October 2009 Archives

A matter of policy

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This has been a long standing policy in Technical Services, dating to the previous VP-IT and endorsed by the current one. This policy concerns email like this, generally from a manager of some kind:
"[Person X] no longer works here. Please change their password and give it to [Person Y] so they can handle email. And please set an out-of-office rule notifiying people of [Person X's] absence."
To which we politely decline. What we will do is set the out-of-office rule, that's just fine. We'll also either give a PST extract of Person X's mailbox, or if there really is no other way (the person was the Coordinator of the Z's for 20+ years and handled all the communications themselves before retiring/dying) we'll grant read-access to the mailbox to another person, and effectively turn the Person X account into a group account but lacking send-as rights.

What we will categorically not do is change a password for an inactive user and give the login to someone else. It comes down to identity theft. If we give Person Y the login info for Person X, Person Y can send email impersonating Person X. And that is wrong on a number of levels.

We resist giving access to the mailbox as well, since a non-trivial proportion of end-users give their work email as the email address for web-registration pages all over the internet. And thus that's where the "password reminder" emails get sent. Having access to someone else's mailbox is a good way to start the process of hacking an identity.

Yes, we do occasionally get a high level manager pushing us on this. But once we explain our rationalle, they've backed down so far. There is a reason we say no when we say no.

Filesystem drop-boxes on NTFS

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We have a need to provide dropboxes on our file-servers. Some professors don't find Blackboard's dropbox functionality meets their needs, so they rock it 1990's style. On NetWare/OES, this is a simple thing. Take this directory structure:

CLASS1:\CAS\Physics\PHYS-1234

And a group called PHYS-1234.CLASSES.WWU

Under NetWare, you set an Inherited rights filter or explicitly remove inherited rights, grant the PHYS-1245.CLASSES.WWU group the "C" trustee to the directory, and the professor's user object full rights to it. This allows students to copy files into the directory, but not see anything. On the day the assignment is due, the professor revokes the class-group's rights and tada. A classic dropbox. Dead simple, and we've probably been doing it this way since 1996 if not earlier.

It's not so simple on Windows.

First of all, Windows has different rights for Directories and Files. They use the same bits, but the bits mean different things for files and directories. For instance, one bit means both "write files" for directories, allowing users with this right to create files in the directory (analogus to the "C" NSS trustee right), and "write data" which grants the ability for a user to modify data in a file (analogus to the "M" NSS trustee right). So, this bit on a Directory grants Create, but this bit on a file grants Modify. Right.

To create a dropbox on NTFS, several things need to happen:
  • Inherited rights need to be copied to the directory, and inheritence blocked. (There is no Inherited Rights Filter on NTFS)
  • Extranious rights need to be deleted from the directory. (again with the no IRFs)
  • The class group needs to be granted the 'Read' rights suite to "This Folder Only", as well as "Create files".
    • Traverse Folder
    • List Folder
    • Read Attributes
    • Read Extended Attributes
    • Read Permissions
  • "CREATOR OWNER" (a.k.a. S-1-3-0) needs to be granted the 'Read' rights suite to "Subfolders and files only"
The key thing to remember here is that "Subfolders and files only" is an inheritance setting, where "This Folder Only" is a direct rights grant. Files created in this directory will get the rights defined under 'creator owner'. If the professor wishes to remove student visibility to their files, they'll have to Take Owner each file. I have found that Windows Explorer really, really likes being able to View files it just wrote, and this rights config allows that.

This series of actions will create a drop box in which students can then copy their files and still see them, but then can't do anything with it. This is because Delete is a separate right that is not being granted, and the users are not getting the "Write Data" right either. Once the file is in the directory, it is stuck as far as that user's concerned. If a user attempts to save over the invisible file of another user, perhaps the file names are predictable, they'll get access-denied since they don't have Write Data or Delete to that invisible file.

If you're scripting this, and for this kind of operation I strongly recommend it, use icacls. It'd look something like this:

icacls PHYS-1234 /inheritance:d
icacls PHYS-1234 /remove CAS-Section
icacls PHYS-1234 /grant Classes-PHYS-1234:(rx,wd)
icacls PHYS-1234 /grant ProfessorSmith:(M)
icacls PHYS-1234 /grant *S-1-3-0:(oi)(ci)(rx)


(rx,wd) = Read-Execute & Write-Data
(M) = The "Modify" simple right. Essentially Read/Write without access-control.
(oi) = Object-Inherit, a.k.a. Files
(ci) = Container-Inherit, a.k.a. Directories
(rx) = Read-Execute
*S-1-3-0 = The SID of "CREATOR OWNER". An explicit grant to this SID works better than using the name, in my experience.

This hasn't been battle tested yet, but it seems to work from my pounding on it.
Last night while I was sleeping, I had a dream. In my dream I was at my desk at work. I picked up my flashlight for some reason and just then the power decided to drop. DARKNESS. And the UPS alarm in the distance. This was concerning since my workstation is on a power outlet attached to the datacenter UPS, so if my computer was out, chances were real good the entire datacenter was also down. Very bad.

Happily I just happened to have my flashlight in hand! So I powered on and went to the datacenter door. But my access card wouldn't work. The card-reader has its own internal battery, so it not reading me at all, or even giving me the access-denied angry-beep, was doubly bad. Happily, coworker dropped by and could get in so I ghosted on in behind him. The room was noisy and had all the right lights. But the UPS was still alarming. Not surprising, it's supposed to do that.

Then I woke up. I checked the clock, still had power. And there was a beep in the distance.

A smoke alarm was crying for a new battery. At 5:30am. It's just a single beep, but it seems my unconscious mind interpreted that as a UPS alarm even though those are ususally three beeps.

I have a new boss

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And he'll be my boss on the 16th of November.

More info once I know when it's safe to disseminate it.

Insecure applications

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Anyone who deals with network security has run into this problem:

Department/powerful-user buys an application for a lot of money. They would like it to work please. Application's requirement state, "disable all security systems so our crappy-app can work unencumbered." Crappy-app runs into network security problems and dies. Department/PU contacts IT and asks to have network security disabled so their expensive crappy-app can run correctly.

What happens next is a very good test of management's commitment to network security. Will management say:
  • Hmm, that's a lot of money. IT, make an exception for this app.
  • Hmm, that's a lot of money. We'll have to make it work somehow.
  • That's a really insecure app, too bad you spent a lot of money. It will not be installed. Let this be an object lesson to you all.
We just got a request for something like this. Apparently the application's requirements include disabling the Windows firewall. We've turned it on by GPO, so it will always be on. This is the secure way to live. Whether or not we get told to make an exception, make it work somehow, or ignore it remains to be seen.

Windows 7 releases!

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Or rather, its retail availability is today. We're on a Microsoft agreement, so we've had it since late August. And boy do I know that. I've been having a trickle of calls and emails ever since the beta released about various ways Win7 isn't working in my environment and whether I have any thoughts about that. Well, I do. As a matter of fact, Technical Services and ATUS both have thoughts on that:

Don't use it yet. We're not ready. Things will break. Don't call us when it does.

But as with any brand new technology there is demand. Couple that with the loose 'corporate controls' inherent in a public Higher Ed institution and we have it coming in anyway. And I get calls when people can't get to stuff.

The main generator of calls is our replacement of the Novell Login Script. I've spoken about how we feel about our login script in the past. Back on July 9, 2004 I had a long article about that. The environment has changed, but it still largely stands. Microsoft doesn't have a built in login script the same way NetWare/OES has had since the 80's, but there are hooks we can leverage. One of my co-workers has built a cunning .VBS file that we're using for our login script, and does the kinds of things we need out of a login script:
  • Run a series of small applications we need to run, which drive the password change notification process among other things.
  • Maps drives based on group membership.
  • Maps home directories.
  • Allows shelling out to other scripts, which allows less privileged people to manage scripts for their own users.
A fair amount of engineering did go into that script, but it works. Mostly. And that's the problem. It works good enough that at least one department on campus decided to put Vista in their one computer lab and rely on this script to get drive mappings. So I got calls shortly after quarter-start to the effect of, "your script don't work, how can this be fixed." To which my reply was (summarized), "You're on Vista and we told y'all not to do that. This isn't working because of XYZ, you'll have to live with it." And they have, for which I am greatful.

Which brings me to XYZ and Win7.

The main incompatibility has to do with the NetWare CIFS stack. Which I describe here. The NetWare CIFS stack doesn't speak NTLMv2, only LM and NTLM. In this instance, it makes it similar to much older Samba versions. This conflicts with Vista and Windows 7, which both default their LAN Manager Authentication Level to "NTLMv2 Responses Only." Which means that out of the box both Vista and Win7 will require changes to talk to our NetWare servers at all. This is fine, so long as they're domained we've set a Group Policy to change that level down to something the NetWare servers speak.

That's not all of it, though. Windows 7 introduced some changes into the SMB/CIFS stack that make talking to NetWare a bit less of a sure thing even with the LAN Man Auth level set right. Perhaps this is SMB2 negotiations getting in the way. I don't know. But for whatever reason, the NetWare CIFS stack and Win7 don't get along as well as the Vista's SMB/CIFS stack did.

The main effect of this is that the user's home-directory will fail to mount a lot more often on Win7 than on Vista. Also, other static drive mappings will fail more often. It is reasons like these that we are not recommending removing the Novell Client and relying on our still in testing Windows Login Script.

That said, I can understand why people are relying on the crufty script rather than the just-works Novell Login Script. Due to how our environment works, The Vista/Win7 Novell Client is dog slow. Annoyingly slow. So annoyingly slow that not getting some drives when you log in is preferable to dealing with it.

This will all change once we move the main file-serving cluster to Windows 2008. At that point, the Windows script should Just Work (tm). At that point, getting rid of the Novell Client will allow a more functional environment. We are not at that point yet.

It's the little things

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Right now our Microsoft migration schedule is hung up on backup licenses. Backing up clustered servers requires extensions, which we didn't notice back when we priced out the project. It is things like these that make for cost-overruns. The long and the short of it is, we're not migrating anything until we can legally back up the new environment. Period. That's just how it is.

As most of the budget arm-wrestling happens above me, I only get bits and pieces. Since we don't spend our money, we spend other people's money, we have to convince other people that this money needs to be spent. I understand there was some pushback when the quote came in, and we've been educating about what exactly it would mean if we don't do this.

I understand the order is in the works, and we're just waiting on license codes. But until they arrive (electronic delivery? What's dat?) we simply can not move forward. That's just how it is.

Clearly I am missing something

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On the opensuse-factory list this exchange has happened several times:

Q: Installation from LiveDVD is broken. Bug?

A: LiveCD's are not installation sources.

Clearly, something has changed in the Land of Linux Installers. Enough mind-share has shifted to "I install my linux with my LiveDVD" that it has become a very common question on the factory list when it doesn't work. When I was a kid, we installed our linux from an Install CD. LiveCD's were for things like Knoppix, used for ass-saving or quick access to Linux tools that don't exist on Windows. I seem to remember a way to install Knoppix to a hard-drive, but I never did so.

When did this change? Is this something Ubuntu is doing?

BrainShare returns for 2010?

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Novell just posted the Call For Participation, essentially soliciting session proposals, for BrainShare 2010. So it sounds like they're at least planning on going for it for 2010. Obviously, what with this little project I'm working on I won't be going. But it is nice to see it up and running.

Posting will be light. I was out sick last week, and I have family arriving later this week and in to next week.

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