From: Malcolm Priestley <tvboxspy@gmail.com>
Date: Thu, 11 May 2017 17:57:43 +0000 (+0100)
Subject: staging: rtl8192e: rtl92e_fill_tx_desc fix write to mapped out memory.
X-Git-Tag: v4.11.3~45
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d92507d9e5b03f3e12c38108015d80f9cd5ff447;p=thirdparty%2Fkernel%2Fstable.git

staging: rtl8192e: rtl92e_fill_tx_desc fix write to mapped out memory.

commit baabd567f87be05330faa5140f72a91960e7405a upstream.

The driver attempts to alter memory that is mapped to PCI device.

This is because tx_fwinfo_8190pci points to skb->data

Move the pci_map_single to when completed buffer is ready to be mapped with
psdec is empty to drop on mapping error.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c b/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c
index 8d6bca61e7aad..fa1440e15382c 100644
--- a/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c
+++ b/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c
@@ -1184,8 +1184,7 @@ void  rtl92e_fill_tx_desc(struct net_device *dev, struct tx_desc *pdesc,
 			  struct cb_desc *cb_desc, struct sk_buff *skb)
 {
 	struct r8192_priv *priv = rtllib_priv(dev);
-	dma_addr_t mapping = pci_map_single(priv->pdev, skb->data, skb->len,
-			 PCI_DMA_TODEVICE);
+	dma_addr_t mapping;
 	struct tx_fwinfo_8190pci *pTxFwInfo;
 
 	pTxFwInfo = (struct tx_fwinfo_8190pci *)skb->data;
@@ -1196,8 +1195,6 @@ void  rtl92e_fill_tx_desc(struct net_device *dev, struct tx_desc *pdesc,
 	pTxFwInfo->Short = _rtl92e_query_is_short(pTxFwInfo->TxHT,
 						  pTxFwInfo->TxRate, cb_desc);
 
-	if (pci_dma_mapping_error(priv->pdev, mapping))
-		netdev_err(dev, "%s(): DMA Mapping error\n", __func__);
 	if (cb_desc->bAMPDUEnable) {
 		pTxFwInfo->AllowAggregation = 1;
 		pTxFwInfo->RxMF = cb_desc->ampdu_factor;
@@ -1232,6 +1229,14 @@ void  rtl92e_fill_tx_desc(struct net_device *dev, struct tx_desc *pdesc,
 	}
 
 	memset((u8 *)pdesc, 0, 12);
+
+	mapping = pci_map_single(priv->pdev, skb->data, skb->len,
+				 PCI_DMA_TODEVICE);
+	if (pci_dma_mapping_error(priv->pdev, mapping)) {
+		netdev_err(dev, "%s(): DMA Mapping error\n", __func__);
+		return;
+	}
+
 	pdesc->LINIP = 0;
 	pdesc->CmdInit = 1;
 	pdesc->Offset = sizeof(struct tx_fwinfo_8190pci) + 8;