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SigningDigest.javaAPI DocJCIFS 1.3.17 API7323Tue Oct 18 15:26:24 BST 2011jcifs.smb

SigningDigest

public class SigningDigest extends Object implements SmbConstants
To filter 0 len updates and for debugging

Fields Summary
static jcifs.util.LogStream
log
private MessageDigest
digest
private byte[]
macSigningKey
private boolean
bypass
private int
updates
private int
signSequence
Constructors Summary
public SigningDigest(byte[] macSigningKey, boolean bypass)


           
        try {
            digest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException ex) {
            if( log.level > 0 )
                ex.printStackTrace( log );
            throw new SmbException( "MD5", ex );
        }

        this.macSigningKey = macSigningKey;
        this.bypass = bypass;
        this.updates = 0;
        this.signSequence = 0;

        if( log.level >= 5 ) {
            log.println("macSigningKey:");
            Hexdump.hexdump( log, macSigningKey, 0, macSigningKey.length );
        }
public SigningDigest(SmbTransport transport, NtlmPasswordAuthentication auth)

        try {
            digest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException ex) {
            if( log.level > 0 )
                ex.printStackTrace( log );
            throw new SmbException( "MD5", ex );
        }

        try {
            switch (LM_COMPATIBILITY) {
            case 0:
            case 1:
            case 2:
                macSigningKey = new byte[40];
                auth.getUserSessionKey(transport.server.encryptionKey, macSigningKey, 0);
                System.arraycopy(auth.getUnicodeHash(transport.server.encryptionKey),
                            0, macSigningKey, 16, 24);
                break;
            case 3:
            case 4:
            case 5:
                macSigningKey = new byte[16];
                auth.getUserSessionKey(transport.server.encryptionKey, macSigningKey, 0);
                break;
            default:
                macSigningKey = new byte[40];
                auth.getUserSessionKey(transport.server.encryptionKey, macSigningKey, 0);
                System.arraycopy(auth.getUnicodeHash(transport.server.encryptionKey),
                            0, macSigningKey, 16, 24);
                break;
            }
        } catch( Exception ex ) {
            throw new SmbException( "", ex );
        }
        if( log.level >= 5 ) {
            log.println( "LM_COMPATIBILITY=" + LM_COMPATIBILITY );
            Hexdump.hexdump( log, macSigningKey, 0, macSigningKey.length );
        }
Methods Summary
public byte[]digest()

        byte[] b;

        b = digest.digest();

        if( log.level >= 5 ) {
            log.println( "digest: " );
            Hexdump.hexdump( log, b, 0, b.length );
            log.flush();
        }
        updates = 0;

        return b;
voidsign(byte[] data, int offset, int length, ServerMessageBlock request, ServerMessageBlock response)
Performs MAC signing of the SMB. This is done as follows. The signature field of the SMB is overwritted with the sequence number; The MD5 digest of the MAC signing key + the entire SMB is taken; The first 8 bytes of this are placed in the signature field.

param
data The data.
param
offset The starting offset at which the SMB header begins.
param
length The length of the SMB data starting at offset.

        request.signSeq = signSequence;
        if( response != null ) {
            response.signSeq = signSequence + 1;
            response.verifyFailed = false;
        }

        try {
            update(macSigningKey, 0, macSigningKey.length);
            int index = offset + ServerMessageBlock.SIGNATURE_OFFSET;
            for (int i = 0; i < 8; i++) data[index + i] = 0;
            ServerMessageBlock.writeInt4(signSequence, data, index);
            update(data, offset, length);
            System.arraycopy(digest(), 0, data, index, 8);
            if (bypass) {
                bypass = false;
                System.arraycopy("BSRSPYL ".getBytes(), 0, data, index, 8);
            }
        } catch (Exception ex) {
            if( log.level > 0 )
                ex.printStackTrace( log );
        } finally {
            signSequence += 2;
        }
public java.lang.StringtoString()

        return "LM_COMPATIBILITY=" + LM_COMPATIBILITY + " MacSigningKey=" + Hexdump.toHexString(macSigningKey, 0, macSigningKey.length);
public voidupdate(byte[] input, int offset, int len)

        if( log.level >= 5 ) {
            log.println( "update: " + updates + " " + offset + ":" + len );
            Hexdump.hexdump( log, input, offset, Math.min( len, 256 ));
            log.flush();
        }
        if( len == 0 ) {
            return; /* CRITICAL */
        }
        digest.update( input, offset, len );
        updates++;
booleanverify(byte[] data, int offset, ServerMessageBlock response)
Performs MAC signature verification. This calculates the signature of the SMB and compares it to the signature field on the SMB itself.

param
data The data.
param
offset The starting offset at which the SMB header begins.
param
length The length of the SMB data starting at offset.

        update(macSigningKey, 0, macSigningKey.length);
        int index = offset;
        update(data, index, ServerMessageBlock.SIGNATURE_OFFSET); 
        index += ServerMessageBlock.SIGNATURE_OFFSET;
        byte[] sequence = new byte[8]; 
        ServerMessageBlock.writeInt4(response.signSeq, sequence, 0); 
        update(sequence, 0, sequence.length); 
        index += 8;
        if( response.command == ServerMessageBlock.SMB_COM_READ_ANDX ) {
            /* SmbComReadAndXResponse reads directly from the stream into separate byte[] b.
             */
            SmbComReadAndXResponse raxr = (SmbComReadAndXResponse)response;
            int length = response.length - raxr.dataLength;
            update(data, index, length - ServerMessageBlock.SIGNATURE_OFFSET - 8);
            update(raxr.b, raxr.off, raxr.dataLength);
        } else {
            update(data, index, response.length - ServerMessageBlock.SIGNATURE_OFFSET - 8);
        }
        byte[] signature = digest();
        for (int i = 0; i < 8; i++) {
            if (signature[i] != data[offset + ServerMessageBlock.SIGNATURE_OFFSET + i]) {
                if( log.level >= 2 ) {
                    log.println( "signature verification failure" );
                    Hexdump.hexdump( log, signature, 0, 8 );
                    Hexdump.hexdump( log, data,
                        offset + ServerMessageBlock.SIGNATURE_OFFSET, 8 );
                }
                return response.verifyFailed = true;
            }
        }

        return response.verifyFailed = false;