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rt2x00: Fix double usage of skb->cb in USB RX path.

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It is not safe to use the skb->cb area for both the rxd and
skb_frame_desc data at the same time, while they occupy an overlapping
piece of memory. This can lead to hard to trace crashes as pointers
within skb_frame_desc are pointing into nowhere, or the rxd data is
overwritten with non-sense.

Fix it by copying the rxd to a small buffer on the stack.

Signed-off-by: Gertjan van Wingerde <gwingerde@kpnplanet.nl>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Gertjan van Wingerde
2008-06-06 22:54:28 +02:00
committed by John W. Linville
parent 239c249d06
commit a26cbc6508
3 changed files with 9 additions and 19 deletions
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8
drivers/net/wireless/rt2x00/rt2x00usb.c
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@@ -267,6 +267,7 @@ static void rt2x00usb_interrupt_rxdone(struct urb *urb)
struct sk_buff *skb;
struct skb_frame_desc *skbdesc;
struct rxdone_entry_desc rxdesc;
u8 rxd[32];
if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags) ||
!test_and_clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags))
@@ -286,15 +287,12 @@ static void rt2x00usb_interrupt_rxdone(struct urb *urb)
skbdesc = get_skb_frame_desc(entry->skb);
memset(skbdesc, 0, sizeof(*skbdesc));
skbdesc->entry = entry;
skbdesc->desc = rxd;
skbdesc->desc_len = entry->queue->desc_size;
memset(&rxdesc, 0, sizeof(rxdesc));
rt2x00dev->ops->lib->fill_rxdone(entry, &rxdesc);
/*
* Trim the skb to the correct size.
*/
skb_trim(entry->skb, rxdesc.size);
/*
* Allocate a new sk buffer to replace the current one.
* If allocation fails, we should drop the current frame