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authorElena Reshetova <elena.reshetova@intel.com>2017-03-17 14:10:27 +0200
committerIlya Dryomov <idryomov@gmail.com>2017-05-04 09:19:18 +0200
commit06dfa96399a9a3280dd81e47f8696aa89f1783e7 (patch)
tree1f5b529b617e1607087e096be6640b0208ec54aa
parent805692d0e0f7dec42b5e05fb8b2a5c172f66a3c2 (diff)
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libceph: convert ceph_snap_context.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>
-rw-r--r--include/linux/ceph/libceph.h3
-rw-r--r--net/ceph/snapshot.c6
2 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index cecbf5a26e5a..3229ae6c7846 100644
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -14,6 +14,7 @@
#include <linux/wait.h>
#include <linux/writeback.h>
#include <linux/slab.h>
+#include <linux/refcount.h>
#include <linux/ceph/types.h>
#include <linux/ceph/messenger.h>
@@ -161,7 +162,7 @@ struct ceph_client {
* dirtied.
*/
struct ceph_snap_context {
- atomic_t nref;
+ refcount_t nref;
u64 seq;
u32 num_snaps;
u64 snaps[];
diff --git a/net/ceph/snapshot.c b/net/ceph/snapshot.c
index 705414e78ae0..e14a5d038656 100644
--- a/net/ceph/snapshot.c
+++ b/net/ceph/snapshot.c
@@ -49,7 +49,7 @@ struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
if (!snapc)
return NULL;
- atomic_set(&snapc->nref, 1);
+ refcount_set(&snapc->nref, 1);
snapc->num_snaps = snap_count;
return snapc;
@@ -59,7 +59,7 @@ EXPORT_SYMBOL(ceph_create_snap_context);
struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
{
if (sc)
- atomic_inc(&sc->nref);
+ refcount_inc(&sc->nref);
return sc;
}
EXPORT_SYMBOL(ceph_get_snap_context);
@@ -68,7 +68,7 @@ void ceph_put_snap_context(struct ceph_snap_context *sc)
{
if (!sc)
return;
- if (atomic_dec_and_test(&sc->nref)) {
+ if (refcount_dec_and_test(&sc->nref)) {
/*printk(" deleting snap_context %p\n", sc);*/
kfree(sc);
}