November 1997 - Test - lists.nanog.org

Re: Potentially dangerous Pentium bug disc
by Michael McArthur 12 Nov '97

12 Nov '97

On Wed, 12 Nov 1997, Michael 'Moose' Dinn wrote: > > Does anybody know if this affects the Cyrix and AMD "Pentium > > Clone" chips? > > > > It certainly affects the Cyrix - both P166+ and P200+. Don't know about the > Cyrix MX and the AMD tho. > > -- That's the problem -- it isn't a "bug", just an exploitable instruction set that Cyrix, AMD, et al have been faithfully copying. For that matter, the 486 instruction set is a subset of the Pentium instruction set. Does this affect the 486/386 etc..?

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Potentially dangerous Pentium bug discovered
by Jay R. Ashworth 12 Nov '97

12 Nov '97

There tends to be a lot of the following sort of stuff that floats around unattributed, like the email viruses, and such. The following is documented, attributed, and _is_ something you should worry about. Please forward this message around your usual distribution lists. If you work at a company with lots of computers, you're invited to print this up and give it to the people who manage them for you. (If you have lots of computers at your company, and _no one_ to manage them for you, I'm looking for a new gig; have someone call me. :-) -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- This message was originated 11 November 1997, by jra(a)baylink.com... headers have a way of disappearing. Enclosed are four messages from the RISKS Digest, an email forum on risks to the public in computers and related systems, which is one of the oldest standing regular pieces of editory on the Internet. It documents a recently discovered bug in the Intel Pentium<tm> and MMX<tm> processors, which allows user-level code to halt the processor. This is bad because these chips commonly support multi-tasking, and often multi-user, systems; halting such systems arbitrarily can destroy users' work. There appears to be no way to work around this problem that has been discovered as of 11 Nov 97; the only thing I can suggest is be _exceptionally_ careful about running programs the parentage of which you're not certain on production machines... which is good practice, anyway. The first three messages detail the problem, in increasingly technical detail, including a program to demonstrate the problem, and one to search for files containing the deadly instruction; the last message discusses some of the potential implications, and why we should know better. By way of clarification, all processors have a halt instruction. All current multi-tasking operating systems run the processor in such a mode that such instructions are not actually executed as a halt; control is transferred back to the OS. That is: Intel blew it. Badly. RISKS-LIST: Risks-Forum Digest Tuesday 11 November 1997 Volume 19 : Issue 45 FORUM ON RISKS TO THE PUBLIC IN COMPUTERS AND RELATED SYSTEMS (comp.risks) ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator ***** See last item for further information, disclaimers, caveats, etc. ***** ------------------------------ Date: Tue, 11 Nov 1997 16:39:41 -0500 From: Chuck Weinstock <weinstock(a)SEI.CMU.EDU> Subject: New Pentium flaw To summarize, according to today's *Wall Street Journal*: The Pentium and Pentium MMX chips apparently can be halted by a single, unprotected, instruction. Over 200 million computers with these chips are expected to be deployed by year-end. My favorite quote from the article is by Linley Gwennap, editor of *Microprocessor Report* in Sunnyvale, who says that "most PC users shouldn't be overly concerned since they would only be affected if they were the target of a malicious attack." My second most favorite quote came from Tom Waldrop of Intel in Santa Clara who "confirmed that someone with malicious intent could exploit the flaw to cause a system to crash. But a hacker would have to have an ability to send programs to a computer in machine code, rather than the conventional computer languages that most programmers use." [We all know how hard that is...actually maybe these days it is, can we count on the fact that few people know how to write machine code these days?] Chuck Weinstock ------------------------------ Date: 09 Nov 1997 09:26:39 +0100 From: Torsten Hilbrich <Torsten.Hilbrich(a)bln.de> Subject: New Pentium flaw Yesterday (Nov, 8) I found the following information on the news-ticker page of the German Heise-Verlag (shortened to the essential information): > The Pentium in standard and MMX version halts on execution of the > instruction: > F0 0F C7 C8 > This code sequence works independent of any memory protection of the > operating system. I was able to reproduce this bug on a Pentium 133 system with the following operating systems: DOS, Windows 95, Linux 2.0.31, and FreeBSD 2.2.x. I don't know about PentiumPro and Pentium II. The risk? Every pentium based server with user access for executing programs can be crashed using this code sequence. Not to mention Trojan Horses or Active-X controls. Here is an example program: unsigned char hang[] = { 0xf0, 0x0f, 0xc7, 0xc8 }; int main() { void (*kill)(); kill = hang; kill(); /* return can be omitted as there is none */ } More information and example programs for various operating systems can be found on http://www.ccc.de Torsten Hilbrich [Also noted by Jeff Anderson-Lee <jonah(a)EECS.Berkeley.EDU> citing an item from Peter Curran in comp.security.unix, 7 Nov 1997. PGN] ------------------------------ Date: Mon, 10 Nov 1997 01:07:34 -0600 (CST) From: "Steven O. Siegfried" <sos(a)dial324.skypoint.net> Subject: New Pentium flaw New Intel Pentium risk: user mode program locks up system The following program, when compiled and run in __USER__ mode on any Pentium (reported as MMX or not, don't know about Pentium II yet) will lock-up the system. > char x [5] = { 0xf0, 0x0f, 0xc7, 0xc8 }; > main () > { > void (*f)() = x; > f(); > } Any user can execute this program at the lowest level of security provided by the following operating systems: OS/2, NT, W95, Linux. When I tried it, I could _only_ recover by power-cycling my box. The following perl script, courtesy of Sam Trenholme via the security mailing list at Redhat Software is reported to find _all_ occurences of this code sequence on systems running Linux. (It found my bomb program after I used it to kill my system as a test.) It can probably be adapted for use on other operating systems. > #!/usr/bin/perl > # Source: Sam Trenholme via linux-security(a)redhat.com mailing list. > # There is no known software fix to the F0 0F C7 C8 bug at this time. > # usage: $0 dir > # Where dir is the directory you recursively look at all programs in > # for instances of the F0 0F C7 C8 sequence. > # This script will search for programs with this sequence, which will > # help sysadmins take appropriate action against those running such > # programs. > # This script is written (but has not been tested) in Perl4, to > # insure maximum compatibility . > sub findit { > local($dir,$file,@files,$data) = @_; > undef $/; > if(!opendir(DIR,$dir)) { > print STDERR "Can not open $dir: $!\n"; > return 0; > } > @files=readdir(DIR); > foreach $file (@files) { > if($file ne '.' && $file ne '..') { > if( -f "$dir/$file" && open(FILE,"< $dir/$file")) { > $data=<FILE>; > if($data =~ /\xf0\x0f\xc7\xc8/) { > print "$dir/$file contains F0 0F C7 C8\n"; > } > } elsif( -d "$dir/$file") { > &findit("$dir/$file"); > } > } > } > } > $dir = shift || '/home'; > > &findit($dir); Basically, there's no protection from this. Adjust your execution of downline loaded absolutes accordingly. Steve Siegfried sos(a)skypoint.com sos1(a)xtl.msc.edu ------------------------------ Date: Sat, 8 Nov 1997 12:06:42 -0500 (EST) From: "Cary B. O'Brien" <cobrien(a)access.digex.net> Subject: Recent Pentium opcode bug like Monoclonal Agriculture [...] Once again I am reminded of the parallels between nearly complete market domination by a hardware or software product, and the risks of monoclonal agriculture (*). In either case a flaw (be it a hardware error, software bug, or susceptibility to a strain of bacteria or virus) has the potential to cripple an entire industry, with serious sociological consequences. (cf., the Irish Potato Famine). To me, at least, these parallels reinforce the importance of the government's responsibility to prevent monopolistic activity on the part of corporations. Loss of technological diversity is nearly as bad as the loss of genetic diversity (although far easier to reverse). Cary O'Brien (*) By this I mean when a majority of the farms grow genetically identical products. ------------------------------ Date: 1 Apr 1997 (LAST-MODIFIED) From: RISKS-request(a)csl.sri.com Subject: Abridged info on RISKS (comp.risks) The RISKS Forum is a MODERATED digest. Its Usenet equivalent is comp.risks. => SUBSCRIPTIONS: PLEASE read RISKS as a newsgroup (comp.risks or equivalent) if possible and convenient for you. Or use Bitnet LISTSERV. Alternatively, (via majordomo) DIRECT REQUESTS to <risks-request(a)csl.sri.com> with one-line, SUBSCRIBE (or UNSUBSCRIBE) [with net address if different from FROM:] or INFO [for unabridged version of RISKS information] => The INFO file (submissions, default disclaimers, archive sites, .mil/.uk subscribers, copyright policy, PRIVACY digests, etc.) is also obtainable from http://www.CSL.sri.com/risksinfo.html ftp://www.CSL.sri.com/pub/risks.info The full info file will appear now and then in future issues. *** All contributors are assumed to have read the full info file for guidelines. *** => SUBMISSIONS: to risks(a)CSL.sri.com with meaningful SUBJECT: line. => ARCHIVES are available: ftp://ftp.sri.com/risks or ftp ftp.sri.com<CR>login anonymous<CR>[YourNetAddress]<CR>cd risks [volume-summary issues are in risks-*.00] [back volumes have their own subdirectories, e.g., "cd 18" for volume 18] or http://catless.ncl.ac.uk/Risks/VL.IS.html [i.e., VoLume, ISsue]. The ftp.sri.com site risks directory also contains the most recent PostScript copy of PGN's comprehensive historical summary of one liners: get illustrative.PS ------------------------------ -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Cheers, -- jra -- Jay R. Ashworth High Technology Systems Consulting Ashworth Designer Linux: Where Do You Want To Fly Today? & Associates ka1fjx/4 Crack. It does a body good. +1 813 790 7592 jra(a)baylink.com http://rc5.distributed.net NIC: jra3

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Re: I don't want to crash the 'net
by gary flynn 12 Nov '97

12 Nov '97

> From: Paul Ferguson <ferguson(a)cisco.com> > > As an aside, a lot of the same information is contained at: > > BGP Technical Tips > > o EBGP Sample Configuration to Load Balance over Multiple Serial Links > o Using the Border Gateway Protocol for Interdomain Routing Indeed. The second one is written by the author of the book and I found it very useful. However, the book seems better organized with more examples and explanations. I found it worth the investment. His OSPF design guide was also helpful (shoot, it was a priceless) Over the summer I went from: oncampus RIP,classful addressing,static Internet routes to a single provider to oncampus/offcampus OSPF,partial CIDR,BGP4 to multiple providers. My references were: Routing in the Internet Christian Huitema Prentice-Hall ISBN 0-13-132192-7 The afore mentioned book and Cisco BGP web page. OSPF Design Guide Sam Halabi (from Cisco Web server somewhere) RIP and OSPF Redistribution www.cisco.com/univercd/data/doc/cintrnet/ics/icsospf.htm

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Load sharing on BGP on C75xx
by Pascal Petit - SYNET 12 Nov '97

12 Nov '97

Has anyone experienced load balancing on C75xx using BGP. I have noticed that 11.2 introduce multipath support, however I was wondering about performances ... Is it done at Optimal Switching level ? Thanks for sharing any type of experiences as multipath BGP, asymetric traffic on two links, .... ------------------------------------------------------------------------ Pascal Petit SYNET tel: 33 1 4696 0040 74, rue Roque de Fillol fax: 33 1 4696 0041 92800 Puteaux email: ppetit(a)synet.fr FRANCE http://www.synet.fr

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Re: I don't want to crash the 'net
by gary flynn 12 Nov '97

12 Nov '97

> From: Sheryl Chapin <schapin(a)ctel.net> > > So if anyone has any advice, caveats, pointers to docs, > things I absolutely should do or things I absolutely > shouldn't do, I would be EXTREMELY grateful. Sheryl, I recently went through the same learning experience and found the following document very helpful when combined with the references you already listed: Internet Routing Architectures Bassam Halabi Cisco Press/New Riders Publishing Besides applied theory, it contains practical approaches to solving various realistic problems including the whys, the alternate solutions, and related Cisco IOS commands. My copy doesn't have an ISBN number. I think I got it from www.amazon.com (but it may have been Borders). It helped me a lot in making our previous T1 link a backup to our new primary DS3 link. Its worked twice although I think there are still some problems because the BGP table revision keeps incrementing. Nobody's complained of any flaps though. (anyone can take this as an open invitation to complain or suggest fixes <GRIN>) AS 10357 Gary Flynn Network Analyst James Madison University

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I don't want to crash the 'net
by Sheryl Chapin 12 Nov '97

12 Nov '97

Hi all, First, an apology if this is off topic. A (brief) intro/explanation. My name is Sheryl Chapin. I am the network administrator for a startup ISP in Maine. I would say that I am the sr. network admin, except I am the *only* network admin. I have 18 years expierience in computers, 10 years with Unix and 3 with Cisco routers. I am not a programmer, I am a system and network administrator. My topology: I have two 7513's in two different cities in Maine: Portland and Winthrop. They are connected via a T3. I have a T3 connection to UU Net from Portland and in a week I will have a T3 connection to AGIS from Winthrop. I have a *very* basic BGP configuration running on the Portland router right now. What I need is some practical help/advice on how to configure my routers once AGIS is also connected. I want to be able to load balance and I would like to do it without crashing a major portion of the internet. I have been reading everything I can find on BGP, Avi Freedman's columns and web pages have been extremely helpfull, but the Cisco documentation just gives me a headache. I am not a stupid person, but I am willing to admit that I have never done this level of configuration before. I figure I can either ask for some help and look stupid or crash the internet, and quite frankly, I would rather look stupid then do something stupid. (Mr. Freedman's columns do a really good job of putting the fear of God into someone just starting out with BGP :-) Part of my problem is the documenation does a good job of giving me syntax, but not of explaining WHY I should or should not do something. For example, UU Net gave me configuration commands for turning on BGP which included a "redistribute connected" command. Someone else from another ISP here in Maine (that we are co-locating with) told me not to use it. Now I know what the redistribute command does, I just haven't found anything anywhere to explain what the pros and cons are for using it. How does it affect the routing? I really work better when I understand how things work. So if anyone has any advice, caveats, pointers to docs, things I absolutely should do or things I absolutely shouldn't do, I would be EXTREMELY grateful. If this is just totally off topic, again, my apologies. Thanks for your time. Sheryl Chapin CommTel Internet 207.377.3508 schapin(a)ctel.net

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Re: Potentially dangerous Pentium bug disc
by sob＠academ.com 12 Nov '97

12 Nov '97

I tested the test program (using both signed and unsigned char) on Pentium Pros running BSD/OS 3.0 and got "illegal instruction, core dumped" and no hang. On regular Pentiums running the same OS, I got the hang. -- Stan | Academ Consulting Services |internet: sob(a)academ.com Olan | For more info on academ, see this |uucp: {mcsun|amdahl}!academ!sob Barber | URL- http://www.academ.com/academ |Opinions expressed are only mine.

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Re: Announcing new route (What besides BGP?)
by Joe Provo - Network Architect 12 Nov '97

12 Nov '97

[snip] > > use. Or, if it has been replaced/supplemented with something else. Is > > there a FAQ I should have bookmarked which contains this information? Or, > > if there isn't could someone point me in the right direction? > > Half of the information in the raddb is outdated and erroneous. That's a bogus statement. The ANS stats show a very good picture, albeit from their perspective, of how much/little error there is. If you look at many MLPAs, newer Bi-lats, BGP requirements for downstreams to be turned up, etc, you'll see people requiring IRR registration. Joe Provo -- Joe Provo, Network Architect 508.229.8400 x3006 Network Operations Center Fax 508.229.2375 UltraNet Communications, Inc. <jprovo(a)ultra.net>

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Re: Inbound prefix filters
by Bradley Reynolds 12 Nov '97

12 Nov '97

On Tue, 11 Nov 1997, John A. Tamplin wrote: > Actually, I view it the other way. If someone is announcing routes for one > of our prefixes, connectivity is at least partially broken for that prefix, I think the whole point of filtering is that you will not send packets to that newly announced route. You can access-list it and if you suddenly see matching on some deny, then you can investigate at somewhere like nitrous and figure out who is announcing what. In general, I would not be willing to sacrifice the performance of the people who are paying me m0ney just to be able to quickly? ascertain who is causing the problem. > BTW, this has happened to us twice, and both times the offender was a > direct competitor in one of our local markets. Does anybody have any > feel for how often these "accidents" are not accidents? > Time to slap the kiddies for playing with daddy's router. brad reynolds ber(a)cwru.edu "Faith: not wanting to know what is true." -- Friedrich Nietzsche

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IPv8 < IPv6
by Jim Fleming 12 Nov '97

12 Nov '97

Thanks for the responses to my IPv8 note. In case people missed the point, IPv8 addresses are smaller than IPv6. Here are the sizes. IPv4 - 32 bits IPv6 - 128 bits IPv8 - 43 bits (3+8+32) There is a natural routing hierarchy with IPv8 addressing....8 regions, 256 distribution centers in each region and full 32 bit Internets from there. IPv8 addresses can fit inside the IPv6 address fields. ==== Now...back to the point...NANOG people have the opportunity to help the Internet Community with Address Management and Governance. The specific protocol header is not nearly as critical as a coherent addressing plan that takes routing into consideration and quality of service. I suggest that people learn to manage 43 bit addresses before they try to deal with 128 bit addresses. It does little good to have huge addresses if people can not route packets from A to B because the Address Management is chaotic. NANOG people can help to bring order to the chaos that larger addresses can bring. Jim Fleming Unir Corporation IBC, Tortola, BVI

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