fuse: convert fuse_req.count 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: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index b681b43..5e815072b 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -45,7 +45,7 @@
INIT_LIST_HEAD(&req->list);
INIT_LIST_HEAD(&req->intr_entry);
init_waitqueue_head(&req->waitq);
- atomic_set(&req->count, 1);
+ refcount_set(&req->count, 1);
req->pages = pages;
req->page_descs = page_descs;
req->max_pages = npages;
@@ -102,14 +102,13 @@
void __fuse_get_request(struct fuse_req *req)
{
- atomic_inc(&req->count);
+ refcount_inc(&req->count);
}
/* Must be called with > 1 refcount */
static void __fuse_put_request(struct fuse_req *req)
{
- BUG_ON(atomic_read(&req->count) < 2);
- atomic_dec(&req->count);
+ refcount_dec(&req->count);
}
static void fuse_req_init_context(struct fuse_req *req)
@@ -264,7 +263,7 @@
void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
{
- if (atomic_dec_and_test(&req->count)) {
+ if (refcount_dec_and_test(&req->count)) {
if (test_bit(FR_BACKGROUND, &req->flags)) {
/*
* We get here in the unlikely case that a background