5.10. DBM Files on UnixAlthough searching a file of usernames and passwords works perfectly well, it is apt to be rather slow once the list gets up to a couple hundred entries. To deal with this, Apache provides a better way of handling large lists by turning them into a database. You need one (not both!) of the modules that appear in the Config file as follows: #Module db_auth_module mod_auth_db.o Module dbm_auth_module mod_auth_dbm.o Bear in mind that they correspond to different directives: AuthDBMUserFile or AuthDBUserFile. A Perl script to manage both types of database, dbmmanage, is supplied with Apache in .../src/support. To decide which type to use, you need to discover the capabilities of your Unix. Explore these by going to the command prompt and typing first: % man db and then: % man dbm Whichever method produces a manpage is the one you should use. You can also use a SQL database, employing MySQLor a third-party package to manage it. Once you have decided which method to use, edit the Config file to include the appropriate module, and then type: % ./Configure and: % make We now have to create a database of our users: bill, ben, sonia, and daphne. Go to ... /apache/src/support, find the utility dbmmanage, and copy it into /usr/local/bin or something similar to put it on your path. This utility may be distributed without execute permission set, so, before attempting to run it, we may need to change the permissions: % chmod +x dbmmanage You may find, when you first try to run dbmmanage, that it complains rather puzzlingly that some unnamed file can't be found. Since dbmmanage is a Perl script, this is probably Perl, a text-handling language, and if you have not installed it, you should. It may also be necessary to change the first line of dbmmanage: #!/usr/bin/perl5 to the correct path for Perl, if it is installed somewhere else. If you provoke it with dbmmanage -?, you get: Usage: dbmmanage [enc] dbname command [username [pw [group[,group] [comment]]]] where enc is -d for crypt encryption (default except on Win32, Netware) -m for MD5 encryption (default on Win32, Netware) -s for SHA1 encryption -p for plaintext command is one of: add|adduser|check|delete|import|update|view pw of . for update command retains the old password pw of--(or blank) for update command prompts for the password groups or comment of . (or blank) for update command retains old values groups or comment of--for update command clears the existing value groups or comment of--for add and adduser commands is the empty value takes the following arguments: dbmmanage [enc] dbname command [username [pw [group[,group] [comment]]]] 'enc' sets the encryption method: -d for crypt (default except Win32, Netware) -m for MD5 (default on Win32, Netware) -s for SHA1 -p for plaintext So, to add our four users to a file /usr/www/APACHE3/ok_dbm/users, we type: % dbmmanage /usr/www/APACHE3/ok_dbm/users.db adduser bill New password:theft Re-type new password:theft User bill added with password encrypted to vJACUCNeAXaQ2 using crypt Perform the same service for ben, sonia, and daphne. The file ... /users is not editable directly, but you can see the results by typing: % dbmmanage /usr/www/APACHE3/ok_dbm/users view bill:vJACUCNeAXaQ2 ben:TPsuNKAtLrLSE sonia:M9x731z82cfDo daphne:7DBV6Yx4.vMjc You can build a group file with dbmmanage,but because of faults in the script that we hope will have been rectified by the time readers of this edition use it, the results seem a bit odd. To add the user fred to the group cleaners, type: % dbmmanage /usr/www/APACHE3/ok_dbm/group add fred cleaners (Note: do not use adduser.) dbmmanagerather puzzlingly responds with the following message: User fred added with password encrypted to cleaners using crypt When we test this with: % dbmmanage /usr/www/APACHE3/ok_dbm/group view we see: fred:cleaners which is correct, because in a group file the name of the group goes where the encrypted password would go in a password file. Since we have a similar file structure, we invoke DBM authentication in ... /conf/httpd.conf by commenting out: #AuthUserFile /usr/www/APACHE3/ok_users/sales #AuthGroupFile /usr/www/APACHE3/ok_users/groups and inserting: AuthDBMUserFile /usr/www/APACHE3/ok_dbm/users AuthDBMGroupFile /usr/www/APACHE3/ok_dbm/users AuthDBMGroupFile is set to the samefile as the AuthDBMUserFile. What happens is that the username becomes the key in the DBM file, and the value associated with the key is password:group. To create a separate group file, a database with usernames as the key and groups as the value (with no colons in the value) would be needed. 5.10.1. AuthDBUserFileThe AuthDBUserFile directive sets the name of a DB file containing the list of users and passwords for user authentication. AuthDBUserFile filename directory, .htaccess filename is the absolute path to the user file. The user file is keyed on the username. The value for a user is the crypt( )-encrypted password, optionally followed by a colon and arbitrary data. The colon and the data following it will be ignored by the server. 5.10.1.1. SecurityMake sure that the AuthDBUserFile is stored outside the document tree of the web server; do not put it in the directory that it protects. Otherwise, clients will be able to download the AuthDBUserFile. TIP: In regards to compatibility, the implementation of dbmopen in the Apache modules reads the string length of the hashed values from the DB data structures, rather than relying upon the string being NULL-appended. Some applications, such as the Netscape web server, rely upon the string being NULL-appended, so if you are having trouble using DB files interchangeably between applications, this may be a part of the problem. A perl script called dbmmanage is included with Apache. This program can be used to create and update DB-format password files for use with this module. 5.10.2. AuthDBMUserFileThe AuthDBMUserFile directive sets the name of a DBM file containing the list of users and passwords for user authentication. AuthDBMUserFile filename directory, .htaccess filename is the absolute path to the user file. The user file is keyed on the username. The value for a user is the crypt( )-encrypted password, optionally followed by a colon and arbitrary data. The colon and the data following it will be ignored by the server. 5.10.2.1. SecurityMake sure that the AuthDBMUserFile is stored outside the document tree of the web server; do not put it in the directory that it protects. Otherwise, clients will be able to download the AuthDBMUserFile. TIP: In regards to compatibility, the implementation of dbmopen in the Apache modules reads the string length of the hashed values from the DBM data structures, rather than relying upon the string being NULL-appended. Some applications, such as the Netscape web server, rely upon the string being NULL-appended, so if you are having trouble using DBM files interchangeably between applications, this may be a part of the problem. A perl script called dbmmanage is included with Apache. This program can be used to create and update DBM-format password files for use with this module. Copyright © 2003 O'Reilly & Associates. All rights reserved. |
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