1 /* $OpenBSD: kex.h,v 1.76 2016/02/08 10:57:07 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 "diffie-hellman-group14-sha1" 55 #define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1" 56 #define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256" 57 #define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256" 58 #define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384" 59 #define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521" 60 #define KEX_CURVE25519_SHA256 "curve25519-sha256@libssh.org" 61 62 #define COMP_NONE 0 63 #define COMP_ZLIB 1 64 #define COMP_DELAYED 2 65 66 #define CURVE25519_SIZE 32 67 68 enum kex_init_proposals { 69 PROPOSAL_KEX_ALGS, 70 PROPOSAL_SERVER_HOST_KEY_ALGS, 71 PROPOSAL_ENC_ALGS_CTOS, 72 PROPOSAL_ENC_ALGS_STOC, 73 PROPOSAL_MAC_ALGS_CTOS, 74 PROPOSAL_MAC_ALGS_STOC, 75 PROPOSAL_COMP_ALGS_CTOS, 76 PROPOSAL_COMP_ALGS_STOC, 77 PROPOSAL_LANG_CTOS, 78 PROPOSAL_LANG_STOC, 79 PROPOSAL_MAX 80 }; 81 82 enum kex_modes { 83 MODE_IN, 84 MODE_OUT, 85 MODE_MAX 86 }; 87 88 enum kex_exchange { 89 KEX_DH_GRP1_SHA1, 90 KEX_DH_GRP14_SHA1, 91 KEX_DH_GEX_SHA1, 92 KEX_DH_GEX_SHA256, 93 KEX_ECDH_SHA2, 94 KEX_C25519_SHA256, 95 KEX_MAX 96 }; 97 98 #define KEX_INIT_SENT 0x0001 99 100 struct sshenc { 101 char *name; 102 const struct sshcipher *cipher; 103 int enabled; 104 u_int key_len; 105 u_int iv_len; 106 u_int block_size; 107 u_char *key; 108 u_char *iv; 109 }; 110 struct sshcomp { 111 u_int type; 112 int enabled; 113 char *name; 114 }; 115 struct newkeys { 116 struct sshenc enc; 117 struct sshmac mac; 118 struct sshcomp comp; 119 }; 120 121 struct ssh; 122 123 struct kex { 124 u_char *session_id; 125 size_t session_id_len; 126 struct newkeys *newkeys[MODE_MAX]; 127 u_int we_need; 128 u_int dh_need; 129 int server; 130 char *name; 131 char *hostkey_alg; 132 int hostkey_type; 133 int hostkey_nid; 134 u_int kex_type; 135 int rsa_sha2; 136 int ext_info_c; 137 struct sshbuf *my; 138 struct sshbuf *peer; 139 sig_atomic_t done; 140 u_int flags; 141 int hash_alg; 142 int ec_nid; 143 char *client_version_string; 144 char *server_version_string; 145 char *failed_choice; 146 int (*verify_host_key)(struct sshkey *, struct ssh *); 147 struct sshkey *(*load_host_public_key)(int, int, struct ssh *); 148 struct sshkey *(*load_host_private_key)(int, int, struct ssh *); 149 int (*host_key_index)(struct sshkey *, int, struct ssh *); 150 int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *, 151 const u_char *, size_t, const char *, u_int); 152 int (*kex[KEX_MAX])(struct ssh *); 153 /* kex specific state */ 154 DH *dh; /* DH */ 155 u_int min, max, nbits; /* GEX */ 156 EC_KEY *ec_client_key; /* ECDH */ 157 const EC_GROUP *ec_group; /* ECDH */ 158 u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */ 159 u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ 160 }; 161 162 int kex_names_valid(const char *); 163 char *kex_alg_list(char); 164 char *kex_names_cat(const char *, const char *); 165 int kex_assemble_names(const char *, char **); 166 167 int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **); 168 int kex_setup(struct ssh *, char *[PROPOSAL_MAX]); 169 void kex_free_newkeys(struct newkeys *); 170 void kex_free(struct kex *); 171 172 int kex_buf2prop(struct sshbuf *, int *, char ***); 173 int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); 174 void kex_prop_free(char **); 175 176 int kex_send_kexinit(struct ssh *); 177 int kex_input_kexinit(int, u_int32_t, void *); 178 int kex_input_ext_info(int, u_int32_t, void *); 179 int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); 180 int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *); 181 int kex_send_newkeys(struct ssh *); 182 int kex_start_rekex(struct ssh *); 183 184 int kexdh_client(struct ssh *); 185 int kexdh_server(struct ssh *); 186 int kexgex_client(struct ssh *); 187 int kexgex_server(struct ssh *); 188 int kexecdh_client(struct ssh *); 189 int kexecdh_server(struct ssh *); 190 int kexc25519_client(struct ssh *); 191 int kexc25519_server(struct ssh *); 192 193 int kex_dh_hash(const char *, const char *, 194 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 195 const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); 196 197 int kexgex_hash(int, const char *, const char *, 198 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 199 int, int, int, 200 const BIGNUM *, const BIGNUM *, const BIGNUM *, 201 const BIGNUM *, const BIGNUM *, 202 u_char *, size_t *); 203 204 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *, 205 const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, 206 const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *); 207 208 int kex_c25519_hash(int, const char *, const char *, const char *, size_t, 209 const char *, size_t, const u_char *, size_t, const u_char *, const u_char *, 210 const u_char *, size_t, u_char *, size_t *); 211 212 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) 213 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 214 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 215 int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], 216 const u_char pub[CURVE25519_SIZE], struct sshbuf *out) 217 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) 218 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); 219 220 int 221 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]); 222 223 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 224 void dump_digest(char *, u_char *, int); 225 #endif 226 227 #if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC) 228 # undef EC_KEY 229 # undef EC_GROUP 230 # undef EC_POINT 231 #endif 232 233 #endif 234