Re: [PATCH 5.10 036/252] ath10k: drop MPDU which has discard flag set by firmware for SDIO

Hi!

commit 079a108feba474b4b32bd3471db03e11f2f83b81 upstream.

When the discard flag is set by the firmware for an MPDU, it should be dropped. This allows a mitigation for CVE-2020-24588 to be implemented in the firmware.

Tested-on: QCA6174 hw3.2 SDIO WLAN.RMH.4.4.1-00049

This introduces bitfields for communication with firmware.

+++ b/drivers/net/wireless/ath/ath10k/rx_desc.h @@ -1282,7 +1282,19 @@ struct fw_rx_desc_base { #define FW_RX_DESC_UDP (1 << 6) struct fw_rx_desc_hl {

• u8 info0;

• union {

• struct {
  

• u8 discard:1,
  

•    forward:1,
  

•    any_err:1,
  

•    dup_err:1,
  

•    reserved:1,
  

•    inspect:1,
  

•    extension:2;
  

• } bits;
  

• u8 info0;
  

• } u;

That is a) quite unusual (see the define just above) and b) very fragile AFAICT. Compilers on LE and BE machines behave differently, for example. Should it use usual bit manipulation functions?

Best regards, Pavel