1 /* $NetBSD: kex.h,v 1.16 2017/10/07 19:39:19 christos Exp $ */ 2 /* $OpenBSD: kex.h,v 1.83 2017/05/30 14:23:52 markus Exp $ */ 3 4 /* 5 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 #ifndef KEX_H 28 #define KEX_H 29 30 #include "mac.h" 31 #include "buffer.h" /* XXX for typedef */ 32 #include "key.h" /* XXX for typedef */ 33 34 #ifdef WITH_LEAKMALLOC 35 #include "leakmalloc.h" 36 #endif 37 38 #define KEX_COOKIE_LEN 16 39 40 #define KEX_DH1 "diffie-hellman-group1-sha1" 41 #define KEX_DH14_SHA1 "diffie-hellman-group14-sha1" 42 #define KEX_DH14_SHA256 "diffie-hellman-group14-sha256" 43 #define KEX_DH16_SHA512 "diffie-hellman-group16-sha512" 44 #define KEX_DH18_SHA512 "diffie-hellman-group18-sha512" 45 #define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1" 46 #define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256" 47 #define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256" 48 #define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384" 49 #define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521" 50 #define KEX_CURVE25519_SHA256 "curve25519-sha256" 51 #define KEX_CURVE25519_SHA256_OLD "curve25519-sha256@libssh.org" 52 53 #define COMP_NONE 0 54 #define COMP_ZLIB 1 55 #define COMP_DELAYED 2 56 57 #define CURVE25519_SIZE 32 58 59 enum kex_init_proposals { 60 PROPOSAL_KEX_ALGS, 61 PROPOSAL_SERVER_HOST_KEY_ALGS, 62 PROPOSAL_ENC_ALGS_CTOS, 63 PROPOSAL_ENC_ALGS_STOC, 64 PROPOSAL_MAC_ALGS_CTOS, 65 PROPOSAL_MAC_ALGS_STOC, 66 PROPOSAL_COMP_ALGS_CTOS, 67 PROPOSAL_COMP_ALGS_STOC, 68 PROPOSAL_LANG_CTOS, 69 PROPOSAL_LANG_STOC, 70 PROPOSAL_MAX 71 }; 72 73 enum kex_modes { 74 MODE_IN, 75 MODE_OUT, 76 MODE_MAX 77 }; 78 79 enum kex_exchange { 80 KEX_DH_GRP1_SHA1, 81 KEX_DH_GRP14_SHA1, 82 KEX_DH_GRP14_SHA256, 83 KEX_DH_GRP16_SHA512, 84 KEX_DH_GRP18_SHA512, 85 KEX_DH_GEX_SHA1, 86 KEX_DH_GEX_SHA256, 87 KEX_ECDH_SHA2, 88 KEX_C25519_SHA256, 89 KEX_MAX 90 }; 91 92 #define KEX_INIT_SENT 0x0001 93 94 struct sshenc { 95 char *name; 96 const struct sshcipher *cipher; 97 int enabled; 98 u_int key_len; 99 u_int iv_len; 100 u_int block_size; 101 u_char *key; 102 u_char *iv; 103 }; 104 struct sshcomp { 105 u_int type; 106 int enabled; 107 char *name; 108 }; 109 struct newkeys { 110 struct sshenc enc; 111 struct sshmac mac; 112 struct sshcomp comp; 113 }; 114 115 struct ssh; 116 117 struct kex { 118 u_char *session_id; 119 size_t session_id_len; 120 struct newkeys *newkeys[MODE_MAX]; 121 u_int we_need; 122 u_int dh_need; 123 int server; 124 char *name; 125 char *hostkey_alg; 126 int hostkey_type; 127 int hostkey_nid; 128 u_int kex_type; 129 int rsa_sha2; 130 int ext_info_c; 131 struct sshbuf *my; 132 struct sshbuf *peer; 133 sig_atomic_t done; 134 u_int flags; 135 int hash_alg; 136 int ec_nid; 137 char *client_version_string; 138 char *server_version_string; 139 char *failed_choice; 140 int (*verify_host_key)(struct sshkey *, struct ssh *); 141 struct sshkey *(*load_host_public_key)(int, int, struct ssh *); 142 struct sshkey *(*load_host_private_key)(int, int, struct ssh *); 143 int (*host_key_index)(struct sshkey *, int, struct ssh *); 144 int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *, 145 const u_char *, size_t, const char *, u_int); 146 int (*kex[KEX_MAX])(struct ssh *); 147 /* kex specific state */ 148 DH *dh; /* DH */ 149 u_int min, max, nbits; /* GEX */ 150 EC_KEY *ec_client_key; /* ECDH */ 151 const EC_GROUP *ec_group; /* ECDH */ 152 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */ 153 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ 154 }; 155 156 int kex_names_valid(const char *); 157 char *kex_alg_list(char); 158 char *kex_names_cat(const char *, const char *); 159 int kex_assemble_names(const char *, char **); 160 161 int kex_new(struct ssh *, const char *[PROPOSAL_MAX], struct kex **); 162 int kex_setup(struct ssh *, const char *[PROPOSAL_MAX]); 163 void kex_free_newkeys(struct newkeys *); 164 void kex_free(struct kex *); 165 166 int kex_buf2prop(struct sshbuf *, int *, char ***); 167 int kex_prop2buf(struct sshbuf *, const char *proposal[PROPOSAL_MAX]); 168 void kex_prop_free(char **); 169 170 int kex_send_kexinit(struct ssh *); 171 int kex_input_kexinit(int, u_int32_t, struct ssh *); 172 int kex_input_ext_info(int, u_int32_t, struct ssh *); 173 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); 174 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *); 175 int kex_send_newkeys(struct ssh *); 176 int kex_start_rekex(struct ssh *); 177 178 int kexdh_client(struct ssh *); 179 int kexdh_server(struct ssh *); 180 int kexgex_client(struct ssh *); 181 int kexgex_server(struct ssh *); 182 int kexecdh_client(struct ssh *); 183 int kexecdh_server(struct ssh *); 184 int kexc25519_client(struct ssh *); 185 int kexc25519_server(struct ssh *); 186 187 int kex_dh_hash(int, const char *, const char *, 188 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 189 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); 190 191 int kexgex_hash(int, const char *, const char *, 192 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 193 int, int, int, 194 const BIGNUM *, const BIGNUM *, const BIGNUM *, 195 const BIGNUM *, const BIGNUM *, 196 u_char *, size_t *); 197 198 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *, 199 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 200 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *); 201 202 int kex_c25519_hash(int, const char *, const char *, 203 const u_char *, size_t, const u_char *, size_t, 204 const u_char *, size_t, const u_char *, const u_char *, 205 const u_char *, size_t, u_char *, size_t *); 206 207 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) 208 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 209 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 210 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], 211 const u_char pub[CURVE25519_SIZE], struct sshbuf *out) 212 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 213 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 214 215 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 216 void dump_digest(char *, u_char *, int); 217 #endif 218 219 #endif 220