Release notes are available at https://www.openssh.com/txt/release-8.9 Some highlights: * ssh(1), sshd(8), ssh-add(1), ssh-agent(1): add a system for restricting forwarding and use of keys added to ssh-agent(1) * ssh(1), sshd(8): add the sntrup761x25519-sha512@openssh.com hybrid ECDH/x25519 + Streamlined NTRU Prime post-quantum KEX to the default KEXAlgorithms list (after the ECDH methods but before the prime-group DH ones). The next release of OpenSSH is likely to make this key exchange the default method. * sshd(8), portable OpenSSH only: this release removes in-built support for MD5-hashed passwords. If you require these on your system then we recommend linking against libxcrypt or similar. Future deprecation notice ========================= A near-future release of OpenSSH will switch scp(1) from using the legacy scp/rcp protocol to using SFTP by default. Legacy scp/rcp performs wildcard expansion of remote filenames (e.g. "scp host:* .") through the remote shell. This has the side effect of requiring double quoting of shell meta-characters in file names included on scp(1) command-lines, otherwise they could be interpreted as shell commands on the remote side. MFC after: 1 month Relnotes: Yes Sponsored by: The FreeBSD Foundation
267 lines
8.6 KiB
C
267 lines
8.6 KiB
C
/* $OpenBSD: kex.h,v 1.117 2022/01/06 21:55:23 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 "crypto_api.h"
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#ifdef WITH_OPENSSL
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# include <openssl/bn.h>
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# include <openssl/dh.h>
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# include <openssl/ecdsa.h>
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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 DH void
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# define BIGNUM void
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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_SHA1 "diffie-hellman-group14-sha1"
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#define KEX_DH14_SHA256 "diffie-hellman-group14-sha256"
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#define KEX_DH16_SHA512 "diffie-hellman-group16-sha512"
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#define KEX_DH18_SHA512 "diffie-hellman-group18-sha512"
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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"
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#define KEX_CURVE25519_SHA256_OLD "curve25519-sha256@libssh.org"
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#define KEX_SNTRUP761X25519_SHA512 "sntrup761x25519-sha512@openssh.com"
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#define COMP_NONE 0
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/* pre-auth compression (COMP_ZLIB) is only supported in the client */
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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_GRP14_SHA256,
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KEX_DH_GRP16_SHA512,
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KEX_DH_GRP18_SHA512,
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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_KEM_SNTRUP761X25519_SHA512,
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KEX_MAX
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};
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/* kex->flags */
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#define KEX_INIT_SENT 0x0001
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#define KEX_INITIAL 0x0002
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#define KEX_HAS_PUBKEY_HOSTBOUND 0x0004
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#define KEX_RSA_SHA2_256_SUPPORTED 0x0008 /* only set in server for now */
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#define KEX_RSA_SHA2_512_SUPPORTED 0x0010 /* only set in server for now */
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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 sshbuf;
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struct kex {
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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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char *server_sig_algs;
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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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struct sshbuf *client_version;
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struct sshbuf *server_version;
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struct sshbuf *session_id;
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struct sshbuf *initial_sig;
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struct sshkey *initial_hostkey;
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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 *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 ssh *, struct sshkey *, struct sshkey *,
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u_char **, size_t *, const u_char *, size_t, const char *);
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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 + KEM */
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u_char c25519_client_pubkey[CURVE25519_SIZE]; /* 25519 */
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u_char sntrup761_client_key[crypto_kem_sntrup761_SECRETKEYBYTES]; /* KEM */
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struct sshbuf *client_pub;
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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(char **, const char *, const char *);
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int kex_exchange_identification(struct ssh *, int, const char *);
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struct kex *kex_new(void);
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int kex_ready(struct ssh *, char *[PROPOSAL_MAX]);
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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_load_hostkey(struct ssh *, struct sshkey **, struct sshkey **);
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int kex_verify_host_key(struct ssh *, struct sshkey *);
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int kex_send_kexinit(struct ssh *);
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int kex_input_kexinit(int, u_int32_t, struct ssh *);
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int kex_input_ext_info(int, u_int32_t, struct ssh *);
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int kex_protocol_error(int, u_int32_t, struct ssh *);
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int kex_derive_keys(struct ssh *, u_char *, u_int, const struct sshbuf *);
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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 kexgex_client(struct ssh *);
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int kexgex_server(struct ssh *);
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int kex_gen_client(struct ssh *);
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int kex_gen_server(struct ssh *);
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int kex_dh_keypair(struct kex *);
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int kex_dh_enc(struct kex *, const struct sshbuf *, struct sshbuf **,
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struct sshbuf **);
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int kex_dh_dec(struct kex *, const struct sshbuf *, struct sshbuf **);
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int kex_ecdh_keypair(struct kex *);
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int kex_ecdh_enc(struct kex *, const struct sshbuf *, struct sshbuf **,
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struct sshbuf **);
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int kex_ecdh_dec(struct kex *, const struct sshbuf *, struct sshbuf **);
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int kex_c25519_keypair(struct kex *);
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int kex_c25519_enc(struct kex *, const struct sshbuf *, struct sshbuf **,
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struct sshbuf **);
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int kex_c25519_dec(struct kex *, const struct sshbuf *, struct sshbuf **);
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int kex_kem_sntrup761x25519_keypair(struct kex *);
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int kex_kem_sntrup761x25519_enc(struct kex *, const struct sshbuf *,
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struct sshbuf **, struct sshbuf **);
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int kex_kem_sntrup761x25519_dec(struct kex *, const struct sshbuf *,
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struct sshbuf **);
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int kex_dh_keygen(struct kex *);
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int kex_dh_compute_key(struct kex *, BIGNUM *, struct sshbuf *);
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int kexgex_hash(int, const struct sshbuf *, const struct sshbuf *,
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const struct sshbuf *, const struct sshbuf *, const struct sshbuf *,
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int, int, int,
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const BIGNUM *, const BIGNUM *, const BIGNUM *,
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const BIGNUM *, const u_char *, size_t,
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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 kexc25519_shared_key_ext(const u_char key[CURVE25519_SIZE],
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const u_char pub[CURVE25519_SIZE], struct sshbuf *out, int)
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__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
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__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
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#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
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void dump_digest(const char *, const 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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