administrators (basic)
PmWiki has built-in support for password-protecting various areas of the wiki site. Passwords can be applied to individual pages, to Wiki Groups, or to the entire wiki site. Note that the password protection mechanisms described here are only a small part of overall system (and wiki) security, see PmWiki.Security for more discussion of this.
Authors can use PmWiki to add passwords to individual pages and WikiGroups as described in PmWiki.Passwords. However, WikiAdministrators can also set passwords in local customization files as described below.
PmWiki supports several levels of access to wiki pages:
read passwords allow viewing the contents of wiki pages
edit passwords control editing and modification of wiki pages
attr passwords control who is able to set passwords on pages (and potentially other future attributes)
upload passwords control uploading of files and attachments
Finally, there is an admin password that allows an administrator to override the passwords set for any individual page or group.
By default, PmWiki has the following password settings:
admin and upload passwords are locked by default.
attr password (in their respective GroupAttributes pages).
An admin password can be used to overcome "locked" passwords, other than that, no password will allow access.
See Passwords for information about setting per-page and per-group passwords. The remainder of this page describes setting site-wide passwords from the local/config.php file.
One of the first things an admin should do is set an admin password for the site. This is done via a line like the following in the local/config.php file:
$DefaultPasswords['admin'] = crypt('secret_password');
Note that the crypt() call is required for this -- PmWiki stores and processes all passwords internally as encrypted strings. See the crypt section below for details about eliminating the cleartext password from the configuration file.
To set the entire site to be editable only by those who know an "edit" password, add a line like the following to local/config.php:
$DefaultPasswords['edit'] = crypt('edit_password');
Similarly, you can set $DefaultPasswords['read'], $DefaultPasswords['attr'], and $DefaultPasswords['upload'] to control default read, edit, and upload passwords for the entire site. The default passwords are used only for pages and groups which do not have passwords set. Also, each of the $DefaultPasswords values may be arrays of encrypted passwords:
$DefaultPasswords['read'] = array(crypt('alpha'), crypt('beta'));
$DefaultPasswords['edit'] = crypt('beta');
This says that either "alpha" or "beta" can be used to read pages, but only the "beta" password will allow someone to edit a page. Since PmWiki remembers any passwords entered during the current session, the "beta" password will allow both reading and writing of pages, while the "alpha" password allows reading only. A person without either password would be unable to view pages at all.
Unlike many systems which have identity-based systems for controlling access to pages (e.g., using a separate username and password for each person), PmWiki defaults to a password-based system as described above. In general password-based systems are often easier to maintain because they avoid the administrative overheads of creating user accounts, recovering lost passwords, and mapping usernames to permitted actions.
However, PmWiki's authuser.php script augments the password-based system to allow access to pages based on a username and password combination. See AuthUser? for more details on controlling access to pages based on user identity.
Administrators need to carefully plan where passwords are applied to avoid opening inadvertent security holes. If your wiki is open (anyone can read and edit), this would not seem to be a concern, except, a malicious or confused user could apply a read password to a group and make the group completely unavailable to all other users. At the very least, even an open wiki should have a site-wide "admin" password and a site-wide "attr" password set in config.php. The sample-config.php file distributed with PmWiki indicates that the PmWiki and Main groups have "attr" locked by default, but if anyone creates a new group, "attr" is unlocked. Administrators must remember to set "attr" passwords for each new group (if desired) in this case. An easier solution is to include these lines in config.php :
$DefaultPasswords['admin'] = crypt('youradminpassword');
$DefaultPasswords['attr'] = crypt('yourattrpassword');
One drawback to using the crypt() function directly to set passwords in config.php is that anyone able to view the file will see the unencrypted password. For example, if config.php contains
$DefaultPasswords['admin'] = crypt('mysecret');
then the "mysecret" password is in plain text for others to see. However, a wiki administrator can obtain and use an encrypted form of the password directly by using ?action=crypt on any PmWiki url (or just jump to PasswordsAdmin?action=crypt). This action presents a form that generates encrypted versions of passwords for use in the config.php file. For example, when ?action=crypt is given the password "mysecret", PmWiki will return a string like
$1$hMMhCdfT$mZSCh.BJOidMRn4SOUUSi1
The string returned from ?action=crypt can then be placed directly into config.php, as in:
$DefaultPasswords['admin'] = '$1$hMMhCdfT$mZSCh.BJOidMRn4SOUUSi1';
Note that in the encrypted form the crypt keyword and parentheses are removed, since the password is already encrypted. Also, the encrypted password must be in single quotes. In this example the password is still "mysecret", but somebody looking at config.php won't be able to see that just from looking at the encrypted form. Crypt may give you different encryptions for the same password--this is normal (and makes it harder for someone else to determine the original password).
To remove a site password entirely, such as the default locked password for uploads, just set it to empty:
$DefaultPasswords['upload'] = '';
You can also use the special password "nopass" (defined by the $AllowPassword variable) via ?action=attr to have a non-password protected page within a password-protected group, or a non-password protected group with a site-wide default password set.
If a password is compromised and the wiki administrator wants to quickly invalidate all uses of that password on a site, a quick solution is the following in local/config.php:
$ForbiddenPasswords = array('secret', 'tanstaafl');
if (in_array(@$_POST['authpw'], $ForbiddenPasswords))
unset($_POST['authpw']);
This prevents "secret" and "tanstaafl" from ever being accepted as a valid authorization password, regardless of what pages may be using it.
$HandleAuth array, which sets the required authentication level that is necessary to perform an action.
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