On Tue, Jun 10, 2008 at 8:20 AM, Jens Alfke <[EMAIL PROTECTED]> wrote: > > On 9 Jun '08, at 10:38 PM, Michael Ash wrote: > >> It's perfectly possible to write safe code that calls C >> str functions. My code is no more vulnerable than the next man's. You >> can call things like strnstr, pass the length of the NSData you're >> working on, and there is exactly zero risk of anything. > > Sure, and it's perfectly possible to shave with a blade without cutting > yourself; that doesn't mean it doesn't happen, though :/ What you're saying > is "if you do everything right, there's zero risk of it being wrong", which > is a tautology. The point is that people can and do make mistakes when > working with C string APIs (even the "n" ones).
This is true but meaningless. People can and do make mistakes with *everything*. The C string APIs don't have a particularly special place as far as security vulnerabilities go. >> No, it's not. A common technique is to use C string APIs to find line >> endings, then try the full line as UTF-8. If it fails, then you can >> fall back on a more forgiving encoding. > > Yes, I do try UTF-8 first. Sorry, I was being brief in the previous message, > describing only the _fallback_ if UTF-8 parsing fails. > > I'm not sure why you would want to use C APIs to look for line endings > first, though? When working with streaming data then you need to find a delimiter to safely cut the stream before trying UTF-8, because if the end of your chunk of data ends in the middle of a UTF-8 code word (or whatever it's called), then the result will be invalid UTF-8 even if the stream as a whole is valid UTF-8. You could write a UTF-8 parser to find good cut points, but it's much easier when working with a line-oriented protocol to just look for CRLF. Mike _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
