Changes between Initial Version and Version 1 of TracFineGrainedPermissions

2014-02-18 13:26:47 (5 years ago)



  • TracFineGrainedPermissions

    v1 v1  
     1[[PageOutline(2-5, Contents, floated)]] 
     2= Fine grained permissions = 
     4Before Trac 0.11, it was only possible to define fine-grained permissions checks on the repository browser sub-system. 
     6Since 0.11, there's a general mechanism in place that allows custom **permission policy plugins** to grant or deny any action on any kind of Trac resources, even at the level of specific versions of such resources. 
     8Note that for Trac 0.12, `authz_policy` has been integrated as an optional module (in `tracopt.perm.authz_policy.*`), so it's installed by default and can simply be activated via the //Plugins// panel in the Trac administration module. 
     11== Permission Policies == 
     13A great diversity of permission policies can be implemented, and Trac comes with a few examples.  
     15Which policies are currently active is determined by a configuration setting in TracIni: 
     19permission_policies = AuthzSourcePolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy 
     21This lists the [#AuthzSourcePolicy] described below as the first policy, 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. 
     23Among the possible optional choices, there is [#AuthzPolicy], a very generic permission policy, based on an Authz-style system. See 
     24[trac:source:branches/0.12-stable/tracopt/perm/] for details.  
     26Another 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. 
     28See also [trac:source:branches/0.12-stable/sample-plugins/permissions sample-plugins/permissions] for more examples. 
     31=== !AuthzPolicy ===  
     32==== Configuration ==== 
     33* Install [ ConfigObj] (still needed for 0.12). 
     34* Copy into your plugins directory (only for Trac 0.11). 
     35* Put a [ 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. 
     36* Update your `trac.ini`: 
     37  1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section 
     41permission_policies = AuthzPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy 
     43  1. add a new `[authz_policy]` section 
     46authz_file = /some/trac/env/conf/authzpolicy.conf 
     48  1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section 
     52# Trac 0.12 
     53tracopt.perm.authz_policy.* = enabled 
     54# for Trac 0.11 use this 
     55#authz_policy.* = enabled  
     59==== Usage Notes ==== 
     60Note that the order in which permission policies are specified is quite critical,  
     61as policies will be examined in the sequence provided. 
     63A 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. 
     65NOTE: Only if the return value is `None` will the ''next'' permission policy be consulted. 
     66If none of the policies explicitly grants the permission, the final result will be `False`  
     67(i.e. permission denied). 
     69The `authzpolicy.conf` file is a `.ini` style configuration file: 
     72john = WIKI_VIEW, !WIKI_MODIFY 
     73jack = WIKI_VIEW 
     74* = 
     76* Each section of the config is a glob pattern used to match against a Trac resource 
     77  descriptor. These descriptors are in the form: 
     79<realm>:<id>@<version>[/<realm>:<id>@<version> ...] 
     81  Resources are ordered left to right, from parent to child. If any 
     82  component is inapplicable, `*` is substituted. If the version pattern is 
     83  not specified explicitely, all versions (`@*`) is added implicitly 
     85  Example: Match the WikiStart page 
     93  Example: Match the attachment `wiki:WikiStart@117/attachment/FOO.JPG@*` 
     94  on WikiStart 
     103* Sections are checked against the current Trac resource descriptor '''IN ORDER''' of 
     104  appearance in the configuration file. '''ORDER IS CRITICAL'''. 
     106* Once a section matches, the current username is matched against the keys  
     107  (usernames) of the section, '''IN ORDER'''.  
     108  * If a key (username) is prefixed with a `@`, it is treated as a group.  
     109  * If a value (permission) is prefixed with a `!`, the permission is 
     110    denied rather than granted. 
     112  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 || 
     114For example, if the `authz_file` contains: 
     117* = WIKI_VIEW 
     120john = WIKI_VIEW 
     121* = !WIKI_VIEW 
     123and the default permissions are set like this: 
     125john           WIKI_VIEW 
     126jack           WIKI_VIEW 
     127# anonymous has no WIKI_VIEW 
     131  * All versions of WikiStart will be viewable by everybody (including anonymous) 
     132  * !PrivatePage will be viewable only by john 
     133  * other pages will be viewable only by john and jack 
     138admins = john, jack 
     139devs = alice, bob 
     142@admins = TRAC_ADMIN 
     143@devs = WIKI_VIEW 
     144* = 
     147@admins = TRAC_ADMIN 
     148* = 
     152- everything is blocked (whitelist approach), but 
     153- admins get all TRAC_ADMIN everywhere and 
     154- devs can view wiki pages. 
     156Some repository examples (Browse Source specific): 
     158# A single repository: 
     160john = BROWSER_VIEW, FILE_VIEW 
     161# John has BROWSER_VIEW and FILE_VIEW for the entire test_repo 
     163# All repositories: 
     165jack = BROWSER_VIEW, FILE_VIEW 
     166# John has BROWSER_VIEW and FILE_VIEW for all repositories 
     169Very fine grain repository access: 
     171# John has BROWSER_VIEW and FILE_VIEW access to trunk/src/some/location/ only 
     173john = BROWSER_VIEW, FILE_VIEW 
     176# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of all files at trunk/src/some/location only 
     178john = BROWSER_VIEW, FILE_VIEW 
     181# John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only  
     183john = BROWSER_VIEW, FILE_VIEW 
     186# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of 'somefile' at trunk/src/some/location only 
     188john = BROWSER_VIEW, FILE_VIEW 
     191Note: In order for Timeline to work/visible for John, we must add CHANGESET_VIEW to the above permission list. 
     194==== Missing Features ==== 
     195Although 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 forgotten authz_policy.2.patch  part of [trac:ticket:6680 #6680]). 
     197You cannot do the following: 
     200team1 = a, b, c 
     201team2 = d, e, f 
     202team3 = g, h, i 
     203departmentA = team1, team2 
     206Permission groups are not supported either. You cannot do the following: 
     209permission_level_1 = WIKI_VIEW, TICKET_VIEW 
     210permission_level_2  = permission_level_1, WIKI_MODIFY, TICKET_MODIFY 
     212@team1 = permission_level_1 
     213@team2 = permission_level_2 
     214@team3 = permission_level_2, TICKET_CREATE 
     217=== !AuthzSourcePolicy  (mod_authz_svn-like permission policy) === #AuthzSourcePolicy 
     219At the time of this writing, the old fine grained 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 point of view, this makes little if no difference. 
     221That kind of fine-grained permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.  
     222More 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. 
     227* = r 
     230harry = rw 
     231sally = r 
     234harry = 
     237 * '''/''' = ''Everyone has read access by default'' 
     238 * '''/branches/calc/bug-142''' = ''harry has read/write access, sally read only'' 
     239 * '''/branches/calc/bug-142/secret''' = ''harry has no access, sally has read access (inherited as a sub folder permission)'' 
     241==== Trac Configuration ==== 
     243To activate fine grained permissions you __must__ specify the {{{authz_file}}} option in the {{{[trac]}}} section of trac.ini. If this option is set to null or not specified the permissions will not be used. 
     247authz_file = /path/to/svnaccessfile 
     250If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add  
     253authz_module_name = modulename 
     256where ''modulename'' refers to the same repository indicated by the `repository_dir` entry in the `[trac]` section. As an example, if the `repository_dir` entry in the `[trac]` section is {{{/srv/active/svn/blahblah}}}, that would yield the following: 
     260authz_file = /path/to/svnaccessfile 
     261authz_module_name = blahblah 
     263repository_dir = /srv/active/svn/blahblah  
     266where the svn access file, {{{/path/to/svnaccessfile}}}, contains entries such as {{{[blahblah:/some/path]}}}. 
     268'''Note:''' Usernames inside the Authz file __must__ be the same as those used inside trac.  
     270As 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. 
     274permission_policies = AuthzSourcePolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy 
     277==== Subversion Configuration ==== 
     279The same access file is typically applied to the corresponding Subversion repository using an Apache directive like this: 
     281<Location /repos> 
     282  DAV svn 
     283  SVNParentPath /usr/local/svn 
     285  # our access control policy 
     286  AuthzSVNAccessFile /path/to/svnaccessfile 
     290For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess] 
     292== Debugging permissions 
     293In trac.ini set: 
     296log_file = trac.log 
     297log_level = DEBUG 
     298log_type = file 
     301And watch: 
     303tail -n 0 -f log/trac.log | egrep '\[perm\]|\[authz_policy\]' 
     306to understand what checks are being performed. See the sourced documentation of the plugin for more info. 
     310See also: TracPermissions, 
     311[ TracHacks:FineGrainedPageAuthzEditorPlugin] for a simple editor plugin.