[Bug 232772] fusefs(4) allows rename to create directory loops

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=232772

            Bug ID: 232772
           Summary: fusefs(4) allows rename to create directory loops
           Product: Base System
           Version: CURRENT
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Many People
          Priority: ---
         Component: kern
          Assignee: bugs at FreeBSD.org
          Reporter: asomers at FreeBSD.org

rename(2) is supposed to return EINVAL if it would create a directory loop. 
This is the behavior of UFS and ZFS.  However, fusefs(4) doesn't detect it. 
fusefs-exfat and fusefs-ext2 both hang when you try, and a closed-source fuse
filesystem created the directory loop just fine.  Steps to reproduce, with
exfat:

# truncate -s 1g /tmp/da1
# mkexfatfs /tmp/da1
mkexfatfs 1.2.7
Creating... done.
Flushing... done.
File system created successfully.
# sudo mount.exfat -d /tmp/da1 /mnt

Then in another window:
# cd /mnt
# mkdir foo
# mkdir foo/sub
# mv foo foo/sub/sub
mv: rename foo to foo/sub/sub: Operation timed out


Note that renaming foo to foo/sub correctly fails; the error only happens with
the additional level of indirection.

Tested on 12.0-ALPHA9 amd64 and TrueOS-Desktop-201803131015.

-- 
You are receiving this mail because:
You are the assignee for the bug.