libceph: convert ceph_pagelist.refcnt 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 2017-03-17 14:10:29 +02:00 committed by Ilya Dryomov
parent 02113a0f14
commit 0e1a5ee657
3 changed files with 5 additions and 5 deletions

View File

@ -1991,7 +1991,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
if (req->r_pagelist) {
struct ceph_pagelist *pagelist = req->r_pagelist;
atomic_inc(&pagelist->refcnt);
refcount_inc(&pagelist->refcnt);
ceph_msg_data_add_pagelist(msg, pagelist);
msg->hdr.data_len = cpu_to_le32(pagelist->length);
} else {

View File

@ -2,7 +2,7 @@
#define __FS_CEPH_PAGELIST_H
#include <asm/byteorder.h>
#include <linux/atomic.h>
#include <linux/refcount.h>
#include <linux/list.h>
#include <linux/types.h>
@ -13,7 +13,7 @@ struct ceph_pagelist {
size_t room;
struct list_head free_list;
size_t num_pages_free;
atomic_t refcnt;
refcount_t refcnt;
};
struct ceph_pagelist_cursor {
@ -30,7 +30,7 @@ static inline void ceph_pagelist_init(struct ceph_pagelist *pl)
pl->room = 0;
INIT_LIST_HEAD(&pl->free_list);
pl->num_pages_free = 0;
atomic_set(&pl->refcnt, 1);
refcount_set(&pl->refcnt, 1);
}
extern void ceph_pagelist_release(struct ceph_pagelist *pl);

View File

@ -16,7 +16,7 @@ static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
void ceph_pagelist_release(struct ceph_pagelist *pl)
{
if (!atomic_dec_and_test(&pl->refcnt))
if (!refcount_dec_and_test(&pl->refcnt))
return;
ceph_pagelist_unmap_tail(pl);
while (!list_empty(&pl->head)) {