Provided by: sfs-server_0.8-0+pre20050819.1-2_i386 bug

NAME

       sfs_users - user-authentication database

DESCRIPTION

       The sfs_users file, maintained and used by the sfsauthd program, maps
       public keys to local users and groups. It is roughly analogous to the
       Unix /etc/passwd and /etc/group files.  Each line of sfs_users can
       specify a user or a group.  Users are specified as follows (split into
       two lines here only for clarity of presentation):

       USER:user:uid:version:gid:owner:pubkey:privs
                                 :srp:privkey:srvprivkey:audit

       Note that the first USER is just the literal string USER.  The rest of
       the fields have the following meanings:

       user
           user is the unique name of a public key in the database.
           Ordinarily it is the same as a username in the local password file.
           However, it is also possible to add SFS users who do not have local
           Unix accounts.  It is also possible map multiple public keys to the
           same local Unix account, as when several people have an account
           with root privileges.  In such cases, each key should be given a
           unique name (e.g., dm/root, kaminsky/root, etc.).

       uid uid is the user’s user ID on the given server.

       version
           version is the version number of this record in the users database.
           Upon registration, this value is set to 1.  Upon every subsequent
           update, this value is incremented by 1.

       gid gid is the users’s group ID on the given server.

       owner
           This field is currently ignored, but in a future version may be
           used to allow users to create ‘‘guest’’ accounts.

       pubkey
           pubkey is an ASCII, human-readable representation of the user’s
           public key.  Can be either a Rabin or 2-Schnorr public key.

       privs
           The privs field contains a comma-separated list of properties of
           the account.  Possible properties are as follows:

           unix=account
               This property states that an SFS user corresponds to the local
               Unix account account.  In many settings, it is common to use
               the unix= property to map every SFS user to a local Unix user
               of the same name.  The unix= property has several consequences.
               First, if there is no local Unix user named account, this SFS
               user will not be allowed to log in.  Second, when the SFS user
               logs in, SFS will search /etc/group for additional groups the
               user might belong to.  Third, the rexd remote login daemon will
               allow remote login access to this account, using the shell and
               home directory specified in /etc/passwd.  Finally, on some
               operating systems, SFS enforces account expiration dates
               specified by /etc/shadow or /etc/spwd.db.

           admin
               Indicates that this particular users has administrative
               privileges in SFS.  The option has no effect unless the
               Userfile directive in sfsauthd_config specifies the -admin
               option.  For sfs_users files with the -admin option, the admin
               privilege allows users to create and modify other user records
               remotely, though currently client-side support for doing this
               is limited.

           refresh
           timeout
               These properties are mostly of use with sfsaclsd, an
               experimental server that is not part of the mainline SFS
               distribution yet.

       srp srp is the server-side information for the SRP protocol.  Unlike
           the previous fields, this information must be kept secret.  If the
           information is disclosed, an attacker may be able to impersonate
           the server by causing the sfskey add command to fetch the wrong
           HostID.  Note also that srp is specific to a particular hostname.
           If you change the Location of a file server, users will need to
           register new SRP.

       privkey
           privkey is actually opaque to sfsauthd.  It is private, per-user
           data that sfsauthd will return to users who successfully complete
           the SRP protocol.  Currently, sfskey users this field to store an
           encrypted copy of a user’s private key, allowing the user to
           retrieve the private key over the network.

       srvprivkey
           If a user has chosen 2-Schnorr proactive signatures, the server’s
           half of the private key is kept in this field.

       audit
           audit contains the time, source IP address, and description of the
           last update to this field.  Useful in recovering from a compromised
           key.

       Each group in sfs_users is specified by a line with the following
       format:

       GROUP:group:gid:version:owners:members:properties:audit

       Here again the first GROUP is just the literal string GROUP, while the
       remaining fields have the following meanings:

       group
           The name of the group.

       gid The numeric group ID.

       version
           version is the version number of this record in the database.  The
           number increments when people edit groups through the sfskey
           interface.

       owners
           List of users who are allowed to edit the group membership list.

       members
           List of users who are in the group.

       properties
           Properties of the group, mostly of use with sfsaclsd, an
           experimental server that is not part of the mainline SFS
           distribution yet.

       audit
           Information about the last time this record was modified through
           the sfskey interface.

       sfs_users files can be stored in one of three formats:  plain ASCII,
       database directories, and database files.  (The latter two require SFS
       to have been compiled with Sleepycat BerkeleyDB support.)  The format
       is determined by the extension of the file name.  File names ending
       .db/ are considered database directories; file names ending .db are
       considered database files; everything else is considered ASCII.  Only
       read-only and exported public databases can be database files; read-
       write databases must be directories, ending .db/.  (The reason is that
       read-write database files require write-ahead logging, which relies on
       auxiliary files.)

       You should always edit sfs_users files using the vidb(8) command, for
       two reasons.  First, whenever editing files by hand, you run the risk
       of overwriting concurrent updates by sfsauthd.  vidb acquires the
       necessary locks to prevent this from happening.  Second, when editing a
       database directory or file, vidb translates from the binary database
       format into the ASCII format described above; when committing updates,
       it also atomically modifies various secondary indexes that SFS relies
       upon.

FILES

       /etc/sfs/sfs_users
       /usr/local/share/sfs/sfs_users
           user-authentication database

       (Files in /etc/sfs supersede default versions in /usr/local/share/sfs.)

SEE ALSO

       dirsearch(1), newaid(1), rex(1), sfsagent(1), sfskey(1), ssu(1),
       sfs_config(5), sfs_hosts(5), sfs_srp_params(5), sfsauthd_config(5),
       sfscd_config(5), sfsrosd_config(5), sfsrwsd_config(5), sfssd_config(5),
       sfs_environ(7), funmount(8), nfsmounter(8), sfsauthd(8), sfscd(8),
       sfsrosd(8), sfsrwcd(8), sfsrwsd(8), sfssd(8), vidb(8)

       The full documentation for SFS is maintained as a Texinfo manual.  If
       the info and SFS programs are properly installed at your site, the
       command info SFS should give you access to the complete manual.

       For updates, documentation, and software distribution, please see the
       SFS website at http://www.fs.net/.

AUTHOR

       sfsdev@redlab.lcs.mit.edu