summaryrefslogtreecommitdiffstats
path: root/fs/nfs/pnfs.h
diff options
context:
space:
mode:
authorElena Reshetova <elena.reshetova@intel.com>2017-10-20 12:53:31 +0300
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2017-11-17 13:47:59 -0500
commita2a5dea7b6cb77365ed9c987f54d160668c8a95f (patch)
tree97c432cfc80701b303d2708e42dbd3df05b9b376 /fs/nfs/pnfs.h
parent3be0f80b5fe9c16eca2d538f799b94ca8aa59433 (diff)
downloadlinux-a2a5dea7b6cb77365ed9c987f54d160668c8a95f.tar.bz2
fs, nfs: convert nfs4_pnfs_ds.ds_count from atomic_t to refcount_t
atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable nfs4_pnfs_ds.ds_count is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'fs/nfs/pnfs.h')
-rw-r--r--fs/nfs/pnfs.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 87f144f14d1e..cefa7daf6e85 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -30,6 +30,7 @@
#ifndef FS_NFS_PNFS_H
#define FS_NFS_PNFS_H
+#include <linux/refcount.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/workqueue.h>
@@ -54,7 +55,7 @@ struct nfs4_pnfs_ds {
char *ds_remotestr; /* comma sep list of addrs */
struct list_head ds_addrs;
struct nfs_client *ds_clp;
- atomic_t ds_count;
+ refcount_t ds_count;
unsigned long ds_state;
#define NFS4DS_CONNECTING 0 /* ds is establishing connection */
};