encfs creating / mouting failed

user@hp:~/temp$ encfs ~/temp/s1 ~/temp/s2
The directory "/home/user/temp/s1/" does not exist. Should it be created? (y,n) y
The directory "/home/user/temp/s2" does not exist. Should it be created? (y,n) y
Creating new encrypted volume.
Please choose from one of the following options:
 enter "x" for expert configuration mode,
 enter "p" for pre-configured paranoia mode,
 anything else, or an empty line will select standard mode.
?>

Standard configuration selected.

Configuration finished. The filesystem to be created has
the following properties:
Filesystem cipher: "ssl/aes", version 2:2:1
Filename encoding: "nameio/block", version 3:0:1
Key Size: 192 bits
Block Size: 1024 bytes
Each file contains 8 byte header with unique IV data.
Filenames encoded using IV chaining mode.
File holes passed through to ciphertext.

Now you will need to enter a password for your filesystem.
You will need to remember this password, as there is absolutely
no recovery mechanism. However, the password can be changed
later using encfsctl.

New Encfs Password:
Verify Encfs Password:
fusermount: failed to access mountpoint /home/user/temp/s2: Permission denied
fuse failed. Common problems:
 - fuse kernel module not installed (modprobe fuse)
 - invalid options -- see usage message

************

root@hp:/etc# lsb_release -rd
Description: Ubuntu 10.04.2 LTS
Release: 10.04
root@hp:/etc# apt-cache policy encfs
encfs:
  Installiert: 1.5.2-2
  Kandidat: 1.5.2-2
  Versions-Tabelle:
 *** 1.5.2-2 0
        500 http://de.archive.ubuntu.com/ubuntu/ lucid/universe Packages
        100 /var/lib/dpkg/status
root@hp:/etc# apt-cache policy fuse-utils
fuse-utils:
  Installiert: 2.8.1-1.1ubuntu3.1
  Kandidat: 2.8.1-1.1ubuntu3.1
  Versions-Tabelle:
 *** 2.8.1-1.1ubuntu3.1 0
        500 http://de.archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
        500 http://security.ubuntu.com/ubuntu/ lucid-security/main Packages
        100 /var/lib/dpkg/status
     2.8.1-1.1ubuntu2 0
        500 http://de.archive.ubuntu.com/ubuntu/ lucid/main Packages

- The user is added to the group fuse (per default).
- /dev/fuse is existing and the rights for the group fuse are set as follows:
  crw-rw-rw- 1 root fuse 10, 229 Mar 28 21:33 /dev/fuse
- Sticky-Bit for fusermount is set:
  -rwsr-xr-x 1 root root 26244 2011-02-11 21:42 /bin/fusermount

This is also happening for me, possibly after a recent kernel update and reboot.

The impact is pretty serious for me as I've got my CA keys on an encfs filesystem which I'm currently unable to mount.

Is fuse listed in /proc/filesystems? Also, any fuse related errors in /var/log/messages?

>cat /proc/filesystems | grep -i fuse
nodev fuse
 fuseblk
nodev fusectl

---

No entries in /var/log/messages after ">encfs ~/dir1 ~/dir2"

>ls -la
drwxr-xr-x 2 user user 4096 2011-03-31 17:58 dir1
d????????? ? ? ? ? ? dir2

This bug is present in maverick too and as far as I can tell was introduced with the latest update of libfuse2 and fuse-utils.

Steps to reproduce:
 1. Try to mount/create an encfs with fuse-utils_2.8.4-1ubuntu1.3 and libfuse2_2.8.4-1ubuntu1.3 installed, e.g.

Actual results:

$ encfs /home/henryk/.secure /home/henryk/_secure/
EncFS Password:
fusermount: failed to access mountpoint /home/henryk/_secure: Permission denied
fuse failed. Common problems:
- fuse kernel module not installed (modprobe fuse)
- invalid options -- see usage message

$ ls -la | grep secure
ls: cannot access _secure: Transport endpoint is not connected
d????????? ? ? ? ? ? _secure
drwxr-xr-x 11 henryk henryk 4096 2011-04-21 16:20 .secure

$ fusermount -u _secure
fusermount: entry for /home/henryk/_secure not found in /etc/mtab

$ sudo umount _secure

Workaround: Downgrade fuse-utils/libfuse2 packages (I only have 2.8.4-1ubuntu1 present, but I believe I have anecdotal evidence that 2.8.4-1ubuntu1.2 works too):

$ sudo aptitude install libfuse2=2.8.4-1ubuntu1 fuse-utils=2.8.4-1ubuntu1
The following packages will be DOWNGRADED:
  fuse-utils libfuse2
...

$ encfs /home/henryk/.secure /home/henryk/_secure/
EncFS Password:

$ ls -la | grep secure
drwxr-xr-x 11 henryk henryk 4096 2011-04-21 16:20 _secure
drwxr-xr-x 11 henryk henryk 4096 2011-04-21 16:20 .secure