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authorWaiman Long <longman@redhat.com>2020-08-06 23:18:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 11:33:22 -0700
commit453431a54934d917153c65211b2dabf45562ca88 (patch)
treee9672e7fb28f59331ff00fe6197360d703cbd9c3 /mm/slab_common.c
parent57c720d4144a9c2b88105c3e8f7b0e97e4b5cc93 (diff)
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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 <joe@perches.com> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Jason A . Donenfeld" <Jason@zx2c4.com> Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c8
1 files changed, 4 insertions, 4 deletions
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