htdbm

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 usernames
       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 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 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 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 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 message
              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 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 executed on a Windows system, the password will be
       encrypted using the modified Apache MD5 algorithm; otherwise, the
       system'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 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)