234 lines
7.0 KiB
C
234 lines
7.0 KiB
C
/* $OpenBSD: kex.h,v 1.76 2016/02/08 10:57:07 djm Exp $ */
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/*
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* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef KEX_H
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#define KEX_H
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#include "mac.h"
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#include "buffer.h" /* XXX for typedef */
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#include "key.h" /* XXX for typedef */
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#ifdef WITH_LEAKMALLOC
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#include "leakmalloc.h"
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#endif
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#ifdef WITH_OPENSSL
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# ifdef OPENSSL_HAS_ECC
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# include <openssl/ec.h>
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# else /* OPENSSL_HAS_ECC */
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# define EC_KEY void
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# define EC_GROUP void
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# define EC_POINT void
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# endif /* OPENSSL_HAS_ECC */
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#else /* WITH_OPENSSL */
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# define EC_KEY void
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# define EC_GROUP void
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# define EC_POINT void
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#endif /* WITH_OPENSSL */
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#define KEX_COOKIE_LEN 16
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#define KEX_DH1 "diffie-hellman-group1-sha1"
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#define KEX_DH14 "diffie-hellman-group14-sha1"
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#define KEX_DHGEX_SHA1 "diffie-hellman-group-exchange-sha1"
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#define KEX_DHGEX_SHA256 "diffie-hellman-group-exchange-sha256"
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#define KEX_ECDH_SHA2_NISTP256 "ecdh-sha2-nistp256"
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#define KEX_ECDH_SHA2_NISTP384 "ecdh-sha2-nistp384"
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#define KEX_ECDH_SHA2_NISTP521 "ecdh-sha2-nistp521"
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#define KEX_CURVE25519_SHA256 "curve25519-sha256@libssh.org"
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#define COMP_NONE 0
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#define COMP_ZLIB 1
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#define COMP_DELAYED 2
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#define CURVE25519_SIZE 32
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enum kex_init_proposals {
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PROPOSAL_KEX_ALGS,
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PROPOSAL_SERVER_HOST_KEY_ALGS,
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PROPOSAL_ENC_ALGS_CTOS,
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PROPOSAL_ENC_ALGS_STOC,
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PROPOSAL_MAC_ALGS_CTOS,
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PROPOSAL_MAC_ALGS_STOC,
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PROPOSAL_COMP_ALGS_CTOS,
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PROPOSAL_COMP_ALGS_STOC,
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PROPOSAL_LANG_CTOS,
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PROPOSAL_LANG_STOC,
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PROPOSAL_MAX
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};
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enum kex_modes {
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MODE_IN,
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MODE_OUT,
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MODE_MAX
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};
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enum kex_exchange {
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KEX_DH_GRP1_SHA1,
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KEX_DH_GRP14_SHA1,
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KEX_DH_GEX_SHA1,
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KEX_DH_GEX_SHA256,
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KEX_ECDH_SHA2,
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KEX_C25519_SHA256,
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KEX_MAX
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};
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#define KEX_INIT_SENT 0x0001
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struct sshenc {
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char *name;
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const struct sshcipher *cipher;
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int enabled;
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u_int key_len;
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u_int iv_len;
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u_int block_size;
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u_char *key;
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u_char *iv;
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};
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struct sshcomp {
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u_int type;
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int enabled;
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char *name;
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};
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struct newkeys {
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struct sshenc enc;
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struct sshmac mac;
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struct sshcomp comp;
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};
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struct ssh;
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struct kex {
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u_char *session_id;
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size_t session_id_len;
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struct newkeys *newkeys[MODE_MAX];
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u_int we_need;
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u_int dh_need;
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int server;
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char *name;
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char *hostkey_alg;
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int hostkey_type;
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int hostkey_nid;
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u_int kex_type;
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int rsa_sha2;
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int ext_info_c;
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struct sshbuf *my;
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struct sshbuf *peer;
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sig_atomic_t done;
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u_int flags;
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int hash_alg;
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int ec_nid;
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char *client_version_string;
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char *server_version_string;
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char *failed_choice;
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int (*verify_host_key)(struct sshkey *, struct ssh *);
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struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
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struct sshkey *(*load_host_private_key)(int, int, struct ssh *);
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int (*host_key_index)(struct sshkey *, int, struct ssh *);
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int (*sign)(struct sshkey *, struct sshkey *, u_char **, size_t *,
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const u_char *, size_t, const char *, u_int);
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int (*kex[KEX_MAX])(struct ssh *);
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/* kex specific state */
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DH *dh; /* DH */
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u_int min, max, nbits; /* GEX */
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EC_KEY *ec_client_key; /* ECDH */
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const EC_GROUP *ec_group; /* ECDH */
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u_char c25519_client_key[CURVE25519_SIZE]; /* 25519 */
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u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */
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};
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int kex_names_valid(const char *);
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char *kex_alg_list(char);
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char *kex_names_cat(const char *, const char *);
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int kex_assemble_names(const char *, char **);
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int kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **);
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int kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
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void kex_free_newkeys(struct newkeys *);
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void kex_free(struct kex *);
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int kex_buf2prop(struct sshbuf *, int *, char ***);
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int kex_prop2buf(struct sshbuf *, char *proposal[PROPOSAL_MAX]);
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void kex_prop_free(char **);
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int kex_send_kexinit(struct ssh *);
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int kex_input_kexinit(int, u_int32_t, void *);
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int kex_input_ext_info(int, u_int32_t, void *);
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int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *);
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int kex_derive_keys_bn(struct ssh *, u_char *, u_int, const BIGNUM *);
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int kex_send_newkeys(struct ssh *);
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int kex_start_rekex(struct ssh *);
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int kexdh_client(struct ssh *);
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int kexdh_server(struct ssh *);
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int kexgex_client(struct ssh *);
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int kexgex_server(struct ssh *);
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int kexecdh_client(struct ssh *);
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int kexecdh_server(struct ssh *);
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int kexc25519_client(struct ssh *);
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int kexc25519_server(struct ssh *);
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int kex_dh_hash(const char *, const char *,
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const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
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const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *);
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int kexgex_hash(int, const char *, const char *,
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const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
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int, int, int,
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const BIGNUM *, const BIGNUM *, const BIGNUM *,
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const BIGNUM *, const BIGNUM *,
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u_char *, size_t *);
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int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *,
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const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
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const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *);
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int kex_c25519_hash(int, const char *, const char *, const char *, size_t,
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const char *, size_t, const u_char *, size_t, const u_char *, const u_char *,
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const u_char *, size_t, u_char *, size_t *);
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void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
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__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
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__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
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int kexc25519_shared_key(const u_char key[CURVE25519_SIZE],
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const u_char pub[CURVE25519_SIZE], struct sshbuf *out)
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__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
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__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
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int
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derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]);
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#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
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void dump_digest(char *, u_char *, int);
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#endif
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#if !defined(WITH_OPENSSL) || !defined(OPENSSL_HAS_ECC)
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# undef EC_KEY
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# undef EC_GROUP
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# undef EC_POINT
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#endif
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#endif
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