The DMZ

Iszi

15:00

@lynks 32 IPs, yes. But only 30 are useable in each subnet, and 32 would not be one of those.

The first IP in a subnet is the network ID, the last is the broadcast.

Terry Chia

Well, he didn't mention usable ips :P

Iszi

If you want a usable IP at x.x.x.32, your subnet needs to be at most /26.

Terry Chia

I always refer to this particular PDF: media.packetlife.net/media/library/15/IPv4_Subnetting.pdf

I keep forgetting how to calculate them manually.

Iszi

@TerryChia Yeah, the only problem with that chart is it gives you the total IPs in the subnet - subtract two for usable IPs.

lynks

@Iszi yeah you're right; .32 would be the broadcast on a /27

Iszi

15:03

@lynks No, it would be the network ID of the second subnet.

Terry Chia

@Iszi Simple enough to remember.

Iszi

@lynks 31 and 63 are broadcast

lynks

@Iszi yep, right again, for some reason 32 = 1 1111 in my head today :/

Terry Chia

Ahh networking. I kinda miss doing it.

No networking modules this semester. :(

Tinned_Tuna

lol

AviD

15:10

@lynks thanks, that's what I thought, though as @ScottPack pointed out I would need to modify the netmask on the .32 device anyway, so I may as well change the IP.

@lynks ayup, I agree - that's what's confusing me.

I do so little raw networking as it is, I dont need the decimal notation being forced down my throat by the low end router.

@Iszi ah dang, right forgot about that. so I'd need to shift another bit in...

@lynks you switched to little endian...?

@TerryChia nope, I DONT!

I do miss knowing it well, though. I've forgotten more about networking than I care to relearn.

I prefer learning new things.

Terry Chia

Well, I'm more interested in the administration (system/network) side of things than the programming side of things.

lynks

@AviD as IT professionals, we all have to realise that we are doomed to spend our careers drowning in the infinite flow of new knowledge, with no hope of ever understanding everything, or even close to it. the only way to do well is to actively learn new things as often as possible.

3

well that was depressing.

AviD

absolutely. I crave knowledge, and I enjoy wrestling with new ideas, new technologies, new shortcuts. I love seeing a problem that used to be complicated, solved quickly and easily through new tools or new techniques.

However, my senility causes me to forget almost everything I don't handle on a near-daily basis.

@lynks depressing? I find it uplifting! positively invigorating!

I guess I just identify with DC's Felix Faust.

Terry Chia

@AviD Imagine how @RoryAlsop feels.

AviD

@TerryChia he maybe ancient, but he has not had the touch of dementia.

He stays healthier. It helps.

lynks

15:20

@AviD I meant the part about never being able to stay afloat; knowledge is being produced in our field alone at a rate faster than any one person can learn it. so you have to pick and choose and do your best

Thomas Pornin

@AviD He was already crazy to begin with. This makes him immune to further degradation.

3

AviD

@lynks ah, I see. Yeah, I wish I had more time, enough time to learn EVERYTHING. A touch of the Faustism.

Scott Pack

15:32

Ooo...lockdown.

AviD

@Iszi I couldnt figure out what you were on about. Then I noticed that you edited that link to point to something completely different... Was that on purpose?

Iszi

@AviD Umm... No? First time was a cut and paste error.

AviD

@Iszi no, first time was right.

I assume you meant howtogeek.com/135546/… and not howtogeek.com/136078/…

Iszi

@AviD Exactly

Oh, what the crap?

Cut-and-paste error when I went to fix a cut-and-paste error, really?

@AviD Mind fixing that for me?

AviD

ftfy

actually I found the block size one useful, if not revelatory.

Iszi

15:37

Thanks. First time was still an error. Was missing the http:// bit, so it didn't make a hyperlink.

AviD

what happens if a device has the wrong netmask, but the right IP, configured?

Iszi

@AviD Generally, it won't play well with others.

AviD

@Iszi dont need others. just the router.

Rory Alsop

@terry - you called?

Who says I'm not mental. Maybe I just compartmentalise well and store all the mental in my other persona...

Or maybe I don't :-)

Mwahahahahahaha

AviD

@RoryAlsop thats what @ThomasPornin said. and that prevents further deterioration, such as senility.

@RoryAlsop maybe this is the other persona, and your other one is the sane one.

now there's a scary thought.

Iszi

15:43

In theory the device should be able to talk to any target within its configured subnet, provided that said target is configured to use a subnet that includes the device.

It may also, in theory, be able to talk to other subnets if a router is within its configured subnet.

Scott Pack

@AviD Not necessarily. We could probably work something out, but it wouldn't necessarily be ideal. It would be easier to just readdress.

Iszi

Also, in theory, it should really have problems talking to devices in the gap (if there is one) between its subnet and the router's configured subnet (even if it can talk to the router).

All of this is in theory, though. In practice, it's a crap shoot.

Scott Pack

You tend to more run into problems with firewalls and such later on.

AviD

@Iszi heh. especially with my current crap router.

Scott Pack

I've seen it work, but you have to do some magic.

AviD

15:46

@Iszi The difference between theory and practice: In theory, there is no difference, in practice there is.

3

@ScottPack my magic is confined to other areas, dont got no network magic

aint no one gots time for dat

Scott Pack

You're a terrible person.

AviD

heh

lynks

16:18

why is nothing ever simple in rails

trying to figure out how to set a global variable to a different value depending on environment, should be simple. every site has a different suggestion, none appear to work :(

Adnan

@AviD, that infographic was actually very interesting

Actually that gave me a little motivation to get into Python

lynks

17:17

@Adnan link?

Tinned_Tuna

Python is an excellent language for just getting stuff done.

Adnan

@lynks, udemy.com/blog/wp-content/uploads/2012/01/…

@lynks, there's also a cool video version

►

Jeff Ferland

@Tinned_Tuna Very much agreed

I'm a former Perl guy who converted to Python.

Tinned_Tuna

How do we add a tag to the room? Can we have Rory, Rory, Python?

:-p

Iszi

@Tinned_Tuna That would be up to the room owner - @ScottPack

lynks

17:22

yeah i really need to get to grips with python a bit more

Scott Pack

Why would I want to sully the room's reputation with python?

4

Jeff Ferland

@ScottPack Because you can't post anything worse than scott

Iszi

@lynks Sounds like a personal problem to me.

Scott Pack

@JeffFerland Blasphemy.

lynks

@Iszi :P

Iszi

17:30

"The ad is due. Quick, get any and I mean ANY picture." http://t.co/z9OocQGm

Tweeted by croninwhocares on January 30, 2013 at 4:27 AM

^ Could be worse. They could have gotten Goatse.

Stack Exchange

Blog - Stack Exchange: About Page 2.0: The QuickStartening

Jay Hanlon on January 29, 2013

We’ve just rolled out a new Quick Start guide to help new users learn the basics. Here’s one example, but you can find any site’s version by going to sitename.com/about.

“Please, make yourself at home. Oh, actually, could you not sit on that? Yes, it looks like a couch. That’s what makes it so avant-garde. But it’s actually art. Whoah, careful there, too – I see your confusion, as that does resemble a doorknob, but it’s actually a very small furnace. And – I’m sorry, but – could you NOT use a coaster? We’re testing the effects of wet drinks on finished wood, and coaster usage generates noise in our data.” …

Iszi

18:11

@RoryAlsop @JeffFerland @AviD - Re-wrote this question so it should be more suitable, if we'd like to migrate it:

-3

Q: Why do we need IP addresses to communicate within the local network segment?

Because MAC addresses are only usable across the local network segment, we use IP addresses to communicate with other segments via routers. Meanwhile, for local targets, ARP is used to translate IPs into MAC addresses and the MAC addresses are used from then on in the conversation. This leaves ...

network

Aarthi

19:16

Anyone know a guy at the CIA or NSA?

Iszi

@Aarthi No, but I'm sure they're listening anyway.

Aarthi

:D

Iszi

'sup?

Aarthi

not much! how about yourself?

Rory McCune

@ScottPack I'd suggest ruby, but then given their security record at the moment ...

Iszi

19:19

@Aarthi Hangin' in. Telework days are always nice.

Dare I ask what you need from the TLAs?

Aarthi

@Iszi that's rad!

@Iszi ha, well, i'm sure they'd like to hire programmers. :P

Zoredache

19:35

Does someone happen to have a good link to an article describing the risk of temp files and how to use them safely?

Scott Pack

@RoryMcCune What? No. Perl. Monk Life bitches!

@Zoredache This looks pretty reasonable. codeproject.com/Articles/15956/…

Zoredache

That will work. It covers the sym link issue. I see so many scripts or code fragements in SF questions where people have a hard coded name for temp files.

Scott Pack

I've honestly never looked for one, but on a brief read it looked pretty usable.

Iszi

Argh. Networking fail.

1. Tried accessing local router config page to check something. Router config page inaccessible, can't figure out why.
2. Realized I was on an RDP session to another network.
3. Tried accessing router config page from local machine. Still inaccessible for no apparent reason.
4. For unrelated reasons, Internet connection drops momentarily.
5. Error: VPN connection terminated locally by client.

-FACEPALM-

Lucas Kauffman

19:56

@Iszi wait what?

Iszi

@LucasKauffman Problem was that I was trying to access a local network resource while connected to a VPN - something which is often prohibited by the VPN configuration.

Scott Pack

Silly boy

Thomas Pornin

"Facepalm" is often used to indicate your state of mind when confronted to the abysmal stupidity of somebody else; does it apply when the moron is yourself ?

Lucas Kauffman

@Iszi I meant the cheese

Iszi

@ThomasPornin Indeed it can.

@LucasKauffman Cheese?

Rory McCune

20:03

@ScottPack Oddly I saw my first perl that I've seen recently this week... someone using it for CGI's... and did it have command injection... yes it did

Scott Pack

@RoryMcCune That's a usability feature.

Rory McCune

heh I should put that in the report..

Scott Pack

You know I think Webmin is my favorite command injection vulnerability.

Rory McCune

it is v. useful tho'. I don't use it so much any more but when I was getting started with Linux server it was very handy to be able to do things without understanding the syntax of sendmail configs!

Scott Pack

@Iszi It's a product derived from animal milk and processed in such a way that some of the milk proteins coagulate.

@RoryMcCune You have just proven your unfitness.

Iszi

20:08

@ScottPack I figured that much. Just trying to figure out why @LucasKauffman is bringing it into the conversation.

Rory McCune

@ScottPack hey I said back when I was learning (Although sendmail still makes me shudder) the idea that M4 macros are the simple version

Scott Pack

@RoryMcCune Fun Fact: My boss tells me that when he was on the UNIX admin team at his last employer that they configured sendmail by modifying the mc file directly. None of that cf and m4 garbage.

Thomas Pornin

@ScottPack Yes, cheese is mouldy milk, whereas yoghurt is rotten milk.

Rory McCune

@ScottPack .... wow

Thomas Pornin

@ScottPack I concur. I also did that myself. It was actually simpler to understand than a forest of M4 macros.

Scott Pack

20:10

@RoryMcCune They were mostly a Solaris shop. So that happened.

Thomas Pornin

With the .cf, you just had to understand what the macro replacement algorithm was.

With the M4 macros, you also had to understand what the designer of the M4 macros understood of the .cf files

Scott Pack

Polynomial

@ScottPack Sounds about right.

AviD

@Iszi done.

@Aarthi if we did, we wouldnt be able to tell you.

Aarthi

@AviD TRUE ENOUGH.

AviD

20:19

Wasnt ol' Andrew a leading director of the CIA...?

@Aarthi howarya? long time no read.

@Zoredache also seems to be quite a few q's onsite here (not all of them match, but there are a few specific ones)

Lucas Kauffman

It was either you or @AviD that said something about cheese

Iszi

@LucasKauffman Would be more useful if you'd find the actual line and reply to it.

AviD

@Iszi @ThomasPornin in those cases the facepalm is often accompanied by a faceslap, or just extra force on the facepalm. Yknow, so ya really feel it.

Lucas Kauffman

6 hours ago, by AviD

Hmm @LucasKauffman wanna go into cheese production? ;-)

Zoredache

@AviD Yeah, I had searched, but I didn't see anything that covered the potential of using a symlink in place of a known fixed temp file name to damage/replace files with the privileges of the program using the temp file.

AviD

20:26

@LucasKauffman heh, actually it was @ScottPack that brought it up. Did you see the article linked shortly above that?

Zoredache

I occasionally see scripts on SF with soemthing like TEMPFILE=/tmp/blahblah ; echo something > $TEMPFILE running from cron as root.

AviD

@Zoredache ah, specifically symlinks I dont think I saw.

Scott Pack

20:46

@Zoredache That sounds perfectly cromulent to me.

@Zoredache I have been guilty of using TMPFILE=/tmp/myprog.$$ These days I mostly use mktemp.

Zoredache

@ScottPack Oh, I am sure I have done it as well. I just was looking for a somewhat decent article I could link to when I encouraged to avoid the practice.

Scott Pack

oh sure

The good thing about that article is that it's not overly language specific. The examples are all C(++)? sure, but don't overwhelm the content.

Lucas Kauffman

@Zoredache what's the danger with that?

Zoredache

@LucasKauffman what is the danger with what?

using a hard coded temp file?

Scott Pack

1 hour ago, by Scott Pack

@Zoredache This looks pretty reasonable. http://www.codeproject.com/Articles/15956/Security-Tips-for-Temporary-File-Usage-in-Applicat

Zoredache

20:55

Consider a tempfile=/tmp/blah; the script using the temp file runs as root. Lets assume you have interactive users on your server. Lets assume you have some process that deletes things in /tmp, or /tmp is ramdisk and your system as been recently been rebooted so /tmp/blah doesn't exist.

as a dweeb users I could do ln -s /tmp/blah /etc/passwd

Then your silly cron script goes and does something like echo blah > $tempfile

Lucas Kauffman

@Zoredache yea

@Zoredache are normal users allowed to make symlinks like that?

Zoredache

Sure

I can make a symlink to anything I want

I don't need access to a file to create a symlink.

Lucas Kauffman

I actually didn't know that

Zoredache

and /tmp is almost always drwxrwxrwt so I can create links in that folder all I want, so long as they don't already exist.

Lucas Kauffman

learned another thing today

Gilles

21:00

in The Heap, 3 mins ago, by JNK

We have the awesomest chat room in StackExchange-dom.

Zoredache

If the end user has some control of what the program using the temp file is doing then a lot more sophisticated badness can happen. You often see temp file problems in relation to setuid programs.

AviD

@Gilles flagged as offensive.

Gilles

@AviD oy, don't do that

Polynomial

►

Gilles

@AviD Hmm, I thought your flagging would have automatically deleted the message, since you're a mod, but apparently not

Lucas Kauffman

21:04

Goddamn DBA's thinking they have the coolest chatroom and shit

and then BOOM, I just owned their database

AviD

@Gilles heh, not really. scare "you are a mod" message....

@Gilles I lied.

Gilles

@AviD Someone did flag it though!

Polynomial

yeah, I lol'd at that

AviD

@LucasKauffman I would love to penetrate some SE sites. Would be awesome.

7

Better yet, code review.

Polynomial

@AviD giggity.

Lucas Kauffman

21:06

@AviD We could make it a CTF challenge!

AviD

@Gilles heh, really? probably from the comms room.

@LucasKauffman someone suggested this as a birthday contest. It was roundly rejected by SE.

but not after some heated internal discussions...

they don't even have any security hat on staff at all!

they really should... hint hint (for any listening SE staffer...)

Gilles

@AviD they don't even outsource their security by asking on IT Security, they ask on Meta Stack Overflow!

AviD

@Gilles haha

Polynomial

@Gilles Yeah, I remember that. It was a bad idea, really.

then again, Jeff has a lot of strange views on security stuff.

not necessarily bad views, but certainly not widely held views.

AviD

wait, there were a couple of q's they asked here too...

Scott Pack

21:09

@Polynomial %s/ on security stuff//

Polynomial

@ScottPack Good point.

Lucas Kauffman

Where is @petergrace when you need him

Scott Pack

Petey allegedly managed a security team at some point in his career. I don't know any details, though.

Lucas Kauffman

@ScottPack An IT Security team or a bunch of ex-deltas

Gilles

@AviD yes, they did after you and I prodded them: security.stackexchange.com/questions/3913/…

AviD

21:11

@ScottPack yeah, but I think that was network security, not apps.

@Gilles heh, senility... at least it was familiar

Scott Pack

@LucasKauffman The IS kind.

@AviD Nobody cares about apps security.

AviD

hehe, apparently

Lucas Kauffman

@ScottPack SQLi is just normal application behavior!

AviD

@LucasKauffman I have had developers say "No, we don't support that feature".

Me: "Umm, well, yeah ya do, and its not a feature. Goddamn it."

actually, even better|worse was the one that said "Oh yeah, we need that feature, the users love it.".

Scott Pack

@AviD The semantic difference between feature and vulnerability is thinner than a strand of hair.

Aarthi

21:25

@AviD been busy :(

but good :)

AviD

@ScottPack it is naught but a point of view.

@Aarthi good, busy is good :-)

Lucas Kauffman

@Aarthi can we haz permission to pentest SE :3?

AviD

@LucasKauffman naw, tolja, thats been discussed.

aint nobody gots time for dat!

;-)

besides, it would need to be done by somebody on the inside, first. opening it up to anonymous users, too risky.

Lucas Kauffman

Rory McCune

@AviD in surface news, there's a Metro/Modern SSH client now that works on the Surface RT

AviD

21:39

4

A: Security Stack Exchange's Anniversary Competition

Idea for contest: Most significant hack of the SE stack. That's right, calling open season (with appropriate ground rules, of course) on security vulnerabilities on StackExchange sites. The winner could either be decided by SE, e.g. according to the relative risk rating - we could help w...

Rory McCune

although that said the missus seems to be having more fun getting doom to work on it at the moment

AviD

@RoryMcCune cool. now we just need that 3g...

@RoryMcCune hahah

Rory McCune

yeah I reckon that'll come in the next generation

@AviD seriously she just spent 30 mins tweaking the settings so it would full screen on the external monitor without being jerky!

AviD

excellent

hows it work with touch?

Rory McCune

ooh dunno, it's dosbox, so I'm not sure how well it'll take touch events...

in theory I guess it should just work like the mouse,I'll get her to try it once she's finished fragging things

the jailbroken stuff is moving along too. They've got Java work in a roundabout way

so burpsuite will run

Lucas Kauffman

21:42

@RoryMcCune wait what are you doing :p?

Rory McCune

@LucasKauffman well she's turning the surfaceRT into a pen testing tool, I'm listening to the dulcet sounds of doom from the other room

Lucas Kauffman

@RoryMcCune omai

@RoryMcCune is Metasploit already running?

AviD

@RoryMcCune ah, she's jailbroke?

Rory McCune

@LucasKauffman AFAIK they haven't got ruby running yet, it could be tricky, but if they get that at least some metasploit stuff would run...

Lucas Kauffman

cause it wouldn't surprise me if your tablet ended up melting :/

Rory McCune

21:46

@AviD yeah

@LucasKauffman yeah even if it ran it wouldn't be nippy!

@AviD 'cause of the talk she did at Securi-Tay she's been looking at the jailbreak stuff a lot, but I think she'd prefer not to have it jailbroken in the long term...

AviD

for most of that stuff, shed be better off running in a remote vm. maybe hack up a redirector/proxy for when you need to be inside a network.

Rory McCune

@AviD yeah I think it works best as a device for office/email stuff and remote access to servers

is nice for that

Lucas Kauffman

@RoryMcCune and your tablet would be considerable more vulnerable :p

Rory McCune

@LucasKauffman was that a not so subtle dig at ruby!

Lucas Kauffman

on the other hand java has as many zero days as well

Rory McCune

21:49

this latest one was lame it was postmodern checking out a vuln and from what I read he didn't intend for the exlpoit to be public but it got made public anyway and now the rubygems guys are having to audit all the gems on the server :/

which as they're volunteers sucks for them.

Lucas Kauffman

@RoryMcCune well me and a colleague here are always arguing what our standard scripting language should be, I'm pro python and he's pro ruby.

Rory McCune

@LucasKauffman well he's right and you're wrong :) there you go sorted the argument for you :)

Lucas Kauffman

but we both agree we don't want to use perl!

Rory McCune

ah well you're right there

perl <shudder>

Lucas Kauffman

@RoryMcCune naaaw, python is awesome

and for some reason SE is not loading automatically and I need to refresh my page every 5 seconds

Rory McCune

21:53

@LucasKauffman white space should not be significant!

Gilles

@RoryMcCune Ineverunderstoodthisargument

Thomas Pornin

@LucasKauffman You do not need to refresh every 5 seconds. You just want to follow the chat session. You need to breathe.

Lucas Kauffman

@RoryMcCune .strip()

and I agree, that does give me some headaches as well :p

Rory McCune

@Gilles I'm not a fan of it, I like my { } to help tell where blocks start and end

Gilles

@RoryMcCune I'm not a fan of this either, but as flaws go, it's rather benign

Rory McCune

21:55

BTW not sure if anyone follows EVE online at all but I thought this article was interesting themittani.com/news/asakai-aftermath-all-over-cobalt-moon , in that it's like the speak a totally different language...

Gilles

and at least it forces people to indent half-decently

Rory McCune

@Gilles yeah I just tease pythonistas about it, really that/ruby are pretty similar..

Gilles

My ideal language would both have {} (or the like) and reject misindented programs

Lucas Kauffman

@RoryMcCune I like python because I don't have to use {}

Rory McCune

@LucasKauffman yeah ultimately I think that programming language choice can come down to "what works well for the programmer"

I like the way ruby works, so that's what I use

AviD

21:59

@Gilles indentation is a tool responsibility. A good tool would automatically handle indentations.

Gilles

@AviD but the only tool I can force other people to use is the compiler

I use Emacs, I never worry about indentation when I'm writing code

AviD

@Gilles heh, sometimes not even that.

but it depends - e.g. maybe your source control can enforce some policies.

Lucas Kauffman

@Gilles Emacs shudders

that's like an operating system on its own :/

Gilles

@AviD we have that at work, sort of (if you check in badly indented code, someone yells at you)

but not in SO posts

AviD

@Gilles ahhh, now we get to where it really matters

Rory Alsop

22:03

evening all

AviD

@Rory!

Thomas Pornin

@RoryMcCune What works well for the programmer and for his fellow programmers who must maintain the code when the first programmer has cowardly run away into another job.

Rory McCune

@ThomasPornin well yeah it's a bit different if you're coding professionally...

@RoryAlsop watcha'

Rory Alsop

How has the room been today - I have been intermittent, to say the least - blimming trains

Rory McCune

@RoryAlsop where were you on yer travels today? I've been down in dumfries for a couple of days

AviD

22:09

you can usually check the sidebar for the highlights, for the most part

Rory McCune

weather has been "interesting" to drive in

Rory Alsop

@RoryMcCune Leeds for a client meeting

journey down - lovely, sunny, views out over the North Sea. Single train from Edin to Leeds

journey back - late trains, missed trains, many trains, much rain, meh

not so great

Rory McCune

@RoryAlsop I've not been down Leeds way since my HBOS days. Still probably best you didn't fly, I'd bet Leeds bradford was shut in this wind..

Lucas Kauffman

@RoryAlsop I had my first sale the other day!

Rory Alsop

@RoryMcCune wasn't windy down there - until we left the client :-)

@LucasKauffman result!

AviD

22:14

@LucasKauffman congrats! vodka should get the taste out.

Lucas Kauffman

I actually didn't think the sales part could be as fun as the technical part

Rory McCune

@LucasKauffman I actually quite like the pre-sales technical bit, finding out about a customers problems and thinking up a way to address them

Lucas Kauffman

@RoryMcCune and try to make up a reasonable price and play around with the ERP

AviD

@RoryMcCune me too. I really got to stretch my mind's legs on some of those occasions.

@LucasKauffman that part, less so.

I enjoyed the part of convincing them how great we/I am, and we can give them what they need. The price-negotiation part, not so much.

Lucas Kauffman

@AviD It's still new, so it's fun to see how these things happen

also clients don't always know what they want

AviD

22:17

I... guess.

Rory McCune

@AviD yeah I'm rotten at price stuff. I tend to tell people what I think it costs rather than do anything subtle

Sadaluk

@ThomasPornin I seek the wisdom of the mighty bear - if I can. Any idea why the aeskeygenassist AES-NI instruction takes four 32-bit values (called say x0,x1,x2,x3) and returns subword(x1), xorrcon(subword(rotword(x1))), subword(x3), xorrcon(subword(rotword(x3))). What baffles me is... well why bother making it a 128-bit block, why not just use a standard 32-bit one? The work required to compute parallel key schedules by correctly packing an xmm word hurts my head!

AviD

I've worked up some spreadsheet to help me with it: I start with the SoW breakdown, attach time estimates, spreadsheet calculates buffers, overhead, etc, and gives me a final result, depending on the rate I want.

Sadaluk

(yes, you're reading that right, it does discard x0, x2 entirely)

AviD

Then I throw that out and make something up.

@Sadaluk read that as "ask a geek". Would be a great podcast...

Lucas Kauffman

22:20

@AviD yea I use an excel for that as well

AviD

@Sadaluk not familiar with those instructions, but I'd guess that its because AES usually uses 128bit blocks...?

@LucasKauffman the last step is the important part.

Sadaluk

@AviD Yeah. aesenc et al use 128-bit registers, e.g. xmm1-15, that's all fine. What I'm not sure I understand is why the key schedule instruction bothers - Intel's own example entirely discards three of the four 32-bit words after running the aeskeygenassist instruction.

AviD

ah. cant help ya there, mate.

Sadaluk

@AviD Yeah, I know. Bizarre. But if anyone can save me, it's the Bear Team.

Thomas Pornin

@Sadaluk I have to go right now; I will look into it later tonight, or tomorrow.

Sadaluk

22:25

@ThomasPornin Thanks :) If I manage to articulate my confusion successfully I might write up a question on crypto or SO - if so I'll pop a link over.

Apologies for the interruption with that everyone else, please carry on! (feels awkward like the guy who interrupts a boring lecture to ask the same question twice in five minutes)

@AviD Gotta get those time estimates right though - otherwise you do more work than you get paid for (or get paid less per hour than you intended)

AviD

@Sadaluk right, hence the buffers and such.

Rory Alsop

@LucasKauffman yep - me too :-)

AviD

Estimating is its own set of skills, though.

Essential. comes with experience, but also theory.

Sadaluk

@AviD Yeah. I discovered that idea after I did a website as a contract and underestimated... only make that mistake once!

AviD

that said, there is always error.

@Sadaluk yup, similar mistake here :)

most consultancies have a simple solution for that - you do not do more hours than the estimate.

no matter what.

Lucas Kauffman

22:39

indeed

AviD

23:46

is it a bad idea to buy refurbished hardware?

factory refurbished, by the original manufacturer.

Specifically, a router.

Gilles

@AviD depends. Are you more worried about someone adding a backdoor, or more interested in finding someone's unwiped passwords?

AviD

@Gilles neither.

I plan to flash it regardless, put on either dd-wrt or tomato.

More worried about hardware failure.

Gilles

how much $$ are you saving?

AviD

umm... about half price.

Gilles

on a $50 router or a $50k router?

wrt so I guess $50

do you need $20 that badly?

AviD

23:49

heh. 80$. so saving about $40

Gilles

how bad is it if it fails?

AviD

40. and thats the question, innit?

I cant make a risk decision if I dont know the likelihood of failure.

@Gilles worst case, I replace it - and I'm out that cash.

so I guess thats about even there.

Gilles

@AviD no, the worst case would be the service interruption

if it fails under warranty, would you return it with a 6–8 weeks turnaround, or buy another?

AviD

my question is, is it usually safe to buy one of these - are they usually crap, or usually great?

@Gilles eh. so i'll spend a couple hours, and replace it with my old router.

@Gilles if i can, sure.

Gilles

some are someone realizing they bought the wrong color, some have been damaged. I don't know the proportion

all in all I think it's more a matter of worst case

if you don't need high availability, go for the refurbished

If you need high availability, buy two half-price refurbished

for extra geek points, plug them both in a failover configuration

(and have them both fry when lightning strikes)

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