VLAN: Warn about interface name truncation

Add more snprintf checks to make it clearer if some of the ifname
constructions would end up being too long.

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/ap/vlan_full.c b/src/ap/vlan_full.c
index aa42335b96a19be3de47f3ca337e6cffc7d4898f..93cef958dfa3dbfe8ce3fccdd1c4418ce6e48a89 100644 (file)
--- a/src/ap/vlan_full.c
+++ b/src/ap/vlan_full.c
@@ -363,12 +363,18 @@ static void vlan_newlink_tagged(int vlan_naming, const char *tagged_interface,
 {
        char vlan_ifname[IFNAMSIZ];
        int clean;
+       int ret;
 
        if (vlan_naming == DYNAMIC_VLAN_NAMING_WITH_DEVICE)
-               os_snprintf(vlan_ifname, sizeof(vlan_ifname), "%s.%d",
-                           tagged_interface, vid);
+               ret = os_snprintf(vlan_ifname, sizeof(vlan_ifname), "%s.%d",
+                                 tagged_interface, vid);
        else
-               os_snprintf(vlan_ifname, sizeof(vlan_ifname), "vlan%d", vid);
+               ret = os_snprintf(vlan_ifname, sizeof(vlan_ifname), "vlan%d",
+                                 vid);
+       if (ret >= (int) sizeof(vlan_ifname))
+               wpa_printf(MSG_WARNING,
+                          "VLAN: Interface name was truncated to %s",
+                          vlan_ifname);
 
        clean = 0;
        ifconfig_up(tagged_interface);
@@ -387,16 +393,21 @@ static void vlan_newlink_tagged(int vlan_naming, const char *tagged_interface,
 static void vlan_bridge_name(char *br_name, struct hostapd_data *hapd, int vid)
 {
        char *tagged_interface = hapd->conf->ssid.vlan_tagged_interface;
+       int ret;
 
        if (hapd->conf->vlan_bridge[0]) {
-               os_snprintf(br_name, IFNAMSIZ, "%s%d",
-                           hapd->conf->vlan_bridge, vid);
+               ret = os_snprintf(br_name, IFNAMSIZ, "%s%d",
+                                 hapd->conf->vlan_bridge, vid);
        } else if (tagged_interface) {
-               os_snprintf(br_name, IFNAMSIZ, "br%s.%d",
-                           tagged_interface, vid);
+               ret = os_snprintf(br_name, IFNAMSIZ, "br%s.%d",
+                                 tagged_interface, vid);
        } else {
-               os_snprintf(br_name, IFNAMSIZ, "brvlan%d", vid);
+               ret = os_snprintf(br_name, IFNAMSIZ, "brvlan%d", vid);
        }
+       if (ret >= IFNAMSIZ)
+               wpa_printf(MSG_WARNING,
+                          "VLAN: Interface name was truncated to %s",
+                          br_name);
 }
 
 
@@ -474,12 +485,19 @@ static void vlan_dellink_tagged(int vlan_naming, const char *tagged_interface,
 {
        char vlan_ifname[IFNAMSIZ];
        int clean;
+       int ret;
 
        if (vlan_naming == DYNAMIC_VLAN_NAMING_WITH_DEVICE)
-               os_snprintf(vlan_ifname, sizeof(vlan_ifname), "%s.%d",
-                           tagged_interface, vid);
+               ret = os_snprintf(vlan_ifname, sizeof(vlan_ifname), "%s.%d",
+                                 tagged_interface, vid);
        else
-               os_snprintf(vlan_ifname, sizeof(vlan_ifname), "vlan%d", vid);
+               ret = os_snprintf(vlan_ifname, sizeof(vlan_ifname), "vlan%d",
+                                 vid);
+       if (ret >= (int) sizeof(vlan_ifname))
+               wpa_printf(MSG_WARNING,
+                          "VLAN: Interface name was truncated to %s",
+                          vlan_ifname);
+
 
        clean = dyn_iface_put(hapd, vlan_ifname);