Re: [PATCH 1/2] mm, treewide: Rename kzfree() to kfree_sensitive()

[Waiman Long]

On 6/15/20 2:07 PM, Dan Carpenter wrote:
> On Mon, Apr 13, 2020 at 05:15:49PM -0400, Waiman Long wrote:
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > index 23c7500eea7d..c08bc7eb20bd 100644
> > --- a/mm/slab_common.c
> > +++ b/mm/slab_common.c
> > @@ -1707,17 +1707,17 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags)
> >   EXPORT_SYMBOL(krealloc);
> >   
> >   /**
> > - * kzfree - like kfree but zero memory
> > + * kfree_sensitive - Clear sensitive information in memory before freeing
> >    * @p: object to free memory of
> >    *
> >    * The memory of the object @p points to is zeroed before freed.
> > - * If @p is %NULL, kzfree() does nothing.
> > + * If @p is %NULL, kfree_sensitive() does nothing.
> >    *
> >    * Note: this function zeroes the whole allocated buffer which can be a good
> >    * deal bigger than the requested buffer size passed to kmalloc(). So be
> >    * careful when using this function in performance sensitive code.
> >    */
> > -void kzfree(const void *p)
> > +void kfree_sensitive(const void *p)
> >   {
> >   	size_t ks;
> >   	void *mem = (void *)p;
> > @@ -1725,10 +1725,10 @@ void kzfree(const void *p)
> >   	if (unlikely(ZERO_OR_NULL_PTR(mem)))
> >   		return;
> >   	ks = ksize(mem);
> > -	memset(mem, 0, ks);
> > +	memzero_explicit(mem, ks);
>          ^^^^^^^^^^^^^^^^^^^^^^^^^
> This is an unrelated bug fix.  It really needs to be pulled into a
> separate patch by itself and back ported to stable kernels.
>
> >   	kfree(mem);
> >   }
> > -EXPORT_SYMBOL(kzfree);
> > +EXPORT_SYMBOL(kfree_sensitive);
> >   
> >   /**
> >    * ksize - get the actual amount of memory allocated for a given object
> regards,
> dan carpenter
Thanks for the suggestion. I will break it out and post a version soon.

Cheers,
Longman