At work, we tend to spend time that we’re not on
projects however we want. Ideally, however meaning - technically
however – not being on Facebook 8 hours a day. But jokes apart,
usually someone picks up a skill that he/she isn’t familiar with
and tries to learn the same when not on projects. Since most of my
professional life in information security has been to break things,
I’ve always been curious on how things are on the other side – to
build things. What challenges does a developer face? Why is there
still such a lot of truly awful insecure code still out there? This
despite there being tons of resources to learn from? After all, as a
hacker that’s how I’ve learnt all my life – don’t know how to
hack a new technology? Go read. Learn. Master. Hack. Why should it be
any different from developers?
And so, I decided to fix a ton of bugs in Whetstone, our internal
appraisal system which our boss wrote while he was on paternity
leave. He takes his vacations seriously, as you can see. Whetstone
was written in Ruby on Rails – which is one of my favorite
languages for web development – just because of how easy it is to
get started. So I go, ooh nice – how hard can it be? And that’s
where it all began going wrong…
So obviously, I can’t gut the whole thing and start re-writing the
entire system. I have to fix bugs that currently exist. I launch
GitHub and see 78 existing bugs. So now I have to prioritize which
ones to fix first. I start the process. I pick a simple one to start
off with and quickly fix it. I’m excited. I want my change to be
visible immediately. Oh but wait, that’s not how it goes.
Apparently, git has something called branches that I first need to
learn about – so as to not mess with other people pushing code back
as well. That puts and end to my coding for the present, and I spend
2 hours reading about how Git handles versions and branches and why
its better than SVN and so on. Then I push my code and see it appear
on Github. But then someone has to “pull” my changes or accept
them. And clearly, while I have permission – it makes no sense to
approve my own code – that defeats the purpose. And boss is on
leave. No push. No warm fuzzy feeling of first ever fix. Process
problems.
Anyway, I’m now feeling better and pick up a few moderately complex
issues. It seems I know how to fix it. Code. Compile. Fail. WTF.
Google. Stack Overflow. Fail. As it turns out, I’ve upgraded Rails
to 4.3 or something and all the fixes on the Internet which have
up-votes on Stack Overflow all fail. Somehow after a lot of trial and
error I find a fix, but it has taken way way longer than I’d ever
expect it to take. And note, this is a simple internal application.
If I fixed bugs at that speed in production, as a developer – I’d
probably be fired in a week. Skill problems.
Then, I get put on a billable project and forget all about this for a
bit. Boss comes back, my 4 changes are accepted. Am I having fun, he
asks? Yes yes of course I say, drunk with the success of my 4 massive
quashed bugs. Okay, have fun – fix some more says boss. So 2 months
later, I pick it up again. So let’s start now. Er, why did I write
this code this way? F***, it was so long ago – I should have
commented. Lets look at some old code, maybe that explains it. Er no,
no comments there either. Just some fancy one-liner SQL looking
query. Ha, I’ll just comment the old code then and write new fresh
code! That’ll fix it. For sure…… 2 hours later. Undo. Undo.
Undo. Okay that broke everything :| and clearly I can’t code. I
suck.
And now, after all the undoing, something else isn’t working too.
Screw it. Let me revert to a clean state. Let me just delete that
stupid whetstone_old directory that I created. And I’ll
rebuild everything from Git again – from my old state. Delete.
Rebuild. Ugh. Read Me isn’t good. How the hell did I build it last
time? What does this error even mean? Note here, that I have NOT
fixed 1 single bug yet… 1 hour later – AH so all you needed to do
was change the config file entry? Okay. Anyway, let me first collect
all my old notes from whetstone_old before I forget stuff like
this. Don’t want to waste time.
Eh. Where’s whetstone_old?? Oh no!!! Don’t don’t tell me
it was in the directory I deleted #-o. Yes. It WAS in the directory I
deleted. Woo Hoo. All gone. I’m screwed. Backups are important.
There’s a reason you backed up to whetstone_old. Why
would you delete it?
Another day wasted then. Okay okay, now lets fix bugs. Ah, here’s
an easy bug – “Display last login time for a user”. 10 minutes.
I got this. Just print a date out in the view. Adds date to view. But
this is just printing the current date each time ffs :-o. We want it
for each user. Oh. That means a new column. In the user database. I
know a little MySQL though, from all my SQL injections over years
gone by, so this should still be quick….
Error. Can’t connect to MySQL database. Eh? Different port? No. 15
minutes. Can’t figure out where the DB is. RTFM. Sqlite. NOT MySQL.
Now if I want to debug anything, I need to learn Sqlite querying.
Learn how to use a database. NO ffs I have still not fixed the
bug. Okay, now I understand sqlite. But how do I add that column?
Learn Rails migrations. Wow. Another half an hour. Add column.
Finally fix bug. It lunch time. I should stick to hacking things –
I clearly am not good at this stuff. But wait, now I got it.. I know
how the DB works, so things should now work out...
Okay, lets login and see if our date prints right. Just to check lol.
Obviously nothing can go wrong. Hmm, looks okay. Oh wait, we need to
do some stuff with the Date. Why do none of the in-built functions
work? Oh no, its not a varchar – its DateTime –
only then will some functions work. Or I’ll have to write my own
functions. Which would be stupid for such a trivial task. So I have
to change the data type in the DB. Learn how to change Rails
migrations. And while that looked simple, it didn’t work. The
accepted solution was to “DROP TABLE” and “Recreate TABLE”.
Ugh.
Now remember, I hadn’t created the table in the first *^%$#@!
place. So I now have to find out the structure of every single column
of that table and re-create it. Screw it. I don’t want a fancy
date. I’ll just leave it as it is and go on… But now that failed
migration attempt has screwed something else up – and all my normal
code that I never never touched is not working. Fantastic. Things
you never coded can break despite you never touching it.
Meaning, I now have to learn the entire old schema. Luckily logging
was turned on by default, and the old old old log file was never
truncated. Extract the old old query. Convert it into a valid Sqlite
query. Drop old table. Create new table. Okay error gone. But now no
date display. WTF!!! That’s cause recreating the table destroyed my
Rails migration. So do that again. Finally done. In short, playing
with the DB isn’t particularly fun, and any re-architecting brings
up weird weird problems.
And after all this, all I’ve done is fix one lousy feature request
that displays the last login time. Okay let’s move on to the next
bug. It’s a security issue now, user IDs are generated sequentially
and that’s a problem – a hacker could enumerate all valid
numbers. So I need to randomize stuff. Meaning I have to change the
data type of a column. Right now, the id column is an integer,
I need to convert it to a GUID. Looks very similar to the
previous DateTime problem haha. I got this one for sure. Migrations.
Change. Blah. . Er. Why did
something else break again? Why is nothing working now? Why can’t I
even login? Panic. Turns out that id was the Primary Key for the DB.
And messing around with the primary key is a bad bad idea. Even worse
than messing around with a database. Don’t do it. Just just don’t
do it. Deny that feature request.
Learn how to change a primary key.
This is terrible. Is this what fixing other people’s code is like?
And this is for a small internal application which is relatively well
written, compared to some of the bloated code that I’ve seen over
the years. Anyway, more hours wasted – I figure out what to do. But
now, for some reason I can’t find out where the hell to put the
‘randomizing code logic’. A few more hours… oh wtf.. you know
by now that I’m spending more time fixing stupid knowledge gaps
than actual bugs.
As it turns out, my boss (correctly) decided to not write a line of
code for authentication, and relied on a third party Ruby Gem
instead. Well whoopee doo doo. #-o Why am I sarcastic, you say. It
means that I now have to hack on some third party module code
instead. Start learning third party module code now. That’s
another fail, and I have to contact the module owners who patiently
explain what to do. Eventually it all works.
Lets look at Bug 3 now. All you need to do is to make a really simple
UI change. This CANT be hard ffs. How hard can it be? But by now, I’m
in a numb state – coz I’m fairly sure something will go wrong. Oh
look. Its CSS. And CoffeeScript. Do I know either? NO. Learn CSS.
Learn Bootstrap. Learn Coffee Script. The saddest part is I just
need enough to fix a tiny bug, but without knowing the basics – I
can’t do it. More time gone.
And this pattern repeats.. again and again and again. Eventually of
course, as expected (else I won’t have a job) I improve and start
fixing things quicker. But something or the other always always
breaks – when you least expect it to. And when its not your code,
its harder to fix it. And now I think of those massive banking
applications, when the chief architect and the lead developer quit a
while ago, and there are 5 new developers. Shudder.
And I still have tons of bugs left. I find my mind thinking of
shortcuts and dirty ways of solving problems all the time. I find
myself thinking of how to somehow get that number of bugs down.
Somehow. Quickly. So I can get back to actually writing new cool
stuff. It isn’t easy to maintain that mental discipline. Honestly
isn’t. And this is for an internal app, which isn’t critical and
with no deadlines except those that I set for myself. I have a
new found additional respect for developers.
I always knew a developer’s job is trickier than that of a hacker –
and I’d like to honestly say I’ve always been respectful to every
dev I have met. But I’ve never sympathized with one. I’ve always
felt that it is yet another job that one learns to do well over time.
And that’s true, sure – but they do work under greater pressures
than I do. There’s other skills in my job as a white-hat hacker,
other traits that maybe developers don’t need to learn – but
whatever a developer does need to do – isn’t easy. IF IF you want
to do it well.
Lastly, I want to tell every white-hat hacker to put on the defensive
hat once. Actually code. Code things that people will look at and
break and tell you how awful your hacks are. And how you should test
more… before releasing to production. See how it feels. :) If not anything else, it’ll make you respect the developer
community more than you already do. And that’s how it should be.
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