Wireshark · Wireshark-commits: [Wireshark-commits] rev 45216: /trunk/epan/dissectors/ /trunk/epan/dissectors/: packet-bgp.c

[alagoutte@xxxxxxxxxxxxx]

http://anonsvn.wireshark.org/viewvc/viewvc.cgi?view=rev&revision=45216

User: alagoutte
Date: 2012/09/30 03:05 AM

Log:
 From Olivier Benghozi via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=7734
 BGP bad decoding for Graceful Restart Capability with only helper support
 
 BGP Capability in OPEN message: Graceful restart capability (64).
 
 So when the length of the capability value is smaller that 6 (6 meaning full
 support of GR capa, with significants elements and at least one AFI/SAFI), the
 code interprets it as erroneous.
 
 However,as described in RFC4724: " When a sender of this capability does not
 include any <AFI, SAFI> in the capability, it means that the sender is not
 capable of preserving its forwarding state during BGP restart, but supports
 procedures for the Receiving Speaker (as defined in Section 4.2 of this
 document). In that case, the value of the Restart Time field advertised by the
 sender is irrelevant".
 
 So, length of exactly 2 is valid but has to be interpreted with a particular
 meaning.
 
 In the dissector code, a length of 2 should be a special case for this capa,
 decoding as "Graceful Restart helper mode only" or something like that, and
 maybe also displaying an expert message if the Restart flag is not 0 in this
 case, since here it's not expected to be possible.

Directory: /trunk/epan/dissectors/
  Changes    Path            Action
  +6 -1      packet-bgp.c    Modified