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| author | holger@eitzenberger.org <holger@eitzenberger.org> | 2013-05-03 00:02:20 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-19 11:38:36 -0700 |
| commit | 0699987cf38e112c5a8a02452bf7e92c23f6c26a (patch) | |
| tree | 1d9fc07fcef62e47205e42e3b83ccf8da83984bd | |
| parent | 4b44cbc7a2395229ab3e7b9165fc5dfee3145208 (diff) | |
| download | lwn-0699987cf38e112c5a8a02452bf7e92c23f6c26a.tar.gz lwn-0699987cf38e112c5a8a02452bf7e92c23f6c26a.zip | |
asix: fix BUG in receive path when lowering MTU
[ Upstream commit c5060cec6ba27ad3f0e7facfdf05d2f18e3e3010 ]
There is bug in the receive path of the asix driver at the time a
packet is received larger than MTU size and DF bit set:
BUG: unable to handle kernel paging request at 0000004000000001
IP: [<ffffffff8126f65b>] skb_release_head_state+0x2d/0xd2
...
Call Trace:
<IRQ>
[<ffffffff8126f86d>] ? skb_release_all+0x9/0x1e
[<ffffffff8126f8ad>] ? __kfree_skb+0x9/0x6f
[<ffffffffa00b4200>] ? asix_rx_fixup_internal+0xff/0x1ae [asix]
[<ffffffffa00fb3dc>] ? usbnet_bh+0x4f/0x226 [usbnet]
...
It is easily reproducable by setting an MTU of 512 e. g. and sending
something like
ping -s 1472 -c 1 -M do $SELF
from another box.
And this is because the rx->ax_skb is freed on error, but rx->ax_skb
is not reset, and the size is not reset to zero in this case.
And since the skb is added again to the usbnet->done skb queue it is
accessing already freed memory, resulting in the BUG when freeing a
2nd time. I therefore think the value 0x0000004000000001 show in the
trace is more or less random data.
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/usb/asix_common.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c index f7f623a5390e..577c72d5f369 100644 --- a/drivers/net/usb/asix_common.c +++ b/drivers/net/usb/asix_common.c @@ -100,6 +100,9 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb, netdev_err(dev->net, "asix_rx_fixup() Bad RX Length %d\n", rx->size); kfree_skb(rx->ax_skb); + rx->ax_skb = NULL; + rx->size = 0U; + return 0; } |