1 /* $OpenBSD: kex.h,v 1.93 2018/12/27 03:25:25 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 31 #ifdef WITH_LEAKMALLOC 32 #include "leakmalloc.h" 33 #endif 34 35 #define KEX_COOKIE_LEN 16 36 37 #define KEX_DH1 "diffie-hellman-group1-sha1" 38 #define KEX_DH14_SHA1 "diffie-hellman-group14-sha1" 39 #define KEX_DH14_SHA256 "diffie-hellman-group14-sha256" 40 #define KEX_DH16_SHA512 "diffie-hellman-group16-sha512" 41 #define KEX_DH18_SHA512 "diffie-hellman-group18-sha512" 42 #define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1" 43 #define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256" 44 #define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256" 45 #define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384" 46 #define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521" 47 #define KEX_CURVE25519_SHA256 "curve25519-sha256" 48 #define KEX_CURVE25519_SHA256_OLD "curve25519-sha256@libssh.org" 49 50 #define COMP_NONE 0 51 /* pre-auth compression (COMP_ZLIB) is only supported in the client */ 52 #define COMP_ZLIB 1 53 #define COMP_DELAYED 2 54 55 #define CURVE25519_SIZE 32 56 57 enum kex_init_proposals { 58 PROPOSAL_KEX_ALGS, 59 PROPOSAL_SERVER_HOST_KEY_ALGS, 60 PROPOSAL_ENC_ALGS_CTOS, 61 PROPOSAL_ENC_ALGS_STOC, 62 PROPOSAL_MAC_ALGS_CTOS, 63 PROPOSAL_MAC_ALGS_STOC, 64 PROPOSAL_COMP_ALGS_CTOS, 65 PROPOSAL_COMP_ALGS_STOC, 66 PROPOSAL_LANG_CTOS, 67 PROPOSAL_LANG_STOC, 68 PROPOSAL_MAX 69 }; 70 71 enum kex_modes { 72 MODE_IN, 73 MODE_OUT, 74 MODE_MAX 75 }; 76 77 enum kex_exchange { 78 KEX_DH_GRP1_SHA1, 79 KEX_DH_GRP14_SHA1, 80 KEX_DH_GRP14_SHA256, 81 KEX_DH_GRP16_SHA512, 82 KEX_DH_GRP18_SHA512, 83 KEX_DH_GEX_SHA1, 84 KEX_DH_GEX_SHA256, 85 KEX_ECDH_SHA2, 86 KEX_C25519_SHA256, 87 KEX_MAX 88 }; 89 90 #define KEX_INIT_SENT 0x0001 91 #define KEX_INITIAL 0x0002 92 93 struct sshenc { 94 char *name; 95 const struct sshcipher *cipher; 96 int enabled; 97 u_int key_len; 98 u_int iv_len; 99 u_int block_size; 100 u_char *key; 101 u_char *iv; 102 }; 103 struct sshcomp { 104 u_int type; 105 int enabled; 106 char *name; 107 }; 108 struct newkeys { 109 struct sshenc enc; 110 struct sshmac mac; 111 struct sshcomp comp; 112 }; 113 114 struct ssh; 115 116 struct kex { 117 u_char *session_id; 118 size_t session_id_len; 119 struct newkeys *newkeys[MODE_MAX]; 120 u_int we_need; 121 u_int dh_need; 122 int server; 123 char *name; 124 char *hostkey_alg; 125 int hostkey_type; 126 int hostkey_nid; 127 u_int kex_type; 128 char *server_sig_algs; 129 int ext_info_c; 130 struct sshbuf *my; 131 struct sshbuf *peer; 132 struct sshbuf *client_version; 133 struct sshbuf *server_version; 134 sig_atomic_t done; 135 u_int flags; 136 int hash_alg; 137 int ec_nid; 138 char *failed_choice; 139 int (*verify_host_key)(struct sshkey *, struct ssh *); 140 struct sshkey *(*load_host_public_key)(int, int, struct ssh *); 141 struct sshkey *(*load_host_private_key)(int, int, struct ssh *); 142 int (*host_key_index)(struct sshkey *, int, struct ssh *); 143 int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *, 144 const u_char *, size_t, const char *, u_int); 145 int (*kex[KEX_MAX])(struct ssh *); 146 /* kex specific state */ 147 DH *dh; /* DH */ 148 u_int min, max, nbits; /* GEX */ 149 EC_KEY *ec_client_key; /* ECDH */ 150 const EC_GROUP *ec_group; /* ECDH */ 151 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */ 152 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ 153 }; 154 155 int kex_names_valid(const char *); 156 char *kex_alg_list(char); 157 char *kex_names_cat(const char *, const char *); 158 int kex_assemble_names(char **, const char *, const char *); 159 160 int kex_exchange_identification(struct ssh *, int, const char *); 161 162 struct kex *kex_new(void); 163 int kex_ready(struct ssh *, char *[PROPOSAL_MAX]); 164 int kex_setup(struct ssh *, char *[PROPOSAL_MAX]); 165 void kex_free_newkeys(struct newkeys *); 166 void kex_free(struct kex *); 167 168 int kex_buf2prop(struct sshbuf *, int *, char ***); 169 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); 170 void kex_prop_free(char **); 171 172 int kex_send_kexinit(struct ssh *); 173 int kex_input_kexinit(int, u_int32_t, struct ssh *); 174 int kex_input_ext_info(int, u_int32_t, struct ssh *); 175 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); 176 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *); 177 int kex_send_newkeys(struct ssh *); 178 int kex_start_rekex(struct ssh *); 179 180 int kexdh_client(struct ssh *); 181 int kexdh_server(struct ssh *); 182 int kexgex_client(struct ssh *); 183 int kexgex_server(struct ssh *); 184 int kexecdh_client(struct ssh *); 185 int kexecdh_server(struct ssh *); 186 int kexc25519_client(struct ssh *); 187 int kexc25519_server(struct ssh *); 188 189 int kex_dh_hash(int, const struct sshbuf *, const struct sshbuf *, 190 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 191 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); 192 193 int kexgex_hash(int, const struct sshbuf *, const struct sshbuf *, 194 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 195 int, int, int, 196 const BIGNUM *, const BIGNUM *, const BIGNUM *, 197 const BIGNUM *, const BIGNUM *, 198 u_char *, size_t *); 199 200 int kex_ecdh_hash(int, const EC_GROUP *, 201 const struct sshbuf *, const struct sshbuf *, 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 struct sshbuf *, const struct sshbuf *, 206 const u_char *, size_t, const u_char *, size_t, 207 const u_char *, size_t, const u_char *, const u_char *, 208 const u_char *, size_t, u_char *, size_t *); 209 210 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) 211 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 212 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 213 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], 214 const u_char pub[CURVE25519_SIZE], struct sshbuf *out) 215 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 216 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 217 218 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 219 void dump_digest(char *, u_char *, int); 220 #endif 221 222 #endif 223