[security-dev] IdentityManager API review
Jason Porter
lightguard.jp at gmail.com
Wed Nov 7 14:37:19 EST 2012
Aren't those implementation details though?
On Wed, Nov 7, 2012 at 12:16 PM, Shane Bryzak <sbryzak at redhat.com> wrote:
> On 11/08/2012 04:08 AM, Jason Porter wrote:
>
> Replies inline
>
> On Wed, Nov 7, 2012 at 3:54 AM, Shane Bryzak <sbryzak at redhat.com> wrote:
>
>> Hey guys,
>>
>> I spent some time reviewing the IdentityManager API today to identify
>> any redundancies and also locate any holes where we might not properly
>> support required features, as well as a general "sanity" check to ensure
>> that what we're exposing via this API makes sense and is intuitive for
>> consumers. As Anil has pointed out already, our short term priority for
>> the project is to stabilize the API - this is extremely important as
>> PicketLink will provide the security foundation for many other
>> projects. With that in mind I'd like to strongly encourage everyone
>> with a stake in this to carefully review the API and provide feedback,
>> as once we release it it will be essentially set in stone.
>>
>> To try and avoid a wall of text (and make this post easier to reply to),
>> I'm going to break this post up into sub-sections, one for each feature
>> group. For each section, I'll include the API as it currently exists,
>> followed by a brief summary of my thoughts and any recommendations I may
>> have - this is especially where I want to hear any feedback indicating
>> whether you agree or disagree with my assessment. Let's start with the
>> user-related methods:
>>
>> User management
>> -------------------------
>>
>> User createUser(String name);
>>
>> void createUser(User user);
>>
>> void removeUser(User user);
>>
>> void removeUser(String name);
>>
>> User getUser(String name);
>>
>> My thoughts:
>>
>> 1. I'm wondering if we should remove the createUser(String) method and
>> just have createUser(User). This would make sense in a way because I
>> can't think of many use cases where you might want to create a User with
>> just a username and not any of the other typical information (such as
>> first name, last name, e-mail address, etc). Creating a User via
>> createUser(String) when you actually want to set the other details after
>> the initial User creation is also horribly inefficient, requiring
>> multiple round trips to the database (or whatever identity store backend
>> you use). To add to that, the actual parameter name is a little
>> unintuitive - "name" could refer to any number of things - is it the
>> username or the user's actual name that you need to provide here? My +1
>> goes to removing createUser(String).
>>
>
> I like removing the strings. For most of the rest of this API we have a
> very type safe idea here. Maybe I'm thinking a little overboard on things,
> but I really like the idea of having wrappers around things (simple
> wrappers for our API so people could implement an interface or use a base
> class or something to be able to interact with our API but still easily get
> to the information they need).
>
>
>> 2. Similar to point 1), having two removeUser() methods seems equally
>> redundant. The User object that needs to be provided to the
>> removeUser(User) method can be easily looked up by calling getUser(), as
>> per this example:
>>
>> identityManager.removeUser(identityManager.getUser("jsmith"));
>>
>
> +1
>
>
>>
>> 3. As I also pointed out in point 1), the "name" parameter is a little
>> unintuitive. In regard to the getUser() method I think we should rename
>> the "name" parameter to "username" just so it's perfectly clear what the
>> method expects.
>>
>
> +1
>
>
>> 4. We don't currently have any way to update User details. I recommend
>> that we add an updateUser() method as follows:
>>
>> void updateUser(User user);
>>
>
> I like this idea. I've seen on a few sites where you start with a basic
> username and password, then your confirmation is to complete their identity
> for yourself, so it's not completely out there that people wouldn't do this.
>
>
>> This will allow User details such as their first and last name, e-mail
>> address etc to be updated without having to delete and re-create the
>> User. Extending on this a little further, I'm wondering if we should
>> think about adding an audit API that logs these changes. Perhaps it's
>> something to think about for a later release.
>>
>> Group management
>> --------------------------
>>
>> Group createGroup(String id);
>>
>> Group createGroup(String id, Group parent);
>>
>> Group createGroup(String id, String parent);
>>
>> void removeGroup(Group group);
>>
>> void removeGroup(String groupId);
>>
>> Group getGroup(String groupId);
>>
>> Group getGroup(String groupId, Group parent);
>>
>> void addToGroup(IdentityType identityType, Group group);
>>
>> void removeFromGroup(IdentityType identityType, Group group);
>>
>> My thoughts:
>>
>> 1. I think there is a little bit of ambiguity here in regard to the
>> differences between a Group's ID and name. To assist in understanding
>> the differences, here's the JavaDoc pasted from the Group interface:
>>
>> /**
>> * Groups are stored in tree hierarchy and therefore ID represents
>> a path. ID string always begins with "/" element that
>> * represents root of the tree
>> * <p/>
>> * Example: Valid IDs are "/acme/departments/marketing",
>> "/security/administrator" or "/administrator". Where "acme",
>> * "departments", "marketing", "security" and "administrator" are
>> group names.
>> *
>> * @return Group Id in String representation.
>> */
>> String getId();
>>
>> /**
>> * Group name is unique identifier in specific group tree branch.
>> For example group with id "/acme/departments/marketing"
>> * will have name "marketing" and parent group of id
>> "/acme/departments"
>> *
>> * @return name
>> */
>> String getName();
>>
>> Taking the above JavaDoc into account, it seems that where we are
>> specifying "id" as a method parameter we should be specifying "name"
>> instead. If we are indeed providing a "fully qualified" path to the
>> createGroup() method, then there is no need to also specify the parent
>> as it can be easily derived from the path. More on this in the
>> following points.
>>
>> 2. We currently have three createGroup() methods for creating a new
>> Group. I think we should remove the (String, String) variant, as the
>> parent parameter is ambiguous (is it the parent's ID or name we need to
>> specify here?), and rename the "id" parameter of the (String, Group)
>> variant to "name", leaving us with the following:
>>
>> Group createGroup(String id);
>>
>> Group createGroup(String name, Group parent);
>>
>> This then gives us two ways of creating a group. We can either specify
>> the fully qualified group ID:
>>
>> Group employees = identityManager.createGroup("/employees");
>>
>> Or we can specify a subgroup name and parent Group:
>>
>> Group managers = identityManager.createGroup("managers", employees);
>>
>> We can also use this second form to create a "root" group by just
>> specifying null for the parent:
>>
>> Group admins = identityManager.createGroup("admins", null);
>>
>
> I mentioned this earlier, but I don't see why we need the Strings. We
> could simply use Group and have a basic constructor that would take a
> String for the name and possibly another one with a String and a parent
> group.
>
>
> My only reservation here is that the createGroup() method (this is true of
> createRole() also) sets some additional state during Group (or Role)
> creation, such as the created date and enabled status. I'm not a big fan
> of mutating the object that's passed in like this, which is why I kept the
> String variants of these methods, as a Group (and Role also) is little more
> than its name. Of course, User breaks this rule but I see it as being an
> exception as it requires a whole bunch of extended information beyond just
> the username itself. I could make this clearer with an example if it helps.
>
>
>
>
>>
>> 3. For the removeGroup() methods, I think what we have is fine.
>>
>> 4. For the getGroup() methods, I'm happy with the first one (String
>> groupId) but I think the second one (String groupId, Group parent) needs
>> to be (String name, Group parent) instead. The first method would be
>> used when the fully qualified group ID is known, and the second one
>> would be used when you already have the parent Group and know the name
>> of the subgroup.
>>
>> 5. The addToGroup() and removeFromGroup() methods seem fine to me.
>>
>> 6. One thing we don't have is a method to test whether an IdentityType
>> is a member of a Group. I suggest we add another method to support this:
>>
>> boolean inGroup(IdentityType identityType, Group group);
>>
>>
> +1 for the above (with the type idea for #4).
>
>
>> Roles
>> ----------
>>
>> Role createRole(String name);
>>
>> void removeRole(Role role);
>>
>> void removeRole(String name);
>>
>> Role getRole(String name);
>>
>> boolean hasRole(Role role, IdentityType identityType, Group group);
>>
>> void grantRole(Role role, IdentityType identityType, Group group);
>>
>> void revokeRole(Role role, IdentityType identityType, Group group);
>>
>> My thoughts:
>>
>> 1. I would remove the removeRole(String) method as the same thing can be
>> achieved with removeRole(getRole(String)).
>>
>
> +1
>
>
>> 2. I would swap the order of the Role and IdentityType parameters within
>> the hasRole(), grantRole() and revokeRole() methods. As the
>> IdentityType is the primary artifact in these operations it makes sense
>> to have it listed first.
>>
>
> +1
>
>
>> 3. We don't have any explicit support for application roles, which are
>> roles where there is no Group component (for example, an
>> application-wide "admin" role). We could support this by just allowing
>> hasRole(), grantRole() etc to accept null values for the Group
>> parameter, however I feel it would be more semantically correct to
>> provide a distinct set of methods for the purpose of supporting
>> application roles, as follows:
>>
>> boolean hasApplicationRole(IdentityType identityType, Role role);
>>
>> void grantApplicationRole(IdentityType identityType, Role role);
>>
>> void revokeApplicationRole(IdentityType identityType, Role role);
>>
>
> +1
>
>
>> Query API
>> --------------
>>
>> <T extends IdentityType> IdentityQuery<T> createQuery();
>>
>> My thoughts:
>>
>> 1. After our recent rewrite of the Query API I'm satisfied with what we
>> have now.
>>
>> Credential management
>> -------------------------------
>>
>> boolean validateCredential(User user, Credential credential);
>>
>> void updateCredential(User user, Credential credential);
>>
>> My thoughts:
>>
>> 1. I'm satisfied with what we currently have, however we still need to
>> review the mechanism that we provide for encoding passwords. I'm not
>> sure that it will have any effect on these methods though (I'm toying
>> with the idea of integrating the password encoding functionality via the
>> IdentityStoreInvocationContext).
>>
>> Identity expiry
>> ------------------
>>
>> void setEnabled(IdentityType identityType, boolean enabled);
>>
>> void setExpirationDate(IdentityType identityType, Date
>> expirationDate);
>>
>> My thoughts:
>>
>> 1. I think these methods are fine the way they are. One discrepancy
>> that I've identified is that a User can be created already being
>> disabled or having an expiry date, while for a Role or Group the
>> equivalent status must be set via these methods after creation. I'm not
>> sure this is a big deal though.
>>
>
> All good.
>
>
>> Attributes
>> -------------
>>
>> void setAttribute(IdentityType identityType, String attributeName,
>> String attributeValue);
>>
>> String getAttribute(IdentityType identityType, String attributeName);
>>
>> My thoughts:
>>
>> 1. This area poses a slight dilemma. Currently the API only supports
>> simple String-based attribute values, however I'm pretty sure that
>> people are going to want to store all sorts of things, ranging from
>> boolean and Date values through to large byte arrays that store a User's
>> photograph or other data. If everyone is in agreement that we need to
>> support more than just String values, then the first thing we probably
>> need to do is modify these methods to work with a Serializable instead.
>>
>> 2. If we all agree on point 1), the next thing we need to decide is
>> whether we want the capability to make some attribute values "lazy
>> loaded". If we want to do a quick lookup of a User object for the
>> express purpose of assigning a Role or Group membership (or any other
>> type of simple operation) then we probably don't want the performance
>> hit of having to load bulky attribute data.
>>
>> 3. With the above two points in mind, I'm going to hold off on surmising
>> any further on attributes until some of you guys weigh in with your
>> opinions. I do have some rough ideas, however I'll wait until we have a
>> consensus of exactly what we want to achieve here before we proceed
>> further.
>>
>
> Serializable works for me. Do we do have a generic Attribute<? extends
> Serializable> or just forgo the generics?
>
>
>> Utility methods
>> --------------------
>>
>> IdentityType lookupIdentityByKey(String key);
>>
>> My thoughts:
>>
>> 1. This method is required by other features, such as the Permissions
>> API. I'm fine with what we have here.
>>
>> In summary
>> ----------------
>>
>> I apologise for yet another epic e-mail to the list, however this is
>> everyone's chance to review the API for themselves and decide whether or
>> not it will be suitable for addressing all of your requirements. I'd
>> like to get this API stable by next week so please don't be shy about
>> speaking up. I'm especially looking forward to hearing your opinions
>> about how we handle attributes (there may even be some relevant JSR-351
>> stuff that we should be looking at here).
>>
>> Thanks,
>> Shane
>> _______________________________________________
>> security-dev mailing list
>> security-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/security-dev
>>
>
>
>
> --
> Jason Porter
> http://lightguard-jp.blogspot.com
> http://twitter.com/lightguardjp
>
> Software Engineer
> Open Source Advocate
>
> PGP key id: 926CCFF5
> PGP key available at: keyserver.net, pgp.mit.edu
>
>
>
--
Jason Porter
http://lightguard-jp.blogspot.com
http://twitter.com/lightguardjp
Software Engineer
Open Source Advocate
PGP key id: 926CCFF5
PGP key available at: keyserver.net, pgp.mit.edu
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