1 /* $OpenBSD: kex.h,v 1.73 2015/07/30 00:01:34 djm Exp $ */ 2 3 /* 4 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 5 * 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. 14 * 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 29 #include "mac.h" 30 #include "buffer.h" /* XXX for typedef */ 31 #include "key.h" /* XXX for typedef */ 32 33 #ifdef WITH_LEAKMALLOC 34 #include "leakmalloc.h" 35 #endif 36 37 #ifdef WITH_OPENSSL 38 # ifdef OPENSSL_HAS_ECC 39 # include <openssl/ec.h> 40 # else /* OPENSSL_HAS_ECC */ 41 # define EC_KEY void 42 # define EC_GROUP void 43 # define EC_POINT void 44 # endif /* OPENSSL_HAS_ECC */ 45 #else /* WITH_OPENSSL */ 46 # define EC_KEY void 47 # define EC_GROUP void 48 # define EC_POINT void 49 #endif /* WITH_OPENSSL */ 50 51 #define KEX_COOKIE_LEN 16 52 53 #define KEX_DH1 "diffie-hellman-group1-sha1" 54 #define KEX_DH14 "diffie-hellman-group14-sha1" 55 #define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1" 56 #define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256" 57 #define KEX_RESUME "resume (at) appgate.com" 58 #define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256" 59 #define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384" 60 #define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521" 61 #define KEX_CURVE25519_SHA256 "curve25519-sha256 (at) libssh.org" 62 63 #define COMP_NONE 0 64 #define COMP_ZLIB 1 65 #define COMP_DELAYED 2 66 67 #define CURVE25519_SIZE 32 68 69 enum kex_init_proposals { 70 PROPOSAL_KEX_ALGS, 71 PROPOSAL_SERVER_HOST_KEY_ALGS, 72 PROPOSAL_ENC_ALGS_CTOS, 73 PROPOSAL_ENC_ALGS_STOC, 74 PROPOSAL_MAC_ALGS_CTOS, 75 PROPOSAL_MAC_ALGS_STOC, 76 PROPOSAL_COMP_ALGS_CTOS, 77 PROPOSAL_COMP_ALGS_STOC, 78 PROPOSAL_LANG_CTOS, 79 PROPOSAL_LANG_STOC, 80 PROPOSAL_MAX 81 }; 82 83 enum kex_modes { 84 MODE_IN, 85 MODE_OUT, 86 MODE_MAX 87 }; 88 89 enum kex_exchange { 90 KEX_DH_GRP1_SHA1, 91 KEX_DH_GRP14_SHA1, 92 KEX_DH_GEX_SHA1, 93 KEX_DH_GEX_SHA256, 94 KEX_ECDH_SHA2, 95 KEX_C25519_SHA256, 96 KEX_MAX 97 }; 98 99 #define KEX_INIT_SENT 0x0001 100 101 struct sshenc { 102 char *name; 103 const struct sshcipher *cipher; 104 int enabled; 105 u_int key_len; 106 u_int iv_len; 107 u_int block_size; 108 u_char *key; 109 u_char *iv; 110 }; 111 struct sshcomp { 112 u_int type; 113 int enabled; 114 char *name; 115 }; 116 struct newkeys { 117 struct sshenc enc; 118 struct sshmac mac; 119 struct sshcomp comp; 120 }; 121 122 struct ssh; 123 124 struct kex { 125 u_char *session_id; 126 size_t session_id_len; 127 struct newkeys *newkeys[MODE_MAX]; 128 u_int we_need; 129 u_int dh_need; 130 int server; 131 char *name; 132 int hostkey_type; 133 int hostkey_nid; 134 u_int kex_type; 135 int roaming; 136 struct sshbuf *my; 137 struct sshbuf *peer; 138 sig_atomic_t done; 139 u_int flags; 140 int hash_alg; 141 int ec_nid; 142 char *client_version_string; 143 char *server_version_string; 144 char *failed_choice; 145 int (*verify_host_key)(struct sshkey *, struct ssh *); 146 struct sshkey *(*load_host_public_key)(int, int, struct ssh *); 147 struct sshkey *(*load_host_private_key)(int, int, struct ssh *); 148 int (*host_key_index)(struct sshkey *, int, struct ssh *); 149 int (*sign)(struct sshkey *, struct sshkey *, 150 u_char **, size_t *, const u_char *, size_t, u_int); 151 int (*kex[KEX_MAX])(struct ssh *); 152 /* kex specific state */ 153 DH *dh; /* DH */ 154 u_int min, max, nbits; /* GEX */ 155 EC_KEY *ec_client_key; /* ECDH */ 156 const EC_GROUP *ec_group; /* ECDH */ 157 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */ 158 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ 159 }; 160 161 int kex_names_valid(const char *); 162 char *kex_alg_list(char); 163 char *kex_names_cat(const char *, const char *); 164 int kex_assemble_names(const char *, char **); 165 166 int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **); 167 int kex_setup(struct ssh *, char *[PROPOSAL_MAX]); 168 void kex_free_newkeys(struct newkeys *); 169 void kex_free(struct kex *); 170 171 int kex_buf2prop(struct sshbuf *, int *, char ***); 172 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); 173 void kex_prop_free(char **); 174 175 int kex_send_kexinit(struct ssh *); 176 int kex_input_kexinit(int, u_int32_t, void *); 177 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); 178 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *); 179 int kex_send_newkeys(struct ssh *); 180 181 int kexdh_client(struct ssh *); 182 int kexdh_server(struct ssh *); 183 int kexgex_client(struct ssh *); 184 int kexgex_server(struct ssh *); 185 int kexecdh_client(struct ssh *); 186 int kexecdh_server(struct ssh *); 187 int kexc25519_client(struct ssh *); 188 int kexc25519_server(struct ssh *); 189 190 int kex_dh_hash(const char *, const char *, 191 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 192 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); 193 194 int kexgex_hash(int, const char *, const char *, 195 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 196 int, int, int, 197 const BIGNUM *, const BIGNUM *, const BIGNUM *, 198 const BIGNUM *, const BIGNUM *, 199 u_char *, size_t *); 200 201 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *, 202 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 203 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *); 204 205 int kex_c25519_hash(int, const char *, const char *, const char *, size_t, 206 const char *, size_t, const u_char *, size_t, const u_char *, const u_char *, 207 const u_char *, size_t, u_char *, size_t *); 208 209 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) 210 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 211 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 212 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], 213 const u_char pub[CURVE25519_SIZE], struct sshbuf *out) 214 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 215 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 216 217 int 218 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]); 219 220 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 221 void dump_digest(char *, u_char *, int); 222 #endif 223 224 #if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC) 225 # undef EC_KEY 226 # undef EC_GROUP 227 # undef EC_POINT 228 #endif 229 230 #endif 231
