filter imports in safe mode

basvs · basvs · commit 3f8f88a6fab2 · 2017-08-07T12:32:01.000+02:00
diff --git a/esp32/main.c b/esp32/main.c
@@ -76,6 +76,44 @@ STATIC uint8_t mp_task_heap[MP_TASK_HEAP_SIZE];
 extern uint32_t reset_cause;
 extern bool in_safe_mode;
 
+static const char *import_blacklist[] = {
+	"/lib/json",
+	"/lib/os",
+	"/lib/socket",
+	"/lib/struct",
+	"/lib/time",
+};
+
+mp_import_stat_t
+mp_import_stat(const char *path) {
+	if (in_safe_mode) {
+		// be more strict in which modules we would like to load
+		if (strncmp(path, "/lib/", 5) != 0) {
+			return MP_IMPORT_STAT_NO_EXIST;
+		}
+
+		/* check blacklist */
+		int i;
+		for (i=0; i<sizeof(import_blacklist)/sizeof(const char *); i++) {
+			if (strcmp(path, import_blacklist[i]) == 0) {
+				return MP_IMPORT_STAT_NO_EXIST;
+			}
+		}
+
+		const char *x = index(&path[5], '/');
+		if (x == NULL) {
+			// only allow directories
+			mp_import_stat_t res = mp_vfs_import_stat(path);
+			if (res != MP_IMPORT_STAT_DIR) {
+				return MP_IMPORT_STAT_NO_EXIST;
+			}
+			return res;
+		}
+	}
+
+    return mp_vfs_import_stat(path);
+}
+
 void mp_task(void *pvParameter) {
     volatile uint32_t sp = (uint32_t)get_sp();
     #if MICROPY_PY_THREAD
diff --git a/esp32/mpconfigport.h b/esp32/mpconfigport.h
@@ -159,8 +159,7 @@
 #define MICROPY_SDMMC_USE_DRIVER            (1)
 #define MICROPY_SDMMC_SHOW_INFO             (1)
 
-// use vfs's functions for import stat and builtin open
-#define mp_import_stat mp_vfs_import_stat
+// use vfs's functions for builtin open
 #define mp_builtin_open mp_vfs_open
 #define mp_builtin_open_obj mp_vfs_open_obj
 
