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https://issues.apache.org/jira/browse/COUCHDB-1838?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13711926#comment-13711926
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Alexander Shorin commented on COUCHDB-1838:
-------------------------------------------
[~rnewson], I have two ideas how to solve this problem:
1. Via special list function
What if we replace /_users/_all_docs resource internally will be not a system
_all_docs view, but a special list function that wraps this view?
I call list function special, because regular lists couldn't make any config
lookups to get list of public fields. Also, this special list function have
always to call _all_docs view with include_docs=true options, regardless the
user request, but the returned result respects the request query parameters.
I still call it list function because it acts as list function customizing
view's result.
Previously you'd noted, that calling _all_docs view without include_docs=true
parameter makes impossible to lookup document stuff. So the big and only profit
of this method is not to expose internal CouchDB implementation "routines"
outside.
2. Special design document
More tricky and complex solution: there is special design document with special
view function that emits results only for documents with public fields. The
view's code autoupdates after each public_fields option change.
Problems:
- additional view index;
- need to cleanup public_fields values to prevent code injections ;
- stale=ok ruins everything ;
But it worth to try.
> Specifying public_fields parameter discloses all user docs
> ----------------------------------------------------------
>
> Key: COUCHDB-1838
> URL: https://issues.apache.org/jira/browse/COUCHDB-1838
> Project: CouchDB
> Issue Type: Bug
> Reporter: Alexander Shorin
>
> When public_fields are specified it's possible to retrieve all available user
> docs, no matter does they contains specified public fields or not.
> 0. Setup some users:
> {code}
> curl -X PUT http://localhost:5984/_users/org.couchdb.user:abc -d
> '{"name":"abc", "roles":[], "type":"user", "password": "cba"}' -H
> "Content-Type: application/json"
> curl -X PUT http://localhost:5984/_users/org.couchdb.user:def -d
> '{"name":"def", "roles":[], "type":"user", "password": "fed"}' -H
> "Content-Type: application/json"
> {code}
> 1. Check the old behavior without public_fields:
> {code}
> curl -v http://abc:cba@localhost:5984/_users/_all_docs
> HTTP/1.1 403 Forbidden
> Server: CouchDB/1.4.0+build.8d7ab8b (Erlang OTP/R16B)
> Date: Fri, 21 Jun 2013 23:12:13 GMT
> Content-Type: text/plain; charset=utf-8
> Content-Length: 87
> Cache-Control: must-revalidate
> {"error":"forbidden","reason":"Only admins can access _all_docs of system
> databases."}
> {code}
> 2. Specify some public fields that no one actually has:
> {code}
> curl -X PUT http://localhost:5984/_config/couch_httpd_auth/public_fields -d
> '"no_user_will_never_has_ziz_field_in_his_doc"' -H "Content-Type:
> application/json" --user couch_admin
> {code}
> 3. Try step 1 one more time:
> {code}
> curl -v http://abc:cba@localhost:5984/_users/_all_docs
> HTTP/1.1 200 OK
> Transfer-Encoding: chunked
> Server: CouchDB/1.4.0+build.8d7ab8b (Erlang OTP/R16B)
> ETag: "55N0CA8VM2Z0DQO85L1PM20XS"
> Date: Fri, 21 Jun 2013 23:15:05 GMT
> Content-Type: text/plain; charset=utf-8
> Cache-Control: must-revalidate
> {"total_rows":6,"offset":0,"rows":[
> {"id":"_design/_auth","key":"_design/_auth","value":{"rev":"1-619db7ba8551c0de3f3a178775509611"}},
> {"id":"org.couchdb.user:abc","key":"org.couchdb.user:abc","value":{"rev":"1-64d299987b4df59c048171a8ab8ba951"}},
> {"id":"org.couchdb.user:def","key":"org.couchdb.user:def","value":{"rev":"1-479a3e8a66652838706cc49544730a34"}},
> {"id":"org.couchdb.user:foo","key":"org.couchdb.user:foo","value":{"rev":"1-3859ee3742314dcb4b4f1ffaba398c91"}},
> {"id":"org.couchdb.user:mia","key":"org.couchdb.user:mia","value":{"rev":"1-f87f5003323e705d8c7a533cdd0a267c"}},
> {"id":"org.couchdb.user:root","key":"org.couchdb.user:root","value":{"rev":"1-f43dadbe5e780f392a6bd283686b3704"}}
> ]}
> {code}
> Same for anonymous user:
> {code}
> curl -v http://localhost:5984/_users/_all_docs
> HTTP/1.1 200 OK
> Transfer-Encoding: chunked
> Server: CouchDB/1.4.0+build.8d7ab8b (Erlang OTP/R16B)
> ETag: "55N0CA8VM2Z0DQO85L1PM20XS"
> Date: Sat, 22 Jun 2013 00:04:17 GMT
> Content-Type: text/plain; charset=utf-8
> Cache-Control: must-revalidate
> {"total_rows":6,"offset":0,"rows":[
> {"id":"_design/_auth","key":"_design/_auth","value":{"rev":"1-619db7ba8551c0de3f3a178775509611"}},
> {"id":"org.couchdb.user:abc","key":"org.couchdb.user:abc","value":{"rev":"1-64d299987b4df59c048171a8ab8ba951"}},
> {"id":"org.couchdb.user:def","key":"org.couchdb.user:def","value":{"rev":"1-479a3e8a66652838706cc49544730a34"}},
> {"id":"org.couchdb.user:foo","key":"org.couchdb.user:foo","value":{"rev":"1-3859ee3742314dcb4b4f1ffaba398c91"}},
> {"id":"org.couchdb.user:mia","key":"org.couchdb.user:mia","value":{"rev":"1-f87f5003323e705d8c7a533cdd0a267c"}},
> {"id":"org.couchdb.user:root","key":"org.couchdb.user:root","value":{"rev":"1-f43dadbe5e780f392a6bd283686b3704"}}
> ]}
> {code}
> The problem is that with specified public_fields it's possible to retrieve
> all user's names no matter has their public field or not. This behaviour a
> bit violates implemented [System Database
> Security|https://git-wip-us.apache.org/repos/asf?p=couchdb.git;a=commit;h=e5503ff]:
> [CouchDB 1.2.0 release
> notes|https://blogs.apache.org/couchdb/entry/apache_couchdb_1_2_0]:
> {quote}
> Documents in the _users database can no longer be read by everyone
> Documents in the _users databases can now only be read by the respective
> authenticated user and administrators. Before, all docs were world-readable
> including their password hashes and salts.
> {quote}
> [Security Features
> Overview|http://wiki.apache.org/couchdb/Security_Features_Overview#Authentication%20database]:
> {quote}
> In addition, the _users database is now treated different from other
> databases:
> An anonymous user can only create a new document.
> An authenticated user can only update their own document.
> A server or database admin can access and update all documents.
> Only server or database admins can create design documents and access
> views and _all_docs and _changes.
> {quote}
> Expected behaviour when `public_fields` specified:
> `_all_docs` should returns only those user docs, that are actually contains
> public fields. Users that has no such fields has nothing to publish. If user
> doc has public fields it shouldn't be mentioned in `_all_docs` response.
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