lkml.org 
[lkml]   [2020]   [Nov]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.19 023/191] p54: avoid accessing the data mapped to streaming DMA
Date
From: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>

commit 478762855b5ae9f68fa6ead1edf7abada70fcd5f upstream.

In p54p_tx(), skb->data is mapped to streaming DMA on line 337:
mapping = pci_map_single(..., skb->data, ...);

Then skb->data is accessed on line 349:
desc->device_addr = ((struct p54_hdr *)skb->data)->req_id;

This access may cause data inconsistency between CPU cache and hardware.

To fix this problem, ((struct p54_hdr *)skb->data)->req_id is stored in
a local variable before DMA mapping, and then the driver accesses this
local variable instead of skb->data.

Cc: <stable@vger.kernel.org>
Signed-off-by: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200802132949.26788-1-baijiaju@tsinghua.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/intersil/p54/p54pci.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/wireless/intersil/p54/p54pci.c
+++ b/drivers/net/wireless/intersil/p54/p54pci.c
@@ -332,10 +332,12 @@ static void p54p_tx(struct ieee80211_hw
struct p54p_desc *desc;
dma_addr_t mapping;
u32 idx, i;
+ __le32 device_addr;

spin_lock_irqsave(&priv->lock, flags);
idx = le32_to_cpu(ring_control->host_idx[1]);
i = idx % ARRAY_SIZE(ring_control->tx_data);
+ device_addr = ((struct p54_hdr *)skb->data)->req_id;

mapping = pci_map_single(priv->pdev, skb->data, skb->len,
PCI_DMA_TODEVICE);
@@ -349,7 +351,7 @@ static void p54p_tx(struct ieee80211_hw

desc = &ring_control->tx_data[i];
desc->host_addr = cpu_to_le32(mapping);
- desc->device_addr = ((struct p54_hdr *)skb->data)->req_id;
+ desc->device_addr = device_addr;
desc->len = cpu_to_le16(skb->len);
desc->flags = 0;


\
 
 \ /
  Last update: 2020-11-03 22:02    [W:0.653 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site