In rtl92de_tx_fill_cmddesc(), skb->data is mapped to streaming DMA on
line 667:
dma_addr_t mapping = dma_map_single(..., skb->data, ...);
On line 669, 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 670:
__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@xxxxxxxxx>
---
drivers/net/wireless/realtek/rtlwifi/rtl8192de/trx.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/trx.c
index 8944712274b5..c02813fba934 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/trx.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/trx.c
@@ -664,12 +664,14 @@ void rtl92de_tx_fill_cmddesc(struct ieee80211_hw *hw,
struct rtl_ps_ctl *ppsc = rtl_psc(rtlpriv);
struct rtl_hal *rtlhal = rtl_hal(rtlpriv);
u8 fw_queue = QSLT_BEACON;
- dma_addr_t mapping = dma_map_single(&rtlpci->pdev->dev, skb->data,
- skb->len, DMA_TO_DEVICE);
+
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)(skb->data);
__le16 fc = hdr->frame_control;
__le32 *pdesc = (__le32 *)pdesc8;
+ dma_addr_t mapping = dma_map_single(&rtlpci->pdev->dev, skb->data,
+ skb->len, DMA_TO_DEVICE);
+
if (dma_mapping_error(&rtlpci->pdev->dev, mapping)) {
rtl_dbg(rtlpriv, COMP_SEND, DBG_TRACE,
"DMA mapping error\n");
--
2.17.1
