Changes between Version 2 and Version 3 of TracFineGrainedPermissions


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Timestamp:
Jun 9, 2024, 11:14:44 AM (6 weeks ago)
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trac
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  • TracFineGrainedPermissions

    v2 v3  
    1 = Fine grained permissions =
     1= Fine grained permissions
    22[[PageOutline(2-5, Contents, floated)]]
    33[[TracGuideToc]]
    44
    5 There is a general mechanism in place that allows custom **permission policy plugins** to grant or deny any action on any kind of Trac resource, even at the level of specific versions of such resources.
    6 
    7 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.
    8 
    9 == Permission Policies ==
    10 
    11 A great diversity of permission policies can be implemented and Trac comes with a few examples.
    12 
    13 Which policies are currently active is determined by a configuration setting in TracIni:
    14 
    15 {{{#!ini
    16 [trac]
    17 permission_policies = ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    18 }}}
    19 This lists the [#ReadonlyWikiPolicy] which controls readonly access to wiki pages, followed by the !DefaultPermissionPolicy which checks for the traditional coarse grained style permissions described in TracPermissions, and the !LegacyAttachmentPolicy which knows how to use the coarse grained permissions for checking the permissions available on attachments.
    20 
    21 Among the optional choices, there is [#AuthzPolicy], a very generic permission policy, based on an Authz-style system. See
    22 [trac:source:branches/1.0-stable/tracopt/perm/authz_policy.py authz_policy.py] for details.
    23 
    24 Another popular permission policy [#AuthzSourcePolicy], re-implements the pre-0.12 support for checking fine-grained permissions limited to Subversion repositories in terms of the new system.
    25 
    26 See also [trac:source:branches/1.0-stable/sample-plugins/permissions sample-plugins/permissions] for more examples.
    27 
    28 === !AuthzPolicy ===
    29 ==== Configuration ====
    30 * Put a [http://swapoff.org/files/authzpolicy.conf authzpolicy.conf] file somewhere, preferably on a secured location on the server, not readable for others than the webuser. If the  file contains non-ASCII characters, the UTF-8 encoding should be used.
     5There 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.
     6
     7That mechanism is `AuthzPolicy`, an optional component in `tracopt.perm.authz_policy.*` which is not activated by default. It can be activated via the //Plugins// panel in the Trac administration module.
     8
     9See TracPermissions for a more general introduction to Trac permissions and permission policies.
     10
     11== Permission Policies
     12
     13A great diversity of permission policies can be implemented and Trac comes with a few examples.
     14
     15The active policies are determined by a [TracIni#trac-permission_policies-option configuration setting]:
     16
     17{{{#!ini
     18[trac]
     19permission_policies = DefaultWikiPolicy,
     20 DefaultTicketPolicy,
     21 DefaultPermissionPolicy,
     22 LegacyAttachmentPolicy
     23}}}
     24
     25* [#DefaultWikiPolicyandDefaultTicketPolicy DefaultWikiPolicy] controls readonly access to wiki pages.
     26* [#DefaultWikiPolicyandDefaultTicketPolicy DefaultTicketPolicy] provides elevated privileges in the ticket system for authenticated users.
     27* !DefaultPermissionPolicy checks for the traditional coarse-grained permissions described in TracPermissions.
     28* !LegacyAttachmentPolicy uses the coarse-grained permissions to check permissions on attachments.
     29
     30Among the optional choices, there is [#AuthzPolicy], a very generic permission policy, based on an Authz-style system. See [trac:source:branches/1.4-stable/tracopt/perm/authz_policy.py authz_policy.py] for details.
     31
     32Another permission policy [#AuthzSourcePolicy], uses the [http://svnbook.red-bean.com/nightly/en/svn.serverconfig.pathbasedauthz.html path-based authorization] defined by Subversion to enforce permissions on the version control system.
     33
     34See also [trac:source:branches/1.4-stable/sample-plugins/permissions sample-plugins/permissions] for more examples.
     35
     36=== !AuthzPolicy
     37==== Configuration
     38
     39* Put an empty conf file (`authzpolicy.conf`) in a secure location on the server, not readable by users other than the webuser. If the file contains non-ASCII characters, the UTF-8 encoding should be used.
    3140* Update your `trac.ini`:
    32   1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section:
    33 {{{#!ini
    34 [trac]
    35 ...
    36 permission_policies = AuthzPolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    37 }}}
    38   1. add a new `[authz_policy]` section:
     41  1. modify the [TracIni#trac-permission_policies-option permission_policies] option in the `[trac]` section:
     42{{{#!ini
     43[trac]
     44permission_policies = AuthzPolicy, DefaultWikiPolicy, DefaultTicketPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
     45}}}
     46  1. add a new `[authz_policy]` section and point the `authz_file` option to the conf file:
    3947{{{#!ini
    4048[authz_policy]
     
    4755}}}
    4856
    49 ==== Usage Notes ====
     57==== Usage Notes
    5058
    5159Note the order in which permission policies are specified: policies are implemented in the sequence provided and therefore may override earlier policy specifications.
     
    5361A 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.
    5462
    55 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.
     63'''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.
    5664
    5765The `authzpolicy.conf` file is a `.ini` style configuration file:
     
    8694* Sections are checked against the current Trac resource descriptor '''IN ORDER''' of appearance in the configuration file. '''ORDER IS CRITICAL'''.
    8795
    88 * Once a section matches, the current username is matched against the keys (usernames) of the section, '''IN ORDER'''. 
    89   * If a key (username) is prefixed with a `@`, it is treated as a group. 
     96* Once a section matches, the current username is matched against the keys (usernames) of the section, '''IN ORDER'''.
     97  * If a key (username) is prefixed with a `@`, it is treated as a group.
    9098  * If a value (permission) is prefixed with a `!`, the permission is denied rather than granted.
    9199
    92 The username will match any of 'anonymous', 'authenticated', <username> or '*', using normal Trac permission rules. || '''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 [trac:ticket:5648 #5648] for details about this missing feature. ||
     100The username will match any of 'anonymous', 'authenticated', <username> or '*', using normal Trac permission rules.
     101
     102'''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 [trac:#5648] for details about this missing feature.
    93103
    94104For example, if the `authz_file` contains:
     
    108118}}}
    109119
    110 Then: 
     120Then:
    111121  * All versions of WikiStart will be viewable by everybody, including anonymous
    112122  * !PrivatePage will be viewable only by john
     
    162172john = BROWSER_VIEW, FILE_VIEW
    163173
    164 # John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only 
     174# John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only
    165175[repository:test_repo@*/source:trunk/src/some/location/somefile@*]
    166176john = BROWSER_VIEW, FILE_VIEW
     
    173183Note: In order for Timeline to work/visible for John, we must add CHANGESET_VIEW to the above permission list.
    174184
    175 ==== Missing Features ====
    176 Although possible with the !DefaultPermissionPolicy handling (see Admin panel), fine-grained permissions still miss those grouping features (see [trac:ticket:9573 #9573], [trac:ticket:5648 #5648]). Patches are partially available, see authz_policy.2.patch, part of [trac:ticket:6680 #6680].
     185==== Missing Features
     186
     187Although possible with the !DefaultPermissionPolicy handling (see Admin panel), fine-grained permissions still miss those grouping features (see [trac:#9573], [trac:#5648]). Patches are partially available, see authz_policy.2.patch, part of [trac:ticket:6680 #6680].
    177188
    178189You cannot do the following:
     
    189200[groups]
    190201permission_level_1 = WIKI_VIEW, TICKET_VIEW
    191 permission_level_2  = permission_level_1, WIKI_MODIFY, TICKET_MODIFY
     202permission_level_2 = permission_level_1, WIKI_MODIFY, TICKET_MODIFY
    192203[*]
    193204@team1 = permission_level_1
     
    196207}}}
    197208
    198 === !AuthzSourcePolicy  (mod_authz_svn-like permission policy) === #AuthzSourcePolicy
    199 
    200 At the time of this writing, the old granular permissions system from Trac 0.11 and before used for restricting access to the repository has been converted to a permission policy component. But from the user's point of view, this makes little if any difference.
    201 
    202 That kind of granular permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.
    203 More information about this file format and about its usage in Subversion is available in the [http://svnbook.red-bean.com/en/1.5/svn.serverconfig.pathbasedauthz.html Path-Based Authorization] section in the Server Configuration chapter of the svn book.
     209=== !AuthzSourcePolicy (`mod_authz_svn`-like permission policy) #AuthzSourcePolicy
     210
     211`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`.
     212More information about this file format and about its usage in Subversion is available in the [http://svnbook.red-bean.com/en/1.7/svn.serverconfig.pathbasedauthz.html Path-Based Authorization] section in the Server Configuration chapter of the svn book.
    204213
    205214Example:
     
    220229 * '''/branches/calc/bug-142/secret''' = ''harry has no access, sally has read access (inherited as a sub folder permission)''
    221230
    222 ==== Trac Configuration ====
     231==== Trac Configuration
    223232
    224233To 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.
     
    243252...
    244253[repositories]
    245 somemodule.dir = /srv/active/svn/somemodule 
     254somemodule.dir = /srv/active/svn/somemodule
    246255}}}
    247256
    248257where the svn access file, {{{/path/to/svnaccessfile}}}, contains entries such as {{{[somemodule:/some/path]}}}.
    249258
    250 '''Note:''' Usernames inside the Authz file __must__ be the same as those used inside trac. 
    251 
    252 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.
    253 
    254 {{{#!ini
    255 [trac]
    256 permission_policies = AuthzSourcePolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    257 }}}
    258 
    259 ==== Subversion Configuration ====
     259'''Note:''' Usernames inside the Authz file __must__ be the same as those used inside trac.
     260
     261Make sure you have ''!AuthzSourcePolicy'' included in the permission_policies list in trac.ini, otherwise the authz permissions file will be ignored.
     262
     263{{{#!ini
     264[trac]
     265permission_policies = AuthzSourcePolicy, DefaultWikiPolicy, DefaultTicketPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
     266}}}
     267
     268==== Subversion Configuration
    260269
    261270The same access file is typically applied to the corresponding Subversion repository using an Apache directive like this:
     
    272281For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess].
    273282
    274 === ReadonlyWikiPolicy
    275 
    276 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:
    277 {{{
    278 [trac]
    279 permission_policies = ReadonlyWikiPolicy,
     283=== !DefaultWikiPolicy and !DefaultTicketPolicy
     284
     285Since 1.1.2, the read-only attribute of wiki pages is enabled and enforced when `DefaultWikiPolicy` is in the list of active permission policies (`DefaultWikiPolicy` was named `ReadonlyWikiPolicy` from Trac 1.1.2 to 1.3.1). The default for new Trac installations in 1.3.2 and later is:
     286{{{#!ini
     287[trac]
     288permission_policies = DefaultWikiPolicy,
     289 DefaultTicketPolicy,
    280290 DefaultPermissionPolicy,
    281291 LegacyAttachmentPolicy
    282292}}}
    283293
    284 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.
    285 
    286 **!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.
    287 
    288 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.
    289 
    290 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.
    291 {{{
     294`DefaultWikiPolicy` 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, which causes the next permission policy in the list to be consulted.
     295
     296Since 1.3.2 `DefaultTicketPolicy` implements the following behaviors:
     297* Authenticated user can edit their own comments.
     298* Authenticated user with `TICKET_APPEND` or `TICKET_CHGPROP` can modify the description of a ticket they reported.
     299* User with `MILESTONE_VIEW` can change  the ticket milestone.
     300
     301The wiki- and ticket-specific behaviors are implemented in permission policies so they can be easily replaced in case other behavior is desired.
     302
     303When upgrading from earlier versions of Trac, `DefaultWikiPolicy, DefaultTicketPolicy` will be appended to the list of `permission_policies` when upgrading the environment, provided that `permission_policies` has the default value (`ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy` if upgrading from Trac 1.1.2 or later). If any non-default `permission_polices` are active, `DefaultWikiPolicy, DefaultTicketPolicy` **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.
     304
     305**!DefaultWikiPolicy and !DefaultTicketPolicy 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. Similarly, some of the behaviors implemented in `DefaultTicketPolicy` won't be considered if `DefaultPermissionPolicy` is executed first.
     306
     307When active, the [#AuthzPolicy] should therefore come before `DefaultWikiPolicy, DefaultTicketPolicy`, allowing it to grant or deny the actions on individual resources, which is the usual ordering for `AuthzPolicy` in the `permission_policies` list.
     308{{{#!ini
    292309[trac]
    293310permission_policies = AuthzPolicy,
    294  ReadonlyWikiPolicy,
     311 DefaultWikiPolicy,
     312 DefaultTicketPolicy,
    295313 DefaultPermissionPolicy,
    296314 LegacyAttachmentPolicy
    297315}}}
    298316
    299 The placement of [#AuthzSourcePolicy] relative to `ReadonlyWikiPolicy` does not matter since they don't perform checks on the same realms.
    300 
    301 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.
     317The placement of [#AuthzSourcePolicy] relative to `DefaultWikiPolicy, DefaultTicketPolicy` does not matter since they don't perform checks on the same realms.
     318
     319For all other permission policies, the user will need to decide the proper ordering. Generally, if the permission policy should be capable of overriding the checks performed by `DefaultWikiPolicy` or `DefaultTicketPolicy`, it should come before the policy it overrides. If `DefaultWikiPolicy` or `DefaultTicketPolicy` should override the check performed by another permission policy, as is the case for those policies relative to `DefaultPermissionPolicy`, then the overriding policy should come first.
    302320
    303321== Debugging permissions
     322
    304323In trac.ini set:
    305324{{{#!ini
     
    319338----
    320339See also: TracPermissions,
    321 [http://trac-hacks.org/wiki/FineGrainedPageAuthzEditorPlugin TracHacks:FineGrainedPageAuthzEditorPlugin] for a simple editor plugin.
     340[https://trac-hacks.org/wiki/FineGrainedPageAuthzEditorPlugin FineGrainedPageAuthzEditorPlugin] for a simple editor.