Re: SNMP query to icon with no attributes

Juergen Schoenwaelder (schoenw@cs.utwente.nl)
Thu, 12 Sep 1996 15:52:01 +0200

Jan Klingel <klingel@erls02.siemens.de> said:

Jan> I have got a icon with no attributes and did a SNMP system information
Jan> query on this icon. After waiting a little bit I got back a

Jan> correo.ceit.es [193.145.249.210] [Thu Sep 12 11:11:42 1996]:

Jan> Our domain is the erls02.siemens.de domain and we are sitting behind a
Jan> firewall. Is this the reason for the strange behaviour of Tkined?

Jan helped me to understand the problem by sending me the output of
some tests. I finally came to the conclusion that this machine (a
Linux box) returns bogus results if you call gethostbyname() with an
empty string.

There was also a CERT advisory a couple of weeks ago about security
problems caused by resolver libraries that do not carefully check the
allowed character set in host names.

I decided to add some code that does strict checks whenever the Tnm
extension tries to call the resolver. This will make the behaviour
platform independent (and it does solve this problem). This change
should not break existing code - at least as long as you use only the
allowed character set in your host names. ;-)

Juergen

--
Juergen Schoenwaelder schoenw@cs.utwente.nl http://www.cs.utwente.nl/~schoenw
Computer Science Department, University of Twente,   (Fax: +31-53-489-3247)
P.O. Box 217, NL-7500 AE Enschede, The Netherlands.  (Tel. +31-53-489-3678)