qemu-ga: Plug leaks on qmp_guest_network_get_interfaces() error paths

Spotted by Coverity.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

qga/commands-posix.c

@@ -935,9 +935,11 @@ GuestNetworkInterfaceList *qmp_guest_network_get_interfaces(Error **errp)
                 error_setg_errno(errp, errno,
                                  "failed to get MAC address of %s",
                                  ifa->ifa_name);
+                close(sock);
                 goto error;
             }
 
+            close(sock);
             mac_addr = (unsigned char *) &ifr.ifr_hwaddr.sa_data;
 
             info->value->hardware_address =
@@ -947,20 +949,19 @@ GuestNetworkInterfaceList *qmp_guest_network_get_interfaces(Error **errp)
                                 (int) mac_addr[4], (int) mac_addr[5]);
 
             info->value->has_hardware_address = true;
-            close(sock);
         }
 
         if (ifa->ifa_addr &&
             ifa->ifa_addr->sa_family == AF_INET) {
             /* interface with IPv4 address */
-            address_item = g_malloc0(sizeof(*address_item));
-            address_item->value = g_malloc0(sizeof(*address_item->value));
             p = &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
             if (!inet_ntop(AF_INET, p, addr4, sizeof(addr4))) {
                 error_setg_errno(errp, errno, "inet_ntop failed");
                 goto error;
             }
 
+            address_item = g_malloc0(sizeof(*address_item));
+            address_item->value = g_malloc0(sizeof(*address_item->value));
             address_item->value->ip_address = g_strdup(addr4);
             address_item->value->ip_address_type = GUEST_IP_ADDRESS_TYPE_IPV4;
 
@@ -973,14 +974,14 @@ GuestNetworkInterfaceList *qmp_guest_network_get_interfaces(Error **errp)
         } else if (ifa->ifa_addr &&
                    ifa->ifa_addr->sa_family == AF_INET6) {
             /* interface with IPv6 address */
-            address_item = g_malloc0(sizeof(*address_item));
-            address_item->value = g_malloc0(sizeof(*address_item->value));
             p = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
             if (!inet_ntop(AF_INET6, p, addr6, sizeof(addr6))) {
                 error_setg_errno(errp, errno, "inet_ntop failed");
                 goto error;
             }
 
+            address_item = g_malloc0(sizeof(*address_item));
+            address_item->value = g_malloc0(sizeof(*address_item->value));
             address_item->value->ip_address = g_strdup(addr6);
             address_item->value->ip_address_type = GUEST_IP_ADDRESS_TYPE_IPV6;