xref: /openbsd-src/usr.bin/ssh/kex.h (revision 43003dfe3ad45d1698bed8a37f2b0f5b14f20d4f)
1 /* $OpenBSD: kex.h,v 1.47 2009/05/27 06:34:36 andreas 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 <openssl/evp.h>
30 #include <openssl/hmac.h>
31 
32 #define KEX_COOKIE_LEN	16
33 
34 #define	KEX_DH1			"diffie-hellman-group1-sha1"
35 #define	KEX_DH14		"diffie-hellman-group14-sha1"
36 #define	KEX_DHGEX_SHA1		"diffie-hellman-group-exchange-sha1"
37 #define	KEX_DHGEX_SHA256	"diffie-hellman-group-exchange-sha256"
38 
39 #define COMP_NONE	0
40 #define COMP_ZLIB	1
41 #define COMP_DELAYED	2
42 
43 enum kex_init_proposals {
44 	PROPOSAL_KEX_ALGS,
45 	PROPOSAL_SERVER_HOST_KEY_ALGS,
46 	PROPOSAL_ENC_ALGS_CTOS,
47 	PROPOSAL_ENC_ALGS_STOC,
48 	PROPOSAL_MAC_ALGS_CTOS,
49 	PROPOSAL_MAC_ALGS_STOC,
50 	PROPOSAL_COMP_ALGS_CTOS,
51 	PROPOSAL_COMP_ALGS_STOC,
52 	PROPOSAL_LANG_CTOS,
53 	PROPOSAL_LANG_STOC,
54 	PROPOSAL_MAX
55 };
56 
57 enum kex_modes {
58 	MODE_IN,
59 	MODE_OUT,
60 	MODE_MAX
61 };
62 
63 enum kex_exchange {
64 	KEX_DH_GRP1_SHA1,
65 	KEX_DH_GRP14_SHA1,
66 	KEX_DH_GEX_SHA1,
67 	KEX_DH_GEX_SHA256,
68 	KEX_MAX
69 };
70 
71 #define KEX_INIT_SENT	0x0001
72 
73 typedef struct Kex Kex;
74 typedef struct Mac Mac;
75 typedef struct Comp Comp;
76 typedef struct Enc Enc;
77 typedef struct Newkeys Newkeys;
78 
79 struct Enc {
80 	char	*name;
81 	Cipher	*cipher;
82 	int	enabled;
83 	u_int	key_len;
84 	u_int	block_size;
85 	u_char	*key;
86 	u_char	*iv;
87 };
88 struct Mac {
89 	char	*name;
90 	int	enabled;
91 	u_int	mac_len;
92 	u_char	*key;
93 	u_int	key_len;
94 	int	type;
95 	const EVP_MD	*evp_md;
96 	HMAC_CTX	evp_ctx;
97 	struct umac_ctx *umac_ctx;
98 };
99 struct Comp {
100 	int	type;
101 	int	enabled;
102 	char	*name;
103 };
104 struct Newkeys {
105 	Enc	enc;
106 	Mac	mac;
107 	Comp	comp;
108 };
109 struct Kex {
110 	u_char	*session_id;
111 	u_int	session_id_len;
112 	Newkeys	*newkeys[MODE_MAX];
113 	u_int	we_need;
114 	int	server;
115 	char	*name;
116 	int	hostkey_type;
117 	int	kex_type;
118 	Buffer	my;
119 	Buffer	peer;
120 	sig_atomic_t done;
121 	int	flags;
122 	const EVP_MD *evp_md;
123 	char	*client_version_string;
124 	char	*server_version_string;
125 	int	(*verify_host_key)(Key *);
126 	Key	*(*load_host_key)(int);
127 	int	(*host_key_index)(Key *);
128 	void	(*kex[KEX_MAX])(Kex *);
129 };
130 
131 Kex	*kex_setup(char *[PROPOSAL_MAX]);
132 void	 kex_finish(Kex *);
133 
134 void	 kex_send_kexinit(Kex *);
135 void	 kex_input_kexinit(int, u_int32_t, void *);
136 void	 kex_derive_keys(Kex *, u_char *, u_int, BIGNUM *);
137 
138 Newkeys *kex_get_newkeys(int);
139 
140 void	 kexdh_client(Kex *);
141 void	 kexdh_server(Kex *);
142 void	 kexgex_client(Kex *);
143 void	 kexgex_server(Kex *);
144 
145 void
146 kex_dh_hash(char *, char *, char *, int, char *, int, u_char *, int,
147     BIGNUM *, BIGNUM *, BIGNUM *, u_char **, u_int *);
148 void
149 kexgex_hash(const EVP_MD *, char *, char *, char *, int, char *,
150     int, u_char *, int, int, int, int, BIGNUM *, BIGNUM *, BIGNUM *,
151     BIGNUM *, BIGNUM *, u_char **, u_int *);
152 
153 void
154 derive_ssh1_session_id(BIGNUM *, BIGNUM *, u_int8_t[8], u_int8_t[16]);
155 
156 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
157 void	dump_digest(char *, u_char *, int);
158 #endif
159 
160 #endif
161