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djm@openbsd.org04c091f2019-01-19 21:43:56 +00001/* $OpenBSD: kex.h,v 1.94 2019/01/19 21:43:56 djm Exp $ */
Ben Lindstrom36579d32001-01-29 07:39:26 +00002
Damien Miller33b13562000-04-04 14:38:59 +10003/*
Ben Lindstrom44697232001-07-04 03:32:30 +00004 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
Damien Miller33b13562000-04-04 14:38:59 +10005 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
Damien Miller33b13562000-04-04 14:38:59 +100014 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26#ifndef KEX_H
27#define KEX_H
28
markus@openbsd.org128343b2015-01-13 19:31:40 +000029#include "mac.h"
30
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000031#ifdef WITH_LEAKMALLOC
32#include "leakmalloc.h"
Darren Tucker8ccb7392010-09-10 12:28:24 +100033#endif
Damien Millerd8337c52006-07-24 14:14:19 +100034
Damien Miller773dda22015-01-30 23:10:17 +110035#ifdef WITH_OPENSSL
36# ifdef OPENSSL_HAS_ECC
37# include <openssl/ec.h>
38# else /* OPENSSL_HAS_ECC */
39# define EC_KEY void
40# define EC_GROUP void
41# define EC_POINT void
42# endif /* OPENSSL_HAS_ECC */
43#else /* WITH_OPENSSL */
Damien Millereef14472018-07-12 14:49:26 +100044# define DH void
45# define BIGNUM void
Damien Miller773dda22015-01-30 23:10:17 +110046# define EC_KEY void
47# define EC_GROUP void
48# define EC_POINT void
49#endif /* WITH_OPENSSL */
50
Darren Tucker5b48cdd2009-06-21 18:15:25 +100051#define KEX_COOKIE_LEN 16
52
djm@openbsd.orgb97739d2016-09-22 21:15:41 +000053#define KEX_DH1 "diffie-hellman-group1-sha1"
54#define KEX_DH14_SHA1 "diffie-hellman-group14-sha1"
55#define KEX_DH14_SHA256 "diffie-hellman-group14-sha256"
56#define KEX_DH16_SHA512 "diffie-hellman-group16-sha512"
57#define KEX_DH18_SHA512 "diffie-hellman-group18-sha512"
58#define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1"
59#define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256"
60#define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256"
61#define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384"
62#define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521"
63#define KEX_CURVE25519_SHA256 "curve25519-sha256"
64#define KEX_CURVE25519_SHA256_OLD "curve25519-sha256@libssh.org"
Damien Miller33b13562000-04-04 14:38:59 +100065
Damien Miller9786e6e2005-07-26 21:54:56 +100066#define COMP_NONE 0
sf@openbsd.org984bacf2018-07-10 09:36:58 +000067/* pre-auth compression (COMP_ZLIB) is only supported in the client */
sf@openbsd.orgab392672018-07-06 09:06:14 +000068#define COMP_ZLIB 1
sf@openbsd.org168b46f2018-07-09 13:37:10 +000069#define COMP_DELAYED 2
Damien Miller9786e6e2005-07-26 21:54:56 +100070
markus@openbsd.org57d10cb2015-01-19 20:16:15 +000071#define CURVE25519_SIZE 32
72
Damien Miller33b13562000-04-04 14:38:59 +100073enum kex_init_proposals {
74 PROPOSAL_KEX_ALGS,
75 PROPOSAL_SERVER_HOST_KEY_ALGS,
76 PROPOSAL_ENC_ALGS_CTOS,
77 PROPOSAL_ENC_ALGS_STOC,
78 PROPOSAL_MAC_ALGS_CTOS,
79 PROPOSAL_MAC_ALGS_STOC,
80 PROPOSAL_COMP_ALGS_CTOS,
81 PROPOSAL_COMP_ALGS_STOC,
82 PROPOSAL_LANG_CTOS,
83 PROPOSAL_LANG_STOC,
84 PROPOSAL_MAX
85};
86
87enum kex_modes {
88 MODE_IN,
89 MODE_OUT,
90 MODE_MAX
91};
92
Damien Miller874d77b2000-10-14 16:23:11 +110093enum kex_exchange {
Damien Miller8e7fb332003-02-24 12:03:03 +110094 KEX_DH_GRP1_SHA1,
Damien Millerf675fc42004-06-15 10:30:09 +100095 KEX_DH_GRP14_SHA1,
djm@openbsd.org0e8eeec2016-05-02 10:26:04 +000096 KEX_DH_GRP14_SHA256,
97 KEX_DH_GRP16_SHA512,
98 KEX_DH_GRP18_SHA512,
Damien Miller8e7fb332003-02-24 12:03:03 +110099 KEX_DH_GEX_SHA1,
Damien Millera63128d2006-03-15 12:08:28 +1100100 KEX_DH_GEX_SHA256,
Damien Millereb8b60e2010-08-31 22:41:14 +1000101 KEX_ECDH_SHA2,
Damien Miller1e124262013-11-04 08:26:52 +1100102 KEX_C25519_SHA256,
Damien Miller8e7fb332003-02-24 12:03:03 +1100103 KEX_MAX
Damien Miller874d77b2000-10-14 16:23:11 +1100104};
Kevin Stevesef4eea92001-02-05 12:42:17 +0000105
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000106#define KEX_INIT_SENT 0x0001
djm@openbsd.orga6a07882018-12-07 03:39:40 +0000107#define KEX_INITIAL 0x0002
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000108
markus@openbsd.org091c3022015-01-19 19:52:16 +0000109struct sshenc {
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000110 char *name;
markus@openbsd.org091c3022015-01-19 19:52:16 +0000111 const struct sshcipher *cipher;
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000112 int enabled;
Damien Miller963f6b22002-02-19 15:21:23 +1100113 u_int key_len;
Damien Miller1d75abf2013-01-09 16:12:19 +1100114 u_int iv_len;
Damien Miller963f6b22002-02-19 15:21:23 +1100115 u_int block_size;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000116 u_char *key;
117 u_char *iv;
Damien Miller33b13562000-04-04 14:38:59 +1000118};
markus@openbsd.org091c3022015-01-19 19:52:16 +0000119struct sshcomp {
120 u_int type;
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000121 int enabled;
122 char *name;
Damien Miller33b13562000-04-04 14:38:59 +1000123};
markus@openbsd.org091c3022015-01-19 19:52:16 +0000124struct newkeys {
125 struct sshenc enc;
126 struct sshmac mac;
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000127 struct sshcomp comp;
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000128};
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000129
130struct ssh;
131
markus@openbsd.org091c3022015-01-19 19:52:16 +0000132struct kex {
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000133 u_char *session_id;
markus@openbsd.org091c3022015-01-19 19:52:16 +0000134 size_t session_id_len;
135 struct newkeys *newkeys[MODE_MAX];
Damien Millereccb9de2005-06-17 12:59:34 +1000136 u_int we_need;
Damien Miller76eea4a2014-01-26 09:37:25 +1100137 u_int dh_need;
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000138 int server;
139 char *name;
markus@openbsd.org76c9fbb2015-12-04 16:41:28 +0000140 char *hostkey_alg;
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000141 int hostkey_type;
djm@openbsd.org5104db72015-01-26 06:10:03 +0000142 int hostkey_nid;
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000143 u_int kex_type;
djm@openbsd.org4ba0d542018-07-03 11:39:54 +0000144 char *server_sig_algs;
markus@openbsd.org76c9fbb2015-12-04 16:41:28 +0000145 int ext_info_c;
markus@openbsd.org091c3022015-01-19 19:52:16 +0000146 struct sshbuf *my;
147 struct sshbuf *peer;
djm@openbsd.org0a843d92018-12-27 03:25:24 +0000148 struct sshbuf *client_version;
149 struct sshbuf *server_version;
Damien Miller97c91f62006-04-23 12:08:37 +1000150 sig_atomic_t done;
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000151 u_int flags;
Damien Millerb3051d02014-01-10 10:58:53 +1100152 int hash_alg;
Damien Millerea111192013-04-23 19:24:32 +1000153 int ec_nid;
djm@openbsd.orgf3199122015-07-29 04:43:06 +0000154 char *failed_choice;
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000155 int (*verify_host_key)(struct sshkey *, struct ssh *);
djm@openbsd.org5104db72015-01-26 06:10:03 +0000156 struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
157 struct sshkey *(*load_host_private_key)(int, int, struct ssh *);
djm@openbsd.org523463a2015-02-16 22:13:32 +0000158 int (*host_key_index)(struct sshkey *, int, struct ssh *);
djm@openbsd.org04c091f2019-01-19 21:43:56 +0000159 int (*sign)(struct ssh *, struct sshkey *, struct sshkey *,
160 u_char **, size_t *, const u_char *, size_t, const char *);
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000161 int (*kex[KEX_MAX])(struct ssh *);
162 /* kex specific state */
163 DH *dh; /* DH */
164 u_int min, max, nbits; /* GEX */
165 EC_KEY *ec_client_key; /* ECDH */
166 const EC_GROUP *ec_group; /* ECDH */
167 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */
168 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */
Damien Miller33b13562000-04-04 14:38:59 +1000169};
170
Damien Millerd5f62bf2010-09-24 22:11:14 +1000171int kex_names_valid(const char *);
Damien Miller690d9892013-11-08 12:16:49 +1100172char *kex_alg_list(char);
djm@openbsd.orgf9eca242015-07-30 00:01:34 +0000173char *kex_names_cat(const char *, const char *);
djm@openbsd.org312d2f22018-07-04 13:49:31 +0000174int kex_assemble_names(char **, const char *, const char *);
Damien Millerd5f62bf2010-09-24 22:11:14 +1000175
djm@openbsd.org0a843d92018-12-27 03:25:24 +0000176int kex_exchange_identification(struct ssh *, int, const char *);
177
178struct kex *kex_new(void);
179int kex_ready(struct ssh *, char *[PROPOSAL_MAX]);
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000180int kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
181void kex_free_newkeys(struct newkeys *);
182void kex_free(struct kex *);
Ben Lindstrom238abf62001-04-04 17:52:53 +0000183
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000184int kex_buf2prop(struct sshbuf *, int *, char ***);
185int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]);
186void kex_prop_free(char **);
187
188int kex_send_kexinit(struct ssh *);
markus@openbsd.org2ae666a2017-05-30 14:23:52 +0000189int kex_input_kexinit(int, u_int32_t, struct ssh *);
190int kex_input_ext_info(int, u_int32_t, struct ssh *);
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000191int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *);
192int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *);
193int kex_send_newkeys(struct ssh *);
djm@openbsd.org19bcf2e2016-02-08 10:57:07 +0000194int kex_start_rekex(struct ssh *);
Damien Miller33b13562000-04-04 14:38:59 +1000195
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000196int kexdh_client(struct ssh *);
197int kexdh_server(struct ssh *);
198int kexgex_client(struct ssh *);
199int kexgex_server(struct ssh *);
200int kexecdh_client(struct ssh *);
201int kexecdh_server(struct ssh *);
202int kexc25519_client(struct ssh *);
203int kexc25519_server(struct ssh *);
Damien Miller8e7fb332003-02-24 12:03:03 +1100204
djm@openbsd.org0a843d92018-12-27 03:25:24 +0000205int kex_dh_hash(int, const struct sshbuf *, const struct sshbuf *,
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000206 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
207 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *);
Damien Miller1e124262013-11-04 08:26:52 +1100208
djm@openbsd.org0a843d92018-12-27 03:25:24 +0000209int kexgex_hash(int, const struct sshbuf *, const struct sshbuf *,
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000210 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
211 int, int, int,
212 const BIGNUM *, const BIGNUM *, const BIGNUM *,
213 const BIGNUM *, const BIGNUM *,
214 u_char *, size_t *);
215
djm@openbsd.org0a843d92018-12-27 03:25:24 +0000216int kex_ecdh_hash(int, const EC_GROUP *,
217 const struct sshbuf *, const struct sshbuf *,
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000218 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
219 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *);
220
djm@openbsd.org0a843d92018-12-27 03:25:24 +0000221int kex_c25519_hash(int, const struct sshbuf *, const struct sshbuf *,
djm@openbsd.org1a31d022016-05-02 08:49:03 +0000222 const u_char *, size_t, const u_char *, size_t,
223 const u_char *, size_t, const u_char *, const u_char *,
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000224 const u_char *, size_t, u_char *, size_t *);
225
226void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
Damien Miller686c7d92014-05-15 14:37:03 +1000227 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
228 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
markus@openbsd.org57d10cb2015-01-19 20:16:15 +0000229int kexc25519_shared_key(const u_char key[CURVE25519_SIZE],
230 const u_char pub[CURVE25519_SIZE], struct sshbuf *out)
Damien Miller686c7d92014-05-15 14:37:03 +1000231 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
232 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
Damien Miller8e7fb332003-02-24 12:03:03 +1100233
Damien Millereb8b60e2010-08-31 22:41:14 +1000234#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
Ben Lindstrom16ae3d02001-07-04 04:02:36 +0000235void dump_digest(char *, u_char *, int);
Ben Lindstrom20d7c7b2001-04-04 01:56:17 +0000236#endif
237
Damien Miller773dda22015-01-30 23:10:17 +1100238#if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC)
239# undef EC_KEY
240# undef EC_GROUP
241# undef EC_POINT
242#endif
243
Damien Miller33b13562000-04-04 14:38:59 +1000244#endif