rtlwifi: rtl8723ae: avoid accessing the data mapped to streaming DMA

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In rtl8723e_tx_fill_cmddesc(), skb->data is mapped to streaming DMA on
line 531:
  dma_addr_t mapping = dma_map_single(..., skb->data, ...);

On line 534, skb->data is assigned to hdr after cast:
  struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)(skb->data);

Then hdr->frame_control is accessed on line 535:
  __le16 fc = hdr->frame_control;

This DMA access may cause data inconsistency between CPU and hardwre.

To fix this bug, hdr->frame_control is accessed before the DMA mapping.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201119015218.12220-1-baijiaju1990@gmail.com

...

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Jia-Ju Bai 2020-11-19 09:52:18 +08:00 • committed by Kalle Valo

parent ff76548338

commit 8b2c13b2e5

1 changed files with 3 additions and 3 deletions

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drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.c

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