From 453431a54934d917153c65211b2dabf45562ca88 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 6 Aug 2020 23:18:13 -0700 Subject: mm, treewide: rename kzfree() to kfree_sensitive() As said by Linus: A symmetric naming is only helpful if it implies symmetries in use. Otherwise it's actively misleading. In "kzalloc()", the z is meaningful and an important part of what the caller wants. In "kzfree()", the z is actively detrimental, because maybe in the future we really _might_ want to use that "memfill(0xdeadbeef)" or something. The "zero" part of the interface isn't even _relevant_. The main reason that kzfree() exists is to clear sensitive information that should not be leaked to other future users of the same memory objects. Rename kzfree() to kfree_sensitive() to follow the example of the recently added kvfree_sensitive() and make the intention of the API more explicit. In addition, memzero_explicit() is used to clear the memory to make sure that it won't get optimized away by the compiler. The renaming is done by using the command sequence: git grep -w --name-only kzfree |\ xargs sed -i 's/kzfree/kfree_sensitive/' followed by some editing of the kfree_sensitive() kerneldoc and adding a kzfree backward compatibility macro in slab.h. [akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h] [akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more] Suggested-by: Joe Perches Signed-off-by: Waiman Long Signed-off-by: Andrew Morton Acked-by: David Howells Acked-by: Michal Hocko Acked-by: Johannes Weiner Cc: Jarkko Sakkinen Cc: James Morris Cc: "Serge E. Hallyn" Cc: Joe Perches Cc: Matthew Wilcox Cc: David Rientjes Cc: Dan Carpenter Cc: "Jason A . Donenfeld" Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds --- mm/slab_common.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/slab_common.c') diff --git a/mm/slab_common.c b/mm/slab_common.c index fe8b68482670..f47a097bb4b8 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1729,17 +1729,17 @@ 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; @@ -1750,7 +1750,7 @@ void kzfree(const void *p) memzero_explicit(mem, ks); kfree(mem); } -EXPORT_SYMBOL(kzfree); +EXPORT_SYMBOL(kfree_sensitive); /** * ksize - get the actual amount of memory allocated for a given object -- cgit