There is a general mechanism in place that allows custom permission policies to grant or deny any action on any Trac resource, or even specific versions of a resource.
That mechanism is authz_policy, which is an optional module in tracopt.perm.authz_policy.*, so it is installed by default. It can be activated via the Plugins panel in the Trac administration module.
A great diversity of permission policies can be implemented and Trac comes with a few examples.
The active policies are determined by a configuration setting:
[trac] permission_policies = ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
Among the optional choices, there is #AuthzPolicy, a very generic permission policy, based on an Authz-style system. See authz_policy.py for details.
Another permission policy #AuthzSourcePolicy, uses the path-based authorization defined by Subversion to enforce permissions on the version control system.
See also sample-plugins/permissions for more examples.
trac.ini:
[trac] section:
[trac] permission_policies = AuthzPolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
[authz_policy] section and point the authz_file option to the conf file:
[authz_policy] authz_file = /some/trac/env/conf/authzpolicy.conf
[components] section:
[components] tracopt.perm.authz_policy.* = enabled
Note the order in which permission policies are specified: policies are implemented in the sequence provided and therefore may override earlier policy specifications.
A policy will return either True, False or None for a given permission check. True is returned if the policy explicitly grants the permission. False is returned if the policy explicitly denies the permission. None is returned if the policy is unable to either grant or deny the permission.
NOTE: Only if the return value is None will the next permission policy be consulted. If none of the policies explicitly grants the permission, the final result will be False, i.e. permission denied.
The authzpolicy.conf file is a .ini style configuration file:
[wiki:PrivatePage@*] john = WIKI_VIEW, !WIKI_MODIFY jack = WIKI_VIEW * =
<realm>:<id>@<version>[/<realm>:<id>@<version> ...]
Resources are ordered left to right, from parent to child. If any component is inapplicable, * is substituted. If the version pattern is not specified explicitly, all versions (@*) is added implicitly. Example: Match the WikiStart page:
[wiki:*] [wiki:WikiStart*] [wiki:WikiStart@*] [wiki:WikiStart]
Example: Match the attachment wiki:WikiStart@117/attachment:FOO.JPG@* on WikiStart:
[wiki:*] [wiki:WikiStart*] [wiki:WikiStart@*] [wiki:WikiStart@*/attachment:*] [wiki:WikiStart@117/attachment:FOO.JPG]
@, it is treated as a group.
!, the permission is denied rather than granted.
| Note: Other groups which are created by user (e.g. by 'adding subjects to groups' on web interface page Admin / Permissions) cannot be used. See #5648 for details about this missing feature. |
For example, if the authz_file contains:
[wiki:WikiStart@*] * = WIKI_VIEW [wiki:PrivatePage@*] john = WIKI_VIEW * = !WIKI_VIEW
and the default permissions are set like this:
john WIKI_VIEW jack WIKI_VIEW # anonymous has no WIKI_VIEW
Then:
Groups:
[groups] admins = john, jack devs = alice, bob [wiki:Dev@*] @admins = TRAC_ADMIN @devs = WIKI_VIEW * = [*] @admins = TRAC_ADMIN * =
Then:
Some repository examples (Browse Source specific):
# A single repository: [repository:test_repo@*] john = BROWSER_VIEW, FILE_VIEW # John has BROWSER_VIEW and FILE_VIEW for the entire test_repo # The default repository (requires Trac 1.0.2 or later): [repository:@*] john = BROWSER_VIEW, FILE_VIEW # John has BROWSER_VIEW and FILE_VIEW for the entire default repository # All repositories: [repository:*@*] jack = BROWSER_VIEW, FILE_VIEW # Jack has BROWSER_VIEW and FILE_VIEW for all repositories
Very granular repository access:
# John has BROWSER_VIEW and FILE_VIEW access to trunk/src/some/location/ only [repository:test_repo@*/source:trunk/src/some/location/*@*] john = BROWSER_VIEW, FILE_VIEW # John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of all files at trunk/src/some/location only [repository:test_repo@*/source:trunk/src/some/location/*@1] john = BROWSER_VIEW, FILE_VIEW # John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only [repository:test_repo@*/source:trunk/src/some/location/somefile@*] john = BROWSER_VIEW, FILE_VIEW # John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of 'somefile' at trunk/src/some/location only [repository:test_repo@*/source:trunk/src/some/location/somefile@1] john = BROWSER_VIEW, FILE_VIEW
Note: In order for Timeline to work/visible for John, we must add CHANGESET_VIEW to the above permission list.
Although possible with the DefaultPermissionPolicy handling (see Admin panel), fine-grained permissions still miss those grouping features (see #9573, #5648). Patches are partially available, see authz_policy.2.patch, part of #6680.
You cannot do the following:
[groups] team1 = a, b, c team2 = d, e, f team3 = g, h, i departmentA = team1, team2
Permission groups are not supported either, so you cannot do the following:
[groups] permission_level_1 = WIKI_VIEW, TICKET_VIEW permission_level_2 = permission_level_1, WIKI_MODIFY, TICKET_MODIFY [*] @team1 = permission_level_1 @team2 = permission_level_2 @team3 = permission_level_2, TICKET_CREATE
AuthzSourcePolicy can be used for restricting access to the repository. Granular permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.
More information about this file format and about its usage in Subversion is available in the Path-Based Authorization section in the Server Configuration chapter of the svn book.
Example:
[/] * = r [/branches/calc/bug-142] harry = rw sally = r [/branches/calc/bug-142/secret] harry =
To activate granular permissions you must specify the authz_file option in the [svn] section of trac.ini. If this option is set to null or not specified, the permissions will not be used.
[svn] authz_file = /path/to/svnaccessfile
If you want to support the use of the [modulename:/some/path] syntax within the authz_file, add:
authz_module_name = modulename
where modulename refers to the same repository indicated by the <name>.dir entry in the [repositories] section. As an example, if the somemodule.dir entry in the [repositories] section is /srv/active/svn/somemodule, that would yield the following:
[svn] authz_file = /path/to/svnaccessfile authz_module_name = somemodule ... [repositories] somemodule.dir = /srv/active/svn/somemodule
where the svn access file, /path/to/svnaccessfile, contains entries such as [somemodule:/some/path].
Note: Usernames inside the Authz file must be the same as those used inside trac.
As of version 0.12, make sure you have AuthzSourcePolicy included in the permission_policies list in trac.ini, otherwise the authz permissions file will be ignored.
[trac] permission_policies = AuthzSourcePolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
The same access file is typically applied to the corresponding Subversion repository using an Apache directive like this:
<Location /repos> DAV svn SVNParentPath /usr/local/svn # our access control policy AuthzSVNAccessFile /path/to/svnaccessfile </Location>
For information about how to restrict access to entire projects in a multiple project environment see wiki:TracMultipleProjectsSVNAccess.
Since 1.1.2, the read-only attribute of wiki pages is enabled and enforced when ReadonlyWikiPolicy is in the list of active permission policies. The default for new Trac installations in 1.1.2 and later is:
[trac] permission_policies = ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
When upgrading from earlier versions of Trac, ReadonlyWikiPolicy will be appended to the list of permission_policies when upgrading the environment, provided that permission_policies has the default value. If any non-default permission_polices are active, ReadonlyWikiPolicy will need to be manually added to the list. A message will be echoed to the console when upgrading the environment, indicating if any action needs to be taken.
ReadonlyWikiPolicy must be listed before DefaultPermissionPolicy. The latter returns True to allow modify, delete or rename actions when the user has the respective WIKI_* permission, without consideration for the read-only attribute.
The ReadonlyWikiPolicy returns False to deny modify, delete and rename actions on wiki pages when the page has the read-only attribute set and the user does not have WIKI_ADMIN, regardless of WIKI_MODIFY, WIKI_DELETE and WIKI_RENAME permissions. It returns None for all other cases.
When active, the #AuthzPolicy should therefore come before ReadonlyWikiPolicy, allowing it to grant or deny the actions on individual resources, which is the usual ordering for AuthzPolicy in the permission_policies list.
[trac] permission_policies = AuthzPolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
The placement of #AuthzSourcePolicy relative to ReadonlyWikiPolicy does not matter since they don't perform checks on the same realms.
For all other permission policies, the user will need to decide the proper ordering. Generally, if the permission policy should be capable of overriding the check performed by ReadonlyWikiPolicy, it should come before ReadonlyWikiPolicy in the list. If the ReadonlyWikiPolicy should override the check performed by another permission policy, as is the case for DefaultPermissionPolicy, then ReadonlyWikiPolicy should come first.
In trac.ini set:
[logging] log_file = trac.log log_level = DEBUG log_type = file
Display the trac.log to understand what checks are being performed:
tail -n 0 -f log/trac.log | egrep '\[perm\]|\[authz_policy\]'
See the sourced documentation of the plugin for more info.
See also: TracPermissions, TracHacks:FineGrainedPageAuthzEditorPlugin for a simple editor plugin.