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Covert Channel Detection in INTEL SMT
by Russell 15 Jan '18

15 Jan '18

Anders Focht: Covert shotgun At one point he says of two options; either read the cache or RTFM. Fascinating talk for security professionals, so he keeps stuff simple. (His words not mine.) https://www.youtube.com/watch?v=oVmPQCT5VkY&feature=youtu.be -- Russell

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the layers of things underneath Linux
by D. Hugh Redelmeier 14 Jan '18

14 Jan '18

"Replace Your Exploit-Ridden Firmware with Linux - Ronald Minnich, Google" I just watched <https://www.youtube.com/watch?v=iffTJ1vPCSo> Recommended if you want to know underground the landscape.

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Spectre type 2: Branch Target Injection
by D. Hugh Redelmeier 13 Jan '18

13 Jan '18

[background] At the last meeting, I said that I hadn't yet understood the Spectre variant that uses the Branch Target Injection CVE-2017-5715. I now do. Recall that Spectre and Meltdown use a side-channel for sneaking information past barriers. Speculative execution of instructions are supposed to have no observable effect when the misprediction occurs. The side-channel is the CPU cache for memory: that can be affected by mispredicted speculation. In the case of Meltdown, speculation is allowed to reference forbidden memory. An artifact of Intel's implementation. It can be fixed over by annoyingly expensive page table changes at the kernel / userland boundary. It can be fixed by an OS exploiting PCID feature added by Intel with Haswell processors but that is made intricate by the PCID field being too narrow. This mitigation can be done once-and-for-all in an OS. Spectre comes in two forms: mispredicting a simple conditional branch (one that can branch to a manifest location, or not) and mispredicting an indirect branch. To mitigate Spectre problem, each dangerous conditional branch needs to have code added by the programmer (or compiler). This code is expensive so it isn't a great idea to add it everywhere (which could be automatic). The fix for dangerous conditional branches is easy: add an LFENCE instruction. Unfortuately that slows down processing quite a lot. WebKit is using "index masking" instead, for speed. <https://webkit.org/blog/8048/what-spectre-and-meltdown-mean-for-webkit/> [foreground] Now we get to Branch Target Injection, the second form of Spectre. The indirect branch case is much trickier. An indirect branch is one where the target is not manifest in the instruction. Instead, it is somehow computed. Think: - call through a function pointer variable - method call in an object oriented language (a call through a function pointer, at least in the general case) - a return from a function - a case statement Fast processors nowadays predict where such a branch will lead. The heuristics used can be outsmarted by carefully crafted code and led to speculate ANYWHERE in the address space. This is awesomely scary. You cannot add protective code on the target because there is no single target. This has similarities to the attack exploitation method called "Return Oriented Programming": the attacker just has to find a useful code fragment somewhere in your codebase and aim the branch target prediction towards it. Google researchers have devised a trick to prevent indirect branch misprediction from doing a bad guy's bidding. They constructed a "retpoline" that essentially ties up misprediction in a harmless bit of code. See the "Construction (x86)" section of <https://support.google.com/faqs/answer/7625886> The cost is an ugly piece of code and no useful speculation.

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Re: [GTALUG] Meltdown performance hit.
by o1bigtenor 12 Jan '18

12 Jan '18

On Thu, Jan 11, 2018 at 11:52 PM, ac via talk <talk(a)gtalug.org> wrote: > On Thu, 11 Jan 2018 23:35:23 -0500 > Alvin Starr via talk <talk(a)gtalug.org> wrote: > <snip> > > >> A bit of searching shows that others are complaining about the same > > >> problem. > > > That does look like a substantial hit. What happens if you try the > > > workload on a new VM? Roll the dice until you get lucky maybe? > > This server is not so bad but it really shows the change in > > performance. The one that keeled over on me was on a small instance > > and I had to move it to a large instance. > > I did a bunch of database clean and hopefully that will be enough to > > be able to put it back on a small instance. > > Otherwise my costs at AWS till jump significantly. > > > am also seeing major perfomance hits at other providers, costs are > going to be a lot higher for some projects > --- > Maybe time to renegotiate pricing? Dee

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Intel Meltdown Bug -- Conundrum For New Desktop PC Build Spec (to run debian Linux) -- Switch From Intel CPU To AMD CPU ??
by Steve Petrie, P.Eng. 11 Jan '18

11 Jan '18

Warm Greetings To GTALUG Members, Just as year 2018 arrived and I prepared to push the Order button, on the various parts for building a new desktop PC to run debian LInux, replacing an ancient Dell Windows XP PC, along comes revelation of the Intel Meltdown CPU bug, to muddy the picture. My present new desktop PC build spec (much modified according to some excellent earlier advice from GTALUG members) has an Intel Z97 LGA 1150 Intel 4-Core i5-4460 3.2GHz Haswell Processor. (I know, I know, the Intel Haswell CPU series is obsolete, but let's just ignore this fact for the present discussion.) I attach a copy of the present build spec: a.. <ca.pcpartpicker.com -- deb8_PC_business_24_7_duty_bare_v1 - summary - Steve_Petrie - 20170722.odt.pdf>; b.. <ca.pcpartpicker.com -- deb8_PC_business_24_7_duty_bare_v1 - accessories - Steve_Petrie - 20170722.odt.pdf>; * * * * * * It seems to me that, with regard to the Intel Meltdown bug, I have two basic options: a.. 1. Just accept the Meltdown bug situation, proceed with the PC build using the Intel CPU, and live with the perforrmance hit that comes with the fix in the Linux kernel for the Meltdown bug. b.. 2. Invest a week or two to investigate AMD CPU options that will avoid altogether the Intel Meltdown bug. This strategy could lead to a lengthy necessary respecification of other components in the PC build spec, depending on how an AMD architecture fits with peripherals. An ARM CPU is not an option, as one of the other operating system I plan to run on the new PC is DragonFlyBSD, which only runs on Intel and AMD processors (not ARM). * * * * * * *** LATE BREAKING NEWS *** Speaking of DragonFlyBSD, here is an interesting snippet just in from the dfly <users(a)dragonflybsd.org> email discussion forum: Subject: Re: Meltdown and Spectre information update Matthew Dillon wrote: > (2) Intel is supplying a Microcode patch for newer CPUs, but it's hard > to say how many BIOS makers will ever adopt it. I wouldn't count on it very much, especially nowadays when hardware is very usable far longer than vendors are even willing to support it. But that's the reason why Linux kernel provides a way to update a microcode early during boot or even in runtime. Maybe it's a good idea to implement it for DragonFly as well. https://github.com/torvalds/linux/blob/master/Documentation/x86/microcode.t… Could be a promising fix for Meltdown, using the Linux microcode update facility to install the Intel microcode patch for the Meltdown bug. I may need to switch to a newer Intel CPU (than Haswell), if no Meltdown microcode fix is forthcoming from Intel for Haswell. * * * * * * Do GTALUG members have any opinions on the relative merits of the strategies I suggest above ?? Any comments / advice from GTALUG members, regarding the above strategies (or any other strategy that comes to mind) would be gratefully received. And then there is the Spectre bug also lurking ... Thanks in advance, Steve apetrie(a)aspetrie.net

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[GTALUG-Announce] Play it Again, Sam with David Collier-Brown
by hi＠gtalug.org 11 Jan '18

11 Jan '18

<http://gtalug.org/meeting/2018-01/> # Play it Again, Sam with David Collier-Brown A talk and demo of a modern open source tool for load testing: record and replay real loads on test servers. ## Location George Vari Engineering and Computing Centre 245 Church Street, Room 203 Ryerson University <http://goo.gl/maps/16oJ2> <http://www.openstreetmap.org/way/23447525> ## Schedule * 6:00 pm - Please discuss on the general mailing list (i.e. <talk(a)gtalug.org>) where you want to go for dinner. * 7:30 pm - Meeting and presentation. * 9:00 pm - After each meeting, a group of GTALUGers move to The Imperial Pub (54 Dundas St East) for refreshments and more socialising. # Code of Conduct We want a productive happy community that can welcome new ideas, improve every process every year, and foster collaboration between individuals with differing needs, interests and skills. We gain strength from diversity, and actively seek participation from those who enhance it. This code of conduct exists to ensure that diverse groups collaborate to mutual advantage and enjoyment. We will challenge prejudice that could jeopardise the participation of any person in the community. The Code of Conduct governs how we behave in public or in private whenever the Linux community will be judged by our actions. We expect it to be honoured by everyone who represents the community officially or informally, claims affiliation or participates directly. It applies to activities online or offline. We invite anybody to participate. Our community is open. Please read more about the GTALUG Code of Conduct here: <http://gtalug.org/about/code-of-conduct/>. If you have any questions, comments, or concerns about the GTALUG Code of Conduct please contact the GTALUG Board @ <board(a)gtalug.org>. --- GTALUG Announce mailing list announce(a)gtalug.org https://gtalug.org/mailman/listinfo/announce

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Dinner in the usual place?
by David Collier-Brown 09 Jan '18

09 Jan '18

The last few times it was Kabul Express, are we headed there tonight? --dave

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November 2017 talk is up on youtube
by Alex Volkov 07 Jan '18

07 Jan '18

Hi everyone, I posted November presentation -- Docker for Web Development with Greg Martyn https://youtu.be/JO74a_aN-A4 Alex.

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HP Battery recall
by Russell 05 Jan '18

05 Jan '18

Batteries made in China and Mexico due for replacement. https://arstechnica.com/gadgets/2018/01/hp-recalls-select-laptop-batteries-… List of affected products. http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2018/65510r-en… -- Russell

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Re: [GTALUG] pip for Python3 installation issues on macOS (was python sweetness — The mysterious case of the Linux Page Table)
by Russell 05 Jan '18

05 Jan '18

Forwarding this solution. -------- Original Message -------- From: Russell <rreiter91(a)gmail.com> Sent: January 5, 2018 10:21:02 AM EST To: R360 Design INC <r360design(a)gmail.com> Subject: Re: [GTALUG] pip for Python3 installation issues on macOS (was python sweetness — The mysterious case of the Linux Page Table) Nice step by step guide. Perhaps you should add it to the thread Myles forked. Did you hit reply all? Cheers Russell On January 5, 2018 9:37:39 AM EST, R360 Design INC <r360design(a)gmail.com> wrote: >Okay with the help of a more articulate guide >(https://davidegerosa.com/installpython/) we were able to figure it >out: > >Currently we have three versions of Python installed: >2.7.10 (Native to Mac) >2.7.13 (Homebrew) >3.6.4 (Homebrew) > >To invoke PIP specific to the Python version, we had to use >"python(x) -m PIP list" >r360design.ca > > >On Fri, Jan 5, 2018 at 9:11 AM, Russell <rreiter91(a)gmail.com> wrote: >> >> >> On January 5, 2018 8:59:13 AM EST, "Myles Braithwaite 👾 via talk" ><talk(a)gtalug.org> wrote: >>>R360 Design INC via talk wrote: >>>> Hi, Was wondering if we could squeeze in a question about Python >>>> installation on OS X on this thread: >>>> >>>> To set up Python on Mac, we were advised to install the latest >>>version >>>> of Python 3.6.4 and PIP3 (According to the Hitchhiker's Guide to >>>> Python >http://docs.python-guide.org/en/latest/starting/install3/osx/) >>>> . The installation folder is: >>>> >>>> MacBook-Pro: which python3 >>>> /usr/local/bin/python3 >>>> >>>> >>>> However, when we checked the package list, the packages are still >>>> pointed at the Python 2.7 packages folder (the native version of >>>> Python that ships with Mac). Is this correct or we need to >re-install >>>> the packages for Python 3.6.4 using PIP3? >>>> >>>> MacBook-Pro:bin owner$ pip3 show pandas >>>> Name: pandas >>>> Version: 0.22.0 >>>> Summary: Powerful data structures for data analysis, time >series,and >>>statistics >>>> Home-page: http://pandas.pydata.org >>>> Author: The PyData Development Team >>>> Author-email: pydata(a)googlegroups.com >>>> License: BSD >>>> Location: >>>/Library/Python/2.7/site-packages/pandas-0.22.0-py2.7-macosx-10.12-intel.egg >>>> Requires: numpy, python-dateutil, pytz >>>> MacBook-Pro:bin owner$ pip3 show six >>>> Name: six >>>> Version: 1.11.0 >>>> Summary: Python 2 and 3 compatibility utilities >>>> Home-page: http://pypi.python.org/pypi/six/ >>>> Author: Benjamin Peterson >>>> Author-email: benjamin(a)python.org >>>> License: MIT >>>> Location: /Library/Python/2.7/site-packages >>> >>>What does `pip3 --version` and `python3 -m pip show pip` show you? >>> >>>As an example mine shows: >>> >>>``` >>>$ pip3 --version >>>pip 9.0.1 from /usr/local/lib/python3.6/site-packages (python 3.6) >>> >>>$ python3 -m pip show pip >>>Name: pip >>>Version: 9.0.1 >>>Summary: The PyPA recommended tool for installing Python packages. >>>Home-page: https://pip.pypa.io/ >>>Author: The pip developers >>>Author-email: python-virtualenv(a)groups.google.com >>>License: MIT >>>Location: /usr/local/lib/python3.6/site-packages >>>Requires: >>>``` >>> >>>I think pip for Python3 wasn't installed correctly. You might want to >>>try reinstalled pip, <https://pip.pypa.io/en/stable/installing/> with >>>python3. >>> >>>Also it's generally best practice when replying to a thread in a >>>mailing >>>list with a new topic to change the subject like I did above. It >helps >>>the archiving of the mailing list so people can better browse. >> >> I'm not particularly familiar with OS-X but you also could check out >these links. Homebrew apparently handles package management for easy >upgrades. >> >> >https://stackoverflow.com/questions/17271319/how-do-i-install-pip-on-macos-… >> >> >http://docs.python-guide.org/en/latest/starting/install3/osx/#install3-osx >>>--- >>>Talk Mailing List >>>talk(a)gtalug.org >>>https://gtalug.org/mailman/listinfo/talk >> >> -- >> Russell -- Russell -- Russell

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