edit: submitter has since updated the title, was: "Github giving away your private key"
It looks like people have added their private keys to (public!!!) repos, and voila, a search allows others to find that.
Now he doesn't log in to my server. Just sends me a zip-file that I unpack and test. sigh.
Anyway, as usual the main problem exist between the chair and the keyboard.
Reminds me of google hacking: www.hackersforcharity.org/ghdb/ (which is way more fun)
Also Github, provide an option to protect those who are less security savy.
private keys are private. these people -know- that they are pushing a git repo to a very public site. as such, they should recognize that * is going to be visible in their dotfiles repo. it's not git or github's fault that users are doin it wrong!
Adding a default .gitignore file with some sensible defaults has no negative trade offs. If you really do want to commit your .ssh folder, just remove that line from your .gitignore.
I will admit that adding .DS_Store, while convenient, might be impractical since git is meant to be platform agnostic, and they probably don't want to start adding all sorts of platform-specific files.
Even more rare than that is the user being dumb enough to not consider all files in the home directory before pushing to a public site. I'm sorry but I definitely agree more with the other guy's logic than yours.
You say it has no negative tradeoffs? I say besides changing the whole game (as of right now github does not subject me to a single line of opinionated code) some projects are meant to be small. Sure you can just take out the github .gitignore but thats an extra step. I'm really tired of the stance that we should make development so easy even someone who refuses to RTFM can do it. I'm all against re-inventing the wheel, but dumbing things down like that is not something I can get behind.
This doesn't dumb down programming. It improves UX for everybody, while also improving security for beginners. Why does GitHub offer to autogenerate a readme file? Because it's convenient. That doesn't dumb down programming for anybody.
The key word in your second point is 'offer'. If they were to protect these keys from being pushed they would have to interfere with your first push and add a line to your .gitignore, which you would then have to remove EVERY TIME... if your a developer I don't know how at this point your not like "eh, actually I don't really feel like doing that in every project, that would be annoying".
I would also argue that allowing newbs to become developers without realizing that they are ignoring private key files inside their git repo is just allowing them to continue on to become developers who are not security conscious. You could of course argue back that having to take .ssh/ out of your .gitignore for every project you do hammers the point home for everyone, and it sure would! I don't believe most of us need that, and if that is your idea of improved UX then please don't ever work with me ;) (I'm j/k about that by the way, tabule looks pretty nice and this is all just my opinion, please don't take it personally. I would welcome an opportunity to work with you... just don't go adding .ssh/ in my .gitignore!! :P)
However, I agree with your point that allowing new devs to keep making this mistake and just shielding them from it is a bad idea. With that in mind, it might be nicer if GitHub checked for .ssh files on commit and showed a warning within the web app, letting you know what you did wrong.
But there is a certain probability that the token on the GitHub-page is not identical to the production site's token.
(afaik, the token is digested with the user's ID and stored in the user's cookie so a user cannot change his ID while he's signed in - knowledge of the token can let you change your ID to whatever you like)