Wireshark-bugs: [Wireshark-bugs] [Bug 6302] OSPF LSA length minimum values

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Date: Mon, 30 Sep 2013 20:54:20 +0000

changed bug 6302

What Removed Added
CC   [email protected]

Comment # 11 on bug 6302 from
I had a look at both capture files and the frames marked by Wireshark as
"Malformed", are malformed indeed.

Capture 1 / bug6302-sample1.pcap

Frame 27:

Right after the flags field is a 1 byte "reserved" field, followed by a 2 byte
"links" field. However the links field is only 1 byte long in that case and
hence the frame is malformed.

http://tools.ietf.org/html/rfc2328#appendix-A.4.2

The links field with its 2 bytes is always there, but could have a value of 0
in case of Virtual Links for example.



Capture 2 / bug6302-sample2.pcap

Frame: 29 and 32

They both contain a Type 5 (AS-External) LSA which is supposed to always have a
4 byte "tag" field at the end. However it is only 3 bytes long which makes the
frame malformed.


Short summary:

Wireshark's length field calculations were in all cases correct, but your
captured malformed frames look like they are truncated by 1 byte. To me it
doesn't look like a Wireshark bug, but more like a bug in the software
generating those frames.


Best regards,

Jochen

Tested with: Version 1.11.0 (SVN Rev 52063 from master)


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