DoS - Linux 2.0.33 printk()

James Thomason (james@exodus.net)
Sun, 19 Apr 1998 00:20:38 -0700

Looks like there is another DoS floating around. This one apparently eats
CPU by
abusing the printk() function. (I havent looked in detail, so correct me
if I'm wrong).

Originally from rootshell:

http://www.rootshell.com/archiveybhats7qq2cdgmj6/199804/overdrop.c

Patch is included.

Regards,
James Thomason

-------------------
Snip
-------------------
Here's a DoS exploit against Linux 2.0.33... It doesn't crash
anything, but it's very annoying ;)

Fix:

--- ip_fragment.c.orig Fri Apr 17 16:42:38 1998
+++ ip_fragment.c Fri Apr 17 17:17:15 1998
@@ -345,7 +345,7 @@

if(len>65535)
{
- printk("Oversized IP packet from %s.\n",
in_ntoa(qp->iph->saddr));
+ NETDEBUG(printk("Oversized IP packet from %s.\n",
in_ntoa(qp->iph->saddr)));
ip_statistics.IpReasmFails++;
ip_free(qp);
return NULL;

-
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