Re: [PATCH v3] vsprintf: Prevent crash when dereferencing invalid pointers

[Sergey Senozhatsky]

On (03/15/18 16:58), Sergey Senozhatsky wrote:
> On (03/14/18 15:09), Petr Mladek wrote:
> [..]
> > +static const char *check_pointer_access(const void *ptr)
> > +{
> > +	unsigned char byte;
> > +
> > +	if (!ptr)
> > +		return "(null)";
> > +
> > +	if (probe_kernel_read(&byte, ptr, 1))
>                                         ^^^^^
> Why one byte? 			     sizeof(ptr)?

I think there is a shorter version - probe_kernel_address(),
which, seems, was designed for this particular kind of stuff.

	void *p;

	if (probe_kernel_address(ptr, p))
		....

	-ss