source: java/net/deterlab/abac/Context.java @ 53f5c27

package net.deterlab.abac;

import org.apache.commons.collections15.*;
import org.apache.commons.collections15.functors.*;

import edu.uci.ics.jung.graph.*;
import edu.uci.ics.jung.graph.event.*;
import edu.uci.ics.jung.graph.util.*;

import java.awt.geom.Point2D;
import java.io.*;
import java.util.*;
import java.util.zip.*;
import java.security.*;
import java.security.cert.*;

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

/**
 * Represents a global graph of credentials in the form of principals and
 * attributes.
 */
public class Context {
    static final int ABAC_CERT_SUCCESS = 0;
    static final int ABAC_CERT_INVALID = -1;
    static final int ABAC_CERT_BAD_SIG = -2;
    static final int ABAC_CERT_MISSING_ISSUER = -3;

    protected Graph<Role,Credential> g;
    protected Set<Credential> derived_edges;
    protected Query pq;
    protected boolean dirty;
    protected Set<Identity> identities;

    protected Map<String, String> nicknames;
    protected Map<String, String> keys;

    public Context() {
        /* create the graph */
        g = Graphs.<Role,Credential>synchronizedDirectedGraph(
                new DirectedSparseGraph<Role,Credential>());
        derived_edges = new HashSet<Credential>();
        pq = new Query(g);
        dirty = false;
        identities = new TreeSet<Identity>();
        nicknames = new TreeMap<String, String>();
        keys = new TreeMap<String, String>();
    }

    public Context(Context c) {
        this();
        for (Identity i: c.identities) 
            loadIDChunk(i);
        for (Credential cr: c.credentials()) 
            loadAttributeChunk(cr);
        derive_implied_edges();
    }

    public int loadIDFile(String fn) { return loadIDFile(new File(fn)); }
    public int loadIDFile(File fn) {
        try {
            addIdentity(new Identity(fn));
        }
        catch (SignatureException sig) {
            return ABAC_CERT_BAD_SIG;
        }
        catch (Exception e) {
            return ABAC_CERT_INVALID;
        }
        return ABAC_CERT_SUCCESS;
    }

    public int loadIDChunk(Object c) {
        try {
            if (c instanceof Identity)
                addIdentity((Identity) c);
            else if (c instanceof String) 
                addIdentity(new Identity((String) c));
            else if (c instanceof File) 
                addIdentity(new Identity((File) c));
            else if (c instanceof X509Certificate) 
                addIdentity(new Identity((X509Certificate) c));
            else 
                return ABAC_CERT_INVALID;
        }
        catch (SignatureException sig) {
            return ABAC_CERT_BAD_SIG;
        }
        catch (Exception e) {
            return ABAC_CERT_INVALID;
        }
        return ABAC_CERT_SUCCESS;
    }

    public int loadAttributeFile(String fn) { 
        return loadAttributeFile(new File(fn));
    }

    public int loadAttributeFile(File fn) {
        try {
            add_credential(new Credential(fn, identities));
        }
        catch (InvalidKeyException sig) {
            return ABAC_CERT_MISSING_ISSUER;
        }
        catch (Exception e) {
            return ABAC_CERT_INVALID;
        }
        return ABAC_CERT_SUCCESS;
    }

    public int loadAttributeChunk(Object c) {
        try {
            if (c instanceof Credential)
                add_credential((Credential) c);
            else if (c instanceof String) 
                add_credential(new Credential((String) c, identities));
            else if (c instanceof File) 
                add_credential(new Credential((File) c, identities));
            else if ( c instanceof X509V2AttributeCertificate) 
                add_credential(new Credential((X509V2AttributeCertificate)c,
                            identities));
            else 
                return ABAC_CERT_INVALID;
        }
        catch (SignatureException sig) {
            return ABAC_CERT_BAD_SIG;
        }
        catch (Exception e) {
            return ABAC_CERT_INVALID;
        }
        return ABAC_CERT_SUCCESS;
    }

    public Collection<Credential> query(String role, String principal) {
        derive_implied_edges();

        Query q = new Query(g);
        Graph<Role, Credential> rg = q.run(role, principal);
        return rg.getEdges();
    }

    /**
     * Returns a collection of the credentials in the graph.
     */
    public Collection<Credential> credentials() {
        Collection<Credential> creds = new HashSet<Credential>();

        // only return creds with a cert: all others are derived edges
        for (Credential cred : g.getEdges())
            if (cred.cert() != null)
                creds.add(cred);

        return creds;
    }

    public boolean knowsIdentity(Identity i) { return identities.contains(i); }
    public boolean knowsKeyID(String k) {
        boolean known = false;
        for (Identity i: identities)
            if (k.equals(i.getKeyID())) return true;
        return false;
    }


    /**
     * Add a credential to the graph.
     */
    public void add_credential(Credential cred) {
        Role tail = cred.tail();
        Role head = cred.head();

        /* explicitly add the vertices, otherwise get a null pointer exception */
        if ( !g.containsVertex(head)) 
            g.addVertex(head);
        if ( !g.containsVertex(tail)) 
            g.addVertex(tail);

        if (!g.containsEdge(cred))
            g.addEdge(cred, tail, head);

        // add the prereqs of an intersection to the graph
        if (tail.is_intersection())
            for (Role prereq : tail.prereqs())
                g.addVertex(prereq);

        dirty = true;
    }

    /**
     * Remove a credential from the graph.
     */
    public void remove_credential(Credential cred) {
        if (g.containsEdge(cred))
            g.removeEdge(cred);
        dirty = true;
    }

    /**
     * Add a role w/o an edge
     */
    public void add_vertex(Role v) {
        if (!g.containsVertex(v)) {
            g.addVertex(v);
            dirty = true;
        }
    }

    public void remove_vertex(Role v) {
        if (g.containsVertex(v)) {
            g.removeVertex(v);
            dirty = true;
        }
    }
    public Collection<Role> roles() {
        return g.getVertices();
    }

    /**
     * Derive the implied edges in the graph, according to RT0 derivation rules.
     * They are added to this graph. See "Distributed Credential Chain Discovery
     * in Trust Management" by Ninghui Li et al. for details. Note that a
     * derived linking edge can imply a new intersection edge and vice versa.
     * Therefore we iteratively derive edges, giving up when an iteration
     * produces 0 new edges.
     */
    protected synchronized void derive_implied_edges() {
        // nothing to do on a clean graph
        if (!dirty)
            return;

        clear_old_edges();

        // iteratively derive links. continue as long as new links are added
        while (derive_links_iter() > 0)
            ;
        dirty = false;
    }

    /**
     * Single iteration of deriving implied edges. Returns the number of new
     * links added.
     */
    protected int derive_links_iter() {
        int count = 0;

        /* for every node in the graph.. */
        for (Role vertex : g.getVertices()) {
            if (vertex.is_intersection()) {
                // for each prereq edge:
                //     find set of principals that have the prereq
                // find the intersection of all sets (i.e., principals that satisfy all prereqs)
                // for each principal in intersection:
                //     add derived edge

                Set<Role> principals = null;

                for (Role prereq : vertex.prereqs()) {
                    Set<Role> cur_principals = pq.find_principals(prereq);

                    if (principals == null)
                        principals = cur_principals;
                    else
                        // no, they couldn't just call it "intersection"
                        principals.retainAll(cur_principals);

                    if (principals.size() == 0)
                        break;
                }

                // add em
                for (Role principal : principals)
                    if (add_derived_edge(vertex, principal))
                        ++count;
            }

            else if (vertex.is_linking()) {
                // make the rest of the code a bit clearer
                Role A_r1_r2 = vertex;

                Role A_r1 = new Role(A_r1_r2.A_r1());
                String r2 = A_r1_r2.r2();

                /* locate the node A.r1 */
                if (!g.containsVertex(A_r1)) continue; /* boring: nothing of the form A.r1 */

                /* for each B that satisfies A_r1 */
                for (Role principal : pq.find_principals(A_r1)) {
                    Role B_r2 = new Role(principal + "." + r2);
                    if (!g.containsVertex(B_r2)) continue;

                    if (add_derived_edge(A_r1_r2, B_r2))
                        ++count;
                }
            }
        }

        return count;
    }

    /**
     * Add a derived edge in the graph. Returns true only if the edge does not
     * exist.
     */
    protected boolean add_derived_edge(Role head, Role tail) {
        // edge exists: return false
        if (g.findEdge(tail, head) != null)
            return false;

        // add the new edge
        Credential derived_edge = new Credential(head, tail);
        derived_edges.add(derived_edge);
        g.addEdge(derived_edge, tail, head);

        return true;
    }

    /**
     * Clear the derived edges that currently exist in the graph. This is done
     * before the edges are rederived. The derived edges in filtered graphs are
     * also cleared.
     */
    protected void clear_old_edges() { 
        for (Credential i: derived_edges) 
            g.removeEdge(i);
        derived_edges = new HashSet<Credential>();
    }
    /**
     * Put the Identity into the set of ids used to validate certificates.
     * Also put the keyID and name into the translation mappings used by Roles
     * to pretty print.  In the role mapping, if multiple ids use the same
     * common name they are disambiguated.  Only one entry for keyid is
     * allowed.
     */
    protected void addIdentity(Identity id) { 
        identities.add(id);
        if (id.getName() != null && id.getKeyID() != null) {
            if ( !keys.containsKey(id.getKeyID()) ) {
                String name = id.getName();
                int n= 1;

                while (nicknames.containsKey(name)) {
                    name = id.getName() + n++;
                }
                nicknames.put(name, id.getKeyID());
                keys.put(id.getKeyID(), name);
            }
        }
    }
    /**
     * Translate either keys to nicknames or vice versa.  Break the string into
     * space separated tokens and then each of them into period separated
     * strings.  If any of the smallest strings is in the map, replace it with
     * the value.
     */
    protected String replace(String is, Map<String, String> m) {
        String rv = "";
        for (String tok: is.split(" ")) {
            String term = "";
            for (String s: tok.split("\\.")) {
                String next = m.containsKey(s) ? m.get(s) : s;

                if (term.isEmpty()) term = next;
                else term += "." + next;
            }
            if (rv.isEmpty()) rv = term;
            else rv += " " + term;
        }
        return rv;
    }

    public String expandKeyID(String s) { return replace(s, nicknames); }
    public String expandNickname(String s) { return replace(s, keys); }

    /**
     * Import a zip file.  First import all the identities
     * (pem), then the credentials (der) into the credential graph then any
     * alias files into the two maps.  If keys is not null, any key pairs in
     * PEM files are put in there.  If errors is not null, errors reading files
     * are added indexed by filename.
     */
    public void readZipFile(File zf, Collection<KeyPair> keys, 
            Map<String, Exception> errors) throws IOException {
        Vector<ZipEntry> derEntries = new Vector<ZipEntry>();
        Map<String, Identity> ids = new TreeMap<String, Identity>();
        Map<String, KeyPair> kps = new TreeMap<String, KeyPair>();

        ZipFile z = new ZipFile(zf);

        for (Enumeration<? extends ZipEntry> ze = z.entries(); 
                ze.hasMoreElements();) {
            ZipEntry  f = ze.nextElement();
            try {
                PEMReader r = new PEMReader(
                        new InputStreamReader(z.getInputStream(f)));
                Object o = readPEM(r);

                if ( o != null ) {
                    if (o instanceof Identity) {
                        Identity i = (Identity) o;
                        String kid = i.getKeyID();

                        if (kps.containsKey(kid) ) {
                            i.setKeyPair(kps.get(kid));
                            kps.remove(kid);
                        }
                        else if (i.getKeyPair() == null ) 
                            ids.put(i.getKeyID(), i);

                        loadIDChunk(i);
                    }
                    else if (o instanceof KeyPair ) {
                        KeyPair kp = (KeyPair) o;
                        String kid = extractKeyID(kp.getPublic());

                        if (ids.containsKey(kid)) {
                            Identity i = ids.get(kid);

                            i.setKeyPair(kp);
                            ids.remove(kid);
                        }
                        else {
                            kps.put(kid, kp);
                        }
                    }
                }
                else {
                    // Not a PEM file
                    derEntries.add(f);
                    continue;
                }
            }
            catch (Exception e ) {
                if (errors != null ) errors.put(f.getName(), e);
            }
        }

        for ( ZipEntry f : derEntries ) {
            try {
                add_credential(new Credential(z.getInputStream(f), identities));
            }
            catch (Exception e ) {
                if (errors != null ) errors.put(f.getName(), e);
            }
        }
    }

    public void readZipFile(File d) 
            throws IOException {
        readZipFile(d, null, null);
    }
    public void readZipFile(File d, 
            Map<String, Exception> errors) throws IOException {
        readZipFile(d, null, errors);
    }
    public void readZipFile(File d, 
            Collection<KeyPair> keys) throws IOException {
        readZipFile(d, keys, null);
    }

    protected Object readPEM(PEMReader r) throws IOException {
        Identity i = null;
        KeyPair keys = null;
        Object o = null;

        while ( (o = r.readObject()) != null ) {
            if (o instanceof X509Certificate) {
                if ( i == null ) {
                    try {
                        i = new Identity((X509Certificate)o);
                    }
                    catch (Exception e) {
                        // Translate Idenitiy exceptions to IOException
                        throw new IOException(e);
                    }
                    if (keys != null ) {
                        i.setKeyPair(keys);
                        keys = null;
                    }
                }
                else throw new IOException("Two certificates");
            }
            else if (o instanceof KeyPair ) {
                if ( i != null ) i.setKeyPair((KeyPair) o);
                else keys = (KeyPair) o;
            }
            else {
                throw new IOException("Unexpected PEM object: " + 
                        o.getClass().getName());
            }
        }

        if ( i != null ) return i;
        else if ( keys != null) return keys;
        else return null;
    }

    /**
     * Import a directory full of files.  First import all the identities
     * (pem), then the credentials (der) into the credential graph then any
     * alias files into the two maps.  If keys is not null, any key pairs in
     * PEM files are put in there.  If errors is not null, errors reading files
     * are added indexed by filename.
     */
    public void readDirectory(File d, Collection<KeyPair> keys, 
            Map<String, Exception> errors) {
        Vector<File> derFiles = new Vector<File>();
        Collection<File> files = new Vector<File>();
        Map<String, Identity> ids = new TreeMap<String, Identity>();
        Map<String, KeyPair> kps = new TreeMap<String, KeyPair>();

        if (d.isDirectory() ) 
            for (File f : d.listFiles()) 
                files.add(f);
        else files.add(d);

        for (File f: files ) {
            try {
                PEMReader r = new PEMReader(new FileReader(f));
                Object o = readPEM(r);

                if ( o != null ) {
                    if (o instanceof Identity) {
                        Identity i = (Identity) o;
                        String kid = i.getKeyID();

                        if (kps.containsKey(kid) ) {
                            i.setKeyPair(kps.get(kid));
                            kps.remove(kid);
                        }
                        else if (i.getKeyPair() == null ) 
                            ids.put(i.getKeyID(), i);

                        loadIDChunk(i);
                    }
                    else if (o instanceof KeyPair ) {
                        KeyPair kp = (KeyPair) o;
                        String kid = extractKeyID(kp.getPublic());

                        if (ids.containsKey(kid)) {
                            Identity i = ids.get(kid);

                            i.setKeyPair(kp);
                            ids.remove(kid);
                        }
                        else {
                            kps.put(kid, kp);
                        }
                    }
                }
                else {
                    // Not a PEM file
                    derFiles.add(f);
                    continue;
                }
            }
            catch (Exception e ) {
                if (errors != null ) errors.put(f.getName(), e);
            }
        }

        for ( File f : derFiles ) {
            try {
                add_credential(new Credential(f, identities));
            }
            catch (Exception e ) {
                if (errors != null ) errors.put(f.getName(), e);
            }
        }
    }

    public void readDirectory(File d) {
        readDirectory(d, null, null);
    }
    public void readDirectory(File d, Map<String, Exception> errors) {
        readDirectory(d, null, errors);
    }
    public void readDirectory(File d, Collection<KeyPair> keys) {
        readDirectory(d, keys, null);
    }

    public void writeZipFile(File f, boolean allIDs, boolean withPrivateKeys) 
            throws IOException {
        ZipOutputStream z = new ZipOutputStream(new FileOutputStream(f));
        Set<Identity> ids = allIDs ?  identities : new TreeSet<Identity>();

        int n = 0;
        for (Credential c: credentials()) {
            z.putNextEntry(new ZipEntry("attr" + n++  + ".der"));
            c.write(z);
            z.closeEntry();
            if ( c.getID() != null && !allIDs) ids.add(c.getID());
        }
        for (Identity i: ids) {
            z.putNextEntry(new ZipEntry(i.getName() + ".pem"));
            i.write(z);
            if (withPrivateKeys)
                i.writePrivateKey(z);
            z.closeEntry();
        }
        z.close();
    }

    /**
     * Get to the SHA1 hash of the key.
     */
    public static String extractKeyID(PublicKey k) {
        SubjectPublicKeyInfo ki = extractSubjectPublicKeyInfo(k);
        SubjectKeyIdentifier id = 
            SubjectKeyIdentifier.createSHA1KeyIdentifier(ki);

        // Now format it into a string for keeps
        Formatter fmt = new Formatter(new StringWriter());
        for (byte b: id.getKeyIdentifier())
            fmt.format("%02x", b);
        return fmt.out().toString();
    }

    /**
     * Extratct the SubjectPublicKeyInfo.  Useful for some other encryptions,
     * notably Certificate.make_cert().
     */
    public static SubjectPublicKeyInfo extractSubjectPublicKeyInfo(
            PublicKey k) {
        ASN1Sequence seq = null;
        try {
            seq = (ASN1Sequence) new ASN1InputStream(
                    k.getEncoded()).readObject();
        }
        catch (IOException ie) {
            // Badly formatted key??
            return null;
        }
        return new SubjectPublicKeyInfo(seq);
    }


}