man > HTDBM(1)

HTDBM(1)                                        htdbm                                       HTDBM(1)

NAME
       htdbm - Manipulate DBM password databases


SYNOPSIS
       htdbm  [  -TDBTYPE ] [ -i ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] file‐
       name username


       htdbm -b [ -TDBTYPE ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [  -v  ]  filename
       username password


       htdbm -n [ -i ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] username


       htdbm -nb [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ] username password


       htdbm  -v  [  -TDBTYPE  ]  [ -i ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v ]
       filename username


       htdbm -vb [ -TDBTYPE ] [ -c ] [ -m | -B | -d | -s | -p ] [ -C cost ] [ -t ] [ -v  ]  filename
       username password


       htdbm -x [ -TDBTYPE ] filename username


       htdbm -l [ -TDBTYPE ]



SUMMARY
       htdbm is used to manipulate the DBM format files used to store usernames and password for ba‐
       sic  authentication of HTTP users via mod_authn_dbm. See the dbmmanage documentation for more
       information about these DBM files.



OPTIONS
       -b     Use batch mode; i.e., get the password from the command line rather than prompting for
              it. This option should be used with extreme care, since the password is clearly  visi‐
              ble on the command line. For script use see the -i option.

       -i     Read the password from stdin without verification (for script usage).

       -c     Create  the  passwdfile.  If passwdfile already exists, it is rewritten and truncated.
              This option cannot be combined with the -n option.

       -n     Display the results on standard output rather than updating a  database.  This  option
              changes  the  syntax  of  the command line, since the passwdfile argument (usually the
              first one) is omitted. It cannot be combined with the -c option.

       -m     Use MD5 encryption for passwords. On Windows and Netware, this is the default.

       -B     Use bcrypt encryption for passwords. This is currently considered to be very secure.

       -C     This flag is only allowed in combination with -B (bcrypt encryption). It sets the com‐
              puting time used for the bcrypt algorithm (higher is more secure but slower,  default:
              5, valid: 4 to 31).

       -d     Use  crypt()  encryption  for  passwords. The default on all platforms but Windows and
              Netware. Though possibly supported by htdbm on all platforms, it is not  supported  by
              the  httpd  server on Windows and Netware. This algorithm is insecure by today's stan‐
              dards.

       -s     Use SHA encryption for passwords. Facilitates migration from/to Netscape servers using
              the LDAP Directory Interchange Format (ldif). This algorithm is  insecure  by  today's
              standards.

       -p     Use  plaintext  passwords.  Though  htdbm  will support creation on all platforms, the
              httpd daemon will only accept plain text passwords on Windows and Netware.

       -l     Print each of the usernames and comments from the database on stdout.

       -v     Verify the username and password. The program will print a message indicating  whether
              the supplied password is valid. If the password is invalid, the program exits with er‐
              ror code 3.

       -x     Delete user. If the username exists in the specified DBM file, it will be deleted.

       -t     Interpret  the  final  parameter as a comment. When this option is specified, an addi‐
              tional string can be appended to the command line; this string will be stored  in  the
              "Comment" field of the database, associated with the specified username.

       filename
              The filename of the DBM format file. Usually without the extension .db, .pag, or .dir.
              If -c is given, the DBM file is created if it does not already exist, or updated if it
              does exist.

       username
              The  username  to  create  or update in passwdfile. If username does not exist in this
              file, an entry is added. If it does exist, the password is changed.

       password
              The plaintext password to be encrypted and stored in the DBM file. Used only with  the
              -b flag.

       -TDBTYPE
              Type of DBM file (SDBM, GDBM, DB, or "default").


BUGS
       One  should  be aware that there are a number of different DBM file formats in existence, and
       with all likelihood, libraries for more than one format may exist on your system.  The  three
       primary  examples  are  SDBM, NDBM, GNU GDBM, and Berkeley/Sleepycat DB 2/3/4. Unfortunately,
       all these libraries use different file formats, and you must make sure that the  file  format
       used  by filename is the same format that htdbm expects to see. htdbm currently has no way of
       determining what type of DBM file it is looking at. If used against the  wrong  format,  will
       simply return nothing, or may create a different DBM file with a different name, or at worst,
       it may corrupt the DBM file if you were attempting to write to it.


       One can usually use the file program supplied with most Unix systems to see what format a DBM
       file is in.


EXIT STATUS
       htdbm  returns  a  zero  status  ("true") if the username and password have been successfully
       added or updated in the DBM File. htdbm returns 1 if it  encounters  some  problem  accessing
       files,  2  if there was a syntax problem with the command line, 3 if the password was entered
       interactively and the verification entry didn't match, 4 if its operation was interrupted,  5
       if  a  value  is  too long (username, filename, password, or final computed record), 6 if the
       username contains illegal characters (see the Restrictions section), and 7 if the file is not
       a valid DBM password file.


EXAMPLES
             htdbm /usr/local/etc/apache/.htdbm-users jsmith



       Adds or modifies the password for user jsmith. The user is prompted for the password. If exe‐
       cuted on a Windows system, the password will be encrypted using the modified Apache MD5 algo‐
       rithm; otherwise, the system's crypt() routine will be used. If the file does not exist,  ht‐
       dbm will do nothing except return an error.


             htdbm -c /home/doe/public_html/.htdbm jane



       Creates  a  new  file  and  stores a record in it for user jane. The user is prompted for the
       password. If the file exists and cannot be read, or cannot be written, it is not altered  and
       htdbm will display a message and return an error status.


             htdbm -mb /usr/web/.htdbm-all jones Pwd4Steve



       Encrypts  the  password from the command line (Pwd4Steve) using the MD5 algorithm, and stores
       it in the specified file.


SECURITY CONSIDERATIONS
       Web password files such as those managed by htdbm should not be within the Web  server's  URI
       space -- that is, they should not be fetchable with a browser.


       The  use  of the -b option is discouraged, since when it is used the unencrypted password ap‐
       pears on the command line.


       When using the crypt() algorithm, note that only the first 8 characters of the  password  are
       used  to  form the password. If the supplied password is longer, the extra characters will be
       silently discarded.


       The SHA encryption format does not use salting: for a given password, there is only  one  en‐
       crypted  representation. The crypt() and MD5 formats permute the representation by prepending
       a random salt string, to make dictionary attacks against the passwords more difficult.


       The SHA and crypt() formats are insecure by today's standards.


RESTRICTIONS
       On the Windows platform, passwords encrypted with htdbm are limited to no more than 255 char‐
       acters in length. Longer passwords will be truncated to 255 characters.


       The MD5 algorithm used by htdbm is specific to the Apache software; passwords encrypted using
       it will not be usable with other Web servers.


       Usernames are limited to 255 bytes and may not include the character :.


Apache HTTP Server                           2018-07-06                                     HTDBM(1)