net: qrtr: start MHI channel after endpoit creation

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: start MHI channel after endpoit creation MHI channel may generates event/interrupt right after enabling. It may leads to 2 race conditions issues. 1) Such event may be dropped by qcom_mhi_qrtr_dl_callback() at check: if (!qdev || mhi_res->transaction_status) return; Because dev_set_drvdata(&mhi_dev->dev, qdev) may be not performed at this moment. In this situation qrtr-ns will be unable to enumerate services in device. --------------------------------------------------------------- 2) Such event may come at the moment after dev_set_drvdata() and before qrtr_endpoint_register(). In this case kernel will panic with accessing wrong pointer at qcom_mhi_qrtr_dl_callback(): rc = qrtr_endpoint_post(&qdev->ep, mhi_res->buf_addr, mhi_res->bytes_xferd); Because endpoint is not created yet. -------------------------------------------------------------- So move mhi_prepare_for_transfer_autoqueue after endpoint creation to fix it.

References

• https://git.kernel.org/stable/c/c682fb70a7dfc25b848a4ff3a385b0471b470606
• https://git.kernel.org/stable/c/a1a75f78a2937567946b1b756f82462874b5ca20
• https://git.kernel.org/stable/c/68a838b84effb7b57ba7d50b1863fc6ae35a54ce