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SubjectRe: Ping with a 65510 bytes pack
On Sat, 19 Oct 1996, Jon Lewis wrote:

> Could you just do something like this before trashing the packet?
>
> printk("Invalid packet received from %s\n",in_ntoa(skb->saddr));
>
> It would be interesting to log attempts to crash our systems.

It doesn't seem to work, Jon. I put the line above before put the big
packet in trash. Take a look on what I got ... The address returned seemd
to be kind of randomic. It should be 200.18.234.2. And I have only issued
two big pings ... why do the syslog points 3 attempts ?!

Script started on Sat Oct 19 19:44:13 1996
ZeTrovao:/var/log# tail syslog
Oct 19 19:36:50 ZeTrovao kernel: NE*000 ethercard probe at 0x340: 00 40 05 19 8d 3c
Oct 19 19:36:50 ZeTrovao kernel: eth0: NE2000 found at 0x340, using IRQ 5.
Oct 19 19:36:50 ZeTrovao kernel: Partition check:
Oct 19 19:36:50 ZeTrovao kernel: hda:Started kswapd v 1.4.2.2
Oct 19 19:36:50 ZeTrovao kernel: hda1 hda2 hda3
Oct 19 19:36:50 ZeTrovao kernel: VFS: Mounted root (ext2 filesystem) readonly.
Oct 19 19:36:50 ZeTrovao kernel: Adding Swap: 16124k swap-space
Oct 19 19:42:53 ZeTrovao kernel: Invalid packet size received from 0.240.155.0
Oct 19 19:43:12 ZeTrovao kernel: Invalid packet size received from 0.240.155.0
Oct 19 19:44:00 ZeTrovao kernel: Invalid packet size received from 108.109.110.111
ZeTrovao:/var/log# exit
exit

Script done on Sat Oct 19 19:44:29 1996

Here is what I did in ip_fragment.c:

/*
* Attempt to construct an oversize packet.
*/
if(ntohs(iph->tot_len)+(int)offset>65535)
{
printk("Invalid packet size received from %s\n",in_ntoa(skb->saddr));
skb->sk = NULL;
frag_kfree_skb(skb, FREE_READ);
ip_statistics.IpReasmFails++;
return NULL;
}
/*
* Determine the position of this fragment.
*/

Is there anything wrong ?!

Best Regards from :

Bruno Kraychete da Costa Voice: +55(71)382-2834
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