[Quagga-bugs] [Bug 396] BGPD on SPARC64 crashes all BGP sessions if the updates contain too many AS numbers

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http://bugzilla.quagga.net/show_bug.cgi?id=396  
  




------- Additional Comments From chrisbinnie at gmail.com  2007-08-21 20:06 -------
Please see some of the requested info below.

     The AS path that caused the problem was: 3257 18747 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803 27803
27803 27803 27803 27803 27803 27803 27803 I make this 130 AS numbers long.

     This caused SIGBUS error (signal 10), probably due to the BGP path
attribute (AS path in this case) having the extended length bit set and using
bytes 3 & 4 of the attribute to hold the length information. Process dead after
this of course.

    This is actually a legal path in BGP however, despite the length, though
obviously it has no legitimate real world use.

    Quagga should have parsed this correctly without crashing (the SIGBUS
causing a complete crash is never a desirable outcome), and perhaps should have
a feature similar to the Cisco IOS command ‘bgp maxas-limit’ which discards
paths longer than a set value.

     For an independent confirmation the Team Cymru Internet Monitor
(http://www.cymru.com/BGP/max_aspath_len.html) recorded this path overnight on
the 20th of August.

   
  
  
  
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