April 2018 - Talk - lists.gtalug.org

war story: power failure makes CentOS system unbootable
by D. Hugh Redelmeier 30 Sep '22

30 Sep '22

tl;dr / spoiler: change fstab so that /boot/efi is not automatically mounted. See the recommendation at the end of this message. My gateway computer is a little PC running CentOS. It does not come back after a power failure. The reason (as best I can tell) is interesting and I think that I have a fix. My system is UEFI. It boots from a UEFI system partition, known as /boot/efi to Linux. If this gets corrupted, it won't boot. It is a VFAT partition. On my gateway (a Zotac Zbox RI321, a cute little box with two ethernet ports), the UEFI firmware apparently won't boot if the dirty bit is set in the system partition. CentOS normally runs with /boot/efi mounted. So when the system isn't shut down cleanly, the dirty bit will be on. Consequence: the system is not going to boot after a power failure. Odd observation 1: if I put a live Fedora 25 USB stick in the system and try to boot in this otherwise-unbootable state, CentOS boots from the main disk. So this really looks like a firmware bug/quirk. Odd observation 2: fsck doesn't seem to automatically fix the system partition. Once CentOS 7 booted, I dismounted /boot/efi and did an fsck on it. $ sudo fsck /dev/sda1 fsck from util-linux 2.23.2 fsck.fat 3.0.20 (12 Jun 2013) 0x25: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt. 1) Remove dirty bit 2) No action ? 1 Leaving filesystem unchanged. /dev/sda1: 16 files, 2420/51145 clusters Googling got me to <https://www.centos.org/forums/viewtopic.php?t=50917> In particular, this advice seemed quite good: ==== recommendation ==== Two other changes I recommend for UEFI systems, to each OS's /etc/fstab. - For the /boot/efi mountpoint, add the mount options x-systemd.automount,noauto - Change fs_passno (last column) to a 1 or 2; the canonical fstab instructions suggest 2, but systemd treats 1 and 2 as the same. The first change means the EFI System partition will not be automatically read-write mounted at boot time; it's a bad idea this is the default because it puts the ESP at risk especially if ther are crashes, FAT has no journal and will therefore always be marked dirty in such a case; no other UEFI OS mounts the ESP by default. Second, if anything tries to access /boot/efi (read or write), systemd will automatically mount it, and because of the fs_passno 1 or 2, it will fsck it first and that fixes and clears the dirty bit in case it's set. Right now without these changes, it's just a matter of having the right number and bad timing of crashes to render the EFI System partition corrupt.

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Dont post this please, Just introducing myself and moderator approval
by Kumash Patel 27 Apr '18

27 Apr '18

This is meant to be a signup email. I am interested in the malware talk happening on may 8th. Just came across the community and it looks like the thing i have been searching for a while. I am a novice at linux, installed manjaro on my now-dead thinkpad x210. but yeah nothing beyond that with linux so far. I have done a few university courses in python based fundamental programming concepts. And have been following an online tutorial for UE4 programming in c++. I would like to learn more about website hosting and development because i wanna make a blog that acts as a personal website to keep adding things to (modifying/experimenting on different features). I cant do it alone, I need help from people who already know about these things and are willing to share. Thanks for reading this, Kumash Patel

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[GTALUG-Announce] GTALUG Meeting on Tuesday 8 May at 7:30pm
by hi＠gtalug.org 26 Apr '18

26 Apr '18

<http://gtalug.org/meeting/2018-05/> # Malware! with Garry Pejski Due to poor life decisions I made malware for a while. This is my story. Handsome local computerist GARRY PEJSKI™ steps out of the shadows to warn the Toronto hacker community about the perils of performing cyber crimes. Heed his incredibly interesting words of wisdom or invite doom upon the world! ## 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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IBM - cache skirmish story.
by Russell 25 Apr '18

25 Apr '18

Actually this is more of a can't see the forrest for the trees issue. Or; when your only tool is a hammer, everything looks like a nail type thing, rather than one of Hughs war stories. I'm a corporate correctness kind of guy, so in my mind Wars are sanctioned. This was a pure and simple un-sanctioned tech skirmish. I only ever did one hack on IBM owned equipment. It was while I was visiting at their Celistica site. The problem, which had been happening to my friend, who worked there and did some of the jobs she did remotely from home in the early 90's, was typematic delay. However IBM Staff told her it was the network lagging. Both at home and at the office. My friend was an internal event planner and would login to something, VAX/VMS I think. I never looked or asked. Her words not mine. I just checked the bios. After I booted to dos I noticed severe cache lag in typing. If you weren't a touch typist, you'd hardly notice the issue. I'm touch trained and so was my friend. I rebooted and went into the bios and increased the buffer from 4cps to 12cps. I am a fast typist, my friend was lightning fast. She dragged me up to Celstica the next day to do the same thing on her office computer. For that hack and helping out with some tech stuff ie. setting up hw, which was being awarded to students at the Annual banquet, I got to see Celine Dion perform with Pebo Bryson and eat an outstanding meal, coordinated by the event group at the Inn on the Park Also since the group got an award for their coordination of the banquet, I got to share in that award at Marche. I'll always remember my friend saying nobody will ever believe that "my carpenter boyfriend fixed a computer issue that IBM techieboobies, could not." So, I hope that the cache wiring diagrams have improved at IBM over the years, or this snippet of ledger news doesn't bode well at all. https://www.ibm.com/blogs/blockchain/2018/04/blockchain-based-batavia-platf… -- Russell

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Key Signing follow up, what shall I do next?
by Antonio Sun 20 Apr '18

20 Apr '18

So I attend the Key Signing party, exchanged my signatures, and even get emails telling me that my key is signed. I'm now a bit lost on what shall I do next, and trying to google for the answer didn't help much either. The closest I found is: GPG Tutorial https://futureboy.us/pgp.html#UpdatingKeys and I've checked the following sections: Updating Keys People are constantly updating their keys for various reasons: - Keys get compromised or lost and they are revoked. - Keys are signed by more people, building a Web of Trust <https://futureboy.us/pgp.html#WebOfTrust>. . . Who Signed My Key? Now that you've updated keys from a keyserver, you might want to see who has signed your key. After all, *anyone* can sign *any* key and re-upload that key to a key server. You can see the signatures with the --list-sigs command to gpg . . . However, I'm still at lost understanding them. I.e., I tried both the suggested commands, but can't see any sign that my key is signed by more people, and any of their emails. All that I know is that - I get an email telling me that my key is signed. - I'm able to decrypt it, and see an attachment of mykey.asc: --------------B954318AC305B6429BF6150D Content-Type: text/plain; charset=UTF-8; name="mykey.asc" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="mykey.asc" What steps I shall do next? (Instruction for the command line is more welcome than using GUI) Thanks!

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Recommendations for a root filesystem
by David Collier-Brown 20 Apr '18

20 Apr '18

I'm running Fedora, and want a filesystem with a write cache that I can put on flash, as I occasionally run some evil write-intensive tasks. I'd love to simulate the Sun trick of flash for write cache and ephemeral for read cache. Alas, my brain is roughly at the samfs/qfs level (a predecessor of zfs) and it's not clear what of the more modern filesystem I should consider for everyday use. --dave -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb(a)spamcop.net | -- Mark Twain

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Build critique request and the story behind it.
by Russell 19 Apr '18

19 Apr '18

This year I purchased an APC UPS because of my flakey connection to the grid. Ominous read clicks coming from my boot drive cemented that decision. I am happy to say that not only did I avoid my biannual unexpected shutdowns, the UPS also sensed transient RF spikes. It begins to click, switching to the battery and back to mains, even though there is no visible disruption to service, although the emergency lighting in the hallway was triggered and beeped itself on. I decided to purchase a case and build a new desktop. I waited till now because I was loosely following Sarah Sharp, of Intel and listened to her comments on USB. Version 3.0 is RMA as of Jan this year and her general comment is that hardware development has peaked and so the immediate future is in developing software. Here is the case I chose. I take delivery tomorrow. http://www.coolermaster.com/case/lan-box-haf-series/haf-xb-evo/ Newegg has this combo on offer. Intel Core i5-7500 Kaby Lake 4-Core 3.4 GHz CPU w water cooling unit ASUS STRIX H270F GAMING MB G.SKILL 2 x 8G DDR4 As a creative anachronist or purposefull recycler, I haven't built a complete system from all new parts in a dozen years. I thought I'd get my hand in before arthritis takes over my hardware chops completely. I'd appreciate any warnings and caveats regarding this combo. I'm still window shopping but what I'm looking for is stability and longevity over gaming. This combo has DDR4 and USB 3.1. I'm kind of fixed on the usb but I'm not married to the ram. So suggestions which lower the cost are most appreciated. I have a 650w Corsair p/s which is ok but a big factor for me is the ambient noise and recommendations on a quiet supply would be appreciated. Noise is why I'm trying out water cooling. From the reviews on the case I'll probably have to replace the case fans, but who knows I might get lucky. I follow with interest the posts on UEFI, secure boot, SElinux, USB, udisks, udev, mobile linux and systemd. Now is my time to see if I have learned anything. Thanks to all posters. Regards -- Russell Sent by K-9 Mail

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Microsoft says its new Linux-based OS will secure IoT devices for a decade - TechRepublic
by James Knott 19 Apr '18

19 Apr '18

What's this? Microsoft developing a Linux based OS?? https://www.techrepublic.com/article/microsoft-says-its-new-linux-based-os-… It's amazing the changes at Microsoft, since Bill & Steve left.

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Turris MOX: Commercially supported OpenWRT, Modular Router
by Scott Sullivan 19 Apr '18

19 Apr '18

I've been CZ.NICs previous router, the OMNIA for over a year and a half now. It's been reliable, self-updating, and very solid with it's WIFI performance. Their launching a next generation, that more flexible in configuration so you can only what you need. Or all the features you want. https://www.indiegogo.com/projects/turris-mox-modular-open-source-router-se… -- Scott Sullivan

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New Desktop PC -- debian Linux - Proposed 2 TB HDD Partitioning;
by Steve Petrie, P.Eng. 18 Apr '18

18 Apr '18

Warm Greetings To GTALUG Members, This coming weekend (Friday 13 April 2018) I will be building my new desktop PC with the help of my friend who has built quite a few PCs for his employer. The new PC will be running debian Linux and will soon take over duties from an ancient Dell desktop PC running Windows XP (acquired new in March 2005).. I will post the final hardware configuration on PCPartPicker once the new PC is operational. * * * * * * Meanwhile, I would like to ask GTALUG members please to itake a look at the partitioning configuraiton I am proposing for the 2 TB Western Digital HDD (best to stretch your email client window to defeat word wrap): ==> *** STANDARD LINUX *** /device partition ==> linux normal boot #1: (current active version of linux os, will be recycled for next version) /dev/sda1 gpt001 ext2 ??? /boot /dev/sda2 gpt002 ext3 50 / (root), /bin, /dev, /etc, /initrd, /lib, sbin ==> linux normal boot #2: (next version of linux os, will become current version) /dev/sda1 gpt003 ext2 ??? /boot /dev/sda2 gpt004 ext3 50 / (root), /bin, /dev, /etc, /initrd, /lib, sbin ==> linux rescue boot: /dev/sda1 gpt005 ext2 ??? /boot /dev/sda2 gpt006 ext3 50 / (root), /bin, /dev, /etc, /initrd, /lib, sbin ----------------------------------------------------------------------------------------- 150 GB + 3X boot ==> linux temporary: /dev/sda3 gpt103 ext4 64 (swap1) /dev/sda4 gpt104 ext4 64 (swap2) /dev/sda5 gpt105 ext4 64 (swap3) /dev/sda6 gpt106 ext4 200 /tmp ------------------------------------------------- 392 GB ==> linux permanent: /dev/sda7 gpt207 ext4 100 /var /dev/sda8 gpt208 ext4 100 /usr ==> linux user permanent: /dev/sda9 gpt309 ext4 100 /usr/local /dev/sda10 gpt310 ext4 100 /home ---------------------------------------------------- 400 GB ==> *** USER-DEFINED *** /dev/sda51 gpt551..557 ext4 75X7 /!_d ... /!_j (current, clone winxp partition structure, allow for growth) /dev/sda52 gpt599 ext4 70 /!~dell (WinXP archive C..J: ../winxp_c .. ../winxp_j (WinXP archive C..J)) --------------------------------------------------------------------------------------------------------------------- 595 GB ==> other operating systems: /dev/sda61 gpt661 ext4 ??? /._win7 virtualized windows 7 /dev/sda62 gpt662 ext4 ??? /._win7_1 /dev/sda63 gpt663 ext4 ??? /._dfly virtualized dragonflybsd /dev/sda64 gpt664 ext4 ??? /._dfly_1 ---------------------------------------------------------------------------- ??? GB ==> ssd partitions: /dev/sda71 gpt771 ext4 -- /.~ssd01 (ssd partition) | total ssd /dev/sda72 gpt772 ext4 -- /.~ssd02 (ssd partition) | capacity /dev/sda73 gpt773 ext4 -- /.~ssd03 (ssd partition) | 256 GB --------- --------- ---- ----- ----------------------------------------------- N/A GB ==> allocated: 1537 GB (+ 3x boot) ==> unallocated: + 463 GB (- 3x boot) --------- --------- ---- ----- ----------------------------------------------- ==> Total HDD Capacity: 2000 GB Note 1: Please be aware that I am a complete Linux newbie but with a software engineering background. Note 2: Hoping to be able to swap back and forth between an "active" version of Linux and the "next" version of Linux, by switching the roles of partitions (gpt001, gpt002) <==> (gpt003,gpt004) . Note 3: Please be aware that I intend to maintain most of my user-related content in the seven (7) partitions gpt551..gpt557 * * * * * * Comments, criticisms, questions welcome. Best Regards, Steve

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