Changes between Version 3 and Version 4 of Trac Fine Grained Permissions


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Timestamp:
Jun 19, 2017, 10:42:06 PM (8 years ago)
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trac
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  • Trac Fine Grained Permissions

    v3 v4  
     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 {{{
     14
     15{{{#!ini
    1816[trac]
    1917permission_policies = ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    … …  
    2119This 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.
    2220
    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.
     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).
    3530* 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.
    3631* Update your `trac.ini`:
    37   1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section
    38 {{{
     32  1. modify the [TracIni#trac-section permission_policies] entry in the `[trac]` section:
     33{{{#!ini
    3934[trac]
    4035...
    4136permission_policies = AuthzPolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    4237}}}
    43   1. add a new `[authz_policy]` section
    44 {{{
     38  1. add a new `[authz_policy]` section:
     39{{{#!ini
    4540[authz_policy]
    4641authz_file = /some/trac/env/conf/authzpolicy.conf
    4742}}}
    48   1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section
    49 {{{
     43  1. enable the plugin through [/admin/general/plugin WebAdmin] or by editing the `[components]` section:
     44{{{#!ini
    5045[components]
    51 ...
    52 # Trac 0.12
    5346tracopt.perm.authz_policy.* = enabled
    54 # for Trac 0.11 use this
    55 #authz_policy.* = enabled
    56 }}}
    57 
     47}}}
    5848
    5949==== 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.
     50
     51Note the order in which permission policies are specified: policies are implemented in the sequence provided and therefore may override earlier policy specifications.
    6252
    6353A 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.
    6454
    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).
     55NOTE: 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.
    6856
    6957The `authzpolicy.conf` file is a `.ini` style configuration file:
    70 {{{
     58{{{#!ini
    7159[wiki:PrivatePage@*]
    7260john = WIKI_VIEW, !WIKI_MODIFY
    … …  
    7462* =
    7563}}}
    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:
     64* Each section of the config is a glob pattern used to match against a Trac resource descriptor. These descriptors are in the form:
    7865{{{
    7966<realm>:<id>@<version>[/<realm>:<id>@<version> ...]
    8067}}}
    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 {{{
     68
     69Resources 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:
     70{{{#!ini
    8771[wiki:*]
    8872[wiki:WikiStart*]
    … …  
    9175}}}
    9276
    93   Example: Match the attachment `wiki:WikiStart@117/attachment:FOO.JPG@*`
    94   on WikiStart
    95 {{{
     77Example: Match the attachment `wiki:WikiStart@117/attachment:FOO.JPG@*` on WikiStart:
     78{{{#!ini
    9679[wiki:*]
    9780[wiki:WikiStart*]
    … …  
    10184}}}
    10285
    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'''.
     86* Sections are checked against the current Trac resource descriptor '''IN ORDER''' of appearance in the configuration file. '''ORDER IS CRITICAL'''.
     87
     88* Once a section matches, the current username is matched against the keys (usernames) of the section, '''IN ORDER'''.
    10889  * 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 ||
     90  * If a value (permission) is prefixed with a `!`, the permission is denied rather than granted.
     91
     92The 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. ||
    11393
    11494For example, if the `authz_file` contains:
    115 {{{
     95{{{#!ini
    11696[wiki:WikiStart@*]
    11797* = WIKI_VIEW
    … …  
    129109
    130110Then:
    131   * All versions of WikiStart will be viewable by everybody (including anonymous)
     111  * All versions of WikiStart will be viewable by everybody, including anonymous
    132112  * !PrivatePage will be viewable only by john
    133113  * other pages will be viewable only by john and jack
    134114
    135115Groups:
    136 {{{
     116{{{#!ini
    137117[groups]
    138118admins = john, jack
    … …  
    155135
    156136Some repository examples (Browse Source specific):
    157 {{{
     137{{{#!ini
    158138# A single repository:
    159139[repository:test_repo@*]
    … …  
    172152}}}
    173153
    174 Very fine grain repository access:
    175 {{{
     154Very granular repository access:
     155{{{#!ini
    176156# John has BROWSER_VIEW and FILE_VIEW access to trunk/src/some/location/ only
    177157[repository:test_repo@*/source:trunk/src/some/location/*@*]
    178158john = BROWSER_VIEW, FILE_VIEW
    179159
    180 
    181160# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of all files at trunk/src/some/location only
    182161[repository:test_repo@*/source:trunk/src/some/location/*@1]
    183162john = BROWSER_VIEW, FILE_VIEW
    184163
    185 
    186164# John has BROWSER_VIEW and FILE_VIEW access to all revisions of 'somefile' at trunk/src/some/location only
    187165[repository:test_repo@*/source:trunk/src/some/location/somefile@*]
    188166john = BROWSER_VIEW, FILE_VIEW
    189167
    190 
    191168# John has BROWSER_VIEW and FILE_VIEW access to only revision 1 of 'somefile' at trunk/src/some/location only
    192169[repository:test_repo@*/source:trunk/src/some/location/somefile@1]
    … …  
    196173Note: In order for Timeline to work/visible for John, we must add CHANGESET_VIEW to the above permission list.
    197174
    198 
    199175==== 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]).
     176Although 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].
    201177
    202178You cannot do the following:
    203 {{{
     179{{{#!ini
    204180[groups]
    205181team1 = a, b, c
    … …  
    209185}}}
    210186
    211 Permission groups are not supported either. You cannot do the following:
    212 {{{
     187Permission groups are not supported either, so you cannot do the following:
     188{{{#!ini
    213189[groups]
    214190permission_level_1 = WIKI_VIEW, TICKET_VIEW
    … …  
    222198=== !AuthzSourcePolicy  (mod_authz_svn-like permission policy) === #AuthzSourcePolicy
    223199
    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.
     200At 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
     202That kind of granular permission control needs a definition file, which is the one used by Subversion's mod_authz_svn.
     203More 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.
    228204
    229205Example:
    230 {{{
     206{{{#!ini
    231207[/]
    232208* = r
    … …  
    246222==== Trac Configuration ====
    247223
    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 {{{
    251 [trac]
     224To 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.
     225
     226{{{#!ini
     227[svn]
    252228authz_file = /path/to/svnaccessfile
    253229}}}
    254230
    255 If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add 
    256 
    257 {{{
     231If you want to support the use of the `[`''modulename''`:/`''some''`/`''path''`]` syntax within the `authz_file`, add:
     232
     233{{{#!ini
    258234authz_module_name = modulename
    259235}}}
    260236
    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 {{{
    264 [trac]
     237where ''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:
     238
     239{{{ #!ini
     240[svn]
    265241authz_file = /path/to/svnaccessfile
    266 authz_module_name = blahblah
     242authz_module_name = somemodule
    267243...
    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]}}}.
     244[repositories]
     245somemodule.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 {{{ 
     254{{{#!ini
    278255[trac]
    279256permission_policies = AuthzSourcePolicy, ReadonlyWikiPolicy, DefaultPermissionPolicy, LegacyAttachmentPolicy
    … …  
    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]
     272For information about how to restrict access to entire projects in a multiple project environment see [trac:wiki:TracMultipleProjectsSVNAccess].
    296273
    297274=== ReadonlyWikiPolicy
    … …  
    326303== Debugging permissions
    327304In trac.ini set:
    328 {{{
     305{{{#!ini
    329306[logging]
    330307log_file = trac.log
    … …  
    333310}}}
    334311
    335 And watch:
    336 {{{
     312Display the trac.log to understand what checks are being performed:
     313{{{#!sh
    337314tail -n 0 -f log/trac.log | egrep '\[perm\]|\[authz_policy\]'
    338315}}}
    339316
    340 to understand what checks are being performed. See the sourced documentation of the plugin for more info.
     317See the sourced documentation of the plugin for more info.
    341318
    342319----