crypto/openssh/kex.h

   1 /* $OpenBSD: kex.h,v 1.83 2017/05/30 14:23:52 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 #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_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 #define COMP_ZLIB       1
  68 #define COMP_DELAYED    2
  69
  70 #define CURVE25519_SIZE 32
  71
  72 enum kex_init_proposals {
  73         PROPOSAL_KEX_ALGS,
  74         PROPOSAL_SERVER_HOST_KEY_ALGS,
  75         PROPOSAL_ENC_ALGS_CTOS,
  76         PROPOSAL_ENC_ALGS_STOC,
  77         PROPOSAL_MAC_ALGS_CTOS,
  78         PROPOSAL_MAC_ALGS_STOC,
  79         PROPOSAL_COMP_ALGS_CTOS,
  80         PROPOSAL_COMP_ALGS_STOC,
  81         PROPOSAL_LANG_CTOS,
  82         PROPOSAL_LANG_STOC,
  83         PROPOSAL_MAX
  84 };
  85
  86 enum kex_modes {
  87         MODE_IN,
  88         MODE_OUT,
  89         MODE_MAX
  90 };
  91
  92 enum kex_exchange {
  93         KEX_DH_GRP1_SHA1,
  94         KEX_DH_GRP14_SHA1,
  95         KEX_DH_GRP14_SHA256,
  96         KEX_DH_GRP16_SHA512,
  97         KEX_DH_GRP18_SHA512,
  98         KEX_DH_GEX_SHA1,
  99         KEX_DH_GEX_SHA256,
 100         KEX_ECDH_SHA2,
 101         KEX_C25519_SHA256,
 102         KEX_MAX
 103 };
 104
 105 #define KEX_INIT_SENT   0x0001
 106
 107 struct sshenc {
 108         char    *name;
 109         const struct sshcipher *cipher;
 110         int     enabled;
 111         u_int   key_len;
 112         u_int   iv_len;
 113         u_int   block_size;
 114         u_char  *key;
 115         u_char  *iv;
 116 };
 117 struct sshcomp {
 118         u_int   type;
 119         int     enabled;
 120         char    *name;
 121 };
 122 struct newkeys {
 123         struct sshenc   enc;
 124         struct sshmac   mac;
 125         struct sshcomp  comp;
 126 };
 127
 128 struct ssh;
 129
 130 struct kex {
 131         u_char  *session_id;
 132         size_t  session_id_len;
 133         struct newkeys  *newkeys[MODE_MAX];
 134         u_int   we_need;
 135         u_int   dh_need;
 136         int     server;
 137         char    *name;
 138         char    *hostkey_alg;
 139         int     hostkey_type;
 140         int     hostkey_nid;
 141         u_int   kex_type;
 142         int     rsa_sha2;
 143         int     ext_info_c;
 144         struct sshbuf *my;
 145         struct sshbuf *peer;
 146         sig_atomic_t done;
 147         u_int   flags;
 148         int     hash_alg;
 149         int     ec_nid;
 150         char    *client_version_string;
 151         char    *server_version_string;
 152         char    *failed_choice;
 153         int     (*verify_host_key)(struct sshkey *, struct ssh *);
 154         struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
 155         struct sshkey *(*load_host_private_key)(int, int, struct ssh *);
 156         int     (*host_key_index)(struct sshkey *, int, struct ssh *);
 157         int     (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *,
 158             const u_char *, size_t, const char *, u_int);
 159         int     (*kex[KEX_MAX])(struct ssh *);
 160         /* kex specific state */
 161         DH      *dh;                    /* DH */
 162         u_int   min, max, nbits;        /* GEX */
 163         EC_KEY  *ec_client_key;         /* ECDH */
 164         const EC_GROUP *ec_group;       /* ECDH */
 165         u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */
 166         u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */
 167 };
 168
 169 int      kex_names_valid(const char *);
 170 char    *kex_alg_list(char);
 171 char    *kex_names_cat(const char *, const char *);
 172 int      kex_assemble_names(const char *, char **);
 173
 174 int      kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **);
 175 int      kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
 176 void     kex_free_newkeys(struct newkeys *);
 177 void     kex_free(struct kex *);
 178
 179 int      kex_buf2prop(struct sshbuf *, int *, char ***);
 180 int      kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]);
 181 void     kex_prop_free(char **);
 182
 183 int      kex_send_kexinit(struct ssh *);
 184 int      kex_input_kexinit(int, u_int32_t, struct ssh *);
 185 int      kex_input_ext_info(int, u_int32_t, struct ssh *);
 186 int      kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *);
 187 int      kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *);
 188 int      kex_send_newkeys(struct ssh *);
 189 int      kex_start_rekex(struct ssh *);
 190
 191 int      kexdh_client(struct ssh *);
 192 int      kexdh_server(struct ssh *);
 193 int      kexgex_client(struct ssh *);
 194 int      kexgex_server(struct ssh *);
 195 int      kexecdh_client(struct ssh *);
 196 int      kexecdh_server(struct ssh *);
 197 int      kexc25519_client(struct ssh *);
 198 int      kexc25519_server(struct ssh *);
 199
 200 int      kex_dh_hash(int, const char *, const char *,
 201     const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
 202     const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *);
 203
 204 int      kexgex_hash(int, const char *, const char *,
 205     const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
 206     int, int, int,
 207     const BIGNUM *, const BIGNUM *, const BIGNUM *,
 208     const BIGNUM *, const BIGNUM *,
 209     u_char *, size_t *);
 210
 211 int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *,
 212     const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
 213     const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *);
 214
 215 int      kex_c25519_hash(int, const char *, const char *,
 216     const u_char *, size_t, const u_char *, size_t,
 217     const u_char *, size_t, const u_char *, const u_char *,
 218     const u_char *, size_t, u_char *, size_t *);
 219
 220 void    kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
 221         __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
 222         __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
 223 int     kexc25519_shared_key(const u_char key[CURVE25519_SIZE],
 224     const u_char pub[CURVE25519_SIZE], struct sshbuf *out)
 225         __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
 226         __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
 227
 228 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
 229 void    dump_digest(char *, u_char *, int);
 230 #endif
 231
 232 #if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC)
 233 # undef EC_KEY
 234 # undef EC_GROUP
 235 # undef EC_POINT
 236 #endif
 237
 238 #endif