	static unsigned int hosts_index = SRC_AH;
 	new->fname = opt_string_alloc(arg);
 	new->index = hosts_index++;
 	new->flags = 0;
@@ -4020,10 +4020,11 @@ static int one_file(char *file, int hard_opt)
 /* expand any name which is a directory */
 struct hostsfile *expand_filelist(struct hostsfile *list)
 {
-  int i;
+  unsigned int i;
   struct hostsfile *ah;
 
-  for (i = 0, ah = list; ah; ah = ah->next)
+  /* find largest used index */
+  for (i = SRC_AH, ah = list; ah; ah = ah->next)
     {
       if (i <= ah->index)
 	i = ah->index + 1;