KEYFS(4) Device Drivers Manual KEYFS(4)

keyfs - encrypted key storage

auth/keyfs [ -D ] [ -m mountpoint ] [ -n nvram ] [ keyfile ]

Keyfs serves a two-level name space for storing authentication data, specifically the status and secrets of each user to whom logind (8) can issue a certificate. The data is stored in keyfile (default: /keydb/keys), encrypted by a master key using AES (see keyring-crypt (2)). Keyfs should be started only on the machine acting as authentication server (signer), before a listener is started for signer (8). Note that signer and keyfs must share the name space. Furthermore, no other application except the console should see that name space.

Keyfs prompts for the master key, reads and decrypts keyfile, and serves files representing the contents at mountpoint in the name space (default: /mnt/keys).

Each user in keyfile is represented by a directory mountpoint/user. Each such directory has the following files:

A count of the number of failed authentications. Writing bad to the file increments the count; writing good resets it to 0. When the count reaches some implementation-defined limit, the account status is set to disabled (see the status file below).
The time in seconds since the epoch when the account will expire, or the text never if it has no expiration time. The string never or a number can be written to the file to set a new expiry time.
The secret (supposedly) known only to the user and the authentication service. A secret is any sequence of bytes between 0 and 255 bytes long; it is initially empty. The length of the file returned by sys-stat (2) is the length of the secret. If the account has expired or is disabled, an attempt to read the file will give an error.
The current status of the user's account, either ok or disabled. Either string can be written to the file to change the state accordingly.

To add a new account, make a directory with that name in mountpoint. It must not already exist. To remove an account, remove the corresponding directory; to rename an account, rename the directory.

All changes made via file system operations in mountpoint result in appropriate changes to keyfile.

If the -n option is given, instead of prompting for the master key, keyfs will read it from the file nvram. Obviously that file should be well-protected from ordinary observers.

The -D option enables tracing of the file service protocol, for debugging.

/appl/cmd/auth/keyfs.b

changelogin (8), logind (8), signer (8)