oss-security - Re: CVE request (sort of): Quagga BGP crasher

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Date: Fri, 01 May 2009 22:03:35 +0200
From: Florian Weimer <fw@...eb.enyo.de>
To: oss-security@...ts.openwall.com
Subject: Re: CVE request (sort of): Quagga BGP crasher

* Jon Oberheide:

> Looks like the Quagga code in bgp_aspath.c is assuming that converting
> each ASN of the AS path to a string will be 5 bytes plus a space
> (#define ASN_STR_LEN (5 + 1)).  Therefore, it allocates (ASN_STR_LEN *
> the number of ASNs in the path segment) bytes to snprintf into when
> creating the pretty-print version of the AS path.

Sure, this is the part I understand.  It's not clear why this code is
hit when there isn't much logging going on.  People have also run
"show ip bgp ROUTE" for paths with six-digit ASNs, with
supposedly-broken bgpd versions, and did not observe a crash.

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