permalocked_devices_kernel_modules_header.md

Note for permanently-locked devices' kernel modules

Huawei, to prevent existing (sim-unlocking) kernel modules from being loaded, has changed kernel module header layout on permanently-locked devices with 329+ operator firmware. Now the kernel header is one DWORD (4 bytes) larger. The latest DWORD gets dereferenced, which causes kernel panic of the device on insmod.

The easiest way to fix that is as follows:

--- include/linux/module.h      2020-04-23 21:20:38.354018956 +0300
+++ include/linux/module.h      2020-04-23 21:20:46.116095477 +0300
@@ -225,7 +225,8 @@
        struct list_head list;
 
        /* Unique handle for this module */
-       char name[MODULE_NAME_LEN];
+       char name[MODULE_NAME_LEN + 4]; // for 333 firmware, with signature
+//     char name[MODULE_NAME_LEN]; // for 328 firmware, without signature
 
        /* Sysfs stuff. */
        struct module_kobject mkobj;

Global non-locked 329+ firmware have only X.509 digital signature, which is already patched by patchblocked.sh (in huawei_balong_modfw_kitchen), without header modification.