In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Automobile and Snapdragon Mobile SD 820 and SD 820A, the input to RPMB write response function is a buffer from HLOS that needs to be authenticated (using HMAC) and then processed. However, some of the processing occurs before the buffer is authenticated. The function will return various types of errors depending on the values of the `response` and `result` fields of the buffer before verifying the HMAC tag.

In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Automobile and Snapdragon Mobile SD 820 and SD 820A, the input to RPMB write response function is a buffer from HLOS that needs to be authenticated (using HMAC) and then processed. However, some of the processing occurs before the buffer is authenticated. The function will return various types of errors depending on the values of the `response` and `result` fields of the buffer before verifying the HMAC tag.