On Wed, Mar 17, 2010 at 11:37, Caleb James DeLisle <[email protected]
wrote:
Denis Gervalle wrote:
On Tue, Mar 16, 2010 at 11:08, Caleb James DeLisle < [email protected]
wrote:
Denis Gervalle wrote:
On Tue, Mar 16, 2010 at 03:46, Caleb James DeLisle < [email protected]
wrote: Right now a script which is saved with programming access is allowed
to
do
things which the viewer (who executes it) is not allowed to do. I would like to extend this to scripts which do not have programming access.
Use case example: A page where the viewer can submit an email address to be put on a mailing list. The page needs to be able to save the email address to a list but the viewer should not be able to directly edit (or view) the list.
I would like to add to xwiki.api.Context: void setScriptUser(String) String getScriptUser() (These names are the best I could think of, suggestions would be great)
the input can be either "viewer", "author" or "default" and it stores this in the XWikiContext If the value is set to author, hasAccessLevel will return an access check on the author, not the viewer.
When includeForm is called, or the include macro is invoked, the only explicit change is that changes made by the called document will be reset when the include ends. If scrips are set to run with author's permissions: If DocumentA includes documentB, documentB executes with documentB's author's permissions. If DocumentA includes _in context_ documentB, documentB executes with documentA's author's permissions. When include of documentB ends, scriptUser is set back to the value which documentA left it at.
I think this will help us achieve the goal of no documents with programming rights in the XE xar file.
WDYT?
Caleb
_______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
First of all, I am personally against adding anything to the RightService in its current state. This is already spaghetti code which already lead to some security risks, and trying to improve that partly could be an impossible challenge. Moreover, this code is absolutely not optimized, you just have to put it under debug logging to understand what I mean. +1 I read it and I know exactly what you mean, I *think* a rights check could be done in one query.
I have read it as well, and you may find a document I have written in the drafts of XWiki.org about how it is currently working. But anyway, look at the debug logs even after looking the code, you understand that it even worse than you think.
I was only talking about modifying api.Context and api.Api I have no desire to touch user.impl.xwiki.ANYTHING!
Isn't this moving some of the RightService responsibility out of it ? I am already unhappy with how access are checked, since, these check are not only in the right service, but also in many other part of the core, checking special cases, like skin access, inactive user check, etc....
Regarding the way you expect the inclusion of documents to function, I am not convince that this is the right choice. The behavior of inclusion has been broken since Syntax 2.0 has been introduced, and I have always feel this to be a serious regression. My principal use case is a document (that could have been created by a user) editable by a user, and that store objects in itself, and use an inclusion in context for its content. In this case, the user may save the document, which should therefore be without any special rights, but the code may need to have higher privileges, and still require to be included in context for access to the including documents. This is the typical Sheet case shown in many sample of XWiki Programming, but with programming right requirement. I have used that many times before it became broken, and this design is still missing to me. You bring up an important point which I think is worthy of it's own email. I have thought it would be nice to allow PR code to extend the api or to add velocity macros which will run with programming right.
This is not exactly what I am saying, I hate the idea that code became broken when an unpriviledged user have just save its container without being able to change the code itself. This is currently what happen with inclusion, the user may have no right to change the included document, but it break the code by just saving the document that make the inclusion. This is what I means when I say that the privilege of a script should be tightly linked to who has been able to write it. As a helper mechanism, a script may offered the possibility to release its privilege based on the user using it, but it could not raise it, since this could lead to major security issues, and this release should be the choice of the script author.
I am convince that the rights given to a block of code should be tightly linked to the content author I hereby ammend my proposal to include contentAuthor as a possibility for the set method, I had forgotten about it.
of its containing document, and absolutely not based on any author in the context in which it is executed. Do you mean the viewer? I believe code should never be executed in context of it's viewer because code may set a trap which saves itself when the viewer has greater privileges than the code. I propose the set method because I am -1 to changing default behavior.
This has been broken in Syntax 2.0, and this currently leads to elevation of privilege through inclusions. For the same reason, I do not follow Alex on the idea that the right should be set in place of a user. This would lead to many problem in regards of who and how this could be set, stored and inherited. I completely agree that the programming right is currently not perfect, but in the same time, I do not see the real value you expect to provide. There is already a similar mechanism in place, using the content author, opposed to the last author of a page. I want to extend that same mechanism to authors who do not have programming rights, PR is dangerous and should be used as little as possible and if we need it in the default xar that is an API flaw IMO.
Making PR more fine grained is for me a task for the RightService not the API. Moreover, extending that without thinking about the whole access policy is risky and will create problem for future compatibility.
This is what make commenting page possible without breaking its programming behavior. Extending this to manage other objects in my use case above, is probably a good track to follow. But again, this should be part of a global reengineering of the RightService.
If you want to rethink the RightService starting from scratch, I will surely participate ! I have already some ideas, but not been able to put them properly in a document. Time is always missing, but I hope this to change... I absolutely do want to rethink the RightService, however I think it is held up by the fact that components have no access to the HttpServletRequest.
I do not agree. Are you sure that you do not confuse authentication and authorization ? Yes I suppose I did, so much talk about foaf+ssl and openId, I have been thinking too much about authentication. Still I think they should both be rewritten at once.
It is still hard to review the authentication part, and this one needs to be extensible and partly depends on the container. For authentication, I really like the modularity of Acegi Security (aka Spring Security) model (the model, not the implementation as is), which provide a good separation of each roles, allowing easy integration of many way to provide authentications. Authentication should provide a token identifying a user and what are the "global" privileges allowed to this token (group ownership, admin privileges, ???). It should be able to do so for the connected user, and also for a stored token saved with a document (ie the author of a document). It could base its information from many different sources, coming either from the wiki or external to it. It may also provide directory services to the wiki.
The authorization part is on the other side and should be independent of the container or any other external stuffs, Here we have the trouble of dependence on the user class, rights class, and objects. I see this in core java code: private static final String USER_CLASS = "XWiki.XWikiUsers"; as an eye sore and would like to remove it if possible. Another alternative is to move that kind of ugliness it out to a configuration file.
This should not happen anymore, since for me, users and their privilege and groups, should be provided by the authentication part. Synchronizing 2 directory is always a pain, so this should be avoided. So I would expect that a proper authentication module will provide all the answer for the authorization module, regarding the authenticated user, which means that an LDAP user will not need to be stored in the XWikiUsers anymore.
and, of course, the way we authenticate users. The communication between the two module should be through some sort of token, that the authentication module ask to the authorization module when needed. Asking could be for the current authenticated user, using an existing persisted token or be built temporarily as a mixed of other tokens for controlling a given script execution. This second part has to be called anytime a privileged operation has to be done on a given object. The caller should normally not tell what he really want to check, but just what operation he want to do on which "object". This is the task of the authorization module to know what to check and this is precisely why I dislike continuing to add some sort of "check this right on this user" anymore. I guess I don't understand, the way I see it an authorization check must check the permission for entity (user) x to do action y to object z.
I do not fully agree. An authorization check should check that a certain operation could be executed in the current context on a given entity. Let say that you want to delete a given document, you need to check that you can do so now in your execution context, but I really feel that the conditions to answer your right request should be only the responsibility of the authorization module. In the non-security code, you should only request privilege for an operation, and not thinking carefully about what are the proper conditions for it. Not that I voluntarily do not talk about users, since I would like to be able to execute a script in the context of an authentication token having less privilege than it has at the startup of the script. Tokens are like keychains for your house. You may have the key, or you may have drop it, it depends. You may also gain it in some special situation.
Well, this is quick and dirty description of what I feel is needed for proper and secure right checking, obviously easier to say than to do. But
I
feel the work could be started, especially on the authorization part, using some bridging when require. It will be long, but I really think that it is the price to pay for getting something really secure. Long as in a lot of code? I feel that security (and dependability) require the code to be short and if it can't be short, isolate the code which runs 90% of the time and try to make that short.
Not long code, but short and well formed one should be required. Nice interface and component will lead to a really better implementation anyhow. What could be long is the process to agree on the principle and to also agree on the implementation. This is just ambitious. Denis
Caleb
Denis
_______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
-- Denis Gervalle SOFTEC sa - CEO eGuilde sarl - CTO