Category: Software

I Want to Pay for Dropbox – But It Might Make Me Hate Myself

Dropbox is one of the very few applications I’ve installed that has completely changed the way I use computer systems.

Under most circumstances, I no longer have to think about having to deal with the irritating sending and receiving of files, or stuffing them onto some other system to be retrieved later. I can just save everything onto my local disk – exactly as I’d like to – and know that it will magically pop up at some later point on every other PC that I own. I take photos on my phone knowing they’ll be stuffed onto Dropbox for later retrieval on my PC – indeed, I no longer even think about “copying photos off my phone”, because it just happens.

There are, of course, a few limitations. For example, it’s hard to do this with large volumes of data, simply because the upstream on most broadband plans is woeful. In those cases typically reaching for the USB disk or stuffing bytes onto my phone is a better alternative.

Of course, the other limitation is the few paltry gigabytes of storage you get on the free plan. If you’re dedicated though, it’s pretty trivial to boost this by quite a bit – referring friends, linking devices, all that sort of stuff. At the time of writing I have 4.2GB available on my Dropbox, without spending a cent.

And now, perhaps inevitably, I find myself in the situation of wondering why the hell all my files aren’t on Dropbox. It’s almost like they had some sort of insidious plan to get me hooked on their awesome system by giving me a taste for free.

Unfortunately I don’t really want to use Dropbox. Not really because I don’t want to pay for it, but because I have never really liked their security model. I want my files to be encrypted/decrypted client side.

I suspect the main reason they don’t want to offer this is because it would remove a lot of the basic functionality that the vast majority of users take advantage of regularly – the ability to access and share files quickly and easily via the web interface in particular. Not to mention the support nightmare that would certainly ensue when those users lose their encryption keys and wonder why all their files are now a bunch of unrecoverable gibberish.

In the post-Snowden world this is possibly an even bigger deal. I don’t really have concerns that faceless government agents are going to be poring through my files – but it’s even clearer that you ultimately need to be responsible for the security of putting your data online.

I’ve tried a few of the European alternatives to Dropbox – Wuala and SpiderOak most recently. Their security policies look good, they (appear to) use client side encryption, and they’re located in Europe, so I can rest somewhat comfortably knowing they’re not subject to secret NSA orders or whatever.

With the possible exception of Google Drive (which of course is subject to the same woes as Dropbox), the other services I’ve tried I found almost completely unusable compared to the elegance, simplicity, and sheer Just Workiness of Dropbox. I tried – I really did. I wanted to like them. I’m not sure if it’s all that security stuff just getting in the way of making it a good experience, but they just feel clunky and awkward to use, painful to set up, and I was generally just thinking “why am I doing this?” the whole time.

I’m a big believer in voting with your wallet. It’s not like there aren’t other options. But Dropbox is just so damn convenient in so many different ways that I can feel myself slowly caving and abandoning any lofty principles just so I can go back to Getting Shit Done.

There are two things that Dropbox could do to get me off the fence immediately.

1) Introduce client side encryption/decryption into the Dropbox client. While it remains closed source I can imagine many would still (rightfully) be hesitant to trust it (how would you know they’re not capturing your encryption keys?), but a nod in that direction would be enough for me.

2) Introduce an option to limit storage of my files on Amazon clouds in different regions. I am not intricately familiar with how Amazon’s cloudy stuff works, but it seems that this would not be a complicated feature. Allow me to opt to have my files stored on S3 within particular geographic regions. I can imagine this would be a big deal for many government services who might want to use Dropbox but might be subject to limitations on where their data can be physically stored, and for the security nerds, getting out of the reach of the NSA (yes, yes, subject to their ability to compromise any site anyway), it would be a neat service.

What I suspect I’ll end up doing is signing up for a plan and then encrypting all my stuff locally with gnupg and treating it more like a backup archival system rather than a live working filesystem.

Image Data Only Hashing of JPEG Files

As part of a small project to verify backups, I came across a case where I had two photos that looked identical but with different EXIF data.

The backup verification system (correctly) flagged these as two different files – as the SHA1 file hashes were different. However, the actual photo was – as far as I could tell – absolutely identical, so I started looking to see if there was a way to verify JPEG files based on the image data alone (instead of the entire file, which would include meta stuff like the EXIF data).

A quick look around revealed that ImageMagick has a “signature hash” function as part of ‘identify‘, which sounded perfect. You can test it like so:

identify.exe -verbose -format “%#” test.jpg

At first glance this solved the problem, but testing on a few systems showed that I was getting different hashes for the same file – it looked like different versions of ImageMagick return a different hash. I’ve asked about this on their forum and was told that the signature algorithm has changed a few times – which makes it sort of useless if compatibility across platforms is required.

After looking around a bit more for alternative I found the (possibly Australian made?) PHP JPEG Metadata Toolkit, which (amongst many other things) includes a get_jpeg_image_data() function which (so far) seems to work reliably across systems. Pulling the data out and running it through SHA1 gives a simple usable way to hash the image-only data in a JPEG file.

Terrible Thunderbird v15.x IMAP Performance with AVG

My PC has recently been chugging a lot more than usual – massive disk activity and high CPU utilisation. Looking into it I quickly realised that it was happening whenever Thunderbird received a large bolus of new email – more than 15-20 emails within a minute or two. When I clicked on the folder with the new email, I could see in the status bar at the bottom that Thunderbird was very slowly downloading these new emails, while my disk and CPU went crazy.

Looking further I noticed that in Filemon, AVG was doing a lot of the work. Disabling AVG’s “Resident Shield” during one of these operations almost immediately fixes the symptoms – the email comes down much faster and the disk activity and CPU returns to normal.

This seemed to happen around the same time as Thunderbird v15.x was released, but I don’t want to declare that the culprit, especially as it is probably the same thing that I noticed with Microsoft Security Essentials that started happening around v11.x. I’m curious if something fundamental changed back then – either internally in Thunderbird, or perhaps within AVG – but it’s certainly possible that I’m just getting a little bit more email now and it’s just tripped my PC over the edge. I assume it has something to do with the way AVG hooks into the disk reading/writing operations – possibly Thunderbird changed something low-level there and it is simply reacting badly with how AVG does its real-time checking.

In any case, if you are experiencing massive slowdowns and system chunkiness using Thunderbird in conjunction with AVG, you can simply temporarily disable the real-time checking when getting a large number of emails. Obviously you probably don’t want to leave it off altogether.

MongoDB Fails Updating on Debian

Every so often there’s a MongoDB update on my Debian VPS that fails. The output of ‘aptitude full-upgrade’ is:

# aptitude full-upgrade
The following partially installed packages will be configured:
mongodb-10gen
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B of archives. After unpacking 0 B will be used.
Setting up mongodb-10gen (2.0.5) …
Starting database: mongodb failed!
invoke-rc.d: initscript mongodb, action “start” failed.
dpkg: error processing mongodb-10gen (–configure):
subprocess installed post-installation script returned error exit status 1
configured to not write apport reports
Errors were encountered while processing:
mongodb-10gen
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install. Trying to recover:
Setting up mongodb-10gen (2.0.5) …
Starting database: mongodb failed!
invoke-rc.d: initscript mongodb, action “start” failed.
dpkg: error processing mongodb-10gen (–configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
mongodb-10gen

The update works fine, but mongo just fails to start properly.

The problem in my case is simply that there’s a /var/lib/mongodb/mongod.lock file lying around from some previous process. Deleting that file and re-running the aptitude command will start it properly. (Reminder post because I keep forgetting what the problem is.)

AVG on Linux False Positives for NSIS

As of today, we’re seeing what I’m very confident are false positives in AVG running on Linux on our file servers. This has started happening after this morning’s virus database update. The database release we’re using is:

Virus database version: 271.1.1/4927
Virus database release date: Wed, 11 Apr 2012 05:55:00 +10:00

The output of avgscan is:

utils.exe |%name%=Win32/Validace_partial.nsis3|%idn%=0bcfdae664a2c000|=Win32/Validace_partial.nsis3

Files scanned : 1(1)
Infections found : 1(1)
PUPs found : 0
Files healed : 0
Warnings reported : 0
Errors reported : 0

The ‘nsis’ in the output there is presumably referring to the excellent Nullsoft Scriptable Install System (NSIS). The files I’m testing are largely game installers; when cross-checked with a file I built using NSIS it also triggers the false positive.

We are contacting AVG to report this as a probable false positive signature.

Update 3rd May 2012: AVG recommended we update to the 2012 version to fix this issue, which we did – and it fixed the problem.

Thunderbird Freezes When Deleting or Moving Email

I recently updated to the latest Thunderbird (v11.0) and was disappointed to discover that suddenly whenever I was deleting an email or moving it into a different folder, the entire application would freeze for 1-2 seconds while it processed that command.

I am fastidious about email and spend probably more time than I should ensuring everything is filed into appropriate folders (or deleted if I’m never going to look at it again). When you’re getting hundreds of emails a day, deleting and moving needs to be an operation that consumes near zero time, otherwise you’re suddenly spending way more time “doing email” than you should be. As a result, these freezes were massively irritating and caused no end of problems.

I reinstalled Thunderbird, which seemed to fix it temporarily – but before I knew it was happening again. I tried rebuilding and compacting folders – all for naught. I tried searching the Thunderbird Bugzilla looking for similar reports, but I couldn’t see anyone else having the problem.

I put up with this for a while trying various things, but eventually gave up and fired up the incredibly handy FileMon utility from the SysInternals guys to see if anything obvious was happening on the disk side of things that would account for this freeze.

Immediate pay dirt; this chunk of output in FileMon is shows the main part of what happened when I tried to move an email into a subfolder of the Inbox:

You can see there the operation started at 4:11:37pm and then the next activity was at 4:11:39pm – two seconds was roughly how long I was seeing Thunderbird freeze for.

Next step was looking at what MsMpEng.exe was – Microsoft Security Essentials. Turns out MSE was installed on my PC as part of a general system policy update at around the same time I upgraded to Thunderbird v11.0.

I tried changing the settings to see if that was indeed the cause – in MSE you just look for the Settings tab, select Real-time protection, and uncheck the ‘Turn on real-time protection’ box. Immediately Thunderbird started behaving normally with no more freezes.

Fortunately there’s an ‘Excluded processes’ option in Microsoft Security Essentials so you can add Thunderbird.exe to the list of processes to skip. This completely fixed the problem for me and now I’m back to moving and deleting emails fast as ever.

Fixing Double Encoded Characters in MySQL

If you’re working on any old PHP/MySQL sites, chances are at some point you’re going to need to get into the murky, painful world of character encoding – presumably to convert everything to UTF-8 from whatever original setup you have. It is not fun, but fortunately many people have gone through it before and paved the way with a collection of useful information and scripts.

One problem which struck us recently when migrating our database server was certain characters being “double encoded”. This appears to be relatively common. For us, the cause was exporting our data – all UTF-8 data but stored in tables that were latin1 – via mysqldump and then importing again as if it was UTF-8. This means something like the characters are detected as multibyte, but because the source and destinations were different, they’re re-encoded – so you end up with these double encoded characters that look like squiggly gibberish appearing in all your web pages.

Nathan over at the Blue Box Group has written an extremely comprehensive guide to problems like this. It explains the root cause of these problems, the common symptoms, and – of course, most importantly – precise details on how to safely fix them. If you’re doing anything at all involved in changing character encoding then it is worth a read even before you have problems, just so you can get a better handle on how to fix things and what your end game should be.

There’s a few other ways to fix it, of course. The Blue Box solution is comprehensive and reliable but it requires quite a bit of work to get it going, and you also need to know which database table fields you want to work on specifically – so it can be time consuming unless you’re prepared to really sit down and work on it, either to process everything manually or write a script to do it all for you.

Fortunately there’s an easier way, as described here – basically, all you need to do is export your current dataset with mysqldump, forcing it to latin1, and then re-import it as UTF-8:

mysqldump -h DB_HOST -u DB_USER -p –opt –quote-names –skip-set-charset –default-character-set=latin1 DB_NAME > DB_NAME-dump.sql

mysql -h DB_HOST -u DB_USER -p –default-character-set=utf8 DB_NAME < DB_NAME-dump.sql

We did this for AusGamers.com and it worked perfectly – the only caveat you need to be aware of is that it will mess up UTF-8 characters that are properly encoded aleady. For us this wasn’t a big deal as we were able to clearly identify them and fix them manually.

StackOverflow has yet another approach which might be suitable if you’re dealing with only one or two tables and just want to fix it from the MySQL console or phpMyAdmin or whatever – changing the table character sets on the fly:

ALTER TABLE [tableName] MODIFY [columnName] [columnType] CHARACTER SET latin1
ALTER TABLE MyTable [tableName] [columnName] [columnType] CHARACTER SET binary
ALTER TABLE MyTable [tableName] [columnName] [columnType] CHARACTER SET utf8

This method worked fine for me in a test capacity on a single table but we didn’t end up using it everywhere.

Trials and Tribulations of Updating PGP Desktop

I somehow missed the news in April last year that Symantec would be acquiring PGP. Symantec doesn’t exactly have a stellar reputation amongst technical people (my Dell laptop still has some mystical, seemingly uninstallable software components from a Symantec product that was on there when I bought it that I could never get rid of), so I’m sure if I had known about it, it would have filled me with dread.

I found out about it today when I loaded PGP Desktop and realised I hadn’t checked for updates for a while. Normally I haven’t needed to – PGP were pretty good about emailing me about updates. So I opened the application and hit Help->Update. After a split second of thinking, I’m greeted with a dialog telling me: “Product manifest from the PGP Corporation update server fails the integrity check. Please try again later.” I tried again later, same thing, so I did the next step anyone would try when troubleshooting and Googled the error message.

I was directed to this thread on the Symantec forums (never a good sign when the first hits aren’t in some support knowledge base). Fortunately, it had a reply from a Symantec tech support person, so that was good news.

The reply advised users experiencing the problem to download this PDF. Another bad sign. Why isn’t this just linked on a website? Load the PDF and you’re greeted with something that looks like this:

Really? You can’t even get the slashes the right way around in your hyperlinks? Dread level increasing.

Anyway, I tried the process. Went to the URL in point 1 and was told I need to sign up for an account. No worries, makes sense after reading the rest of the document – you get access to a license management section in the Symantec website, so an account seems like a reasonable thing. A relatively painless process; didn’t even need to activate. Tried to log in – more dread:

Augh. Stuck.

I realise that Symantec probably have a bit of work to do as part of the changeover – they say as much in the forum post. But getting software updates seems like enough of a Big Deal to warrant a bit more effort – not to say attention to detail – if they expect corporate customers to want to keep coming back. If I wanted to go to all this effort with desktop encryption software and keeping it up to date, I’d be using GPG.

Setting Up Infobox Templates in MediaWiki

Note: This guide has been updated as of 2014-09-22 for MediaWiki v1.23. If you’re using this version (or later) please see the Infoboxes in MediaWiki v1.23 post.

** Click here for the updated post. **

If you’ve ever been to any of the more structured Wikipedia pages you probably have seen the neat “infoboxes” that they have on the right hand side. They’re a neat, convenient way to get some of the core metainfo from an article.

If you have your own MediaWiki instance, you’ve probably thought they’d be a nice thing to have, so maybe you copy and pasted the code from Wikipedia and then were surprised when it didn’t just magically work. Turns out that the infobox stuff is part of MediaWiki’s extensive Templating system, so first of all you need the templates. Sounds easy, right?

Well, no. You don’t just flip a switch or download a file, and when you do a search you might find this article which details a process that it says might take 60-90 minutes.

I started looking into it and quickly got lost; you basically need to create a billion different Templates and do all sorts of weird stuff to get it to work. Fortunately I stumbled across this discussion which contained a clue that greatly simplifies the process.

I was able to distill the steps down to a process that I was able to reproduce on a new MediaWiki install in about five minutes. Before we start, I’ll throw in the warning that I have not read the documentation and I don’t understand at a low level what is happening with the templating. I just wanted a working, simple infobox.

  1. Download the MediaWiki extension ParserFunctions and add it to your LocalSettings.php as referred to there.
  2. Copy the CSS required to support the infobox from Wikipedia to your Wiki. The CSS is available in Common.css. You’ll probably need to create the stylesheet – it will be at http://your_wiki/wiki/index.php?title=MediaWiki:Common.css&action=edit – and then you can just copy/paste the contents in there. (I copied the whole file; you can probably just copy the infobox parts.)
  3. Export the infobox Template from Wikipedia:
    1. Go to Wikipedia’s Special:Export page
    2. Leave the field for ‘Add pages from category’ empty
    3. In the big text area field, just put in “Template:Infobox”.
    4. Make sure the three options – “Include only the current revision, not the full history”, “Include templates”, and “Save as file” – are all checked
    5. Hit the ‘Export’ button; it will think for a second then spit out an XML file containing all the Wikipedia Templates for the infobox for you to save to your PC.
  4. Now you have the Template, you need to integrate them into your MediaWiki instance. Simply go to your Import page – http://your_wiki/wiki/index.php/Special:Import – select the file and then hit ‘Upload file’. NOTE: see update at the bottom of the page before doing this.
  5. With the Templates and styles added you should be able to now add a simple infobox. Pick a page and add something like this to the top:{{Infobox
    |title = Infobox Title
    |header1 = Infobox Header
    |label2 = Created by
    |data2 = David
    |label3 = External reference
    |data3 = [https://trog.qgl.org trog.qgl.org]
    }}

The full infobox Template docs are available here – there’s a lot of stuff in there, but if you just want a really basic infobox then this is the simplest way I found to get them working.

I tested this on two separate MediaWiki installs – one running v1.12.1 and one on v1.15.1 – and it worked on both of them, but as always YMMV.

Update 2013-07-27

As many people have noticed, the guide no longer works. Thanks to commenters jh and chojin, it looks like you also need to do the following:

  • Install the Scribunto extension and add it to your LocalSettings.php as usual. It looks like this extension is now required for the InfoBox templates (in fact, it looks like it replaces ParserFunctions entirely, but I’m still testing that).
  • The XML file that is output in step 3 appears to erroneously (?) use text/plain as the format type. If you edit this XML file in your text editor and replace all incidents of ‘text/plain’ with ‘CONTENT_FORMAT_TEXT’ (I only found two), the import will be successful and the infobox tags looks like they work.

If someone else can confirm this for me as a working solution I’ll revise the original post so it takes these steps into account.