Re: Linux 2.0.33 vulnerability: oversized packets

From: Jon Lewis (jlewisat_private)
Date: Mon Apr 20 1998 - 22:34:52 PDT

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    On Fri, 17 Apr 1998, Michal Zalewski wrote:
    
    > I'm not sure if it's known, but I haven't found anything about it.
    > No matter, there's something strange in net/ipv4/ip_fragment.h (it's
    > probably Alan's fault):
    >
    > if(len>65535)
    > {
    >         printk("Oversized IP packet from %s.\n", in_ntoa(qp->iph->saddr));
    
    Actually, I think I have to take credit for that.  I don't remember if the
    original (Alan's) patch printk'd at all (I don't think it did)...but I
    know I was the one who wanted to see claimed source addresses.  Belive it
    or not, I caught one of our own users trying to crash our mail server
    about an hour after adding the fix with the printk.  Can you say luserdel?
    
    Rather than use NETDEBUG to totally disable the printk, I think it might
    be more useful to put in some code to limit frequency of reporting...sort
    of like Solar Designer's secure-linux patch's security_alert() function
    does.
    
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     Jon Lewis <jlewisat_private>  |
     Network Administrator       |
     Florida Digital Turnpike    |
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