1 /* $OpenBSD: kex.h,v 1.81 2016/09/28 21:44:52 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_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 (at) libssh.org" 65 66 #define COMP_NONE 0 67 #define COMP_ZLIB 1 68 #define COMP_DELAYED 2 69 70 #define CURVE25519_SIZE 32 71 72 enum kex_init_proposals { 73 PROPOSAL_KEX_ALGS, 74 PROPOSAL_SERVER_HOST_KEY_ALGS, 75 PROPOSAL_ENC_ALGS_CTOS, 76 PROPOSAL_ENC_ALGS_STOC, 77 PROPOSAL_MAC_ALGS_CTOS, 78 PROPOSAL_MAC_ALGS_STOC, 79 PROPOSAL_COMP_ALGS_CTOS, 80 PROPOSAL_COMP_ALGS_STOC, 81 PROPOSAL_LANG_CTOS, 82 PROPOSAL_LANG_STOC, 83 PROPOSAL_MAX 84 }; 85 86 enum kex_modes { 87 MODE_IN, 88 MODE_OUT, 89 MODE_MAX 90 }; 91 92 enum kex_exchange { 93 KEX_DH_GRP1_SHA1, 94 KEX_DH_GRP14_SHA1, 95 KEX_DH_GRP14_SHA256, 96 KEX_DH_GRP16_SHA512, 97 KEX_DH_GRP18_SHA512, 98 KEX_DH_GEX_SHA1, 99 KEX_DH_GEX_SHA256, 100 KEX_ECDH_SHA2, 101 KEX_C25519_SHA256, 102 KEX_MAX 103 }; 104 105 #define KEX_INIT_SENT 0x0001 106 107 struct sshenc { 108 char *name; 109 const struct sshcipher *cipher; 110 int enabled; 111 u_int key_len; 112 u_int iv_len; 113 u_int block_size; 114 u_char *key; 115 u_char *iv; 116 }; 117 struct sshcomp { 118 u_int type; 119 int enabled; 120 char *name; 121 }; 122 struct newkeys { 123 struct sshenc enc; 124 struct sshmac mac; 125 struct sshcomp comp; 126 }; 127 128 struct ssh; 129 130 struct kex { 131 u_char *session_id; 132 size_t session_id_len; 133 struct newkeys *newkeys[MODE_MAX]; 134 u_int we_need; 135 u_int dh_need; 136 int server; 137 char *name; 138 char *hostkey_alg; 139 int hostkey_type; 140 int hostkey_nid; 141 u_int kex_type; 142 int rsa_sha2; 143 int ext_info_c; 144 struct sshbuf *my; 145 struct sshbuf *peer; 146 sig_atomic_t done; 147 u_int flags; 148 int hash_alg; 149 int ec_nid; 150 char *client_version_string; 151 char *server_version_string; 152 char *failed_choice; 153 int (*verify_host_key)(struct sshkey *, struct ssh *); 154 struct sshkey *(*load_host_public_key)(int, int, struct ssh *); 155 struct sshkey *(*load_host_private_key)(int, int, struct ssh *); 156 int (*host_key_index)(struct sshkey *, int, struct ssh *); 157 int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *, 158 const u_char *, size_t, const char *, u_int); 159 int (*kex[KEX_MAX])(struct ssh *); 160 /* kex specific state */ 161 DH *dh; /* DH */ 162 u_int min, max, nbits; /* GEX */ 163 EC_KEY *ec_client_key; /* ECDH */ 164 const EC_GROUP *ec_group; /* ECDH */ 165 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */ 166 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ 167 }; 168 169 int kex_names_valid(const char *); 170 char *kex_alg_list(char); 171 char *kex_names_cat(const char *, const char *); 172 int kex_assemble_names(const char *, char **); 173 174 int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **); 175 int kex_setup(struct ssh *, char *[PROPOSAL_MAX]); 176 void kex_free_newkeys(struct newkeys *); 177 void kex_free(struct kex *); 178 179 int kex_buf2prop(struct sshbuf *, int *, char ***); 180 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); 181 void kex_prop_free(char **); 182 183 int kex_send_kexinit(struct ssh *); 184 int kex_input_kexinit(int, u_int32_t, void *); 185 int kex_input_ext_info(int, u_int32_t, void *); 186 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); 187 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *); 188 int kex_send_newkeys(struct ssh *); 189 int kex_start_rekex(struct ssh *); 190 191 int kexdh_client(struct ssh *); 192 int kexdh_server(struct ssh *); 193 int kexgex_client(struct ssh *); 194 int kexgex_server(struct ssh *); 195 int kexecdh_client(struct ssh *); 196 int kexecdh_server(struct ssh *); 197 int kexc25519_client(struct ssh *); 198 int kexc25519_server(struct ssh *); 199 200 int kex_dh_hash(int, const char *, const char *, 201 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 202 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); 203 204 int kexgex_hash(int, const char *, const char *, 205 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 206 int, int, int, 207 const BIGNUM *, const BIGNUM *, const BIGNUM *, 208 const BIGNUM *, const BIGNUM *, 209 u_char *, size_t *); 210 211 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *, 212 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 213 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *); 214 215 int kex_c25519_hash(int, const char *, const char *, 216 const u_char *, size_t, const u_char *, size_t, 217 const u_char *, size_t, const u_char *, const u_char *, 218 const u_char *, size_t, u_char *, size_t *); 219 220 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) 221 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 222 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 223 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], 224 const u_char pub[CURVE25519_SIZE], struct sshbuf *out) 225 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 226 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 227 228 int 229 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]); 230 231 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 232 void dump_digest(char *, u_char *, int); 233 #endif 234 235 #if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC) 236 # undef EC_KEY 237 # undef EC_GROUP 238 # undef EC_POINT 239 #endif 240 241 #endif 242
