ath10k: pci: fix memcpy size of bmi response
A compromized ath10k peripheral is able to control the size argument
of memcpy in ath10k_pci_hif_exchange_bmi_msg.
The min result from previous line is not used as the size argument
for memcpy. Instead, xfer.resp_len comes from untrusted stream dma
input. The value comes from "nbytes" in ath10k_pci_bmi_recv_data,
which is set inside _ath10k_ce_completed_recv_next_nolock with the line
nbytes = __le16_to_cpu(sdesc.nbytes);
sdesc is a stream dma region which device can write to.
Signed-off-by: Zekun Shen <bruceshenzk@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200616132544.17478-1-bruceshenzk@gmail.com
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