[ 29/61] netxen: fix off by one bug in netxen_release_tx_buffer()

Greg Kroah-Hartman
2013-02-12T21:04:15Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit a05948f296ce103989b28a2606e47d2e287c3c89 ]

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@uclouvain.be>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Cc: Sony Chacko <sony.chacko@qlogic.com>
Cc: Rajesh Borundia <rajesh.borundia@qlogic.com>
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c | 2 +-
drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)

--- 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 ne
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,
--- 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;