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author | Waiman Long <longman@redhat.com> | 2020-08-06 23:18:13 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-07 11:33:22 -0700 |
commit | 453431a54934d917153c65211b2dabf45562ca88 (patch) | |
tree | e9672e7fb28f59331ff00fe6197360d703cbd9c3 /mm | |
parent | 57c720d4144a9c2b88105c3e8f7b0e97e4b5cc93 (diff) | |
download | lwn-453431a54934d917153c65211b2dabf45562ca88.tar.gz lwn-453431a54934d917153c65211b2dabf45562ca88.zip |
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')
-rw-r--r-- | mm/slab_common.c | 8 |
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 |