1 /* $OpenBSD: kex.h,v 1.91 2018/07/11 18:53:29 markus 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 31 #ifdef WITH_LEAKMALLOC 32 #include "leakmalloc.h" 33 #endif 34 35 #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 */ 44 # define DH void 45 # define BIGNUM void 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@libssh.org" 65 66 #define COMP_NONE 0 67 /* pre-auth compression (COMP_ZLIB) is only supported in the client */ 68 #define COMP_ZLIB 1 69 #define COMP_DELAYED 2 70 71 #define CURVE25519_SIZE 32 72 73 enum 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 87 enum kex_modes { 88 MODE_IN, 89 MODE_OUT, 90 MODE_MAX 91 }; 92 93 enum kex_exchange { 94 KEX_DH_GRP1_SHA1, 95 KEX_DH_GRP14_SHA1, 96 KEX_DH_GRP14_SHA256, 97 KEX_DH_GRP16_SHA512, 98 KEX_DH_GRP18_SHA512, 99 KEX_DH_GEX_SHA1, 100 KEX_DH_GEX_SHA256, 101 KEX_ECDH_SHA2, 102 KEX_C25519_SHA256, 103 KEX_MAX 104 }; 105 106 #define KEX_INIT_SENT 0x0001 107 108 struct sshenc { 109 char *name; 110 const struct sshcipher *cipher; 111 int enabled; 112 u_int key_len; 113 u_int iv_len; 114 u_int block_size; 115 u_char *key; 116 u_char *iv; 117 }; 118 struct sshcomp { 119 u_int type; 120 int enabled; 121 char *name; 122 }; 123 struct newkeys { 124 struct sshenc enc; 125 struct sshmac mac; 126 struct sshcomp comp; 127 }; 128 129 struct ssh; 130 131 struct kex { 132 u_char *session_id; 133 size_t session_id_len; 134 struct newkeys *newkeys[MODE_MAX]; 135 u_int we_need; 136 u_int dh_need; 137 int server; 138 char *name; 139 char *hostkey_alg; 140 int hostkey_type; 141 int hostkey_nid; 142 u_int kex_type; 143 char *server_sig_algs; 144 int ext_info_c; 145 struct sshbuf *my; 146 struct sshbuf *peer; 147 sig_atomic_t done; 148 u_int flags; 149 int hash_alg; 150 int ec_nid; 151 char *client_version_string; 152 char *server_version_string; 153 char *failed_choice; 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 */ 162 DH *dh; /* DH */ 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 */ 168 }; 169 170 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 *); 174 175 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 *); 179 180 int kex_buf2prop(struct sshbuf *, int *, char ***); 181 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); 182 void kex_prop_free(char **); 183 184 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 *); 191 192 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 *); 200 201 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 *); 204 205 int kexgex_hash(int, const char *, const char *, 206 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 207 int, int, int, 208 const BIGNUM *, const BIGNUM *, const BIGNUM *, 209 const BIGNUM *, const BIGNUM *, 210 u_char *, size_t *); 211 212 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 *); 215 216 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 *); 220 221 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))); 228 229 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 230 void dump_digest(char *, u_char *, int); 231 #endif 232 233 #if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC) 234 # undef EC_KEY 235 # undef EC_GROUP 236 # undef EC_POINT 237 #endif 238 239 #endif 240