From 095fc40ace5ffccd306f39fdd1a40b4faa41b8a0 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 11:04:05 +0200 Subject: [PATCH] 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: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: Miklos Szeredi --- fs/fuse/fuse_i.h | 2 +- fs/fuse/inode.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 9d4374032290..6c649f0c58f9 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -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; diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 6fe6a88ecb4a..3961c5f886be 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -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);