fix potential null pointer deref when packets are forged

[project/mdnsd.git] / service.c

diff --git a/service.c b/service.c
index 30f4770..7ae3cde 100644 (file)
--- a/service.c
+++ b/service.c
@@ -57,27 +57,21 @@ static const struct blobmsg_policy service_policy[__SERVICE_MAX] = {
        [SERVICE_TXT] = { .name = "txt", .type = BLOBMSG_TYPE_ARRAY },
 };
 
-static const struct uci_blob_param_list service_attr_list = {
-       .n_params = __SERVICE_MAX,
-       .params = service_policy,
-};
-
 static void
 service_update(struct vlist_tree *tree, struct vlist_node *node_new,
               struct vlist_node *node_old);
 
 static struct blob_buf b;
 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
-char *hostname = NULL;
 static char *sdudp =  "_services._dns-sd._udp.local";
 static char *sdtcp =  "_services._dns-sd._tcp.local";
 
-char *
+static const char *
 service_name(const char *domain)
 {
        static char buffer[256];
 
-       snprintf(buffer, sizeof(buffer), "%s.%s", hostname, domain);
+       snprintf(buffer, sizeof(buffer), "%s.%s", mdns_hostname, domain);
 
        return buffer;
 }
@@ -97,16 +91,14 @@ static void
 service_add_srv(struct service *s)
 {
        struct dns_srv_data *sd = (struct dns_srv_data *) mdns_buf;
-       char *host = service_name("local");
        int len = sizeof(*sd);
 
-       len += dn_comp(host, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
+       len += dn_comp(mdns_hostname_local, mdns_buf + len, sizeof(mdns_buf) - len, NULL, NULL);
        if (len <= sizeof(*sd))
                return;
 
        sd->port = cpu_to_be16(s->port);
        dns_add_answer(TYPE_SRV, mdns_buf, len);
-       service_name(s->service);
 }
 
 #define TOUT_LOOKUP    60
@@ -132,7 +124,7 @@ service_reply_a(struct interface *iface, int type)
 
        dns_init_answer();
        dns_add_answer(TYPE_A, (uint8_t *) &iface->v4_addr.s_addr, 4);
-       dns_send_answer(iface, service_name("local"));
+       dns_send_answer(iface, mdns_hostname_local);
 }
 
 void
@@ -141,7 +133,7 @@ service_reply(struct interface *iface, const char *match)
        struct service *s;
 
        vlist_for_each_element(&services, s, node) {
-               char *host = service_name(s->service);
+               const char *host = service_name(s->service);
                char *service = strstr(host, "._");
 
                if (!s->active || !service || !service_timeout(s))
@@ -281,8 +273,7 @@ service_load(char *path)
 void
 service_init(void)
 {
-       if (!hostname)
-               hostname = get_hostname();
+       get_hostname();
 
        vlist_update(&services);
        service_load("/tmp/run/mdnsd/*");