fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN

Only f_path is used from backing files registered with
FUSE_DEV_IOC_BACKING_OPEN, so it makes sense to allow O_PATH descriptors.

O_PATH files have an empty f_op, so don't check read_iter/write_iter.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2024-09-13 12:47:01 +02:00
parent 862b9a8eb9
commit efad7153bf

View File

@ -228,16 +228,13 @@ int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
if (map->flags || map->padding)
goto out;
file = fget(map->fd);
file = fget_raw(map->fd);
res = -EBADF;
if (!file)
goto out;
res = -EOPNOTSUPP;
if (!file->f_op->read_iter || !file->f_op->write_iter)
goto out_fput;
backing_sb = file_inode(file)->i_sb;
pr_info("%s: %x:%pD %i\n", __func__, backing_sb->s_dev, file, backing_sb->s_stack_depth);
res = -ELOOP;
if (backing_sb->s_stack_depth >= fc->max_stack_depth)
goto out_fput;