Changes between Version 1 and Version 2 of TracFineGrainedPermissions


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Timestamp:
2017-10-15T03:11:40-08:00 (6 months ago)
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trac
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  • TracFineGrainedPermissions

    v1 v2  
     1= Fine grained permissions =
    12[[PageOutline(2-5, Contents, floated)]]
    2 = Fine grained permissions =
    3 
    4 Before Trac 0.11, it was only possible to define fine-grained permissions checks on the repository browser sub-system.
    5 
    6 Since 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 
    8 Note 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 
     3[[TracGuideToc]]
     4
     5There 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
     7That 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.
    108
    119== Permission Policies ==
    1210
    13 A great diversity of permission policies can be implemented, and Trac comes with a few examples.
     11A great diversity of permission policies can be implemented and Trac comes with a few examples.
    1412
    1513Which policies are currently active is determined by a configuration setting in TracIni:
    16 e.g.
    17 {{{
    18 [trac]
    19 permission_policies = ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    20 }}}
    21 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.
    22 
    23 Among 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.
     14
     15{{{#!ini
     16[trac]
     17permission_policies = AuthzSourcePolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
     18}}}
     19This 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.
     20
     21Among 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.
    2523
    2624Another 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.
    2725
    28 See also [trac:source:branches/0.12-stable/sample-plugins/permissions sample-plugins/permissions] for more examples.
    29 
     26See also [trac:source:branches/1.0-stable/sample-plugins/permissions sample-plugins/permissions] for more examples.
    3027
    3128=== !AuthzPolicy ===
    3229==== Configuration ====
    33 * Install [http://www.voidspace.org.uk/python/configobj.html ConfigObj] (still needed for 0.12 and later).
    34 * Copy [browser:/trunk/tracopt/perm/authz_policy.py /tracopt/perm/authz_policy.py] to your environment's plugins directory (only for Trac 0.11).
     30* Install [http://www.voidspace.org.uk/python/configobj.html ConfigObj].
    3531* 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.
    3632* Update your `trac.ini`:
    37   1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section
    38 {{{
     33  1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section:
     34{{{#!ini
    3935[trac]
    4036...
    41 permission_policies = AuthzPolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    42 }}}
    43   1. add a new `[authz_policy]` section
    44 {{{
     37permission_policies = AuthzPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
     38}}}
     39  1. add a new `[authz_policy]` section:
     40{{{#!ini
    4541[authz_policy]
    4642authz_file = /some/trac/env/conf/authzpolicy.conf
    4743}}}
    48   1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section
    49 {{{
     44  1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section:
     45{{{#!ini
    5046[components]
    51 ...
    52 # Trac 0.12
    5347tracopt.perm.authz_policy.* = enabled
    54 # for Trac 0.11 use this
    55 #authz_policy.* = enabled
    56 }}}
    57 
     48}}}
    5849
    5950==== Usage Notes ====
    60 Note that the order in which permission policies are specified is quite critical,
    61 as policies will be examined in the sequence provided.
     51
     52Note the order in which permission policies are specified: policies are implemented in the sequence provided and therefore may override earlier policy specifications.
    6253
    6354A 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.
    6455
    65 NOTE: Only if the return value is `None` will the ''next'' permission policy be consulted.
    66 If none of the policies explicitly grants the permission, the final result will be `False`
    67 (i.e. permission denied).
     56NOTE: 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.
    6857
    6958The `authzpolicy.conf` file is a `.ini` style configuration file:
    70 {{{
     59{{{#!ini
    7160[wiki:PrivatePage@*]
    7261john = WIKI_VIEW, !WIKI_MODIFY
     
    7463* =
    7564}}}
    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:
     65* Each section of the config is a glob pattern used to match against a Trac resource descriptor. These descriptors are in the form:
    7866{{{
    7967<realm>:<id>@<version>[/<realm>:<id>@<version> ...]
    8068}}}
    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 {{{
     69
     70Resources 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
    8772[wiki:*]
    8873[wiki:WikiStart*]
     
    9176}}}
    9277
    93   Example: Match the attachment `wiki:WikiStart@117/attachment:FOO.JPG@*`
    94   on WikiStart
    95 {{{
     78Example: Match the attachment `wiki:WikiStart@117/attachment:FOO.JPG@*` on WikiStart:
     79{{{#!ini
    9680[wiki:*]
    9781[wiki:WikiStart*]
     
    10185}}}
    10286
    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'''.
     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'''.
    10890  * 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.
    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 ||
     91  * If a value (permission) is prefixed with a `!`, the permission is denied rather than granted.
     92
     93The 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. ||
    11394
    11495For example, if the `authz_file` contains:
    115 {{{
     96{{{#!ini
    11697[wiki:WikiStart@*]
    11798* = WIKI_VIEW
     
    129110
    130111Then:
    131   * All versions of WikiStart will be viewable by everybody (including anonymous)
     112  * All versions of WikiStart will be viewable by everybody, including anonymous
    132113  * !PrivatePage will be viewable only by john
    133114  * other pages will be viewable only by john and jack
    134115
    135116Groups:
    136 {{{
     117{{{#!ini
    137118[groups]
    138119admins = john, jack
     
    155136
    156137Some repository examples (Browse Source specific):
    157 {{{
     138{{{#!ini
    158139# A single repository:
    159140[repository:test_repo@*]
     
    172153}}}
    173154
    174 Very fine grain repository access:
    175 {{{
     155Very granular repository access:
     156{{{#!ini
    176157# John has BROWSER_VIEW and FILE_VIEW access to trunk/src/some/location/ only
    177158[repository:test_repo@*/source:trunk/src/some/location/*@*]
    178159john = BROWSER_VIEW, FILE_VIEW
    179160
    180 
    181161# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of all files at trunk/src/some/location only
    182162[repository:test_repo@*/source:trunk/src/some/location/*@1]
    183163john = BROWSER_VIEW, FILE_VIEW
    184164
    185 
    186165# John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only
    187166[repository:test_repo@*/source:trunk/src/some/location/somefile@*]
    188167john = BROWSER_VIEW, FILE_VIEW
    189168
    190 
    191169# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of 'somefile' at trunk/src/some/location only
    192170[repository:test_repo@*/source:trunk/src/some/location/somefile@1]
     
    196174Note: In order for Timeline to work/visible for John, we must add CHANGESET_VIEW to the above permission list.
    197175
    198 
    199176==== Missing Features ====
    200 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 forgotten authz_policy.2.patch  part of [trac:ticket:6680 #6680]).
     177Although 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].
    201178
    202179You cannot do the following:
    203 {{{
     180{{{#!ini
    204181[groups]
    205182team1 = a, b, c
     
    209186}}}
    210187
    211 Permission groups are not supported either. You cannot do the following:
    212 {{{
     188Permission groups are not supported either, so you cannot do the following:
     189{{{#!ini
    213190[groups]
    214191permission_level_1 = WIKI_VIEW, TICKET_VIEW
     
    222199=== !AuthzSourcePolicy  (mod_authz_svn-like permission policy) === #AuthzSourcePolicy
    223200
    224 At 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.
    225 
    226 That kind of fine-grained permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.
    227 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.
     201At 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
     203That kind of granular permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.
     204More 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.
    228205
    229206Example:
    230 {{{
     207{{{#!ini
    231208[/]
    232209* = r
     
    246223==== Trac Configuration ====
    247224
    248 To 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.
    249 
    250 {{{
     225To 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
    251228[trac]
    252229authz_file = /path/to/svnaccessfile
    253230}}}
    254231
    255 If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add 
    256 
    257 {{{
     232If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add:
     233
     234{{{#!ini
    258235authz_module_name = modulename
    259236}}}
    260237
    261 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/blahblah}}}, that would yield the following:
    262 
    263 {{{
     238where ''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
    264241[trac]
    265242authz_file = /path/to/svnaccessfile
    266 authz_module_name = blahblah
     243authz_module_name = somemodule
    267244...
    268 repository_dir = /srv/active/svn/blahblah
    269 }}}
    270 
    271 where the svn access file, {{{/path/to/svnaccessfile}}}, contains entries such as {{{[blahblah:/some/path]}}}.
     245repository_dir = /srv/active/svn/somemodule
     246}}}
     247
     248where the svn access file, {{{/path/to/svnaccessfile}}}, contains entries such as {{{[somemodule:/some/path]}}}.
    272249
    273250'''Note:''' Usernames inside the Authz file __must__ be the same as those used inside trac.
     
    275252As 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.
    276253
    277 {{{ 
    278 [trac]
    279 permission_policies = AuthzSourcePolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
     254{{{#!ini
     255[trac]
     256permission_policies = AuthzSourcePolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    280257}}}
    281258
     
    283260
    284261The same access file is typically applied to the corresponding Subversion repository using an Apache directive like this:
    285 {{{
     262{{{#!apache
    286263<Location /repos>
    287264  DAV svn
     
    293270}}}
    294271
    295 For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess]
    296 
    297 === ReadonlyWikiPolicy
    298 
    299 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:
    300 {{{
    301 [trac]
    302 permission_policies = ReadonlyWikiPolicy,
    303  DefaultPermissionPolicy,
    304  LegacyAttachmentPolicy
    305 }}}
    306 
    307 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.
    308 
    309 **!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.
    310 
    311 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.
    312 
    313 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.
    314 {{{
    315 [trac]
    316 permission_policies = AuthzPolicy,
    317  ReadonlyWikiPolicy,
    318  DefaultPermissionPolicy,
    319  LegacyAttachmentPolicy
    320 }}}
    321 
    322 The placement of [#AuthzSourcePolicy] relative to `ReadonlyWikiPolicy` does not matter since they don't perform checks on the same realms.
    323 
    324 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.
     272For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess].
    325273
    326274== Debugging permissions
    327275In trac.ini set:
    328 {{{
     276{{{#!ini
    329277[logging]
    330278log_file = trac.log
     
    333281}}}
    334282
    335 And watch:
    336 {{{
     283Display the trac.log to understand what checks are being performed:
     284{{{#!sh
    337285tail -n 0 -f log/trac.log | egrep '\[perm\]|\[authz_policy\]'
    338286}}}
    339287
    340 to understand what checks are being performed. See the sourced documentation of the plugin for more info.
     288See the sourced documentation of the plugin for more info.
    341289
    342290----