Re: AUDIT of 2.5.15 copy_to/from_user

[Rui Sousa]

On Sun, 19 May 2002, Alan Cox wrote:

> Looking at 2.4.1x which has the same signal code
> 
> > arch/i386/kernel/signal.c:37:		return __copy_to_user(to, from, sizeof(siginfo_t));
> 
> not a bug
> > arch/sparc/kernel/signal.c:101:		return __copy_to_user(to, from, sizeof(siginfo_t));
> 
> Not a bug
> 
> > arch/alpha/kernel/signal.c:44:		return __copy_to_user(to, from, sizeof(siginfo_t));
> 
> Not a bug
> 

Hi,

Halfway this thread I got I bit confused...

copy_to/from_user() --> will return the number of bytes that were _not_ 
copied. If one does not care about partially successes just use:

if (copy_to/from_user())
	return -EFAULT;

__copy_to/from_user() --> the same as above, but can they actually return 
anything other than 0? My assembler is no good and I'm not able to see if
the macros __constant_copy_user(), __copy_user(), __constant_copy_user_zeroing(),
modify the size argument.

Rui Sousa