Comment 0 for bug 313812

How to reproduce :

1) setup a private directory
2)
sudo -s

cd /

mkdir source

mkdir target

cp ~user/.Private/example.pdf source

file /source/example.pdf
/source/example.pdf: data

mount -t ecryptfs source target
Passphrase: type anything that is not your passphrase or passwords
Select cipher:
 1) aes: blocksize = 16; min keysize = 16; max keysize = 32 (loaded)
 2) blowfish: blocksize = 16; min keysize = 16; max keysize = 32 (not loaded)
 3) des3_ede: blocksize = 8; min keysize = 24; max keysize = 24 (not loaded)
 4) twofish: blocksize = 16; min keysize = 16; max keysize = 32 (not loaded)
 5) cast6: blocksize = 16; min keysize = 16; max keysize = 32 (not loaded)
 6) cast5: blocksize = 8; min keysize = 5; max keysize = 16 (not loaded)
Selection [aes]:
Select key bytes:
 1) 16
 2) 32
 3) 24
Selection [16]:
Enable plaintext passthrough (y/n) [n]: n
Attempting to mount with the following options:
  ecryptfs_key_bytes=16
  ecryptfs_cipher=aes
  ecryptfs_sig=4c748f746abcc24e
WARNING: Based on the contents of [/root/.ecryptfs/sig-cache.txt],
it looks like you have never mounted with this key
before. This could mean that you have typed your
passphrase wrong.

Would you like to proceed with the mount (yes/no)? yes
Would you like to append sig [4c748f746abcc24e] to
[/root/.ecryptfs/sig-cache.txt]
in order to avoid this warning in the future (yes/no)? no
Not adding sig to user sig cache file; continuing with mount.
Mounted eCryptfs

file /source/example.pdf
/source/example.pdf: PDF document, version 1.4

Now I know that the files are really encrypted (using a wrong passphrase on files copied to any computer makes the file unreadable), but I don't understand how root on my system can mount my files without the correct passphrase... is the passphrase stored somewhere? This is really strange and doesn't give me too much confidence in this technology. Let's hope I overlooked something.