fuse: always allow query of st_dev

Fuse mounts without "allow_other" are off-limits to all non-owners.  Yet it
makes sense to allow querying st_dev on the root, since this value is
provided by the kernel, not the userspace filesystem.

Allow statx(2) with a zero request mask to succeed on a fuse mounts for all
users.

Reported-by: Nikolaus Rath <Nikolaus@rath.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2020-05-19 14:50:37 +02:00
parent 614c026e8a
commit 5157da2ca4
1 changed files with 11 additions and 1 deletions

View File

@ -1689,8 +1689,18 @@ static int fuse_getattr(const struct path *path, struct kstat *stat,
struct inode *inode = d_inode(path->dentry);
struct fuse_conn *fc = get_fuse_conn(inode);
if (!fuse_allow_current_process(fc))
if (!fuse_allow_current_process(fc)) {
if (!request_mask) {
/*
* If user explicitly requested *nothing* then don't
* error out, but return st_dev only.
*/
stat->result_mask = 0;
stat->dev = inode->i_sb->s_dev;
return 0;
}
return -EACCES;
}
return fuse_update_get_attr(inode, NULL, stat, request_mask, flags);
}