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From "Martin Zaun (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-2109) System privileges
Date Wed, 27 Feb 2008 20:41:56 GMT

    [ https://issues.apache.org/jira/browse/DERBY-2109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12573059#action_12573059
] 

Martin Zaun commented on DERBY-2109:
------------------------------------


I'm sorry to say that I overlooked one line of debug code in SecurityUtil that made it into
DERBY-2109-10. (I'd forgotten tagged that line as usual.)  Unfortunately, the line is significant
since the published code checks for a "dummy" permission I'd put in there for doAs() v. doAsPrivileged()
debugging purposes:
+                        //AccessController.checkPermission(perm);
+                        AccessController.checkPermission(new java.util.PropertyPermission("user.dir",
"read"));

I'm right now running junit-all (1 error) and will publish another patch update right after.

> Daniel John Debrunner wrote:
> > Bottomline: When evaluating permissions, the (Sun) Java Security Runtime uses the
principal names as found literally in the policy file and not as returned by SystemPrincipal.getName()
(where we could return normalized names).
> It's hard to see how that is the case, since the policy file is read in and converted
to a Policy object containing permissions and for Derby's SystemPermission the class must
be o.a.d.security.SystemPermission.

It's correct that we're using our SystemPermission classes only -- but the issue is in the
realm of Subject/Principal checking by the Java Security Runtime when matching the Subject
instantiated by our code against the Principal declaration in the policy file. This check
is not entirely carried out by means of getName()/equals()/hashCode()  on our SystemPrincipal
class, in which case we could have had the name comparisons always done on the normalized
names.  Instead, the Java Security Runtime uses the literal Principal name as declared in
the policy file and denies permission when it can't find an exact match in our Subject's SystemPrincipal
list.

> - figuring out the principal names in the policy files - I'd be interested to see the
implementation of SystemPrincipal you used to try and implement the required functionality


The SystemPrincipal class in DERBY-2109-09 attempted to encapsulate Authorization Identifiers
and "normalized" the principal name right within the constructor, so that getName()/equals()/hashCode()
 would operate on (normalized) auth ids. 

As commented I also looked into SystemPrincipal implementing com.sun.security.auth.PrincipalComparator
by adding an implies(Subject) method returning true when a the Subject's principal list contains
a normalized name matching this principal's normalized name.  With a few more tricks I got
it working -- but that was just for insight, since PrincipalComparator is a non-standard interface.

>  - related to the previous one is having more time to understand this:
> + // An alternative approach of normalizing all names within
> + // SystemPrincipal has issues; see comments there.
> + principals.add(new SystemPrincipal(user));
> + principals.add(new SystemPrincipal(getAuthorizationId(user))); 

Adding the normalized identifier ensures that a non-delimited principal "FRED" matches users
"fred", "Fred", "FRED" ...

Let me know if you think the code needs more comments.

> Could you confirm the format for names in the policy file in the patch? Does it match
the description here:
https://issues.apache.org/jira/browse/DERBY-2109?focusedCommentId=12561537#action_12561537
> - does it support delimited identifiers of the form "\"fred@acme.com\""?

yes

> - is the only issue that non-delimited identifiers "fred" do not resolve correctly?

They resolve incompletely: non-delimited identifies "fred" only matches "fred", while "FRED"
matches "fred", "Fred", "FRED" ...

Here's what I've verified.  A policy file with belows grants results in the following System
Privileges behaviour for users:

  grant principal org.apache.derby.authentication.SystemPrincipal "MARTIN" { ... }
  checks for users:
     martin -- granted
     marTin -- granted
     MARTIN -- granted
     "marTin" -- denied, missing permission  (delimited identifier, different from marTin)

  grant principal org.apache.derby.authentication.SystemPrincipal "edWard" { ... }
  checks for users:
    edWard -- granted
    edward -- denied, missing permission

  grant principal org.apache.derby.authentication.SystemPrincipal "\"fred@acme.com\"" { ...
}
  checks for users:
    "fred@acme.com" -- granted
    "Fred@ACME.COM" -- denied, missing permission
    fred@acme.com -- denied, illegally formed name as complained by IdUtil.getUserAuthorizationId()
because it's a non-delimited identifier having special characters

However, in the last case the exception is not nicely presented to the client and needs improvement
(I'd expected this case not to pass authentication, but we have to cover for it, especially
since we now can have authorization checks without prior authentication).

> From a security point of view does this have the potential to allow one user to piggy
back on the permissions of another user?

Not really.  Under the rules for Identifiers for authentication and authorization, the non-delimited
identifiers "fred", "Fred", "FRED" all represent the same person.  So, if user "fred" can
piggy-back on a principal grant to "FRED" -- that's the requested feature that took some effort
to implement :)

In contrast, user "marTin" cannot piggy-back on a principal grant for "\"martin\"".

>  - ensuring the new security objects that are serializable have serialization ids to
ensure compatibility across releases

I'm not aware anymore why SystemPrincipal implements Serializable, so, perhaps, I should research
and add a comment.  I'm not sure there's a good reason for this class to be serializable (to
the contrary, often information about user names etc should not be serialized), but if there
is, I agree, a serialization id should be there (with the class being so simple, we probably
won't need readObject() and writeObject()).

Our Permission classes are not serializable, so, I don't think we have other security objects
to think about.

While NetworkServerControlImpl also does not implement Serializable, I wonder if the userArg,
passewordArg, and bootpasswordArg fields should be declared transient as good pactice/precaution.

> - making the new security objects final

Yes, will do for SystemPrincipal, DatabasePermission and SystemPermission.

Martin

> System privileges
> -----------------
>
>                 Key: DERBY-2109
>                 URL: https://issues.apache.org/jira/browse/DERBY-2109
>             Project: Derby
>          Issue Type: New Feature
>          Components: Security
>    Affects Versions: 10.3.1.4
>            Reporter: Rick Hillegas
>            Assignee: Martin Zaun
>         Attachments: DERBY-2109-02.diff, DERBY-2109-02.stat, derby-2109-03-javadoc-see-tags.diff,
DERBY-2109-04.diff, DERBY-2109-04.stat, DERBY-2109-05and06.diff, DERBY-2109-05and06.stat,
DERBY-2109-07.diff, DERBY-2109-07.stat, DERBY-2109-08.diff, DERBY-2109-08.stat, DERBY-2109-08_addendum.diff,
DERBY-2109-08_addendum.stat, DERBY-2109-09.diff, DERBY-2109-09.stat, DERBY-2109-10.diff, DERBY-2109-10.stat,
SystemPrivilegesBehaviour.html, systemPrivs.html, systemPrivs.html, systemPrivs.html, systemPrivs.html
>
>
> Add mechanisms for controlling system-level privileges in Derby. See the related email
discussion at http://article.gmane.org/gmane.comp.apache.db.derby.devel/33151.
> The 10.2 GRANT/REVOKE work was a big step forward in making Derby more  secure in a client/server
configuration. I'd like to plug more client/server security holes in 10.3. In particular,
I'd like to focus on  authorization issues which the ANSI spec doesn't address.
> Here are the important issues which came out of the email discussion.
> Missing privileges that are above the level of a single database:
> - Create Database
> - Shutdown all databases
> - Shutdown System
> Missing privileges specific to a particular database:
> - Shutdown that Database
> - Encrypt that database
> - Upgrade database
> - Create (in that Database) Java Plugins (currently  Functions/Procedures, but someday
Aggregates and VTIs)
> Note that 10.2 gave us GRANT/REVOKE control over the following  database-specific issues,
via granting execute privilege to system  procedures:
> Jar Handling
> Backup Routines
> Admin Routines
> Import/Export
> Property Handling
> Check Table
> In addition, since 10.0, the privilege of connecting to a database has been controlled
by two properties (derby.database.fullAccessUsers and derby.database.defaultConnectionMode)
as described in the security section of the Developer's Guide (see http://db.apache.org/derby/docs/10.2/devguide/cdevcsecure865818.html).

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