On 6/15/20 2:07 PM, Dan Carpenter wrote:

On Mon, Apr 13, 2020 at 05:15:49PM -0400, Waiman Long wrote:

quoted

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.

quoted

  	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