redonkable/alistair23-linux
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qlcnic: dont assume NET_IP_ALIGN is 2

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qlcnic driver allocates rx skbs and gives to hardware too bytes of extra
storage, allowing for corruption of kernel data.

NET_IP_ALIGN being 0 on some platforms (including x86), drivers should
not assume it's 2.

rds_ring->skb_size = rds_ring->dma_size + NET_IP_ALIGN;
...
skb = dev_alloc_skb(rds_ring->skb_size);
skb_reserve(skb, 2);
pci_map_single(pdev, skb->data, rds_ring->dma_size, PCI_DMA_FROMDEVICE);

(and rds_ring->skb_size == rds_ring->dma_size) -> bug


Because of extra alignment (1500 + 32) -> four extra bytes are available
before the struct skb_shared_info, so corruption is not noticed.

Note: this driver could use netdev_alloc_skb_ip_align()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-09-17 22:58:08 -07:00 committed by David S. Miller
parent 4e8cec269d
commit 04746ff128
1 changed files with 1 additions and 1 deletions
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2
drivers/net/qlcnic/qlcnic_init.c
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@ -1316,7 +1316,7 @@ qlcnic_alloc_rx_skb(struct qlcnic_adapter *adapter,
return -ENOMEM;
}
skb_reserve(skb, 2);
skb_reserve(skb, NET_IP_ALIGN);
dma = pci_map_single(pdev, skb->data,
rds_ring->dma_size, PCI_DMA_FROMDEVICE);