Changes between Version 4 and Version 5 of TracFineGrainedPermissions


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Timestamp:
Jan 12, 2016, 11:21:52 PM (4 years ago)
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trac
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  • TracFineGrainedPermissions

    v4 v5  
     1[[PageOutline(2-5, Contents, floated)]]
    12= Fine grained permissions =
    2 [[PageOutline(2-5, Contents, floated)]]
    3 [[TracGuideToc]]
    4 
    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.
     3
     4Before Trac 0.11, it was only possible to define fine-grained permissions checks on the repository browser sub-system.
     5
     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.
     7
     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.
     9
    810
    911== Permission Policies ==
    1012
    11 A great diversity of permission policies can be implemented and Trac comes with a few examples.
     13A great diversity of permission policies can be implemented, and Trac comes with a few examples.
    1214
    1315Which policies are currently active is determined by a configuration setting in TracIni:
    14 
    15 {{{#!ini
     16e.g.
     17{{{
    1618[trac]
    1719permission_policies = AuthzSourcePolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    … …  
    1921This 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.
    2022
    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.
     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/authz_policy.py authz_policy.py] for details.
    2325
    2426Another 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.
    2527
    26 See also [trac:source:branches/1.0-stable/sample-plugins/permissions sample-plugins/permissions] for more examples.
     28See also [trac:source:branches/0.12-stable/sample-plugins/permissions sample-plugins/permissions] for more examples.
     29
    2730
    2831=== !AuthzPolicy ===
    2932==== Configuration ====
    30 * Install [http://www.voidspace.org.uk/python/configobj.html ConfigObj].
     33* Install [http://www.voidspace.org.uk/python/configobj.html ConfigObj] (still needed for 0.12).
     34* Copy authz_policy.py into your plugins directory (only for Trac 0.11).
    3135* 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.
    3236* Update your `trac.ini`:
    33   1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section:
    34 {{{#!ini
     37  1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section
     38{{{
    3539[trac]
    3640...
    3741permission_policies = AuthzPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    3842}}}
    39   1. add a new `[authz_policy]` section:
    40 {{{#!ini
     43  1. add a new `[authz_policy]` section
     44{{{
    4145[authz_policy]
    4246authz_file = /some/trac/env/conf/authzpolicy.conf
    4347}}}
    44   1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section:
    45 {{{#!ini
     48  1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section
     49{{{
    4650[components]
     51...
     52# Trac 0.12
    4753tracopt.perm.authz_policy.* = enabled
    48 }}}
     54# for Trac 0.11 use this
     55#authz_policy.* = enabled
     56}}}
     57
    4958
    5059==== Usage Notes ====
    51 
    52 Note the order in which permission policies are specified: policies are implemented in the sequence provided and therefore may override earlier policy specifications.
     60Note that the order in which permission policies are specified is quite critical,
     61as policies will be examined in the sequence provided.
    5362
    5463A 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.
    5564
    56 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.
     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).
    5768
    5869The `authzpolicy.conf` file is a `.ini` style configuration file:
    59 {{{#!ini
     70{{{
    6071[wiki:PrivatePage@*]
    6172john = WIKI_VIEW, !WIKI_MODIFY
    … …  
    6374* =
    6475}}}
    65 * Each section of the config is a glob pattern used to match against a Trac resource descriptor. These descriptors are in the form:
     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:
    6678{{{
    6779<realm>:<id>@<version>[/<realm>:<id>@<version> ...]
    6880}}}
    69 
    70 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:
    71 {{{#!ini
     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
     84
     85  Example: Match the WikiStart page
     86{{{
    7287[wiki:*]
    7388[wiki:WikiStart*]
    … …  
    7691}}}
    7792
    78 Example: Match the attachment `wiki:WikiStart@117/attachment:FOO.JPG@*` on WikiStart:
    79 {{{#!ini
     93  Example: Match the attachment `wiki:WikiStart@117/attachment/FOO.JPG@*`
     94  on WikiStart
     95{{{
    8096[wiki:*]
    8197[wiki:WikiStart*]
    8298[wiki:WikiStart@*]
    83 [wiki:WikiStart@*/attachment:*]
    84 [wiki:WikiStart@117/attachment:FOO.JPG]
    85 }}}
    86 
    87 * Sections are checked against the current Trac resource descriptor '''IN ORDER''' of appearance in the configuration file. '''ORDER IS CRITICAL'''.
    88 
    89 * Once a section matches, the current username is matched against the keys (usernames) of the section, '''IN ORDER'''.
     99[wiki:WikiStart@*/attachment/*]
     100[wiki:WikiStart@117/attachment/FOO.JPG]
     101}}}
     102
     103* Sections are checked against the current Trac resource descriptor '''IN ORDER''' of
     104  appearance in the configuration file. '''ORDER IS CRITICAL'''.
     105
     106* Once a section matches, the current username is matched against the keys
     107  (usernames) of the section, '''IN ORDER'''.
    90108  * If a key (username) is prefixed with a `@`, it is treated as a group.
    91   * If a value (permission) is prefixed with a `!`, the permission is denied rather than granted.
    92 
    93 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. ||
     109  * If a value (permission) is prefixed with a `!`, the permission is
     110    denied rather than granted.
     111
     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 ||
    94113
    95114For example, if the `authz_file` contains:
    96 {{{#!ini
     115{{{
    97116[wiki:WikiStart@*]
    98117* = WIKI_VIEW
    … …  
    110129
    111130Then:
    112   * All versions of WikiStart will be viewable by everybody, including anonymous
     131  * All versions of WikiStart will be viewable by everybody (including anonymous)
    113132  * !PrivatePage will be viewable only by john
    114133  * other pages will be viewable only by john and jack
    115134
    116135Groups:
    117 {{{#!ini
     136{{{
    118137[groups]
    119138admins = john, jack
    … …  
    136155
    137156Some repository examples (Browse Source specific):
    138 {{{#!ini
     157{{{
    139158# A single repository:
    140159[repository:test_repo@*]
    141160john = BROWSER_VIEW, FILE_VIEW
    142161# John has BROWSER_VIEW and FILE_VIEW for the entire test_repo
    143 
    144 # The default repository (requires Trac 1.0.2 or later):
    145 [repository:@*]
    146 john = BROWSER_VIEW, FILE_VIEW
    147 # John has BROWSER_VIEW and FILE_VIEW for the entire default repository
    148162
    149163# All repositories:
    150164[repository:*@*]
    151165jack = BROWSER_VIEW, FILE_VIEW
    152 # Jack has BROWSER_VIEW and FILE_VIEW for all repositories
    153 }}}
    154 
    155 Very granular repository access:
    156 {{{#!ini
     166# John has BROWSER_VIEW and FILE_VIEW for all repositories
     167}}}
     168
     169Very fine grain repository access:
     170{{{
    157171# John has BROWSER_VIEW and FILE_VIEW access to trunk/src/some/location/ only
    158172[repository:test_repo@*/source:trunk/src/some/location/*@*]
    159173john = BROWSER_VIEW, FILE_VIEW
    160174
     175
    161176# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of all files at trunk/src/some/location only
    162177[repository:test_repo@*/source:trunk/src/some/location/*@1]
    163178john = BROWSER_VIEW, FILE_VIEW
    164179
     180
    165181# John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only
    166182[repository:test_repo@*/source:trunk/src/some/location/somefile@*]
    167183john = BROWSER_VIEW, FILE_VIEW
    168184
     185
    169186# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of 'somefile' at trunk/src/some/location only
    170187[repository:test_repo@*/source:trunk/src/some/location/somefile@1]
    … …  
    174191Note: In order for Timeline to work/visible for John, we must add CHANGESET_VIEW to the above permission list.
    175192
     193
    176194==== Missing Features ====
    177 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].
     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]).
    178196
    179197You cannot do the following:
    180 {{{#!ini
     198{{{
    181199[groups]
    182200team1 = a, b, c
    … …  
    186204}}}
    187205
    188 Permission groups are not supported either, so you cannot do the following:
    189 {{{#!ini
     206Permission groups are not supported either. You cannot do the following:
     207{{{
    190208[groups]
    191209permission_level_1 = WIKI_VIEW, TICKET_VIEW
    … …  
    199217=== !AuthzSourcePolicy  (mod_authz_svn-like permission policy) === #AuthzSourcePolicy
    200218
    201 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.
    202 
    203 That kind of granular permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.
    204 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.
     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.
     220
     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  [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.
    205223
    206224Example:
    207 {{{#!ini
     225{{{
    208226[/]
    209227* = r
    … …  
    223241==== Trac Configuration ====
    224242
    225 To activate granular 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.
    226 
    227 {{{#!ini
     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.
     244
     245{{{
    228246[trac]
    229247authz_file = /path/to/svnaccessfile
    230248}}}
    231249
    232 If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add:
    233 
    234 {{{#!ini
     250If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add 
     251
     252{{{
    235253authz_module_name = modulename
    236254}}}
    237255
    238 where ''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/somemodule}}}, that would yield the following:
    239 
    240 {{{ #!ini
     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:
     257
     258{{{
    241259[trac]
    242260authz_file = /path/to/svnaccessfile
    243 authz_module_name = somemodule
     261authz_module_name = blahblah
    244262...
    245 repository_dir = /srv/active/svn/somemodule
    246 }}}
    247 
    248 where the svn access file, {{{/path/to/svnaccessfile}}}, contains entries such as {{{[somemodule:/some/path]}}}.
     263repository_dir = /srv/active/svn/blahblah
     264}}}
     265
     266where the svn access file, {{{/path/to/svnaccessfile}}}, contains entries such as {{{[blahblah:/some/path]}}}.
    249267
    250268'''Note:''' Usernames inside the Authz file __must__ be the same as those used inside trac.
    … …  
    252270As 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.
    253271
    254 {{{#!ini
     272{{{ 
    255273[trac]
    256274permission_policies = AuthzSourcePolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    … …  
    260278
    261279The same access file is typically applied to the corresponding Subversion repository using an Apache directive like this:
    262 {{{#!apache
     280{{{
    263281<Location /repos>
    264282  DAV svn
    … …  
    270288}}}
    271289
    272 For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess].
     290For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess]
    273291
    274292== Debugging permissions
    275293In trac.ini set:
    276 {{{#!ini
     294{{{
    277295[logging]
    278296log_file = trac.log
    … …  
    281299}}}
    282300
    283 Display the trac.log to understand what checks are being performed:
    284 {{{#!sh
     301And watch:
     302{{{
    285303tail -n 0 -f log/trac.log | egrep '\[perm\]|\[authz_policy\]'
    286304}}}
    287305
    288 See the sourced documentation of the plugin for more info.
     306to understand what checks are being performed. See the sourced documentation of the plugin for more info.
     307
    289308
    290309----