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Commit 095fc40a authored by Elena Reshetova's avatar Elena Reshetova Committed by Miklos Szeredi
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fuse: convert fuse_conn.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: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent ec99f6d3

fs/fuse/fuse_i.h

+1 −1
Original line number Diff line number Diff line
@@ -449,7 +449,7 @@ struct fuse_conn { 
	spinlock_t lock;



	/** Refcount */

	atomic_t count;

	refcount_t count;



	/** Number of fuse_dev's */

	atomic_t dev_count;

fs/fuse/inode.c

+3 −3
Original line number Diff line number Diff line
@@ -608,7 +608,7 @@ void fuse_conn_init(struct fuse_conn *fc) 
	memset(fc, 0, sizeof(*fc));

	spin_lock_init(&fc->lock);

	init_rwsem(&fc->killsb);

	atomic_set(&fc->count, 1);

	refcount_set(&fc->count, 1);

	atomic_set(&fc->dev_count, 1);

	init_waitqueue_head(&fc->blocked_waitq);

	init_waitqueue_head(&fc->reserved_req_waitq);
@@ -631,7 +631,7 @@ EXPORT_SYMBOL_GPL(fuse_conn_init); 


void fuse_conn_put(struct fuse_conn *fc)

{

	if (atomic_dec_and_test(&fc->count)) {

	if (refcount_dec_and_test(&fc->count)) {

		if (fc->destroy_req)

			fuse_request_free(fc->destroy_req);

		fc->release(fc);
@@ -641,7 +641,7 @@ EXPORT_SYMBOL_GPL(fuse_conn_put); 


struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)

{

	atomic_inc(&fc->count);

	refcount_inc(&fc->count);

	return fc;

}

EXPORT_SYMBOL_GPL(fuse_conn_get);