ceph: convert ceph_cap_snap.nref from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Elena Reshetova
2017-03-03 11:15:07 +02:00
committed by Ilya Dryomov
parent 3997c01d26
commit 805692d0e0
3 changed files with 6 additions and 5 deletions

View File

@@ -14,6 +14,7 @@
#include <linux/writeback.h>
#include <linux/slab.h>
#include <linux/posix_acl.h>
#include <linux/refcount.h>
#include <linux/ceph/libceph.h>
@@ -162,7 +163,7 @@ struct ceph_cap_flush {
* data before flushing the snapped state (tracked here) back to the MDS.
*/
struct ceph_cap_snap {
atomic_t nref;
refcount_t nref;
struct list_head ci_item;
struct ceph_cap_flush cap_flush;
@@ -191,7 +192,7 @@ struct ceph_cap_snap {
static inline void ceph_put_cap_snap(struct ceph_cap_snap *capsnap)
{
if (atomic_dec_and_test(&capsnap->nref)) {
if (refcount_dec_and_test(&capsnap->nref)) {
if (capsnap->xattr_blob)
ceph_buffer_put(capsnap->xattr_blob);
kfree(capsnap);