Messages in this thread Patch in this message | | | From | Jia-Ju Bai <> | Subject | [PATCH v2 3/4 resend] rtlwifi: rtl8192de: avoid accessing the data mapped to streaming DMA | Date | Thu, 19 Nov 2020 09:52:05 +0800 |
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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@gmail.com> --- v2: * Use "rtlwifi" as subject prefix and have all rtlwifi patches in the same pathset. Thank Ping and Larry for good advice.
--- 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
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