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libceph: convert ceph_osd.o_ref from atomic_t to refcount_t

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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 2017-03-17 14:10:28 +02:00 committed by Ilya Dryomov
parent 06dfa96399
commit 02113a0f14
2 changed files with 10 additions and 9 deletions
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3
include/linux/ceph/osd_client.h
View File

@ -5,6 +5,7 @@
#include <linux/kref.h>
#include <linux/mempool.h>
#include <linux/rbtree.h>
#include <linux/refcount.h>
#include <linux/ceph/types.h>
#include <linux/ceph/osdmap.h>
@ -27,7 +28,7 @@ typedef void (*ceph_osdc_callback_t)(struct ceph_osd_request *);
/* a given osd we're communicating with */
struct ceph_osd {
atomic_t o_ref;
refcount_t o_ref;
struct ceph_osd_client *o_osdc;
int o_osd;
int o_incarnation;

16
net/ceph/osd_client.c
View File

@ -1005,7 +1005,7 @@ static bool osd_registered(struct ceph_osd *osd)
*/
static void osd_init(struct ceph_osd *osd)
{
atomic_set(&osd->o_ref, 1);
refcount_set(&osd->o_ref, 1);
RB_CLEAR_NODE(&osd->o_node);
osd->o_requests = RB_ROOT;
osd->o_linger_requests = RB_ROOT;
@ -1050,9 +1050,9 @@ static struct ceph_osd *create_osd(struct ceph_osd_client *osdc, int onum)
static struct ceph_osd *get_osd(struct ceph_osd *osd)
{
if (atomic_inc_not_zero(&osd->o_ref)) {
dout("get_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref)-1,
atomic_read(&osd->o_ref));
if (refcount_inc_not_zero(&osd->o_ref)) {
dout("get_osd %p %d -> %d\n", osd, refcount_read(&osd->o_ref)-1,
refcount_read(&osd->o_ref));
return osd;
} else {
dout("get_osd %p FAIL\n", osd);
@ -1062,9 +1062,9 @@ static struct ceph_osd *get_osd(struct ceph_osd *osd)
static void put_osd(struct ceph_osd *osd)
{
dout("put_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref),
atomic_read(&osd->o_ref) - 1);
if (atomic_dec_and_test(&osd->o_ref)) {
dout("put_osd %p %d -> %d\n", osd, refcount_read(&osd->o_ref),
refcount_read(&osd->o_ref) - 1);
if (refcount_dec_and_test(&osd->o_ref)) {
osd_cleanup(osd);
kfree(osd);
}
@ -4126,7 +4126,7 @@ void ceph_osdc_stop(struct ceph_osd_client *osdc)
close_osd(osd);
}
up_write(&osdc->lock);
WARN_ON(atomic_read(&osdc->homeless_osd.o_ref) != 1);
WARN_ON(refcount_read(&osdc->homeless_osd.o_ref) != 1);
osd_cleanup(&osdc->homeless_osd);
WARN_ON(!list_empty(&osdc->osd_lru));