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authorElena Reshetova <elena.reshetova@intel.com>2017-03-03 11:04:03 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2017-04-18 16:58:37 +0200
commit4e8c2eb54327a6f8b0ef6d6afb28ab24b721dbe0 (patch)
tree2d5899fded4f7a002cc8ca492fa1742453f946c0
parentc1ae3cfa0e89fa1a7ecc4c99031f5e9ae99d9201 (diff)
downloadlinux-4e8c2eb54327a6f8b0ef6d6afb28ab24b721dbe0.tar.bz2
fuse: convert fuse_file.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>
-rw-r--r--fs/fuse/file.c8
-rw-r--r--fs/fuse/fuse_i.h3
2 files changed, 6 insertions, 5 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index ec238fb5a584..70770a0db734 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -58,7 +58,7 @@ struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
}
INIT_LIST_HEAD(&ff->write_entry);
- atomic_set(&ff->count, 1);
+ refcount_set(&ff->count, 1);
RB_CLEAR_NODE(&ff->polled_node);
init_waitqueue_head(&ff->poll_wait);
@@ -77,7 +77,7 @@ void fuse_file_free(struct fuse_file *ff)
static struct fuse_file *fuse_file_get(struct fuse_file *ff)
{
- atomic_inc(&ff->count);
+ refcount_inc(&ff->count);
return ff;
}
@@ -88,7 +88,7 @@ static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
static void fuse_file_put(struct fuse_file *ff, bool sync)
{
- if (atomic_dec_and_test(&ff->count)) {
+ if (refcount_dec_and_test(&ff->count)) {
struct fuse_req *req = ff->reserved_req;
if (ff->fc->no_open) {
@@ -293,7 +293,7 @@ static int fuse_release(struct inode *inode, struct file *file)
void fuse_sync_release(struct fuse_file *ff, int flags)
{
- WARN_ON(atomic_read(&ff->count) != 1);
+ WARN_ON(refcount_read(&ff->count) > 1);
fuse_prepare_release(ff, flags, FUSE_RELEASE);
/*
* iput(NULL) is a no-op and since the refcount is 1 and everything's
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 32ac2c9b09c0..1d6d67e64f49 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -24,6 +24,7 @@
#include <linux/workqueue.h>
#include <linux/kref.h>
#include <linux/xattr.h>
+#include <linux/refcount.h>
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32
@@ -137,7 +138,7 @@ struct fuse_file {
u64 nodeid;
/** Refcount */
- atomic_t count;
+ refcount_t count;
/** FOPEN_* flags returned by open */
u32 open_flags;