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
if (ret == 0 && resp_len) {
*resp_len = min(*resp_len, xfer.resp_len);
- memcpy(resp, tresp, xfer.resp_len);
+ memcpy(resp, tresp, *resp_len);
}
err_dma:
kfree(treq);