[PATCH 52/81] netxen: fix off by one bug in netxen_release_tx_buffer()

[Herton Ronaldo Krzesinski]

3.5.7.6 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@xxxxxxxxxx>

commit a05948f296ce103989b28a2606e47d2e287c3c89 upstream.

Christoph Paasch found netxen could trigger a BUG in its dismantle
phase, in netxen_release_tx_buffer(), using full size TSO packets.

cmd_buf->frag_count includes the skb->data part, so the loop must
start at index 1 instead of 0, or else we can make an out
of bound access to cmd_buff->frag_array[MAX_SKB_FRAGS + 2]

Christoph provided the fixes in netxen_map_tx_skb() function.
In case of a dma mapping error, its better to clear the dma fields
so that we don't try to unmap them again in netxen_release_tx_buffer()

Reported-by: Christoph Paasch <christoph.paasch@xxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Tested-by: Christoph Paasch <christoph.paasch@xxxxxxxxxxxx>
Cc: Sony Chacko <sony.chacko@xxxxxxxxxx>
Cc: Rajesh Borundia <rajesh.borundia@xxxxxxxxxx>
Signed-off-by: Christoph Paasch <christoph.paasch@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
---
 .../net/ethernet/qlogic/netxen/netxen_nic_init.c   |    2 +-
 .../net/ethernet/qlogic/netxen/netxen_nic_main.c   |    2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c b/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c
index 8694124..fdddfcc 100644
--- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c
+++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c
@@ -144,7 +144,7 @@ void netxen_release_tx_buffers(struct netxen_adapter *adapter)
 					 buffrag->length, PCI_DMA_TODEVICE);
 			buffrag->dma = 0ULL;
 		}
-		for (j = 0; j < cmd_buf->frag_count; j++) {
+		for (j = 1; j < cmd_buf->frag_count; j++) {
 			buffrag++;
 			if (buffrag->dma) {
 				pci_unmap_page(adapter->pdev, buffrag->dma,
diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
index a77c558..d6a8218 100644
--- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
+++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c
@@ -1963,10 +1963,12 @@ unwind:
 	while (--i >= 0) {
 		nf = &pbuf->frag_array[i+1];
 		pci_unmap_page(pdev, nf->dma, nf->length, PCI_DMA_TODEVICE);
+		nf->dma = 0ULL;
 	}
 
 	nf = &pbuf->frag_array[0];
 	pci_unmap_single(pdev, nf->dma, skb_headlen(skb), PCI_DMA_TODEVICE);
+	nf->dma = 0ULL;
 
 out_err:
 	return -ENOMEM;
-- 
1.7.9.5

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