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>
diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index 71d56f8..e74f239 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -51,7 +51,7 @@ static void free_master_key(struct fscrypt_master_key *mk)
}
key_put(mk->mk_users);
- kzfree(mk);
+ kfree_sensitive(mk);
}
static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec)
@@ -531,7 +531,7 @@ static int fscrypt_provisioning_key_preparse(struct key_preparsed_payload *prep)
static void fscrypt_provisioning_key_free_preparse(
struct key_preparsed_payload *prep)
{
- kzfree(prep->payload.data[0]);
+ kfree_sensitive(prep->payload.data[0]);
}
static void fscrypt_provisioning_key_describe(const struct key *key,
@@ -548,7 +548,7 @@ static void fscrypt_provisioning_key_describe(const struct key *key,
static void fscrypt_provisioning_key_destroy(struct key *key)
{
- kzfree(key->payload.data[0]);
+ kfree_sensitive(key->payload.data[0]);
}
static struct key_type key_type_fscrypt_provisioning = {