1 /* $OpenBSD: kex.h,v 1.91 2018/07/11 18:53:29 markus Exp $ */
4 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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.
31 #ifdef WITH_LEAKMALLOC
32 #include "leakmalloc.h"
36 # ifdef OPENSSL_HAS_ECC
37 # include <openssl/ec.h>
38 # else /* OPENSSL_HAS_ECC */
40 # define EC_GROUP void
41 # define EC_POINT void
42 # endif /* OPENSSL_HAS_ECC */
43 #else /* WITH_OPENSSL */
47 # define EC_GROUP void
48 # define EC_POINT void
49 #endif /* WITH_OPENSSL */
51 #define KEX_COOKIE_LEN 16
53 #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"
67 /* pre-auth compression (COMP_ZLIB) is only supported in the client */
69 #define COMP_DELAYED 2
71 #define CURVE25519_SIZE 32
73 enum kex_init_proposals {
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,
106 #define KEX_INIT_SENT 0x0001
110 const struct sshcipher *cipher;
133 size_t session_id_len;
134 struct newkeys *newkeys[MODE_MAX];
143 char *server_sig_algs;
151 char *client_version_string;
152 char *server_version_string;
154 int (*verify_host_key)(struct sshkey *, struct ssh *);
155 struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
156 struct sshkey *(*load_host_private_key)(int, int, struct ssh *);
157 int (*host_key_index)(struct sshkey *, int, struct ssh *);
158 int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *,
159 const u_char *, size_t, const char *, u_int);
160 int (*kex[KEX_MAX])(struct ssh *);
161 /* kex specific state */
163 u_int min, max, nbits; /* GEX */
164 EC_KEY *ec_client_key; /* ECDH */
165 const EC_GROUP *ec_group; /* ECDH */
166 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */
167 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */
170 int kex_names_valid(const char *);
171 char *kex_alg_list(char);
172 char *kex_names_cat(const char *, const char *);
173 int kex_assemble_names(char **, const char *, const char *);
175 int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **);
176 int kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
177 void kex_free_newkeys(struct newkeys *);
178 void kex_free(struct kex *);
180 int kex_buf2prop(struct sshbuf *, int *, char ***);
181 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]);
182 void kex_prop_free(char **);
184 int kex_send_kexinit(struct ssh *);
185 int kex_input_kexinit(int, u_int32_t, struct ssh *);
186 int kex_input_ext_info(int, u_int32_t, struct ssh *);
187 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *);
188 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *);
189 int kex_send_newkeys(struct ssh *);
190 int kex_start_rekex(struct ssh *);
192 int kexdh_client(struct ssh *);
193 int kexdh_server(struct ssh *);
194 int kexgex_client(struct ssh *);
195 int kexgex_server(struct ssh *);
196 int kexecdh_client(struct ssh *);
197 int kexecdh_server(struct ssh *);
198 int kexc25519_client(struct ssh *);
199 int kexc25519_server(struct ssh *);
201 int kex_dh_hash(int, const char *, const char *,
202 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
203 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *);
205 int kexgex_hash(int, const char *, const char *,
206 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
208 const BIGNUM *, const BIGNUM *, const BIGNUM *,
209 const BIGNUM *, const BIGNUM *,
212 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *,
213 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
214 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *);
216 int kex_c25519_hash(int, const char *, const char *,
217 const u_char *, size_t, const u_char *, size_t,
218 const u_char *, size_t, const u_char *, const u_char *,
219 const u_char *, size_t, u_char *, size_t *);
221 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
222 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
223 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
224 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE],
225 const u_char pub[CURVE25519_SIZE], struct sshbuf *out)
226 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
227 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
229 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
230 void dump_digest(char *, u_char *, int);
233 #if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC)