Grouper Developers Forum

[Chris Hyzer <>]

This is done in v2.1 (trunk) SVN (including 3 examples which are used as the unit tests):

 

https://spaces.internet2.edu/display/Grouper/Grouper+subject+filter+and+attribute+decorator

 

This Grouper enhancement facilitates secure subject attribute release.  This could be used to protect FERPA information, create private subdomains of Grouper where users from one might not be able to see subjects in another, or attributes which can only be seen by certain subjects.

In Grouper 2.0 and previous there is no subject attribute security (unless it is baked into the custom subject source).   This is only available in v2.1 and more recent.

This is an interface point that can be implemented in Java to retrieve more attributes about a subject (i.e. attributes that may require another query, or security, or attributes not always needed when subjects are resolved).  When you implement this interface you should try to only use one (or few) queries, since this will be called a lot (for filters at least).

Implement the interface SubjectCustomizer by extending the class: edu.internet2.middleware.grouper.subj.SubjectCustomizerBase

/**

 * add the ability to decorate a list of subjects with more attributes.

 * note, while you are decorating, you can check security to see if the

 * groupersession is allowed to see those attributes

 * @author mchyzer

 *

 */

public interface SubjectCustomizer {

 

  /**

   * decorate subjects based on attributes requested

   * @param grouperSession

   * @param subjects

   * @param attributeNamesRequested

   * @return the subjects if same set, or make a new set

   */

  public Set<Subject> decorateSubjects(GrouperSession grouperSession, Set<Subject> subjects, Collection<String> attributeNamesRequested);

  

  /**

   * you can edit the subjects (or replace), but you shouldnt remove them

   * @param grouperSession

   * @param subjects

   * @param findSubjectsInStemName if this is a findSubjectsInStem call, this is the stem name.  This is useful

   * to filter when searching for subjects to add to a certain group

   * @return the subjects if same set, or make a new set

   */

  public Set<Subject> filterSubjects(GrouperSession grouperSession, Set<Subject> subjects, String findSubjectsInStemName);

 

  

}

 

 

 

Configure this in the grouper.properties:

# customize subjects by implementing this interface: edu.internet2.middleware.grouper.subj.SubjectCustomizer

# or extending this class: edu.internet2.middleware.grouper.subj.SubjectCustomizerBase (recommended)

# note the instance will be reused to make sure it is threadsafe

subjects.customizer.className = 

Note that the filter and decorator are batched for performance reasons, which is also why this is not configured in the subject source

The filterSubjects() method is called on each SubjectFinder call.  The decorateSubjects() is called when web services resolve subjects

There are two ways to protect data.  

1. You can change the data to protect it, the user will see the subject, but might only see the netId instead of the name.  Or it could just say (protected-data)

2. You could remove the subject from the results and the user will not know the subject exists

Here is an example of hiding names of students to users who aren't allowed to see them (note, you can still search by private information potentially, though you will not see the result.  If you want something more complex you might need a custom source, or only have public information in the search field)

/**

 * filter students private information out from people who cant see them

 * @author mchyzer

 *

 */

public class SubjectCustomizerForDecoratorTestingHideStudentData extends SubjectCustomizerBase {

 

  /** student (protected data) group name */

  public static final String STUDENT_GROUP_NAME = "apps:subjectSecurity:groups:student";

  /** privileged employee group name */

  public static final String PRIVILEGED_EMPLOYEE_GROUP_NAME = "apps:subjectSecurity:groups:privilegedEmployee";

 

  /** source id we care about */

  private static final String SOURCE_ID = "jdbc";

  

  /**

   * @see SubjectCustomizer#filterSubjects(GrouperSession, Set, String)

   */

  @Override

  public Set<Subject> filterSubjects(GrouperSession grouperSession, Set<Subject> subjects, String findSubjectsInStemName) {

    

    //nothing to do if no results

    if (GrouperUtil.length(subjects) == 0) {

      return subjects;

    }

    

    //get results in one query

    MembershipResult groupMembershipResult = new MembershipFinder().assignCheckSecurity(false).addGroup(STUDENT_GROUP_NAME)

        .addGroup(PRIVILEGED_EMPLOYEE_GROUP_NAME).addSubjects(subjects).addSubject(grouperSession.getSubject())

        .findMembershipResult();

      

    //see if the user is privileged

    boolean grouperSessionIsPrivileged = groupMembershipResult.hasGroupMembership(PRIVILEGED_EMPLOYEE_GROUP_NAME, grouperSession.getSubject());

    

    //if so, we are done, they can see stuff

    if (grouperSessionIsPrivileged) {

      return subjects;

    }

    

    //loop through the subjects and see which are students, change their name and description to be their netId, with no other attributes

    Set<Subject> results = new LinkedHashSet<Subject>();

    for (Subject subject : subjects) {

      if (StringUtils.equals(SOURCE_ID, subject.getSourceId()) && groupMembershipResult.hasGroupMembership(STUDENT_GROUP_NAME, subject)) {

        String loginid = subject.getAttributeValue("loginid");

        Subject replacementSubject = new SubjectImpl(subject.getId(), loginid, loginid, subject.getTypeName(), subject.getSourceId());

        results.add(replacementSubject);

      } else {

        results.add(subject);

      }

    }

    return results;

  }

}

 

 

 

API access

In order to use the decorator part, you need to make an extra call to the SubjectFinder for your subjects

SubjectFinder.decorateSubjects(GrouperSession.staticGrouperSession(), subjects, subjectAttributesForDecoratorSet);

WS access

You can use this via WS by configuring which subject attributes will trigger a call to the SubjectFinder.decorateSubjects() method in the grouper-ws.properties:

# customize subjects by implementing this interface: edu.internet2.middleware.grouper.subj.SubjectCustomizer

# or extending this class: edu.internet2.middleware.grouper.subj.SubjectCustomizerBase (recommended)

# note the instance will be reused to make sure it is threadsafe

subjects.customizer.className = edu.internet2.middleware.grouper.subj.decoratorExamples.SubjectCustomizerForDecoratorExtraAttributes

Then when the user requests certain attributes for subjects, if they are allowed to go to the customizer via the config above, it will trigger a call to it.  Here is an example client call:

C:\mchyzer\grouper\trunk\grouperClient\dist>java \-jar grouperClient.jar \--operation=getSubjectsWs \--subjectIds=test.subject.1 \--subjectAttributeNames=title \--outputTemplate="Index: ${index}: success: ${success}, code: ${wsSubject.resultCode}, subject:"${wsSubject.id}, title: ${wsSubject.attributeValues\[0\]}$newline$"

Index: 0: success: T, code: SUCCESS, subject: test.subject.1, title: title1

Here is the XML (POX) request:

<WsRestGetSubjectsRequest>

    <subjectAttributeNames>

        <string>title</string>

    </subjectAttributeNames>

    <wsSubjectLookups>

        <WsSubjectLookup>

            <subjectId>test.subject.1</subjectId>

        </WsSubjectLookup>

    </wsSubjectLookups>

</WsRestGetSubjectsRequest>

And here is the response (the title for this subject is "title1"

<WsGetSubjectsResults>

    <subjectAttributeNames>

        <string>title</string>

    </subjectAttributeNames>

    <wsSubjects>

        <WsSubject>

            <resultCode>SUCCESS</resultCode>

            <success>T</success>

            <id>test.subject.1</id>

            <name>my name is test.subject.1</name>

            <sourceId>jdbc</sourceId>

            <attributeValues>

                <string>title1</string>

            </attributeValues>

        </WsSubject>

    </wsSubjects>

    <resultMetadata>

        <resultCode>SUCCESS</resultCode>

        <resultMessage>Queried 1 subjects</resultMessage>

        <success>T</success>

    </resultMetadata>

    <responseMetadata>

        <resultWarnings></resultWarnings>

        <millis>983</millis>

        <serverVersion>2.1.0</serverVersion>

    </responseMetadata>

</WsGetSubjectsResults>

Example: collaboration groups

Here is an example where subjects not in collab groups are filtered from users not in that group

package edu.internet2.middleware.grouper.subj;

 

import java.util.LinkedHashSet;

import java.util.Set;

 

import org.apache.commons.collections.CollectionUtils;

import org.apache.commons.lang.StringUtils;

 

import edu.internet2.middleware.grouper.GrouperSession;

import edu.internet2.middleware.grouper.membership.GroupMembershipResult;

import edu.internet2.middleware.grouper.util.GrouperUtil;

import edu.internet2.middleware.subject.Subject;

 

/**

 * filter out subjects not in the collaboration group

 * @author mchyzer

 *

 */

public class SubjectCustomizerForDecoratorTesting2 extends SubjectCustomizerBase {

 

  /** student (protected data) group name */

  private static final String COLLAB_STEM_NAME = "collaboration:collabGroups";

 

  /** privileged employee group name */

  private static final String PRIVILEGED_ADMIN_GROUP_NAME = "collaboration:etc:privilegedAdmin";

 

  /** source id we care about */

  private static final String SOURCE_ID = "jdbc";

 

  /**

   * @see SubjectCustomizer#filterSubjects(GrouperSession, Set)

   */

  @Override

  public Set<Subject> filterSubjects(GrouperSession grouperSession, Set<Subject> subjects) {

    

    //nothing to do if no results

    if (GrouperUtil.length(subjects) == 0) {

      return subjects;

    }

    

    //get results in one query

    GroupMembershipResult groupMembershipResult = calculateMembershipsInStems(subjects, IncludeGrouperSessionSubject.TRUE, 

        GrouperUtil.toSet(PRIVILEGED_ADMIN_GROUP_NAME), GrouperUtil.toSet(COLLAB_STEM_NAME));

    

    //see if the user is privileged

    boolean grouperSessionIsPrivileged = groupMembershipResult.hasMembership(PRIVILEGED_ADMIN_GROUP_NAME, grouperSession.getSubject());

    

    //if so, we are done, they can see stuff

    if (grouperSessionIsPrivileged) {

      return subjects;

    }

    

    //get the group names that the grouper session subject is in

    Set<String> grouperSessionGroupNames = groupMembershipResult.groupNamesInStem(grouperSession.getSubject(), COLLAB_STEM_NAME);

    

    //loop through the subjects and see which collab groups the users are in

    Set<Subject> results = new LinkedHashSet<Subject>();

    for (Subject subject : subjects) {

      //only protect one source

      if (!StringUtils.equals(SOURCE_ID, subject.getSourceId())) {

        results.add(subject);

      } else {

        Set<String> subjectGroupNames = groupMembershipResult.groupNamesInStem(subject, COLLAB_STEM_NAME);

        if (CollectionUtils.containsAny(grouperSessionGroupNames, subjectGroupNames)) {

          results.add(subject);

        }

      }

    }

    return results;

  }

 

  

  

}

 

Example: hide student data to most users

Here is an example where student data is hidden to most users

package edu.internet2.middleware.grouper.subj.decoratorExamples;

 

import java.util.LinkedHashSet;

import java.util.Set;

 

import org.apache.commons.lang.StringUtils;

 

import edu.internet2.middleware.grouper.GrouperSession;

import edu.internet2.middleware.grouper.MembershipFinder;

import edu.internet2.middleware.grouper.membership.MembershipResult;

import edu.internet2.middleware.grouper.subj.SubjectCustomizer;

import edu.internet2.middleware.grouper.subj.SubjectCustomizerBase;

import edu.internet2.middleware.grouper.util.GrouperUtil;

import edu.internet2.middleware.subject.Subject;

import edu.internet2.middleware.subject.provider.SubjectImpl;

 

/**

 * filter students private information out from people who cant see them

 * @author mchyzer

 *

 */

public class SubjectCustomizerForDecoratorTestingHideStudentData extends SubjectCustomizerBase {

 

  /** student (protected data) group name */

  public static final String STUDENT_GROUP_NAME = "apps:subjectSecurity:groups:student";

  /** privileged employee group name */

  public static final String PRIVILEGED_EMPLOYEE_GROUP_NAME = "apps:subjectSecurity:groups:privilegedEmployee";

 

  /** source id we care about */

  private static final String SOURCE_ID = "jdbc";

 

  /**

   * @see SubjectCustomizer#filterSubjects(GrouperSession, Set, String)

   */

  @Override

  public Set<Subject> filterSubjects(GrouperSession grouperSession, Set<Subject> subjects, String findSubjectsInStemName) {

    

    //nothing to do if no results

    if (GrouperUtil.length(subjects) == 0) {

      return subjects;

    }

    

    //get results in one query

    MembershipResult groupMembershipResult = new MembershipFinder().assignCheckSecurity(false).addGroup(STUDENT_GROUP_NAME)

        .addGroup(PRIVILEGED_EMPLOYEE_GROUP_NAME).addSubjects(subjects).addSubject(grouperSession.getSubject())

        .findMembershipResult();

      

    //see if the user is privileged

    boolean grouperSessionIsPrivileged = groupMembershipResult.hasGroupMembership(PRIVILEGED_EMPLOYEE_GROUP_NAME, grouperSession.getSubject());

    

    //if so, we are done, they can see stuff

    if (grouperSessionIsPrivileged) {

      return subjects;

    }

    

    //loop through the subjects and see which are students, change their name and description to be their netId, with no other attributes

    Set<Subject> results = new LinkedHashSet<Subject>();

    for (Subject subject : subjects) {

      if (StringUtils.equals(SOURCE_ID, subject.getSourceId()) && groupMembershipResult.hasGroupMembership(STUDENT_GROUP_NAME, subject)) {

        String loginid = subject.getAttributeValue("loginid");

        Subject replacementSubject = new SubjectImpl(subject.getId(), loginid, loginid, subject.getTypeName(), subject.getSourceId());

        results.add(replacementSubject);

      } else {

        results.add(subject);

      }

    }

    return results;

  }

}

Example: securely protect extra subject attributes based on Grouper permissions

This example has extra subject attributes (title and major) protected by Grouper permissions.  This is an extra call, not populated by default, for performance reasons (note the WS examples above, they use this implementation)

package edu.internet2.middleware.grouper.subj.decoratorExamples;

 

import java.util.ArrayList;

import java.util.Collection;

import java.util.HashMap;

import java.util.HashSet;

import java.util.LinkedHashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

 

import org.apache.commons.lang.StringUtils;

 

import edu.internet2.middleware.grouper.GrouperSession;

import edu.internet2.middleware.grouper.MembershipFinder;

import edu.internet2.middleware.grouper.Stem;

import edu.internet2.middleware.grouper.StemFinder;

import edu.internet2.middleware.grouper.Stem.Scope;

import edu.internet2.middleware.grouper.exception.GrouperSessionException;

import edu.internet2.middleware.grouper.hibernate.HibUtils;

import edu.internet2.middleware.grouper.hibernate.HibernateSession;

import edu.internet2.middleware.grouper.misc.GrouperSessionHandler;

import edu.internet2.middleware.grouper.permissions.PermissionFinder;

import edu.internet2.middleware.grouper.permissions.PermissionResult;

import edu.internet2.middleware.grouper.subj.SubjectCustomizer;

import edu.internet2.middleware.grouper.subj.SubjectCustomizerBase;

import edu.internet2.middleware.grouper.util.GrouperUtil;

import edu.internet2.middleware.subject.Subject;

import edu.internet2.middleware.subject.provider.SubjectImpl;

 

/**

 * add attributes securely to the subject

 * @author mchyzer

 *

 */

public class SubjectCustomizerForDecoratorExtraAttributes extends SubjectCustomizerBase {

 

  /** stem name of the permission resources which represent columns in the attribute table */

  public static final String PERMISSIONS_STEM_NAME = "subjectAttributes:permissions:columnNames";

 

  /** privileged employee group name */

  public static final String PRIVILEGED_ADMIN_GROUP_NAME = "etc:privilegedAdmin";

 

  /** source id we care about */

  private static final String SOURCE_ID = "jdbc";

 

  /** subjectAttributes:permissions */

  public static final String SUBJECT_ATTRIBUTES_PERMISSIONS_ATTRIBUTE_DEF = "subjectAttributes:permissions";

 

 

  /**

   * @see SubjectCustomizer#decorateSubjects(GrouperSession, Set, Collection)

   */

  @Override

  public Set<Subject> decorateSubjects(GrouperSession grouperSession,

      final Set<Subject> subjects, final Collection<String> attributeNamesRequested) {

 

    //nothing to do if no results or no attributes

    if (GrouperUtil.length(subjects) == 0 || GrouperUtil.length(attributeNamesRequested) == 0) {

      return subjects;

    }

    

    final Subject subjectChecking = grouperSession.getSubject();

    

    //do all this as admin

    GrouperSession.callbackGrouperSession(grouperSession.internal_getRootSession(), new GrouperSessionHandler() {

      

      public Object callback(GrouperSession theGrouperSession) throws GrouperSessionException {

 

        //see if admin

        boolean isAdmin = new MembershipFinder().assignCheckSecurity(false).addGroup(PRIVILEGED_ADMIN_GROUP_NAME)

          .addSubject(subjectChecking).hasMembership();

        

        //see which attributes the user has access to based on permissions

        PermissionResult permissionResult = null;

        

        //only need to check permissions if not admin

        if (!isAdmin) {

          

          Stem permissionsStem = StemFinder.findByName(theGrouperSession, PERMISSIONS_STEM_NAME, true);

          

          permissionResult = new PermissionFinder().addAction("read").addPermissionDef(SUBJECT_ATTRIBUTES_PERMISSIONS_ATTRIBUTE_DEF)

            .addSubject(subjectChecking).assignPermissionNameFolder(permissionsStem)

            .assignPermissionNameFolderScope(Scope.ONE).findPermissionResult();

          

        }

        

        //see which columns the user can see

        Set<String> columnsSet = isAdmin ? new HashSet<String>(attributeNamesRequested)

            : permissionResult.permissionNameExtensions();

 

        //intersect the columns the user can see with the ones requested

        columnsSet.retainAll(attributeNamesRequested);

 

        if (GrouperUtil.length(columnsSet) == 0) {

          return null;

        }

 

        List<String> columns = new ArrayList<String>(columnsSet);

 

        List<Subject> subjectList = new ArrayList<Subject>(subjects);

        

        int batchSize = 180;

        int numberOfBatches = GrouperUtil.batchNumberOfBatches(subjectList, batchSize);

        

        subjects.clear();

 

        //batch these since you dont know if there will be more than 180 to resolve

        for (int i=0; i<numberOfBatches; i++) {

          

          List<Subject> subjectsBatch = GrouperUtil.batchList(subjectList, batchSize, i);

          

          //get the list of subject ids

          Set<String> subjectIds = new LinkedHashSet<String>();

          for (Subject subject : subjectsBatch) {

            if (StringUtils.equals(SOURCE_ID, subject.getSourceId())) {

              subjectIds.add(subject.getId());

            }

          }

          

          //get the results of these columns for these subjects (by id)

          //make query

          StringBuilder sql = new StringBuilder("select subject_id, ");

          sql.append(GrouperUtil.join(columns.iterator(), ','));

          sql.append(" from testgrouper_subj_attr where subject_id in( ");

          sql.append(HibUtils.convertToInClauseForSqlStatic(subjectIds));

          sql.append(")");

          

          //get the results from the DB

          List<String[]> dbResults = HibernateSession.bySqlStatic().listSelect(String[].class, sql.toString(), GrouperUtil.toListObject(subjectIds.toArray()));

          

          //index the results by id of row

          Map<String, String[]> dbResultLookup = new HashMap<String, String[]>();

          

          Set<String> subjectIdsRelated = new HashSet<String>();

          

          for(String[] row : dbResults) {

            dbResultLookup.put(row[0], row);

            subjectIdsRelated.add(row[0]);

          }

          

          {

            //copy over the subjects since we need new objects...

            for (Subject subject : subjectsBatch) {

              

              //if it is a subject impl or doesnt have new attributes, we are all good...

              if (StringUtils.equals("jdbc", subject.getSourceId()) && subjectIdsRelated.contains(subject.getId())) {

                

                if (!(subject instanceof SubjectImpl)) {

                  subject = new SubjectImpl(subject.getId(), subject.getName(),

                      subject.getDescription(), subject.getTypeName(), subject.getSourceId(),

                      subject.getAttributes(false));

                }

                String[] row = dbResultLookup.get(subject.getId());

                //shouldnt be null at this point

                if (row != null) {

                  //look through the attributes

                  for (int j=0;j<columns.size();j++) {

                    

                    //add one to row index since first is id.  add if null or not, we need the attribute set

                    String columnName = columns.get(j);

                    String value = row[j+1];

 

                    //this should return a modifiable map of attributes for us to work with

                    subject.getAttributes(false).put(columnName, GrouperUtil.toSet(value));

                  }

                }

              }

              

              subjects.add(subject);

              

            }

          

          }

          

        }

        return null;

      }

    });

    

    return subjects;

  }

 

}

 

 

From: [mailto:] On Behalf Of Chris Hyzer
Sent: Sunday, November 06, 2011 2:48 AM
To: Grouper Dev
Subject: [grouper-dev] subject and attribute security

 

This document explains the plan for subject and attribute security improvements in v2.1 per the roadmap:

 

https://spaces.internet2.edu/display/Grouper/Grouper+subject+filter+and+attribute+decorator

 

Comments welcome.

 

Thanks,

Chris