SWRU455M February 2017 – October 2020 CC3120 , CC3120MOD , CC3130 , CC3135 , CC3135MOD , CC3220MOD , CC3220MODA , CC3220R , CC3220S , CC3220SF , CC3230S , CC3230SF , CC3235MODAS , CC3235MODASF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
The SimpleLink Wi-Fi device provides a software tamper detection procedure with a security-alert counter. This procedure can help detect an integrity violation of file system data, the content of a secure-authenticate file, and system files. This procedure can also help detect unauthorized operations, such as trying to read a secure file with an invalid token.
When detecting data tampering, the device data-tampering procedure increases the system security-alert counter, and when the system reaches the security-alert (configured) threshold, the file system is locked. The host receives a lock asynchronous event when the file system is locked (SL_ERROR_DEVICE_LOCKED_SECURITY_ALERT), and each call from the host to a file system interface results in SL_ERROR_FS_FILE_SYSTEM_IS_LOCKED or SL_RET_CODE_DEV_LOCKED.
A locked device provides the host with limited access; to recover from a locked device (if the reason is a security alert), the device can be reprogrammed or recovered using the restore to factory method. The security-alert counter is a persistent counter, and can be set to zero only by the programming or recovery functions.
The default security alerts threshold is set by the UniFlash Image Creator. The host can retrieve the current number of security alerts and the defined threshold using the function sl_FsCtl(SL_FS_CTL_GET_STORAGE_INFO..). This function is also enabled when the device is locked.
There are two kinds of security alerts: