Mercurial > dropbear

comparison common-kex.c @ 755:b07eb3dc23ec ecc

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
refactor kexdh code a bit, start working on ecdh etc
author Matt Johnston <matt@ucc.asn.au>
date Tue, 26 Mar 2013 01:35:22 +0800
parents bf0ac0512ef7
children bf9dc2d9c2b1
comparison
equal deleted inserted replaced
725:49f68a7b7a55 755:b07eb3dc23ec
547 } 547 }
548 548
549 /* Initialises and generate one side of the diffie-hellman key exchange values. 549 /* Initialises and generate one side of the diffie-hellman key exchange values.
550 * See the transport rfc 4253 section 8 for details */ 550 * See the transport rfc 4253 section 8 for details */
551 /* dh_pub and dh_priv MUST be already initialised */ 551 /* dh_pub and dh_priv MUST be already initialised */
552 void gen_kexdh_vals(mp_int *dh_pub, mp_int *dh_priv) { 552 struct kex_dh_param *gen_kexdh_param() {
553 553
554 DEF_MP_INT(dh_p); 554 DEF_MP_INT(dh_p);
555 DEF_MP_INT(dh_q); 555 DEF_MP_INT(dh_q);
556 DEF_MP_INT(dh_g); 556 DEF_MP_INT(dh_g);
557 557
558 TRACE(("enter send_msg_kexdh_reply")) 558 TRACE(("enter send_msg_kexdh_reply"))
559 559
560 m_mp_init_multi(&dh_g, &dh_p, &dh_q, NULL); 560 struct kex_dh_param *param = m_malloc(sizeof(*param));
561 m_mp_init_multi(&param->pub, &param->priv, NULL);
561 562
562 /* read the prime and generator*/ 563 /* read the prime and generator*/
563 load_dh_p(&dh_p); 564 load_dh_p(&dh_p);
564 565
565 if (mp_set_int(&dh_g, DH_G_VAL) != MP_OKAY) { 566 if (mp_set_int(&dh_g, DH_G_VAL) != MP_OKAY) {
566 dropbear_exit("Diffie-Hellman error"); 567 dropbear_exit("Diffie-Hellman error");
567 } 568 }
568 569
569 /* calculate q = (p-1)/2 */ 570 /* calculate q = (p-1)/2 */
570 /* dh_priv is just a temp var here */ 571 /* dh_priv is just a temp var here */
571 if (mp_sub_d(&dh_p, 1, dh_priv) != MP_OKAY) { 572 if (mp_sub_d(&dh_p, 1, &param->priv) != MP_OKAY) {
572 dropbear_exit("Diffie-Hellman error"); 573 dropbear_exit("Diffie-Hellman error");
573 } 574 }
574 if (mp_div_2(dh_priv, &dh_q) != MP_OKAY) { 575 if (mp_div_2(&param->priv, &dh_q) != MP_OKAY) {
575 dropbear_exit("Diffie-Hellman error"); 576 dropbear_exit("Diffie-Hellman error");
576 } 577 }
577 578
578 /* Generate a private portion 0 < dh_priv < dh_q */ 579 /* Generate a private portion 0 < dh_priv < dh_q */
579 gen_random_mpint(&dh_q, dh_priv); 580 gen_random_mpint(&dh_q, &param->priv);
580 581
581 /* f = g^y mod p */ 582 /* f = g^y mod p */
582 if (mp_exptmod(&dh_g, dh_priv, &dh_p, dh_pub) != MP_OKAY) { 583 if (mp_exptmod(&dh_g, &param->priv, &dh_p, &param->pub) != MP_OKAY) {
583 dropbear_exit("Diffie-Hellman error"); 584 dropbear_exit("Diffie-Hellman error");
584 } 585 }
585 mp_clear_multi(&dh_g, &dh_p, &dh_q, NULL); 586 mp_clear_multi(&dh_g, &dh_p, &dh_q, NULL);
587 return param;
588 }
589
590 void free_kexdh_param(struct kex_dh_param *param)
591 {
592 mp_clear_multi(&param->pub, &param->priv, NULL);
593 m_free(param);
586 } 594 }
587 595
588 /* This function is fairly common between client/server, with some substitution 596 /* This function is fairly common between client/server, with some substitution
589 * of dh_e/dh_f etc. Hence these arguments: 597 * of dh_e/dh_f etc. Hence these arguments:
590 * dh_pub_us is 'e' for the client, 'f' for the server. dh_pub_them is 598 * dh_pub_us is 'e' for the client, 'f' for the server. dh_pub_them is
591 * vice-versa. dh_priv is the x/y value corresponding to dh_pub_us */ 599 * vice-versa. dh_priv is the x/y value corresponding to dh_pub_us */
592 void kexdh_comb_key(mp_int *dh_pub_us, mp_int *dh_priv, mp_int *dh_pub_them, 600 void kexdh_comb_key(struct kex_dh_param *param, mp_int *dh_pub_them,
593 sign_key *hostkey) { 601 sign_key *hostkey) {
594 602
595 mp_int dh_p; 603 mp_int dh_p;
596 mp_int *dh_e = NULL, *dh_f = NULL; 604 mp_int *dh_e = NULL, *dh_f = NULL;
605
597 hash_state hs; 606 hash_state hs;
598 607
599 /* read the prime and generator*/ 608 /* read the prime and generator*/
600 m_mp_init(&dh_p); 609 m_mp_init(&dh_p);
601 load_dh_p(&dh_p); 610 load_dh_p(&dh_p);
607 } 616 }
608 617
609 /* K = e^y mod p = f^x mod p */ 618 /* K = e^y mod p = f^x mod p */
610 ses.dh_K = (mp_int*)m_malloc(sizeof(mp_int)); 619 ses.dh_K = (mp_int*)m_malloc(sizeof(mp_int));
611 m_mp_init(ses.dh_K); 620 m_mp_init(ses.dh_K);
612 if (mp_exptmod(dh_pub_them, dh_priv, &dh_p, ses.dh_K) != MP_OKAY) { 621 if (mp_exptmod(dh_pub_them, &param->priv, &dh_p, ses.dh_K) != MP_OKAY) {
613 dropbear_exit("Diffie-Hellman error"); 622 dropbear_exit("Diffie-Hellman error");
614 } 623 }
615 624
616 /* clear no longer needed vars */ 625 /* clear no longer needed vars */
617 mp_clear_multi(&dh_p, NULL); 626 mp_clear_multi(&dh_p, NULL);
618 627
619 /* From here on, the code needs to work with the _same_ vars on each side, 628 /* From here on, the code needs to work with the _same_ vars on each side,
620 * not vice-versaing for client/server */ 629 * not vice-versaing for client/server */
621 if (IS_DROPBEAR_CLIENT) { 630 if (IS_DROPBEAR_CLIENT) {
622 dh_e = dh_pub_us; 631 dh_e = &param->pub;
623 dh_f = dh_pub_them; 632 dh_f = dh_pub_them;
624 } else { 633 } else {
625 dh_e = dh_pub_them; 634 dh_e = dh_pub_them;
626 dh_f = dh_pub_us; 635 dh_f = &param->pub;
627 } 636 }
628 637
629 /* Create the remainder of the hash buffer, to generate the exchange hash */ 638 /* Create the remainder of the hash buffer, to generate the exchange hash */
630 /* K_S, the host key */ 639 /* K_S, the host key */
631 buf_put_pub_key(ses.kexhashbuf, hostkey, ses.newkeys->algo_hostkey); 640 buf_put_pub_key(ses.kexhashbuf, hostkey, ses.newkeys->algo_hostkey);
652 /* create the session_id, this never needs freeing */ 661 /* create the session_id, this never needs freeing */
653 ses.session_id = (unsigned char*)m_malloc(SHA1_HASH_SIZE); 662 ses.session_id = (unsigned char*)m_malloc(SHA1_HASH_SIZE);
654 memcpy(ses.session_id, ses.hash, SHA1_HASH_SIZE); 663 memcpy(ses.session_id, ses.hash, SHA1_HASH_SIZE);
655 } 664 }
656 } 665 }
666
667 #ifdef DROPBEAR_ECDH
668 struct kex_ecdh_param *gen_kexecdh_param() {
669 struct kex_ecdh_param *param = m_malloc(sizeof(*param));
670 if (ecc_make_key_ex(NULL, dropbear_ltc_prng, &param->key
671 }
672 void free_kexecdh_param(struct kex_ecdh_param *param);
673 void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them,
674 sign_key *hostkey);
675 #endif
657 676
658 /* read the other side's algo list. buf_match_algo is a callback to match 677 /* read the other side's algo list. buf_match_algo is a callback to match
659 * algos for the client or server. */ 678 * algos for the client or server. */
660 static void read_kex_algos() { 679 static void read_kex_algos() {
661 680