Re: [PATCH/RFC] don't support %n in printk

[Pavel Machek <pavel@ucw.cz>]

Hi!

> The printf man page has this to say about '%n': 
> 
> "The number of characters written so far is stored into the integer
> indicated by the int * (or variant)  pointer argument.   No argument
> is converted." 
> 
> Very little code actually uses %n for that. Now days, %n has a much
> more common use - in printf format string exploits. Since no kernel
> code appears to be using %n (thus said grep), this patch removes
> support for it. To preempt the obvious argument, I agree that printk
> should look and behave as much as possible as printf - except where
> it's harmful. We don't support floating point, for example, and I
> doubt we should support %n - although I don't strongly care one way or
> another. 

You probably should search the kernel for any uses of %n and fix
them...
								Pavel

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]