source: java/net/deterlab/abac/GENIPrivCredential.java @ 2405adf

package net.deterlab.abac;

import java.io.*;
import java.math.*;
import java.text.*;

import java.util.*;
import java.security.*;
import java.security.cert.*;

import javax.security.auth.x500.*;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.dom.*;
import javax.xml.crypto.dsig.keyinfo.*;
import javax.xml.crypto.dsig.spec.*;

import org.xml.sax.*;
import org.w3c.dom.*;

import org.bouncycastle.asn1.*;
import org.bouncycastle.asn1.x509.*;
import org.bouncycastle.x509.*;
import org.bouncycastle.x509.util.*;
import org.bouncycastle.openssl.*;

/**
 * An ABAC credential formatted as an abac-type GENI credential.
 * @author <a href="http://abac.deterlab.net">ISI ABAC team</a>
 * @version 1.4
 */
public class GENIPrivCredential extends GENICredential {
    /**
     * Create an empty Credential.
     */
    public GENIPrivCredential() {
        m_head = m_tail = null;
        doc = null;
        id = null;
    }
    /**
     * Create a credential from a head and tail role.  This credential has no
     * underlying certificate, and cannot be exported or used in real proofs.
     * make_cert can create a certificate for a credential initialized this
     * way.
     * @param head the Role at the head of the credential
     * @param tail the Role at the tail of the credential
     */
    public GENIPrivCredential(Role head, Role tail, Document d, Identity i) {
        m_head = head;
        m_tail = tail;
        doc = null; 
        id = null;
    }

    /**
     * Create a certificate from this credential issued by the given identity.
     * This is the signed XML ABAC credential.
     * @param i the Identity that will issue the certificate
     * @throws ABACException if xml creation fails
     * @throws MissingIssuerException if the issuer is bad
     * @throws BadSignatureException if the signature creation fails
     */
    public void make_cert(Identity i) 
            throws ABACException {
        throw new ABACException("Cannot generate a GENIPrivCredential");
    }

    /**
     * Class that parses a GENI privilege credential into multiple
     * GENIPrivCredential objects.
     */
    static public class GENIPrivSpecialization 
            extends CredentialFactorySpecialization {

        /**
         * Extract an identity from a field holding a PEM-encoded x.509
         * certificate (for example, owner_gid).
         * @param n a Node that has the certificate in its Text Content
         * @return the Identity
         */
        protected Identity nodeToIdentity(Node n) {
            String certStr = null;

            if ( ( certStr = n.getTextContent()) == null ) return null;
            try {
                certStr = "-----BEGIN CERTIFICATE-----\n" + 
                    certStr + 
                "\n-----END CERTIFICATE-----";
                return new Identity(new StringReader(certStr));
            } 
            catch (Exception e) {
                return null;
            }
        }

        /**
         * Parses the credential into multiple Objects based on the permissions
         * imbued by the credential.
         * @param d a Document, the parsed credential
         * @param issuer an Identity that signed the credential
         * @return an array of GENIPrivCredentials that represent the
         * credential
         */
        protected Credential[] make_creds(Document d, Identity issuer) 
                throws ABACException {
            Node root = null;
            Node credential = null;
            Node owner_gid = null;
            Node target_gid = null;
            Node privileges = null;
            Node priv = null;
            Identity owner = null;
            Identity target = null;
            ArrayList<GENIPrivCredential> rv = 
                new ArrayList<GENIPrivCredential>();


            if ( (root = getChildByName(d, "signed-credential")) == null)
                throw new CertInvalidException("No signed-credential element");
            if ( (credential = getChildByName(root, "credential")) == null )
                throw new CertInvalidException("No credential element");
            if ( (owner_gid = getChildByName(credential, "owner_gid")) == null )
                throw new CertInvalidException("No owner_gid element");
            if ((target_gid = getChildByName(credential,"target_gid")) == null )
                throw new CertInvalidException("No target_gid element");
            if ((privileges = getChildByName(credential,"privileges")) == null )
                throw new CertInvalidException("No privileges element");

            Date exp = getTime(d, "expires");

            if ( exp.before(new Date()))
                throw new CertInvalidException("Certificate Expired " + exp);

            if ( (owner = nodeToIdentity(owner_gid)) == null) 
                throw new CertInvalidException("Bad owner_gid element");
            if ( (target = nodeToIdentity(target_gid)) == null) 
                throw new CertInvalidException("Bad target_gid element");

            for (Node n = privileges.getFirstChild(); n != null; 
                    n = n.getNextSibling()) {
                if (n.getNodeType() != Node.ELEMENT_NODE ||
                        !"privilege".equals(n.getNodeName()))
                    throw new CertInvalidException(
                            "Child of privileges not privilege?");
                Node name = null;
                Node can_delegate = null;
                boolean cd = false;
                String cds = null;
                String pname = null;

                if ( (name = getChildByName(n, "name")) == null)
                    throw new CertInvalidException("No privilege name");

                if ((can_delegate = getChildByName(n, "can_delegate")) == null)
                    throw new CertInvalidException("No privilege delegate");

                if ( (pname = name.getTextContent()) == null)
                    throw new CertInvalidException("No privilege name text");
                if ((cds = can_delegate.getTextContent()) == null)
                    throw new CertInvalidException("No delegate text");
                cd = cds.equals("1") || cds.equals("true");

                /* First privilege includes the basic speaks for defintion 
                 * for this owner */
                if ( rv.isEmpty() ) {
                    rv.add(new GENIPrivCredential(
                                new Role(issuer.getKeyID() + ".speaks_for_" +
                                    owner.getKeyID()),
                                new Role(owner.getKeyID()), d, issuer));
                    rv.add(new GENIPrivCredential(
                                new Role(issuer.getKeyID() + ".speaks_for_" +
                                    owner.getKeyID()),
                                new Role(owner.getKeyID() + ".speaks_for_" +
                                    owner.getKeyID()), d, issuer));
                }

                /* The privilege itself */
                rv.add(new GENIPrivCredential(
                            new Role(issuer.getKeyID() + "." + pname + "_" +
                                target.getKeyID()),
                            new Role(issuer.getKeyID() + ".speaks_for_" +
                                owner.getKeyID()), d, issuer));
                if (cd ) {
                    /* The rules for delegation, if necessary */
                    rv.add(new GENIPrivCredential(
                                new Role(issuer.getKeyID() + "." + pname + 
                                    "_" + target.getKeyID()),
                                new Role(issuer.getKeyID() + ".can_delegate_" 
                                    + pname + "_" + target.getKeyID() + 
                                    "." + pname + "_" + target.getKeyID()), 
                                d, issuer));
                    rv.add(new GENIPrivCredential(
                                new Role(issuer.getKeyID() + 
                                    ".can_delegate_" + pname),
                                new Role(owner.getKeyID()), d, issuer));
                }
            }
            return rv.toArray(new Credential[rv.size()]);
        }

        /**
         * Parse the credential into multiple GENIPrivCredentials that encode
         * its semantics.
         * @param is an InputStream containing the credentals
         * @param ids a Collection of Identities to use in validation
         * @return an array of GENIPrivCredentials that represent the
         * credential
         * @throws CertInvalidException if the stream is unparsable
         * @throws MissingIssuerException if none of the Identities can
         *                      validate the certificate
         * @throws BadSignatureException if the signature check fails
         */
        public Credential[] parseCredential(InputStream is, 
                Collection<Identity> ids) throws ABACException {
            try {
                Document d = read_certificate(is);
                XMLSignatureFactory fac = 
                    XMLSignatureFactory.getInstance("DOM");
                NodeList nl = d.getElementsByTagNameNS(XMLSignature.XMLNS, 
                        "Signature");
                DOMValidateContext valContext = null;
                XMLSignature signature = null;
                Identity lid = null;


                if (nl.getLength() == 0) 
                    throw new CertInvalidException(
                            "Cannot find Signature element");

                setIDAttrs(d);
                valContext = new DOMValidateContext(new X509KeySelector(),
                        nl.item(0));
                if ( valContext == null )
                    throw new ABACException("No validation context!?");

                signature = fac.unmarshalXMLSignature(valContext);
                if (signature == null) 
                    throw new BadSignatureException(
                            "Cannot unmarshal signature");

                if (!signature.validate(valContext))
                    throw new BadSignatureException("bad signature");

                lid = getIdentity(nl.item(0));

                if ( !ids.contains(lid) ) ids.add(lid);

                return make_creds(d, lid);
            }
            catch (ABACException ae) {
                throw ae;
            }
            catch (Exception e) {
                throw new BadSignatureException(e.getMessage(), e);
            }
        }

        /**
         * One cannot create a GENIPrivCredential to encodes a single arbitrary
         * head and tail, so this always fails.
         * @param head a Role to encode
         * @param tail a Role to encode
         */
        public Credential generateCredential(Role head, Role tail) {
            return null;
        }
    };

    /**
     * Return a CredentialCredentialFactorySpecialization for
     * GENIPrivCredentials.  Used by the CredentialFactory to parse these kind
     * of credentials. 
     * @return a CredentialFactorySpecialization for this kind of credential.
     */
    static public CredentialFactorySpecialization 
            getCredentialFactorySpecialization() {
        return new GENIPrivSpecialization();
    }
}