| From | Greg Kroah-Hartman <> | Subject | [ 064/102] asix: fix BUG in receive path when lowering MTU | Date | Fri, 17 May 2013 14:36:19 -0700 |
| |
3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: "holger@eitzenberger.org" <holger@eitzenberger.org>
[ 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> --- drivers/net/usb/asix_common.c | 3 +++ 1 file changed, 3 insertions(+)
--- 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 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; }
|