Added the basics for key exchange.

1 files changed, 16 insertions, 602 deletions

diff --git a/lib/gnutls_dh.c b/lib/gnutls_dh.c
index 754f363dc7..a593b1a669 100644
--- a/lib/gnutls_dh.c
+++ b/lib/gnutls_dh.c
@@ -1,7 +1,7 @@
 #include <defines.h>
 #include <gcrypt.h>
 
-static const byte diffie_hellman_group1_prime[130] = { 0x04, 0x00,
+static const uint8 diffie_hellman_group1_prime[130] = { 0x04, 0x00,
     0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2,
     0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1,
     0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6,
@@ -14,18 +14,29 @@ static const byte diffie_hellman_group1_prime[130] = { 0x04, 0x00,
     0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE6, 0x53, 0x81,
     0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF  };
 
+#if 0 
+     --Example--
+     you: X = g^x mod p;
+     peer: Y = g^y mod p;
+     
+       g = mpi_set_ui( NULL, 2 );
+     /* generate our secret and the public value for it */
+       X = calc_dh_secret( &x );
+     /* now we can calculate the shared secret */
+       key = calc_dh_key( Y, x );
+       mpi_release( x );
+#endif
 
 /****************
  * Choose a random value x and calculate e = g^x mod p.
  * Return: e and if ret_x is not NULL x.
  */
-static MPI
-calc_dh_secret( MPI *ret_x )
+MPI calc_dh_secret( MPI *ret_x )
 {
     MPI e, g, x, prime;
     size_t n = sizeof diffie_hellman_group1_prime;
 
-    if( gcry_mpi_scan( &prime, GCRYMPI_FMT_STD,
+     if( gcry_mpi_scan( &prime, GCRYMPI_FMT_STD,
 		       diffie_hellman_group1_prime, &n ) )
 	abort();
     /*dump_mpi(stderr, "prime=", prime );*/
@@ -48,38 +59,7 @@ calc_dh_secret( MPI *ret_x )
 }
 
 
-
-static void
-hash_mpi( GCRY_MD_HD md, MPI a )
-{
-    char buf[400];
-    size_t n = sizeof buf;
-
-    if( gcry_mpi_print( GCRYMPI_FMT_SSH, buf, &n, a ) )
-	fprintf(stderr,"Oops: MPI too large for hashing\n");
-    else
-	gcry_md_write( md, buf, n );
-}
-
-
-static void
-hash_bstring( GCRY_MD_HD md, BSTRING a )
-{
-    byte buf[4];
-    size_t n = a->len;
-
-    buf[0] = n >> 24;
-    buf[1] = n >> 16;
-    buf[2] = n >>  8;
-    buf[3] = n;
-    gcry_md_write( md, buf, 4 );
-    gcry_md_write( md, a->d, n );
-}
-
-
-
-static MPI
-calc_dh_key( MPI f, MPI x )
+MPI calc_dh_key( MPI f, MPI x )
 {
     MPI k, prime;
     size_t n = sizeof diffie_hellman_group1_prime;
@@ -94,569 +74,3 @@ calc_dh_key( MPI f, MPI x )
     return k;
 }
 
-
-
-
-/****************
- * calculate the exchange hash value and put it into the handle.
- */
-static int
-calc_exchange_hash( GSTIHD hd, BSTRING i_c, BSTRING i_s,
-			       BSTRING k_s, MPI e,  MPI f )
-{
-    GCRY_MD_HD md;
-    int algo = GCRY_MD_SHA1;
-
-    md = gcry_md_open( algo, 0 );
-    if( !md )
-	return map_gcry_rc( gcry_errno() );
-
-    if( hd->we_are_server ) {
-	BSTRING pp;
-	hash_bstring( md, hd->peer_version_string );
-	pp = make_bstring( host_version_string, strlen(host_version_string) );
-	hash_bstring( md, pp );
-	gsti_free(pp);
-    }
-    else {
-	BSTRING pp;
-	pp = make_bstring( host_version_string, strlen(host_version_string) );
-	hash_bstring( md, pp );
-	gsti_free(pp);
-	hash_bstring( md, hd->peer_version_string );
-    }
-    hash_bstring( md, i_c );
-    hash_bstring( md, i_s );
-    hash_bstring( md, k_s );
-    hash_mpi( md, e );
-    hash_mpi( md, f );
-    hash_mpi( md, hd->kex.k );
-
-    hd->kex.h = make_bstring( gcry_md_read( md, algo ),
-			      gcry_md_get_algo_dlen(algo) );
-    if( !hd->session_id ) /* initialize the session id the first time */
-	hd->session_id = make_bstring( gcry_md_read( md, algo ),
-				       gcry_md_get_algo_dlen(algo));
-    gcry_md_close( md );
-/*  dump_hexbuf( stderr, "SesID=", hd->session_id->d, hd->session_id->len );*/
-    return 0;
-}
-
-
-/* Hmm. We need to have a new_kex structure so that the old
- * kex data can be used untip we have send the NEWKEYs msg
- * Well, doesn't matter for now.
- */
-static BSTRING
-construct_one_key( GSTIHD hd, GCRY_MD_HD md1, int algo,
-		   const byte *letter, size_t size )
-{
-    BSTRING hash;
-    GCRY_MD_HD md = gcry_md_copy( md1 );
-    size_t n, n1;
-
-    hash = make_bstring( NULL, size );
-    gcry_md_write( md, letter, 1 );
-    gcry_md_write( md, hd->session_id->d, hd->session_id->len );
-    n = gcry_md_get_algo_dlen(algo);
-    if( n > size )
-	n = size;
-    memcpy( hash->d, gcry_md_read(md, algo), n );
-    while( n < size ) {
-	gcry_md_close( md );
-	md = gcry_md_copy( md1 );
-	gcry_md_write( md, hash->d, n );
-	n1 = gcry_md_get_algo_dlen(algo);
-	if( n1 > size-n )
-	    n1 = size-n;
-	memcpy( hash->d+n, gcry_md_read(md, algo), n1 );
-	n += n1;
-    }
-    gcry_md_close( md );
-
-    return hash;
-}
-
-
-static int
-construct_keys( GSTIHD hd )
-{
-    GCRY_MD_HD md;
-    int algo = GCRY_MD_SHA1;
-
-    if( hd->kex.key_a )
-	return 0;   /* already constructed */
-
-    md = gcry_md_open( algo, 0 );
-    if( !md )
-	return map_gcry_rc( gcry_errno() );
-
-    hash_mpi( md, hd->kex.k );
-    gcry_md_write( md, hd->kex.h->d, hd->kex.h->len );
-
-    hd->kex.key_a = construct_one_key( hd, md, algo, "\x41", 8 );
-    hd->kex.key_b = construct_one_key( hd, md, algo, "\x42", 8 );
-    hd->kex.key_c = construct_one_key( hd, md, algo, "\x43", 24 ); /* des*/
-    hd->kex.key_d = construct_one_key( hd, md, algo, "\x44", 24 );
-    hd->kex.key_e = construct_one_key( hd, md, algo, "\x45", 20 );
-    hd->kex.key_f = construct_one_key( hd, md, algo, "\x46", 20 );
-    gcry_md_close( md );
-  #if 0
-    dump_hexbuf( stderr, "key A=", hd->kex.key_a->d, hd->kex.key_a->len );
-    dump_hexbuf( stderr, "key B=", hd->kex.key_b->d, hd->kex.key_b->len );
-    dump_hexbuf( stderr, "key C=", hd->kex.key_c->d, hd->kex.key_c->len );
-    dump_hexbuf( stderr, "key D=", hd->kex.key_d->d, hd->kex.key_d->len );
-    dump_hexbuf( stderr, "key E=", hd->kex.key_e->d, hd->kex.key_e->len );
-    dump_hexbuf( stderr, "key F=", hd->kex.key_f->d, hd->kex.key_f->len );
-  #endif
-    return 0;
-}
-
-
-static int
-prepare_hmac_pad( GCRY_MD_HD *rhd, BSTRING key, int pad )
-{
-    int algo = GCRY_MD_SHA1;
-    int i;
-    byte buf[64];  /* fixme */
-
-    assert( key->len <= sizeof buf );
-    *rhd = gcry_md_open( algo, 0 );
-    if( !*rhd )
-	return map_gcry_rc( gcry_errno() );
-
-    memset( buf, 0, sizeof buf );
-    memcpy( buf, key->d, key->len );
-    for(i=0; i < sizeof buf; i++ )
-	buf[i] ^= pad;
-    gcry_md_write( *rhd, buf, sizeof buf );
-    return 0;
-}
-
-/****************
- * Prepare a HMAC
- */
-static int
-prepare_mac( GCRY_MD_HD *inner_hd, GCRY_MD_HD *outer_hd, BSTRING key )
-{
-    int rc;
-
-    rc = prepare_hmac_pad( inner_hd, key, '\x36');
-    if( !rc )
-	rc = prepare_hmac_pad( outer_hd, key, '\x5c');
-    return rc;
-}
-
-
-/* fixme: must release some data in case of error or when at end */
-int
-kex_send_init_packet( GSTIHD hd )
-{
-    MSG_kexinit kex;
-    int rc=0;
-
-    /* first send our kexinit packet */
-    memset( &kex, 0, sizeof kex );
-    memset( kex.cookie, 'w', 16 ); /* fixme: send a random one */
-    kex.kex_algorithm = insert_strlist( NULL, "diffie-hellman-group1-sha1" );
-    kex.server_host_key_algorithms = insert_strlist( NULL, "ssh-dss");
-    kex.encryption_algorithms_client_to_server = insert_strlist( NULL, "3des-cbc");
-    kex.encryption_algorithms_server_to_client = insert_strlist( NULL, "3des-cbc");
-    kex.mac_algorithms_client_to_server = insert_strlist( NULL, "hmac-sha1");
-    kex.mac_algorithms_server_to_client = insert_strlist( NULL, "hmac-sha1");
-    kex.compression_algorithms_client_to_server = insert_strlist( NULL, "none");
-    kex.compression_algorithms_server_to_client = insert_strlist( NULL, "none");
-    rc = build_msg_kexinit( &kex, &hd->pkt );
-    if( rc )
-	return rc;
-    rc = write_packet( hd );
-    if( rc )
-	return rc;
-    /* must do it here because write_packet fills in the packet type */
-    hd->host_kexinit_data = make_bstring( hd->pkt.payload, hd->pkt.payload_len );
-    rc = flush_packet( hd );
-    return rc;
-}
-
-
-/****************
- * Process a received keyinit packet.
- */
-int
-kex_proc_init_packet( GSTIHD hd )
-{
-    MSG_kexinit kex;
-    int rc;
-
-    if( hd->pkt.type != SSH_MSG_KEXINIT )
-	return GSTI_BUG;  /* oops */
-    rc = parse_msg_kexinit( &kex, hd->pkt.payload, hd->pkt.payload_len );
-    if( rc )
-	return rc;
-    /* make a copy of the received payload which we will need later */
-    hd->peer_kexinit_data = make_bstring( hd->pkt.payload,
-					  hd->pkt.payload_len );
-
-    dump_msg_kexinit( &kex );
-    return 0;
-}
-
-
-/****************
- * Send a KEX init packet (we are in the client role)
- */
-int
-kex_send_kexdh_init( GSTIHD hd )
-{
-    MSG_kexdh_init kexdh;
-    int rc=0;
-
-    memset( &kexdh, 0, sizeof kexdh );
-    /* FIXME: move secret_x it to secure memory */
-    kexdh.e = hd->kexdh_e = calc_dh_secret( &hd->secret_x );
-    rc = build_msg_kexdh_init( &kexdh, &hd->pkt );
-    if( rc )
-	return rc;
-    rc = write_packet( hd );
-    if( rc )
-	return rc;
-    rc = flush_packet( hd );
-    return rc;
-}
-
-
-/****************
- * Process the received DH init (we are in the server role)
- */
-int
-kex_proc_kexdh_init( GSTIHD hd )
-{
-    int rc;
-    MSG_kexdh_init kexdh;
-
-    if( hd->pkt.type != SSH_MSG_KEXDH_INIT )
-	return GSTI_BUG; /* oops */
-
-    rc = parse_msg_kexdh_init( &kexdh, hd->pkt.payload, hd->pkt.payload_len );
-    if( rc )
-	return rc;
-
-    /* we need the received e later */
-    hd->kexdh_e = kexdh.e;
-
-    dump_msg_kexdh_init( &kexdh );
-    return 0;
-}
-
-
-/****************
- * Send a DH init packet (we are in the server role)
- */
-int
-kex_send_kexdh_reply( GSTIHD hd )
-{
-    MSG_kexdh_reply dhr;
-    int rc;
-    MPI y;
-
-    memset( &dhr, 0, sizeof dhr );
-    dhr.k_s = make_bstring( "servers-pk", 10 ); /* fixme: Get from a DB */
-
-    /* generate our secret and the public value for it */
-    dhr.f = calc_dh_secret( &y );
-    /* now we can calculate the shared secret */
-    hd->kex.k = calc_dh_key( hd->kexdh_e, y );
-    mpi_release( y );
-    /* and the hash */
-    rc = calc_exchange_hash( hd, hd->host_kexinit_data, hd->peer_kexinit_data,
-						 dhr.k_s, hd->kexdh_e, dhr.f );
-    mpi_release( hd->kexdh_e );
-    if( rc )
-	return rc;
-    dhr.sig_h = make_bstring("signature_of_H", 14 );  /*FIXME*/
-
-    rc = build_msg_kexdh_reply( &dhr, &hd->pkt );
-    if( !rc )
-	dump_msg_kexdh_reply( &dhr );
-    if( !rc )
-	rc = write_packet( hd );
-    if( !rc )
-	rc = flush_packet( hd );
-    return rc;
-}
-
-/****************
- * Process the received DH value and take the encryption kes into use.
- * (we are in the client role)
- */
-int
-kex_proc_kexdh_reply( GSTIHD hd )
-{
-    int rc;
-    MSG_kexdh_reply dhr;
-
-    if( hd->pkt.type != SSH_MSG_KEXDH_REPLY )
-	return GSTI_BUG; /* oops */
-
-    rc = parse_msg_kexdh_reply( &dhr, hd->pkt.payload, hd->pkt.payload_len );
-    if( rc )
-	return rc;
-
-    dump_msg_kexdh_reply( &dhr );
-
-    hd->kex.k = calc_dh_key( dhr.f, hd->secret_x );
-    mpi_release( hd->secret_x );
-
-    rc = calc_exchange_hash( hd, hd->host_kexinit_data, hd->peer_kexinit_data,
-						 dhr.k_s, hd->kexdh_e, dhr.f );
-    mpi_release( hd->kexdh_e );
-    if( rc )
-	return rc;
-
-    /* FIXME: check that this is the real host */
-
-    return rc;
-}
-
-
-int
-kex_send_newkeys( GSTIHD hd )
-{
-    int rc;
-
-    rc = construct_keys( hd );
-    if( rc )
-	return rc;
-
-    hd->pkt.type = SSH_MSG_NEWKEYS;
-    hd->pkt.payload_len = 1;
-    rc = write_packet( hd );
-    if( !rc )
-	rc = flush_packet( hd );
-    if( rc )
-	return rc;
-
-    /* now we have to take the encryption keys into use */
-    hd->encrypt_hd = gcry_cipher_open( GCRY_CIPHER_3DES,
-				       GCRY_CIPHER_MODE_CBC, 0 );
-    if( !hd->encrypt_hd )
-	rc = map_gcry_rc( gcry_errno() );
-    else if( hd->we_are_server ) {
-	if( !rc )
-	    rc = gcry_cipher_setkey( hd->encrypt_hd, hd->kex.key_d->d,
-						     hd->kex.key_d->len );
-	if( !rc )
-	    rc = gcry_cipher_setiv( hd->encrypt_hd, hd->kex.key_b->d,
-						    hd->kex.key_b->len );
-	rc = map_gcry_rc(rc);
-	if( !rc )
-	    rc = prepare_mac( &hd->send_mac_inner_hd, &hd->send_mac_outer_hd,
-							    hd->kex.key_f );
-    }
-    else {
-	if( !rc )
-	    rc = gcry_cipher_setkey( hd->encrypt_hd, hd->kex.key_c->d,
-						     hd->kex.key_c->len );
-	if( !rc )
-	    rc = gcry_cipher_setiv( hd->encrypt_hd, hd->kex.key_a->d,
-						    hd->kex.key_a->len );
-	rc = map_gcry_rc(rc);
-	if( !rc )
-	    rc = prepare_mac( &hd->send_mac_inner_hd, &hd->send_mac_outer_hd,
-							    hd->kex.key_e );
-    }
-    if( rc )
-	return debug_rc(rc,"setup encryption keys failed");
-    return rc;
-}
-
-/****************
- * Process a received newkeys message and take the decryption keys in use
- */
-int
-kex_proc_newkeys( GSTIHD hd )
-{
-    int rc;
-
-    if( hd->pkt.type != SSH_MSG_NEWKEYS )
-	return GSTI_BUG; /* ooops */
-
-    rc = construct_keys( hd );
-    if( rc )
-	return rc;
-
-    hd->decrypt_hd = gcry_cipher_open( GCRY_CIPHER_3DES,
-				       GCRY_CIPHER_MODE_CBC, 0 );
-    if( !hd->encrypt_hd )
-	rc = map_gcry_rc( gcry_errno() );
-    else if( hd->we_are_server ) {
-	if( !rc )
-	    rc = gcry_cipher_setkey( hd->decrypt_hd, hd->kex.key_c->d,
-						    hd->kex.key_c->len );
-	if( !rc )
-	    rc = gcry_cipher_setiv( hd->decrypt_hd, hd->kex.key_a->d,
-						    hd->kex.key_a->len );
-	rc = map_gcry_rc(rc);
-	if( !rc )
-	    rc = prepare_mac( &hd->recv_mac_inner_hd, &hd->recv_mac_outer_hd,
-							    hd->kex.key_e );
-    }
-    else {
-	if( !rc )
-	    rc = gcry_cipher_setkey( hd->decrypt_hd, hd->kex.key_d->d,
-						    hd->kex.key_d->len );
-	if( !rc )
-	    rc = gcry_cipher_setiv( hd->decrypt_hd, hd->kex.key_b->d,
-						    hd->kex.key_b->len );
-	rc = map_gcry_rc(rc);
-	if( !rc )
-	    rc = prepare_mac( &hd->recv_mac_inner_hd, &hd->recv_mac_outer_hd,
-							    hd->kex.key_f );
-    }
-
-    if( rc )
-	return debug_rc(rc,"setup decryption keys failed");
-    return rc;
-}
-
-
-
-/****************
- * Parse a SSH_MSG_SERVICE_{ACCEPT,REQUEST} and return the service name.
- * Returns: 0 on success or an errorcode.
- */
-static int
-parse_msg_service( BSTRING *svcname, const byte *msg, size_t msglen, int type )
-{
-    size_t n;
-    int rc = 0;
-
-    *svcname = NULL;
-    if( msglen < (1+4) )
-	return GSTI_TOO_SHORT;
-    if( *msg != type )
-	return GSTI_BUG;
-    msg++; msglen--;
-
-    n = msglen;
-    *svcname = parse_bstring( msg, &n );
-    if( !*svcname )
-	return GSTI_TOO_SHORT;
-    msg += n; msglen -= n;
-
-    /* make sure the msg length matches */
-    if( msglen ) {
-	fprintf(stderr,"parse_msg_service: hmmm, %lu bytes remaining\n",
-			  (ulong)msglen );
-    }
-    return rc;
-}
-
-/****************
- * Build a SERVICE_{Accept,REQUEST} packet.
- */
-static int
-build_msg_service( BSTRING svcname, struct packet_buffer_s *pkt, int type )
-{
-    size_t n;
-    byte *p = pkt->payload;
-    size_t length = pkt->size;
-
-    assert( pkt->size > 100 );
-    if( !svcname ) {
-	fprintf(stderr,"build_msg_service: no service name\n");
-	return GSTI_BUG;
-    }
-
-    pkt->type = type;
-    p++; pkt->payload_len = 1;
-
-    n = build_bstring( p, length, svcname );
-    if( !n )
-	return GSTI_TOO_SHORT; /* provided buffer is too short */
-    p += n; length -= n; pkt->payload_len += n;
-    return 0;
-}
-
-
-
-int
-kex_send_service_request( GSTIHD hd, const char *name )
-{
-    int rc;
-
-    hd->service_name = make_bstring( name, strlen(name) );
-    rc = build_msg_service( hd->service_name, &hd->pkt,SSH_MSG_SERVICE_REQUEST);
-    if( !rc )
-	rc = write_packet( hd );
-    if( !rc )
-	rc = flush_packet( hd );
-
-    if( rc ) {
-	gsti_free( hd->service_name );
-	hd->service_name = NULL;
-    }
-    return rc;
-}
-
-int
-kex_proc_service_request( GSTIHD hd )
-{
-    int rc;
-    BSTRING svcname;
-
-    if( hd->pkt.type != SSH_MSG_SERVICE_REQUEST )
-	return GSTI_BUG;  /* oops */
-    rc = parse_msg_service( &svcname, hd->pkt.payload, hd->pkt.payload_len,
-						    SSH_MSG_SERVICE_REQUEST );
-    if( rc )
-	return rc;
-
-    /* FIXME: here we should whether we provide this service */
-
-    /* store the servicename, so that it can later be answered */
-    if( hd->service_name )
-	return debug_rc( GSTI_BUG, "a service is already in use");
-
-    hd->service_name = svcname;
-    return rc;
-}
-
-
-
-int
-kex_send_service_accept( GSTIHD hd )
-{
-    int rc;
-
-    rc = build_msg_service( hd->service_name, &hd->pkt, SSH_MSG_SERVICE_ACCEPT);
-    if( !rc )
-	rc = write_packet( hd );
-    if( !rc )
-	rc = flush_packet( hd );
-    return rc;
-}
-
-int
-kex_proc_service_accept( GSTIHD hd )
-{
-    int rc;
-    BSTRING svcname;
-
-    if( hd->pkt.type != SSH_MSG_SERVICE_ACCEPT )
-	return GSTI_BUG;  /* oops */
-    rc = parse_msg_service( &svcname, hd->pkt.payload, hd->pkt.payload_len,
-						    SSH_MSG_SERVICE_ACCEPT );
-    if( rc )
-	return rc;
-
-    if( !hd->service_name )
-	return debug_rc( GSTI_BUG, "no service request sent");
-    rc = cmp_bstring( hd->service_name, svcname );
-    gsti_free( svcname );
-    if( rc )
-	return debug_rc( GSTI_PROT_VIOL,
-			 "service name does not match requested one" );
-    return 0;
-}
-