diff options
Diffstat (limited to 'kex.h')
| -rw-r--r-- | kex.h | 266 |
1 files changed, 266 insertions, 0 deletions
@@ -0,0 +1,266 @@ +/* $OpenBSD: kex.h,v 1.117 2022/01/06 21:55:23 djm Exp $ */ + +/* + * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +#ifndef KEX_H +#define KEX_H + +#include "mac.h" +#include "crypto_api.h" + +#ifdef WITH_OPENSSL +# include <openssl/bn.h> +# include <openssl/dh.h> +# include <openssl/ecdsa.h> +# ifdef OPENSSL_HAS_ECC +# include <openssl/ec.h> +# else /* OPENSSL_HAS_ECC */ +# define EC_KEY void +# define EC_GROUP void +# define EC_POINT void +# endif /* OPENSSL_HAS_ECC */ +#else /* WITH_OPENSSL */ +# define DH void +# define BIGNUM void +# define EC_KEY void +# define EC_GROUP void +# define EC_POINT void +#endif /* WITH_OPENSSL */ + +#define KEX_COOKIE_LEN 16 + +#define KEX_DH1 "diffie-hellman-group1-sha1" +#define KEX_DH14_SHA1 "diffie-hellman-group14-sha1" +#define KEX_DH14_SHA256 "diffie-hellman-group14-sha256" +#define KEX_DH16_SHA512 "diffie-hellman-group16-sha512" +#define KEX_DH18_SHA512 "diffie-hellman-group18-sha512" +#define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1" +#define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256" +#define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256" +#define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384" +#define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521" +#define KEX_CURVE25519_SHA256 "curve25519-sha256" +#define KEX_CURVE25519_SHA256_OLD "curve25519-sha256@libssh.org" +#define KEX_SNTRUP761X25519_SHA512 "sntrup761x25519-sha512@openssh.com" + +#define COMP_NONE 0 +/* pre-auth compression (COMP_ZLIB) is only supported in the client */ +#define COMP_ZLIB 1 +#define COMP_DELAYED 2 + +#define CURVE25519_SIZE 32 + +enum kex_init_proposals { + PROPOSAL_KEX_ALGS, + PROPOSAL_SERVER_HOST_KEY_ALGS, + PROPOSAL_ENC_ALGS_CTOS, + PROPOSAL_ENC_ALGS_STOC, + PROPOSAL_MAC_ALGS_CTOS, + PROPOSAL_MAC_ALGS_STOC, + PROPOSAL_COMP_ALGS_CTOS, + PROPOSAL_COMP_ALGS_STOC, + PROPOSAL_LANG_CTOS, + PROPOSAL_LANG_STOC, + PROPOSAL_MAX +}; + +enum kex_modes { + MODE_IN, + MODE_OUT, + MODE_MAX +}; + +enum kex_exchange { + KEX_DH_GRP1_SHA1, + KEX_DH_GRP14_SHA1, + KEX_DH_GRP14_SHA256, + KEX_DH_GRP16_SHA512, + KEX_DH_GRP18_SHA512, + KEX_DH_GEX_SHA1, + KEX_DH_GEX_SHA256, + KEX_ECDH_SHA2, + KEX_C25519_SHA256, + KEX_KEM_SNTRUP761X25519_SHA512, + KEX_MAX +}; + +/* kex->flags */ +#define KEX_INIT_SENT 0x0001 +#define KEX_INITIAL 0x0002 +#define KEX_HAS_PUBKEY_HOSTBOUND 0x0004 +#define KEX_RSA_SHA2_256_SUPPORTED 0x0008 /* only set in server for now */ +#define KEX_RSA_SHA2_512_SUPPORTED 0x0010 /* only set in server for now */ + +struct sshenc { + char *name; + const struct sshcipher *cipher; + int enabled; + u_int key_len; + u_int iv_len; + u_int block_size; + u_char *key; + u_char *iv; +}; +struct sshcomp { + u_int type; + int enabled; + char *name; +}; +struct newkeys { + struct sshenc enc; + struct sshmac mac; + struct sshcomp comp; +}; + +struct ssh; +struct sshbuf; + +struct kex { + struct newkeys *newkeys[MODE_MAX]; + u_int we_need; + u_int dh_need; + int server; + char *name; + char *hostkey_alg; + int hostkey_type; + int hostkey_nid; + u_int kex_type; + char *server_sig_algs; + int ext_info_c; + struct sshbuf *my; + struct sshbuf *peer; + struct sshbuf *client_version; + struct sshbuf *server_version; + struct sshbuf *session_id; + struct sshbuf *initial_sig; + struct sshkey *initial_hostkey; + sig_atomic_t done; + u_int flags; + int hash_alg; + int ec_nid; + char *failed_choice; + int (*verify_host_key)(struct sshkey *, struct ssh *); + struct sshkey *(*load_host_public_key)(int, int, struct ssh *); + struct sshkey *(*load_host_private_key)(int, int, struct ssh *); + int (*host_key_index)(struct sshkey *, int, struct ssh *); + int (*sign)(struct ssh *, struct sshkey *, struct sshkey *, + u_char **, size_t *, const u_char *, size_t, const char *); + int (*kex[KEX_MAX])(struct ssh *); + /* kex specific state */ + DH *dh; /* DH */ + u_int min, max, nbits; /* GEX */ + EC_KEY *ec_client_key; /* ECDH */ + const EC_GROUP *ec_group; /* ECDH */ + u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 + KEM */ + u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */ + u_char sntrup761_client_key[crypto_kem_sntrup761_SECRETKEYBYTES]; /* KEM */ + struct sshbuf *client_pub; +}; + +int kex_names_valid(const char *); +char *kex_alg_list(char); +char *kex_names_cat(const char *, const char *); +int kex_assemble_names(char **, const char *, const char *); + +int kex_exchange_identification(struct ssh *, int, const char *); + +struct kex *kex_new(void); +int kex_ready(struct ssh *, char *[PROPOSAL_MAX]); +int kex_setup(struct ssh *, char *[PROPOSAL_MAX]); +void kex_free_newkeys(struct newkeys *); +void kex_free(struct kex *); + +int kex_buf2prop(struct sshbuf *, int *, char ***); +int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]); +void kex_prop_free(char **); +int kex_load_hostkey(struct ssh *, struct sshkey **, struct sshkey **); +int kex_verify_host_key(struct ssh *, struct sshkey *); + +int kex_send_kexinit(struct ssh *); +int kex_input_kexinit(int, u_int32_t, struct ssh *); +int kex_input_ext_info(int, u_int32_t, struct ssh *); +int kex_protocol_error(int, u_int32_t, struct ssh *); +int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *); +int kex_send_newkeys(struct ssh *); +int kex_start_rekex(struct ssh *); + +int kexgex_client(struct ssh *); +int kexgex_server(struct ssh *); +int kex_gen_client(struct ssh *); +int kex_gen_server(struct ssh *); + +int kex_dh_keypair(struct kex *); +int kex_dh_enc(struct kex *, const struct sshbuf *, struct sshbuf **, + struct sshbuf **); +int kex_dh_dec(struct kex *, const struct sshbuf *, struct sshbuf **); + +int kex_ecdh_keypair(struct kex *); +int kex_ecdh_enc(struct kex *, const struct sshbuf *, struct sshbuf **, + struct sshbuf **); +int kex_ecdh_dec(struct kex *, const struct sshbuf *, struct sshbuf **); + +int kex_c25519_keypair(struct kex *); +int kex_c25519_enc(struct kex *, const struct sshbuf *, struct sshbuf **, + struct sshbuf **); +int kex_c25519_dec(struct kex *, const struct sshbuf *, struct sshbuf **); + +int kex_kem_sntrup761x25519_keypair(struct kex *); +int kex_kem_sntrup761x25519_enc(struct kex *, const struct sshbuf *, + struct sshbuf **, struct sshbuf **); +int kex_kem_sntrup761x25519_dec(struct kex *, const struct sshbuf *, + struct sshbuf **); + +int kex_dh_keygen(struct kex *); +int kex_dh_compute_key(struct kex *, BIGNUM *, struct sshbuf *); + +int kexgex_hash(int, const struct sshbuf *, const struct sshbuf *, + const struct sshbuf *, const struct sshbuf *, const struct sshbuf *, + int, int, int, + const BIGNUM *, const BIGNUM *, const BIGNUM *, + const BIGNUM *, const u_char *, size_t, + u_char *, size_t *); + +void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE]) + __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) + __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); +int kexc25519_shared_key(const u_char key[CURVE25519_SIZE], + const u_char pub[CURVE25519_SIZE], struct sshbuf *out) + __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) + __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); +int kexc25519_shared_key_ext(const u_char key[CURVE25519_SIZE], + const u_char pub[CURVE25519_SIZE], struct sshbuf *out, int) + __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE))) + __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE))); + +#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) +void dump_digest(const char *, const u_char *, int); +#endif + +#if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC) +# undef EC_KEY +# undef EC_GROUP +# undef EC_POINT +#endif + +#endif |