Re: Memory corruption in 8390.c ?

From: Ben Pfaff
Date: Wed Jun 21 2006 - 13:21:54 EST


Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> writes:

> --- drivers/net/8390.c~ 2006-06-21 17:41:12.006145536 +0100
> +++ drivers/net/8390.c 2006-06-21 17:41:12.007145384 +0100
> @@ -275,12 +275,14 @@
> struct ei_device *ei_local = (struct ei_device *) netdev_priv(dev);
> int send_length = skb->len, output_page;
> unsigned long flags;
> + char buf[64];
> + char *data = skb->data;
>
> if (skb->len < ETH_ZLEN) {
> - skb = skb_padto(skb, ETH_ZLEN);
> - if (skb == NULL)
> - return 0;
> + memset(buf, 0, ETH_ZLEN); /* more efficient than doing just the needed bits */
> + memcpy(buf, data, ETH_ZLEN);

Is this really correct? It zeros out ETH_ZLEN bytes only to
immediately copy over all of them again.

> send_length = ETH_ZLEN;
> + data = buf;
> }
>
> /* Mask interrupts from the ethercard.
> @@ -347,7 +349,7 @@
> * trigger the send later, upon receiving a Tx done interrupt.
> */
>
> - ei_block_output(dev, send_length, skb->data, output_page);
> + ei_block_output(dev, send_length, data, output_page);
>
> if (! ei_local->txing)
> {


--
Ben Pfaff
email: blp@xxxxxxxxxxxxxxx
web: http://benpfaff.org

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