upstream: Record session ID, host key and sig at intital KEX

These will be used later for agent session ID / hostkey binding

ok markus@

OpenBSD-Commit-ID: a9af29e33772b18e3e867c6fa8ab35e1694a81fe
This commit is contained in:
djm@openbsd.org 2021-12-19 22:08:06 +00:00 committed by Damien Miller
parent 26ca33d186
commit b42c61d684
5 changed files with 69 additions and 13 deletions

4
kex.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: kex.c,v 1.168 2021/04/03 06:18:40 djm Exp $ */
/* $OpenBSD: kex.c,v 1.169 2021/12/19 22:08:06 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
*
@ -699,6 +699,8 @@ kex_free(struct kex *kex)
sshbuf_free(kex->server_version);
sshbuf_free(kex->client_pub);
sshbuf_free(kex->session_id);
sshbuf_free(kex->initial_sig);
sshkey_free(kex->initial_hostkey);
free(kex->failed_choice);
free(kex->hostkey_alg);
free(kex->name);

5
kex.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: kex.h,v 1.114 2021/01/31 22:55:29 djm Exp $ */
/* $OpenBSD: kex.h,v 1.115 2021/12/19 22:08:06 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
@ -130,6 +130,7 @@ struct newkeys {
};
struct ssh;
struct sshbuf;
struct kex {
struct newkeys *newkeys[MODE_MAX];
@ -148,6 +149,8 @@ struct kex {
struct sshbuf *client_version;
struct sshbuf *server_version;
struct sshbuf *session_id;
struct sshbuf *initial_sig;
struct sshkey *initial_hostkey;
sig_atomic_t done;
u_int flags;
int hash_alg;

View File

@ -1,4 +1,4 @@
/* $OpenBSD: kexgen.c,v 1.7 2021/04/03 06:18:40 djm Exp $ */
/* $OpenBSD: kexgen.c,v 1.8 2021/12/19 22:08:06 djm Exp $ */
/*
* Copyright (c) 2019 Markus Friedl. All rights reserved.
*
@ -218,8 +218,26 @@ input_kex_gen_reply(int type, u_int32_t seq, struct ssh *ssh)
kex->hostkey_alg, ssh->compat, NULL)) != 0)
goto out;
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) != 0 ||
(r = kex_send_newkeys(ssh)) != 0)
goto out;
/* save initial signature and hostkey */
if ((kex->flags & KEX_INITIAL) != 0) {
if (kex->initial_hostkey != NULL || kex->initial_sig != NULL) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
if ((kex->initial_sig = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put(kex->initial_sig, signature, slen)) != 0)
goto out;
kex->initial_hostkey = server_host_key;
server_host_key = NULL;
}
/* success */
out:
explicit_bzero(hash, sizeof(hash));
explicit_bzero(kex->c25519_client_key, sizeof(kex->c25519_client_key));
@ -333,8 +351,15 @@ input_kex_gen_init(int type, u_int32_t seq, struct ssh *ssh)
(r = sshpkt_send(ssh)) != 0)
goto out;
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) != 0 ||
(r = kex_send_newkeys(ssh)) != 0)
goto out;
/* retain copy of hostkey used at initial KEX */
if (kex->initial_hostkey == NULL &&
(r = sshkey_from_private(server_host_public,
&kex->initial_hostkey)) != 0)
goto out;
/* success */
out:
explicit_bzero(hash, sizeof(hash));
sshbuf_free(server_host_key_blob);

View File

@ -1,4 +1,4 @@
/* $OpenBSD: kexgexc.c,v 1.37 2021/01/31 22:55:29 djm Exp $ */
/* $OpenBSD: kexgexc.c,v 1.38 2021/12/19 22:08:06 djm Exp $ */
/*
* Copyright (c) 2000 Niels Provos. All rights reserved.
* Copyright (c) 2001 Markus Friedl. All rights reserved.
@ -206,8 +206,26 @@ input_kex_dh_gex_reply(int type, u_int32_t seq, struct ssh *ssh)
hashlen, kex->hostkey_alg, ssh->compat, NULL)) != 0)
goto out;
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) != 0 ||
(r = kex_send_newkeys(ssh)) != 0)
goto out;
/* save initial signature and hostkey */
if ((kex->flags & KEX_INITIAL) != 0) {
if (kex->initial_hostkey != NULL || kex->initial_sig != NULL) {
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
if ((kex->initial_sig = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put(kex->initial_sig, signature, slen)) != 0)
goto out;
kex->initial_hostkey = server_host_key;
server_host_key = NULL;
}
/* success */
out:
explicit_bzero(hash, sizeof(hash));
DH_free(kex->dh);

View File

@ -1,4 +1,4 @@
/* $OpenBSD: kexgexs.c,v 1.43 2021/01/31 22:55:29 djm Exp $ */
/* $OpenBSD: kexgexs.c,v 1.44 2021/12/19 22:08:06 djm Exp $ */
/*
* Copyright (c) 2000 Niels Provos. All rights reserved.
* Copyright (c) 2001 Markus Friedl. All rights reserved.
@ -194,8 +194,16 @@ input_kex_dh_gex_init(int type, u_int32_t seq, struct ssh *ssh)
(r = sshpkt_send(ssh)) != 0)
goto out;
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
r = kex_send_newkeys(ssh);
if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) != 0 ||
(r = kex_send_newkeys(ssh)) != 0)
goto out;
/* retain copy of hostkey used at initial KEX */
if (kex->initial_hostkey == NULL &&
(r = sshkey_from_private(server_host_public,
&kex->initial_hostkey)) != 0)
goto out;
/* success */
out:
explicit_bzero(hash, sizeof(hash));
DH_free(kex->dh);