crypto/openssh/kex.c

1 /* $OpenBSD: kex.c,v 1.117 2016/02/08 10:57:07 djm Exp $ */
45 #include "kex.h"
165 	debug3("kex names ok: [%s]", names);
278 	/* extract kex init proposal strings */
284 	/* first kex follows / reserved */
320 	error("kex protocol error: type %d seq %u", type, seq);
362 	if (ssh->kex->ext_info_c)
372 	struct kex *kex = ssh->kex;
392 				kex->rsa_sha2 = 256;
397 				kex->rsa_sha2 = 512;
411 	struct kex *kex = ssh->kex;
418 	kex->done = 1;
419 	sshbuf_reset(kex->peer);
420 	/* sshbuf_reset(kex->my); */
421 	kex->flags &= ~KEX_INIT_SENT;
422 	free(kex->name);
423 	kex->name = NULL;
431 	struct kex *kex = ssh->kex;
434 	if (kex == NULL)
436 	if (kex->flags & KEX_INIT_SENT)
438 	kex->done = 0;
441 	if (sshbuf_len(kex->my) < KEX_COOKIE_LEN)
443 	if ((cookie = sshbuf_mutable_ptr(kex->my)) == NULL)
448 	    (r = sshpkt_putb(ssh, kex->my)) != 0 ||
452 	kex->flags |= KEX_INIT_SENT;
461 	struct kex *kex = ssh->kex;
468 	if (kex == NULL)
473 	if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
498 	if (!(kex->flags & KEX_INIT_SENT))
504 	if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)
505 		return (kex->kex[kex->kex_type])(ssh);
511 kex_new(struct ssh *ssh, char *proposal[PROPOSAL_MAX], struct kex **kexp)
513 	struct kex *kex;
517 	if ((kex = calloc(1, sizeof(*kex))) == NULL)
519 	if ((kex->peer = sshbuf_new()) == NULL ||
520 	    (kex->my = sshbuf_new()) == NULL) {
524 	if ((r = kex_prop2buf(kex->my, proposal)) != 0)
526 	kex->done = 0;
529 	*kexp = kex;
532 		kex_free(kex);
568 kex_free(struct kex *kex)
573 	if (kex->dh)
574 		DH_free(kex->dh);
576 	if (kex->ec_client_key)
577 		EC_KEY_free(kex->ec_client_key);
581 		kex_free_newkeys(kex->newkeys[mode]);
582 		kex->newkeys[mode] = NULL;
584 	sshbuf_free(kex->peer);
585 	sshbuf_free(kex->my);
586 	free(kex->session_id);
587 	free(kex->client_version_string);
588 	free(kex->server_version_string);
589 	free(kex->failed_choice);
590 	free(kex->hostkey_alg);
591 	free(kex->name);
592 	free(kex);
600 	if ((r = kex_new(ssh, proposal, &ssh->kex)) != 0)
603 		kex_free(ssh->kex);
604 		ssh->kex = NULL;
617 	if (ssh->kex == NULL) {
618 		error("%s: no kex", __func__);
621 	if (ssh->kex->done == 0) {
625 	ssh->kex->done = 0;
687 choose_kex(struct kex *k, char *client, char *server)
693 	debug("kex: algorithm: %s", k->name ? k->name : "(no match)");
705 choose_hostkeyalg(struct kex *k, char *client, char *server)
709 	debug("kex: host key algorithm: %s",
747 	struct kex *kex = ssh->kex;
755 	debug2("local %s KEXINIT proposal", kex->server ? "server" : "client");
756 	if ((r = kex_buf2prop(kex->my, NULL, &my)) != 0)
758 	debug2("peer %s KEXINIT proposal", kex->server ? "client" : "server");
759 	if ((r = kex_buf2prop(kex->peer, &first_kex_follows, &peer)) != 0)
762 	if (kex->server) {
771 	if (kex->server) {
776 			kex->ext_info_c = 1;
782 	if ((r = choose_kex(kex, cprop[PROPOSAL_KEX_ALGS],
784 		kex->failed_choice = peer[PROPOSAL_KEX_ALGS];
788 	if ((r = choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
790 		kex->failed_choice = peer[PROPOSAL_SERVER_HOST_KEY_ALGS];
799 		kex->newkeys[mode] = newkeys;
800 		ctos = (!kex->server && mode == MODE_OUT) ||
801 		    (kex->server && mode == MODE_IN);
807 			kex->failed_choice = peer[nenc];
816 			kex->failed_choice = peer[nmac];
822 			kex->failed_choice = peer[ncomp];
826 		debug("kex: %s cipher: %s MAC: %s compression: %s",
834 		newkeys = kex->newkeys[mode];
845 	kex->we_need = need;
846 	kex->dh_need = dh_need;
863 	struct kex *kex = ssh->kex;
871 	if ((mdsz = ssh_digest_bytes(kex->hash_alg)) == 0)
879 	if ((hashctx = ssh_digest_start(kex->hash_alg)) == NULL ||
883 	    ssh_digest_update(hashctx, kex->session_id,
884 	    kex->session_id_len) != 0 ||
898 		if ((hashctx = ssh_digest_start(kex->hash_alg)) == NULL ||
927 	struct kex *kex = ssh->kex;
933 		if ((r = derive_key(ssh, 'A'+i, kex->we_need, hash, hashlen,
941 		ctos = (!kex->server && mode == MODE_OUT) ||
942 		    (kex->server && mode == MODE_IN);
943 		kex->newkeys[mode]->enc.iv  = keys[ctos ? 0 : 1];
944 		kex->newkeys[mode]->enc.key = keys[ctos ? 2 : 3];
945 		kex->newkeys[mode]->mac.key = keys[ctos ? 4 : 5];