On Feb 21, 2013, at 8:34 PM, Gerriet M. Denkmann <gerr...@mdenkmann.de> wrote:
> Well, the opposite of: "can store all strings" is: "can store only certain > strings". > My point is that the number of unstorable strings is greater than zero. > Whether it is 1 or any other number is quite beside the point. Yes. What makes this so bad is that it’s pretty likely that some strings stored in an archive are created outside the program’s control, i.e. by a user (or worse, possibly from data received over a network.) That means you have to explicitly guard against un-archivable strings, maybe by escaping them somehow, or run the risk of crashes or corruption. And we don’t even know for sure what the full set of un-archivable strings is. It also doesn’t matter how obscure/unlikely those illegal inputs are. Let’s say you wrote an IRC client that persists transcripts using an NSKeyedArchiver, with a data structure where every message is an NSString. Makes sense. So then all someone has to do is type the message “$null” into an IRC chat, and boom! Everyone in that chat room using your client simultaneously gets kicked out with a crash.* Instant DoS attack. In this case it wouldn’t matter if the illegal string were a specific 800 characters of gibberish; once someone found out the bug, that string would become pretty widely known. —Jens * I had something like this happen in one particular development build of iChat once, due to a bug in the Bonjour status-message code. There was some particular character you could put in your status message, that would instantly crash every copy of iChat running on your subnet. This was lots of fun for a few hours until I fixed the bug. _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
