discover/device-handler: Prevent normal users changing boot target

[petitboot] / discover / device-handler.c

diff --git a/discover/device-handler.c b/discover/device-handler.c
index 729ed2c0f52ae76f9cbc7474cd803ed773bab3a6..e446cab528fb8d53238a6724a8deddb2dbc744a5 100644 (file)
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -81,6 +81,7 @@ struct device_handler {
        struct autoboot_option  *temp_autoboot;
 
        struct discover_boot_option *default_boot_option;
+       struct discover_boot_option *last_boot_option;
        int                     default_boot_option_priority;
 
        struct list             unresolved_boot_options;
@@ -756,6 +757,8 @@ static int default_timeout(void *arg)
 
        opt = handler->default_boot_option;
 
+       handler->last_boot_option = opt;
+
        if (handler->sec_to_boot) {
                countdown_status(handler, opt, handler->sec_to_boot);
                handler->sec_to_boot--;
@@ -1453,13 +1456,22 @@ static struct discover_boot_option *find_boot_option_by_id(
 }
 
 void device_handler_boot(struct device_handler *handler,
-               struct boot_command *cmd)
+               bool change_default, struct boot_command *cmd)
 {
        struct discover_boot_option *opt = NULL;
 
        if (cmd->option_id && strlen(cmd->option_id))
                opt = find_boot_option_by_id(handler, cmd->option_id);
 
+       /* Don't allow a normal client to change the default */
+       if (!change_default && handler->last_boot_option &&
+                       opt != handler->last_boot_option) {
+               pb_log("Non-root user tried to change boot option\n");
+               device_handler_status_err(handler,
+                               "Must be root to change default boot option\n");
+               return;
+       }
+
        if (handler->pending_boot)
                boot_cancel(handler->pending_boot);