1 /* $OpenBSD: kex.h,v 1.78 2016/05/02 10:26:04 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 #define KEX_COOKIE_LEN 16 38 39 #define KEX_DH1 "diffie-hellman-group1-sha1" 40 #define KEX_DH14_SHA1 "diffie-hellman-group14-sha1" 41 #define KEX_DH14_SHA256 "diffie-hellman-group14-sha256" 42 #define KEX_DH16_SHA512 "diffie-hellman-group16-sha512" 43 #define KEX_DH18_SHA512 "diffie-hellman-group18-sha512" 44 #define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1" 45 #define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256" 46 #define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256" 47 #define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384" 48 #define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521" 49 #define KEX_CURVE25519_SHA256 "curve25519-sha256@libssh.org" 50 51 #define COMP_NONE 0 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 92 struct sshenc { 93 char *name; 94 const struct sshcipher *cipher; 95 int enabled; 96 u_int key_len; 97 u_int iv_len; 98 u_int block_size; 99 u_char *key; 100 u_char *iv; 101 }; 102 struct sshcomp { 103 u_int type; 104 int enabled; 105 char *name; 106 }; 107 struct newkeys { 108 struct sshenc enc; 109 struct sshmac mac; 110 struct sshcomp comp; 111 }; 112 113 struct ssh; 114 115 struct kex { 116 u_char *session_id; 117 size_t session_id_len; 118 struct newkeys *newkeys[MODE_MAX]; 119 u_int we_need; 120 u_int dh_need; 121 int server; 122 char *name; 123 char *hostkey_alg; 124 int hostkey_type; 125 int hostkey_nid; 126 u_int kex_type; 127 int rsa_sha2; 128 int ext_info_c; 129 struct sshbuf *my; 130 struct sshbuf *peer; 131 sig_atomic_t done; 132 u_int flags; 133 int hash_alg; 134 int ec_nid; 135 char *client_version_string; 136 char *server_version_string; 137 char *failed_choice; 138 int (*verify_host_key)(struct sshkey *, struct ssh *); 139 struct sshkey *(*load_host_public_key)(int, int, struct ssh *); 140 struct sshkey *(*load_host_private_key)(int, int, struct ssh *); 141 int (*host_key_index)(struct sshkey *, int, struct ssh *); 142 int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *, 143 const u_char *, size_t, const char *, u_int); 144 int (*kex[KEX_MAX])(struct ssh *); 145 /* kex specific state */ 146 DH *dh; /* DH */ 147 u_int min, max, nbits; /* GEX */ 148 EC_KEY *ec_client_key; /* ECDH */ 149 const EC_GROUP *ec_group; /* ECDH */ 150 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */ 151 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ 152 }; 153 154 int kex_names_valid(const char *); 155 char *kex_alg_list(char); 156 char *kex_names_cat(const char *, const char *); 157 int kex_assemble_names(const char *, char **); 158 159 int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **); 160 int kex_setup(struct ssh *, char *[PROPOSAL_MAX]); 161 void kex_free_newkeys(struct newkeys *); 162 void kex_free(struct kex *); 163 164 int kex_buf2prop(struct sshbuf *, int *, char ***); 165 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); 166 void kex_prop_free(char **); 167 168 int kex_send_kexinit(struct ssh *); 169 int kex_input_kexinit(int, u_int32_t, void *); 170 int kex_input_ext_info(int, u_int32_t, void *); 171 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); 172 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *); 173 int kex_send_newkeys(struct ssh *); 174 int kex_start_rekex(struct ssh *); 175 176 int kexdh_client(struct ssh *); 177 int kexdh_server(struct ssh *); 178 int kexgex_client(struct ssh *); 179 int kexgex_server(struct ssh *); 180 int kexecdh_client(struct ssh *); 181 int kexecdh_server(struct ssh *); 182 int kexc25519_client(struct ssh *); 183 int kexc25519_server(struct ssh *); 184 185 int kex_dh_hash(int, const char *, const char *, 186 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 187 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); 188 189 int kexgex_hash(int, const char *, const char *, 190 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 191 int, int, int, 192 const BIGNUM *, const BIGNUM *, const BIGNUM *, 193 const BIGNUM *, const BIGNUM *, 194 u_char *, size_t *); 195 196 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *, 197 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 198 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *); 199 200 int kex_c25519_hash(int, const char *, const char *, 201 const u_char *, size_t, const u_char *, size_t, 202 const u_char *, size_t, const u_char *, const u_char *, 203 const u_char *, size_t, u_char *, size_t *); 204 205 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) 206 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 207 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 208 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], 209 const u_char pub[CURVE25519_SIZE], struct sshbuf *out) 210 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 211 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 212 213 int 214 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]); 215 216 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 217 void dump_digest(char *, u_char *, int); 218 #endif 219 220 #endif 221