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 ] filename 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 user-
       names  and  password  for  basic  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 visible on the  com-
              mand 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  omit-
              ted. 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  consid-
              ered to be very secure.

       -C     This flag is only allowed in combination with -B (bcrypt encryp-
              tion). It sets the computing 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 plat-
              forms 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
              standards.

       -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  mes-
              sage  indicating  whether the supplied password is valid. If the
              password is invalid, the program exits with error 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 additional 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  exten-
              sion .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 for-
       mats 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 interac-
       tively 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  executed  on a Windows system, the password will be
       encrypted using the modified Apache MD5 algorithm; otherwise, the  sys-
       tem's  crypt()  routine will be used. If the file does not exist, htdbm
       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 appears 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 encrypted 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 characters in length. Longer passwords will be trun-
       cated 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                2012-12-12                          HTDBM(1)

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