xref: /freebsd-src/crypto/openssh/ssh_api.c (revision a91a246563dffa876a52f53a98de4af9fa364c52)
1*a91a2465SEd Maste /* $OpenBSD: ssh_api.c,v 1.28 2024/01/09 21:39:14 djm Exp $ */
2bc5531deSDag-Erling Smørgrav /*
3bc5531deSDag-Erling Smørgrav  * Copyright (c) 2012 Markus Friedl.  All rights reserved.
4bc5531deSDag-Erling Smørgrav  *
5bc5531deSDag-Erling Smørgrav  * Permission to use, copy, modify, and distribute this software for any
6bc5531deSDag-Erling Smørgrav  * purpose with or without fee is hereby granted, provided that the above
7bc5531deSDag-Erling Smørgrav  * copyright notice and this permission notice appear in all copies.
8bc5531deSDag-Erling Smørgrav  *
9bc5531deSDag-Erling Smørgrav  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10bc5531deSDag-Erling Smørgrav  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11bc5531deSDag-Erling Smørgrav  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12bc5531deSDag-Erling Smørgrav  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13bc5531deSDag-Erling Smørgrav  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14bc5531deSDag-Erling Smørgrav  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15bc5531deSDag-Erling Smørgrav  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16bc5531deSDag-Erling Smørgrav  */
17bc5531deSDag-Erling Smørgrav 
18bc5531deSDag-Erling Smørgrav #include "includes.h"
19bc5531deSDag-Erling Smørgrav 
2019261079SEd Maste #include <sys/types.h>
2119261079SEd Maste 
2219261079SEd Maste #include <stdio.h>
2319261079SEd Maste #include <stdlib.h>
2419261079SEd Maste 
25bc5531deSDag-Erling Smørgrav #include "ssh_api.h"
26bc5531deSDag-Erling Smørgrav #include "compat.h"
27bc5531deSDag-Erling Smørgrav #include "log.h"
28bc5531deSDag-Erling Smørgrav #include "authfile.h"
29bc5531deSDag-Erling Smørgrav #include "sshkey.h"
30bc5531deSDag-Erling Smørgrav #include "misc.h"
31bc5531deSDag-Erling Smørgrav #include "ssh2.h"
32bc5531deSDag-Erling Smørgrav #include "version.h"
33bc5531deSDag-Erling Smørgrav #include "myproposal.h"
34bc5531deSDag-Erling Smørgrav #include "ssherr.h"
35bc5531deSDag-Erling Smørgrav #include "sshbuf.h"
36bc5531deSDag-Erling Smørgrav 
3719261079SEd Maste #include "openbsd-compat/openssl-compat.h"
3819261079SEd Maste 
39bc5531deSDag-Erling Smørgrav #include <string.h>
40bc5531deSDag-Erling Smørgrav 
41bc5531deSDag-Erling Smørgrav int	_ssh_exchange_banner(struct ssh *);
4219261079SEd Maste int	_ssh_send_banner(struct ssh *, struct sshbuf *);
4319261079SEd Maste int	_ssh_read_banner(struct ssh *, struct sshbuf *);
44bc5531deSDag-Erling Smørgrav int	_ssh_order_hostkeyalgs(struct ssh *);
45bc5531deSDag-Erling Smørgrav int	_ssh_verify_host_key(struct sshkey *, struct ssh *);
46bc5531deSDag-Erling Smørgrav struct sshkey *_ssh_host_public_key(int, int, struct ssh *);
47bc5531deSDag-Erling Smørgrav struct sshkey *_ssh_host_private_key(int, int, struct ssh *);
4819261079SEd Maste int	_ssh_host_key_sign(struct ssh *, struct sshkey *, struct sshkey *,
4919261079SEd Maste     u_char **, size_t *, const u_char *, size_t, const char *);
50bc5531deSDag-Erling Smørgrav 
51bc5531deSDag-Erling Smørgrav /*
52bc5531deSDag-Erling Smørgrav  * stubs for the server side implementation of kex.
53bc5531deSDag-Erling Smørgrav  * disable privsep so our stubs will never be called.
54bc5531deSDag-Erling Smørgrav  */
55bc5531deSDag-Erling Smørgrav int	use_privsep = 0;
56bc5531deSDag-Erling Smørgrav int	mm_sshkey_sign(struct sshkey *, u_char **, u_int *,
5719261079SEd Maste     const u_char *, u_int, const char *, const char *, const char *, u_int);
58bc5531deSDag-Erling Smørgrav 
5919261079SEd Maste #ifdef WITH_OPENSSL
6019261079SEd Maste DH	*mm_choose_dh(int, int, int);
6119261079SEd Maste #endif
62bc5531deSDag-Erling Smørgrav 
63bc5531deSDag-Erling Smørgrav int
mm_sshkey_sign(struct sshkey * key,u_char ** sigp,u_int * lenp,const u_char * data,u_int datalen,const char * alg,const char * sk_provider,const char * sk_pin,u_int compat)64bc5531deSDag-Erling Smørgrav mm_sshkey_sign(struct sshkey *key, u_char **sigp, u_int *lenp,
6519261079SEd Maste     const u_char *data, u_int datalen, const char *alg,
6619261079SEd Maste     const char *sk_provider, const char *sk_pin, u_int compat)
67bc5531deSDag-Erling Smørgrav {
68bc5531deSDag-Erling Smørgrav 	return (-1);
69bc5531deSDag-Erling Smørgrav }
70bc5531deSDag-Erling Smørgrav 
7119261079SEd Maste #ifdef WITH_OPENSSL
72bc5531deSDag-Erling Smørgrav DH *
mm_choose_dh(int min,int nbits,int max)73bc5531deSDag-Erling Smørgrav mm_choose_dh(int min, int nbits, int max)
74bc5531deSDag-Erling Smørgrav {
75bc5531deSDag-Erling Smørgrav 	return (NULL);
76bc5531deSDag-Erling Smørgrav }
7719261079SEd Maste #endif
78bc5531deSDag-Erling Smørgrav 
79bc5531deSDag-Erling Smørgrav /* API */
80bc5531deSDag-Erling Smørgrav 
81bc5531deSDag-Erling Smørgrav int
ssh_init(struct ssh ** sshp,int is_server,struct kex_params * kex_params)82bc5531deSDag-Erling Smørgrav ssh_init(struct ssh **sshp, int is_server, struct kex_params *kex_params)
83bc5531deSDag-Erling Smørgrav {
84bc5531deSDag-Erling Smørgrav 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
85*a91a2465SEd Maste 	char *populated[PROPOSAL_MAX];
86bc5531deSDag-Erling Smørgrav 	struct ssh *ssh;
87bc5531deSDag-Erling Smørgrav 	char **proposal;
88bc5531deSDag-Erling Smørgrav 	static int called;
89bc5531deSDag-Erling Smørgrav 	int r;
90bc5531deSDag-Erling Smørgrav 
91bc5531deSDag-Erling Smørgrav 	if (!called) {
9219261079SEd Maste 		seed_rng();
93bc5531deSDag-Erling Smørgrav 		called = 1;
94bc5531deSDag-Erling Smørgrav 	}
95bc5531deSDag-Erling Smørgrav 
96bc5531deSDag-Erling Smørgrav 	if ((ssh = ssh_packet_set_connection(NULL, -1, -1)) == NULL)
97bc5531deSDag-Erling Smørgrav 		return SSH_ERR_ALLOC_FAIL;
98bc5531deSDag-Erling Smørgrav 	if (is_server)
99bc5531deSDag-Erling Smørgrav 		ssh_packet_set_server(ssh);
100bc5531deSDag-Erling Smørgrav 
101bc5531deSDag-Erling Smørgrav 	/* Initialize key exchange */
102bc5531deSDag-Erling Smørgrav 	proposal = kex_params ? kex_params->proposal : myproposal;
103*a91a2465SEd Maste 	kex_proposal_populate_entries(ssh, populated,
104*a91a2465SEd Maste 	    proposal[PROPOSAL_KEX_ALGS],
105*a91a2465SEd Maste 	    proposal[PROPOSAL_ENC_ALGS_CTOS],
106*a91a2465SEd Maste 	    proposal[PROPOSAL_MAC_ALGS_CTOS],
107*a91a2465SEd Maste 	    proposal[PROPOSAL_COMP_ALGS_CTOS],
108*a91a2465SEd Maste 	    proposal[PROPOSAL_SERVER_HOST_KEY_ALGS]);
109*a91a2465SEd Maste 	r = kex_ready(ssh, populated);
110*a91a2465SEd Maste 	kex_proposal_free_entries(populated);
111*a91a2465SEd Maste 	if (r != 0) {
112bc5531deSDag-Erling Smørgrav 		ssh_free(ssh);
113bc5531deSDag-Erling Smørgrav 		return r;
114bc5531deSDag-Erling Smørgrav 	}
115*a91a2465SEd Maste 
116bc5531deSDag-Erling Smørgrav 	ssh->kex->server = is_server;
117bc5531deSDag-Erling Smørgrav 	if (is_server) {
118bc5531deSDag-Erling Smørgrav #ifdef WITH_OPENSSL
11919261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
12019261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
12119261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
12219261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
12319261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
124bc5531deSDag-Erling Smørgrav 		ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
125bc5531deSDag-Erling Smørgrav 		ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
126bc5531deSDag-Erling Smørgrav # ifdef OPENSSL_HAS_ECC
12719261079SEd Maste 		ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
128bc5531deSDag-Erling Smørgrav # endif
129bc5531deSDag-Erling Smørgrav #endif /* WITH_OPENSSL */
13019261079SEd Maste 		ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_server;
13119261079SEd Maste 		ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
132bc5531deSDag-Erling Smørgrav 		ssh->kex->load_host_public_key=&_ssh_host_public_key;
133bc5531deSDag-Erling Smørgrav 		ssh->kex->load_host_private_key=&_ssh_host_private_key;
134bc5531deSDag-Erling Smørgrav 		ssh->kex->sign=&_ssh_host_key_sign;
135bc5531deSDag-Erling Smørgrav 	} else {
136bc5531deSDag-Erling Smørgrav #ifdef WITH_OPENSSL
13719261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
13819261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
13919261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
14019261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
14119261079SEd Maste 		ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
142bc5531deSDag-Erling Smørgrav 		ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
143bc5531deSDag-Erling Smørgrav 		ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
144bc5531deSDag-Erling Smørgrav # ifdef OPENSSL_HAS_ECC
14519261079SEd Maste 		ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
146bc5531deSDag-Erling Smørgrav # endif
147bc5531deSDag-Erling Smørgrav #endif /* WITH_OPENSSL */
14819261079SEd Maste 		ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
14919261079SEd Maste 		ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
150bc5531deSDag-Erling Smørgrav 		ssh->kex->verify_host_key =&_ssh_verify_host_key;
151bc5531deSDag-Erling Smørgrav 	}
152bc5531deSDag-Erling Smørgrav 	*sshp = ssh;
153bc5531deSDag-Erling Smørgrav 	return 0;
154bc5531deSDag-Erling Smørgrav }
155bc5531deSDag-Erling Smørgrav 
156bc5531deSDag-Erling Smørgrav void
ssh_free(struct ssh * ssh)157bc5531deSDag-Erling Smørgrav ssh_free(struct ssh *ssh)
158bc5531deSDag-Erling Smørgrav {
159bc5531deSDag-Erling Smørgrav 	struct key_entry *k;
160bc5531deSDag-Erling Smørgrav 
16119261079SEd Maste 	if (ssh == NULL)
16219261079SEd Maste 		return;
16319261079SEd Maste 
164bc5531deSDag-Erling Smørgrav 	/*
165bc5531deSDag-Erling Smørgrav 	 * we've only created the public keys variants in case we
166bc5531deSDag-Erling Smørgrav 	 * are a acting as a server.
167bc5531deSDag-Erling Smørgrav 	 */
168bc5531deSDag-Erling Smørgrav 	while ((k = TAILQ_FIRST(&ssh->public_keys)) != NULL) {
169bc5531deSDag-Erling Smørgrav 		TAILQ_REMOVE(&ssh->public_keys, k, next);
170bc5531deSDag-Erling Smørgrav 		if (ssh->kex && ssh->kex->server)
171bc5531deSDag-Erling Smørgrav 			sshkey_free(k->key);
172bc5531deSDag-Erling Smørgrav 		free(k);
173bc5531deSDag-Erling Smørgrav 	}
174bc5531deSDag-Erling Smørgrav 	while ((k = TAILQ_FIRST(&ssh->private_keys)) != NULL) {
175bc5531deSDag-Erling Smørgrav 		TAILQ_REMOVE(&ssh->private_keys, k, next);
176bc5531deSDag-Erling Smørgrav 		free(k);
177bc5531deSDag-Erling Smørgrav 	}
17819261079SEd Maste 	ssh_packet_close(ssh);
179bc5531deSDag-Erling Smørgrav 	free(ssh);
180bc5531deSDag-Erling Smørgrav }
181bc5531deSDag-Erling Smørgrav 
182bc5531deSDag-Erling Smørgrav void
ssh_set_app_data(struct ssh * ssh,void * app_data)183bc5531deSDag-Erling Smørgrav ssh_set_app_data(struct ssh *ssh, void *app_data)
184bc5531deSDag-Erling Smørgrav {
185bc5531deSDag-Erling Smørgrav 	ssh->app_data = app_data;
186bc5531deSDag-Erling Smørgrav }
187bc5531deSDag-Erling Smørgrav 
188bc5531deSDag-Erling Smørgrav void *
ssh_get_app_data(struct ssh * ssh)189bc5531deSDag-Erling Smørgrav ssh_get_app_data(struct ssh *ssh)
190bc5531deSDag-Erling Smørgrav {
191bc5531deSDag-Erling Smørgrav 	return ssh->app_data;
192bc5531deSDag-Erling Smørgrav }
193bc5531deSDag-Erling Smørgrav 
194bc5531deSDag-Erling Smørgrav /* Returns < 0 on error, 0 otherwise */
195bc5531deSDag-Erling Smørgrav int
ssh_add_hostkey(struct ssh * ssh,struct sshkey * key)196bc5531deSDag-Erling Smørgrav ssh_add_hostkey(struct ssh *ssh, struct sshkey *key)
197bc5531deSDag-Erling Smørgrav {
198bc5531deSDag-Erling Smørgrav 	struct sshkey *pubkey = NULL;
199bc5531deSDag-Erling Smørgrav 	struct key_entry *k = NULL, *k_prv = NULL;
200bc5531deSDag-Erling Smørgrav 	int r;
201bc5531deSDag-Erling Smørgrav 
202bc5531deSDag-Erling Smørgrav 	if (ssh->kex->server) {
203bc5531deSDag-Erling Smørgrav 		if ((r = sshkey_from_private(key, &pubkey)) != 0)
204bc5531deSDag-Erling Smørgrav 			return r;
205bc5531deSDag-Erling Smørgrav 		if ((k = malloc(sizeof(*k))) == NULL ||
206bc5531deSDag-Erling Smørgrav 		    (k_prv = malloc(sizeof(*k_prv))) == NULL) {
207bc5531deSDag-Erling Smørgrav 			free(k);
208bc5531deSDag-Erling Smørgrav 			sshkey_free(pubkey);
209bc5531deSDag-Erling Smørgrav 			return SSH_ERR_ALLOC_FAIL;
210bc5531deSDag-Erling Smørgrav 		}
211bc5531deSDag-Erling Smørgrav 		k_prv->key = key;
212bc5531deSDag-Erling Smørgrav 		TAILQ_INSERT_TAIL(&ssh->private_keys, k_prv, next);
213bc5531deSDag-Erling Smørgrav 
214bc5531deSDag-Erling Smørgrav 		/* add the public key, too */
215bc5531deSDag-Erling Smørgrav 		k->key = pubkey;
216bc5531deSDag-Erling Smørgrav 		TAILQ_INSERT_TAIL(&ssh->public_keys, k, next);
217bc5531deSDag-Erling Smørgrav 		r = 0;
218bc5531deSDag-Erling Smørgrav 	} else {
219bc5531deSDag-Erling Smørgrav 		if ((k = malloc(sizeof(*k))) == NULL)
220bc5531deSDag-Erling Smørgrav 			return SSH_ERR_ALLOC_FAIL;
221bc5531deSDag-Erling Smørgrav 		k->key = key;
222bc5531deSDag-Erling Smørgrav 		TAILQ_INSERT_TAIL(&ssh->public_keys, k, next);
223bc5531deSDag-Erling Smørgrav 		r = 0;
224bc5531deSDag-Erling Smørgrav 	}
225bc5531deSDag-Erling Smørgrav 
226bc5531deSDag-Erling Smørgrav 	return r;
227bc5531deSDag-Erling Smørgrav }
228bc5531deSDag-Erling Smørgrav 
229bc5531deSDag-Erling Smørgrav int
ssh_set_verify_host_key_callback(struct ssh * ssh,int (* cb)(struct sshkey *,struct ssh *))230bc5531deSDag-Erling Smørgrav ssh_set_verify_host_key_callback(struct ssh *ssh,
231bc5531deSDag-Erling Smørgrav     int (*cb)(struct sshkey *, struct ssh *))
232bc5531deSDag-Erling Smørgrav {
233bc5531deSDag-Erling Smørgrav 	if (cb == NULL || ssh->kex == NULL)
234bc5531deSDag-Erling Smørgrav 		return SSH_ERR_INVALID_ARGUMENT;
235bc5531deSDag-Erling Smørgrav 
236bc5531deSDag-Erling Smørgrav 	ssh->kex->verify_host_key = cb;
237bc5531deSDag-Erling Smørgrav 
238bc5531deSDag-Erling Smørgrav 	return 0;
239bc5531deSDag-Erling Smørgrav }
240bc5531deSDag-Erling Smørgrav 
241bc5531deSDag-Erling Smørgrav int
ssh_input_append(struct ssh * ssh,const u_char * data,size_t len)242bc5531deSDag-Erling Smørgrav ssh_input_append(struct ssh *ssh, const u_char *data, size_t len)
243bc5531deSDag-Erling Smørgrav {
244bc5531deSDag-Erling Smørgrav 	return sshbuf_put(ssh_packet_get_input(ssh), data, len);
245bc5531deSDag-Erling Smørgrav }
246bc5531deSDag-Erling Smørgrav 
247bc5531deSDag-Erling Smørgrav int
ssh_packet_next(struct ssh * ssh,u_char * typep)248bc5531deSDag-Erling Smørgrav ssh_packet_next(struct ssh *ssh, u_char *typep)
249bc5531deSDag-Erling Smørgrav {
250bc5531deSDag-Erling Smørgrav 	int r;
251bc5531deSDag-Erling Smørgrav 	u_int32_t seqnr;
252bc5531deSDag-Erling Smørgrav 	u_char type;
253bc5531deSDag-Erling Smørgrav 
254bc5531deSDag-Erling Smørgrav 	/*
255bc5531deSDag-Erling Smørgrav 	 * Try to read a packet. Return SSH_MSG_NONE if no packet or not
256bc5531deSDag-Erling Smørgrav 	 * enough data.
257bc5531deSDag-Erling Smørgrav 	 */
258bc5531deSDag-Erling Smørgrav 	*typep = SSH_MSG_NONE;
25919261079SEd Maste 	if (sshbuf_len(ssh->kex->client_version) == 0 ||
26019261079SEd Maste 	    sshbuf_len(ssh->kex->server_version) == 0)
261bc5531deSDag-Erling Smørgrav 		return _ssh_exchange_banner(ssh);
262bc5531deSDag-Erling Smørgrav 	/*
263bc5531deSDag-Erling Smørgrav 	 * If we enough data and a dispatch function then
264bc5531deSDag-Erling Smørgrav 	 * call the function and get the next packet.
265bc5531deSDag-Erling Smørgrav 	 * Otherwise return the packet type to the caller so it
266bc5531deSDag-Erling Smørgrav 	 * can decide how to go on.
267bc5531deSDag-Erling Smørgrav 	 *
268bc5531deSDag-Erling Smørgrav 	 * We will only call the dispatch function for:
269bc5531deSDag-Erling Smørgrav 	 *     20-29    Algorithm negotiation
270bc5531deSDag-Erling Smørgrav 	 *     30-49    Key exchange method specific (numbers can be reused for
271bc5531deSDag-Erling Smørgrav 	 *              different authentication methods)
272bc5531deSDag-Erling Smørgrav 	 */
273bc5531deSDag-Erling Smørgrav 	for (;;) {
274bc5531deSDag-Erling Smørgrav 		if ((r = ssh_packet_read_poll2(ssh, &type, &seqnr)) != 0)
275bc5531deSDag-Erling Smørgrav 			return r;
276bc5531deSDag-Erling Smørgrav 		if (type > 0 && type < DISPATCH_MAX &&
277bc5531deSDag-Erling Smørgrav 		    type >= SSH2_MSG_KEXINIT && type <= SSH2_MSG_TRANSPORT_MAX &&
278bc5531deSDag-Erling Smørgrav 		    ssh->dispatch[type] != NULL) {
279bc5531deSDag-Erling Smørgrav 			if ((r = (*ssh->dispatch[type])(type, seqnr, ssh)) != 0)
280bc5531deSDag-Erling Smørgrav 				return r;
281bc5531deSDag-Erling Smørgrav 		} else {
282bc5531deSDag-Erling Smørgrav 			*typep = type;
283bc5531deSDag-Erling Smørgrav 			return 0;
284bc5531deSDag-Erling Smørgrav 		}
285bc5531deSDag-Erling Smørgrav 	}
286bc5531deSDag-Erling Smørgrav }
287bc5531deSDag-Erling Smørgrav 
288bc5531deSDag-Erling Smørgrav const u_char *
ssh_packet_payload(struct ssh * ssh,size_t * lenp)289bc5531deSDag-Erling Smørgrav ssh_packet_payload(struct ssh *ssh, size_t *lenp)
290bc5531deSDag-Erling Smørgrav {
291bc5531deSDag-Erling Smørgrav 	return sshpkt_ptr(ssh, lenp);
292bc5531deSDag-Erling Smørgrav }
293bc5531deSDag-Erling Smørgrav 
294bc5531deSDag-Erling Smørgrav int
ssh_packet_put(struct ssh * ssh,int type,const u_char * data,size_t len)295bc5531deSDag-Erling Smørgrav ssh_packet_put(struct ssh *ssh, int type, const u_char *data, size_t len)
296bc5531deSDag-Erling Smørgrav {
297bc5531deSDag-Erling Smørgrav 	int r;
298bc5531deSDag-Erling Smørgrav 
299bc5531deSDag-Erling Smørgrav 	if ((r = sshpkt_start(ssh, type)) != 0 ||
300bc5531deSDag-Erling Smørgrav 	    (r = sshpkt_put(ssh, data, len)) != 0 ||
301bc5531deSDag-Erling Smørgrav 	    (r = sshpkt_send(ssh)) != 0)
302bc5531deSDag-Erling Smørgrav 		return r;
303bc5531deSDag-Erling Smørgrav 	return 0;
304bc5531deSDag-Erling Smørgrav }
305bc5531deSDag-Erling Smørgrav 
306bc5531deSDag-Erling Smørgrav const u_char *
ssh_output_ptr(struct ssh * ssh,size_t * len)307bc5531deSDag-Erling Smørgrav ssh_output_ptr(struct ssh *ssh, size_t *len)
308bc5531deSDag-Erling Smørgrav {
309bc5531deSDag-Erling Smørgrav 	struct sshbuf *output = ssh_packet_get_output(ssh);
310bc5531deSDag-Erling Smørgrav 
311bc5531deSDag-Erling Smørgrav 	*len = sshbuf_len(output);
312bc5531deSDag-Erling Smørgrav 	return sshbuf_ptr(output);
313bc5531deSDag-Erling Smørgrav }
314bc5531deSDag-Erling Smørgrav 
315bc5531deSDag-Erling Smørgrav int
ssh_output_consume(struct ssh * ssh,size_t len)316bc5531deSDag-Erling Smørgrav ssh_output_consume(struct ssh *ssh, size_t len)
317bc5531deSDag-Erling Smørgrav {
318bc5531deSDag-Erling Smørgrav 	return sshbuf_consume(ssh_packet_get_output(ssh), len);
319bc5531deSDag-Erling Smørgrav }
320bc5531deSDag-Erling Smørgrav 
321bc5531deSDag-Erling Smørgrav int
ssh_output_space(struct ssh * ssh,size_t len)322bc5531deSDag-Erling Smørgrav ssh_output_space(struct ssh *ssh, size_t len)
323bc5531deSDag-Erling Smørgrav {
324bc5531deSDag-Erling Smørgrav 	return (0 == sshbuf_check_reserve(ssh_packet_get_output(ssh), len));
325bc5531deSDag-Erling Smørgrav }
326bc5531deSDag-Erling Smørgrav 
327bc5531deSDag-Erling Smørgrav int
ssh_input_space(struct ssh * ssh,size_t len)328bc5531deSDag-Erling Smørgrav ssh_input_space(struct ssh *ssh, size_t len)
329bc5531deSDag-Erling Smørgrav {
330bc5531deSDag-Erling Smørgrav 	return (0 == sshbuf_check_reserve(ssh_packet_get_input(ssh), len));
331bc5531deSDag-Erling Smørgrav }
332bc5531deSDag-Erling Smørgrav 
333bc5531deSDag-Erling Smørgrav /* Read other side's version identification. */
334bc5531deSDag-Erling Smørgrav int
_ssh_read_banner(struct ssh * ssh,struct sshbuf * banner)33519261079SEd Maste _ssh_read_banner(struct ssh *ssh, struct sshbuf *banner)
336bc5531deSDag-Erling Smørgrav {
33719261079SEd Maste 	struct sshbuf *input = ssh_packet_get_input(ssh);
338bc5531deSDag-Erling Smørgrav 	const char *mismatch = "Protocol mismatch.\r\n";
33919261079SEd Maste 	const u_char *s = sshbuf_ptr(input);
34019261079SEd Maste 	u_char c;
34119261079SEd Maste 	char *cp = NULL, *remote_version = NULL;
34219261079SEd Maste 	int r = 0, remote_major, remote_minor, expect_nl;
34319261079SEd Maste 	size_t n, j;
344bc5531deSDag-Erling Smørgrav 
345bc5531deSDag-Erling Smørgrav 	for (j = n = 0;;) {
34619261079SEd Maste 		sshbuf_reset(banner);
34719261079SEd Maste 		expect_nl = 0;
34819261079SEd Maste 		for (;;) {
34919261079SEd Maste 			if (j >= sshbuf_len(input))
35019261079SEd Maste 				return 0; /* insufficient data in input buf */
35119261079SEd Maste 			c = s[j++];
35219261079SEd Maste 			if (c == '\r') {
35319261079SEd Maste 				expect_nl = 1;
35419261079SEd Maste 				continue;
355bc5531deSDag-Erling Smørgrav 			}
35619261079SEd Maste 			if (c == '\n')
357bc5531deSDag-Erling Smørgrav 				break;
35819261079SEd Maste 			if (expect_nl)
35919261079SEd Maste 				goto bad;
36019261079SEd Maste 			if ((r = sshbuf_put_u8(banner, c)) != 0)
36119261079SEd Maste 				return r;
36219261079SEd Maste 			if (sshbuf_len(banner) > SSH_MAX_BANNER_LEN)
36319261079SEd Maste 				goto bad;
364bc5531deSDag-Erling Smørgrav 		}
36519261079SEd Maste 		if (sshbuf_len(banner) >= 4 &&
36619261079SEd Maste 		    memcmp(sshbuf_ptr(banner), "SSH-", 4) == 0)
367bc5531deSDag-Erling Smørgrav 			break;
36819261079SEd Maste 		debug_f("%.*s", (int)sshbuf_len(banner),
36919261079SEd Maste 		    sshbuf_ptr(banner));
37019261079SEd Maste 		/* Accept lines before banner only on client */
37119261079SEd Maste 		if (ssh->kex->server || ++n > SSH_MAX_PRE_BANNER_LINES) {
37219261079SEd Maste   bad:
373bc5531deSDag-Erling Smørgrav 			if ((r = sshbuf_put(ssh_packet_get_output(ssh),
374bc5531deSDag-Erling Smørgrav 			    mismatch, strlen(mismatch))) != 0)
375bc5531deSDag-Erling Smørgrav 				return r;
376bc5531deSDag-Erling Smørgrav 			return SSH_ERR_NO_PROTOCOL_VERSION;
377bc5531deSDag-Erling Smørgrav 		}
378bc5531deSDag-Erling Smørgrav 	}
379bc5531deSDag-Erling Smørgrav 	if ((r = sshbuf_consume(input, j)) != 0)
380bc5531deSDag-Erling Smørgrav 		return r;
381bc5531deSDag-Erling Smørgrav 
38219261079SEd Maste 	/* XXX remote version must be the same size as banner for sscanf */
38319261079SEd Maste 	if ((cp = sshbuf_dup_string(banner)) == NULL ||
38419261079SEd Maste 	    (remote_version = calloc(1, sshbuf_len(banner))) == NULL) {
38519261079SEd Maste 		r = SSH_ERR_ALLOC_FAIL;
38619261079SEd Maste 		goto out;
38719261079SEd Maste 	}
38819261079SEd Maste 
389bc5531deSDag-Erling Smørgrav 	/*
390bc5531deSDag-Erling Smørgrav 	 * Check that the versions match.  In future this might accept
391bc5531deSDag-Erling Smørgrav 	 * several versions and set appropriate flags to handle them.
392bc5531deSDag-Erling Smørgrav 	 */
39319261079SEd Maste 	if (sscanf(cp, "SSH-%d.%d-%[^\n]\n",
39419261079SEd Maste 	    &remote_major, &remote_minor, remote_version) != 3) {
39519261079SEd Maste 		r = SSH_ERR_INVALID_FORMAT;
39619261079SEd Maste 		goto out;
39719261079SEd Maste 	}
398bc5531deSDag-Erling Smørgrav 	debug("Remote protocol version %d.%d, remote software version %.100s",
399bc5531deSDag-Erling Smørgrav 	    remote_major, remote_minor, remote_version);
400bc5531deSDag-Erling Smørgrav 
40119261079SEd Maste 	compat_banner(ssh, remote_version);
402bc5531deSDag-Erling Smørgrav 	if  (remote_major == 1 && remote_minor == 99) {
403bc5531deSDag-Erling Smørgrav 		remote_major = 2;
404bc5531deSDag-Erling Smørgrav 		remote_minor = 0;
405bc5531deSDag-Erling Smørgrav 	}
406bc5531deSDag-Erling Smørgrav 	if (remote_major != 2)
40719261079SEd Maste 		r = SSH_ERR_PROTOCOL_MISMATCH;
40819261079SEd Maste 
40919261079SEd Maste 	debug("Remote version string %.100s", cp);
41019261079SEd Maste  out:
41119261079SEd Maste 	free(cp);
41219261079SEd Maste 	free(remote_version);
41319261079SEd Maste 	return r;
414bc5531deSDag-Erling Smørgrav }
415bc5531deSDag-Erling Smørgrav 
416bc5531deSDag-Erling Smørgrav /* Send our own protocol version identification. */
417bc5531deSDag-Erling Smørgrav int
_ssh_send_banner(struct ssh * ssh,struct sshbuf * banner)41819261079SEd Maste _ssh_send_banner(struct ssh *ssh, struct sshbuf *banner)
419bc5531deSDag-Erling Smørgrav {
42019261079SEd Maste 	char *cp;
421bc5531deSDag-Erling Smørgrav 	int r;
422bc5531deSDag-Erling Smørgrav 
42319261079SEd Maste 	if ((r = sshbuf_putf(banner, "SSH-2.0-%.100s\r\n", SSH_VERSION)) != 0)
424bc5531deSDag-Erling Smørgrav 		return r;
42519261079SEd Maste 	if ((r = sshbuf_putb(ssh_packet_get_output(ssh), banner)) != 0)
42619261079SEd Maste 		return r;
42719261079SEd Maste 	/* Remove trailing \r\n */
42819261079SEd Maste 	if ((r = sshbuf_consume_end(banner, 2)) != 0)
42919261079SEd Maste 		return r;
43019261079SEd Maste 	if ((cp = sshbuf_dup_string(banner)) == NULL)
431bc5531deSDag-Erling Smørgrav 		return SSH_ERR_ALLOC_FAIL;
43219261079SEd Maste 	debug("Local version string %.100s", cp);
43319261079SEd Maste 	free(cp);
434bc5531deSDag-Erling Smørgrav 	return 0;
435bc5531deSDag-Erling Smørgrav }
436bc5531deSDag-Erling Smørgrav 
437bc5531deSDag-Erling Smørgrav int
_ssh_exchange_banner(struct ssh * ssh)438bc5531deSDag-Erling Smørgrav _ssh_exchange_banner(struct ssh *ssh)
439bc5531deSDag-Erling Smørgrav {
440bc5531deSDag-Erling Smørgrav 	struct kex *kex = ssh->kex;
441bc5531deSDag-Erling Smørgrav 	int r;
442bc5531deSDag-Erling Smørgrav 
443bc5531deSDag-Erling Smørgrav 	/*
444bc5531deSDag-Erling Smørgrav 	 * if _ssh_read_banner() cannot parse a full version string
445bc5531deSDag-Erling Smørgrav 	 * it will return NULL and we end up calling it again.
446bc5531deSDag-Erling Smørgrav 	 */
447bc5531deSDag-Erling Smørgrav 
448bc5531deSDag-Erling Smørgrav 	r = 0;
449bc5531deSDag-Erling Smørgrav 	if (kex->server) {
45019261079SEd Maste 		if (sshbuf_len(ssh->kex->server_version) == 0)
45119261079SEd Maste 			r = _ssh_send_banner(ssh, ssh->kex->server_version);
452bc5531deSDag-Erling Smørgrav 		if (r == 0 &&
45319261079SEd Maste 		    sshbuf_len(ssh->kex->server_version) != 0 &&
45419261079SEd Maste 		    sshbuf_len(ssh->kex->client_version) == 0)
45519261079SEd Maste 			r = _ssh_read_banner(ssh, ssh->kex->client_version);
456bc5531deSDag-Erling Smørgrav 	} else {
45719261079SEd Maste 		if (sshbuf_len(ssh->kex->server_version) == 0)
45819261079SEd Maste 			r = _ssh_read_banner(ssh, ssh->kex->server_version);
459bc5531deSDag-Erling Smørgrav 		if (r == 0 &&
46019261079SEd Maste 		    sshbuf_len(ssh->kex->server_version) != 0 &&
46119261079SEd Maste 		    sshbuf_len(ssh->kex->client_version) == 0)
46219261079SEd Maste 			r = _ssh_send_banner(ssh, ssh->kex->client_version);
463bc5531deSDag-Erling Smørgrav 	}
464bc5531deSDag-Erling Smørgrav 	if (r != 0)
465bc5531deSDag-Erling Smørgrav 		return r;
466bc5531deSDag-Erling Smørgrav 	/* start initial kex as soon as we have exchanged the banners */
46719261079SEd Maste 	if (sshbuf_len(ssh->kex->server_version) != 0 &&
46819261079SEd Maste 	    sshbuf_len(ssh->kex->client_version) != 0) {
469bc5531deSDag-Erling Smørgrav 		if ((r = _ssh_order_hostkeyalgs(ssh)) != 0 ||
470bc5531deSDag-Erling Smørgrav 		    (r = kex_send_kexinit(ssh)) != 0)
471bc5531deSDag-Erling Smørgrav 			return r;
472bc5531deSDag-Erling Smørgrav 	}
473bc5531deSDag-Erling Smørgrav 	return 0;
474bc5531deSDag-Erling Smørgrav }
475bc5531deSDag-Erling Smørgrav 
476bc5531deSDag-Erling Smørgrav struct sshkey *
_ssh_host_public_key(int type,int nid,struct ssh * ssh)477bc5531deSDag-Erling Smørgrav _ssh_host_public_key(int type, int nid, struct ssh *ssh)
478bc5531deSDag-Erling Smørgrav {
479bc5531deSDag-Erling Smørgrav 	struct key_entry *k;
480bc5531deSDag-Erling Smørgrav 
48119261079SEd Maste 	debug3_f("need %d", type);
482bc5531deSDag-Erling Smørgrav 	TAILQ_FOREACH(k, &ssh->public_keys, next) {
48319261079SEd Maste 		debug3_f("check %s", sshkey_type(k->key));
484bc5531deSDag-Erling Smørgrav 		if (k->key->type == type &&
485bc5531deSDag-Erling Smørgrav 		    (type != KEY_ECDSA || k->key->ecdsa_nid == nid))
486bc5531deSDag-Erling Smørgrav 			return (k->key);
487bc5531deSDag-Erling Smørgrav 	}
488bc5531deSDag-Erling Smørgrav 	return (NULL);
489bc5531deSDag-Erling Smørgrav }
490bc5531deSDag-Erling Smørgrav 
491bc5531deSDag-Erling Smørgrav struct sshkey *
_ssh_host_private_key(int type,int nid,struct ssh * ssh)492bc5531deSDag-Erling Smørgrav _ssh_host_private_key(int type, int nid, struct ssh *ssh)
493bc5531deSDag-Erling Smørgrav {
494bc5531deSDag-Erling Smørgrav 	struct key_entry *k;
495bc5531deSDag-Erling Smørgrav 
49619261079SEd Maste 	debug3_f("need %d", type);
497bc5531deSDag-Erling Smørgrav 	TAILQ_FOREACH(k, &ssh->private_keys, next) {
49819261079SEd Maste 		debug3_f("check %s", sshkey_type(k->key));
499bc5531deSDag-Erling Smørgrav 		if (k->key->type == type &&
500bc5531deSDag-Erling Smørgrav 		    (type != KEY_ECDSA || k->key->ecdsa_nid == nid))
501bc5531deSDag-Erling Smørgrav 			return (k->key);
502bc5531deSDag-Erling Smørgrav 	}
503bc5531deSDag-Erling Smørgrav 	return (NULL);
504bc5531deSDag-Erling Smørgrav }
505bc5531deSDag-Erling Smørgrav 
506bc5531deSDag-Erling Smørgrav int
_ssh_verify_host_key(struct sshkey * hostkey,struct ssh * ssh)507bc5531deSDag-Erling Smørgrav _ssh_verify_host_key(struct sshkey *hostkey, struct ssh *ssh)
508bc5531deSDag-Erling Smørgrav {
509bc5531deSDag-Erling Smørgrav 	struct key_entry *k;
510bc5531deSDag-Erling Smørgrav 
51119261079SEd Maste 	debug3_f("need %s", sshkey_type(hostkey));
512bc5531deSDag-Erling Smørgrav 	TAILQ_FOREACH(k, &ssh->public_keys, next) {
51319261079SEd Maste 		debug3_f("check %s", sshkey_type(k->key));
514bc5531deSDag-Erling Smørgrav 		if (sshkey_equal_public(hostkey, k->key))
515bc5531deSDag-Erling Smørgrav 			return (0);	/* ok */
516bc5531deSDag-Erling Smørgrav 	}
517bc5531deSDag-Erling Smørgrav 	return (-1);	/* failed */
518bc5531deSDag-Erling Smørgrav }
519bc5531deSDag-Erling Smørgrav 
520bc5531deSDag-Erling Smørgrav /* offer hostkey algorithms in kexinit depending on registered keys */
521bc5531deSDag-Erling Smørgrav int
_ssh_order_hostkeyalgs(struct ssh * ssh)522bc5531deSDag-Erling Smørgrav _ssh_order_hostkeyalgs(struct ssh *ssh)
523bc5531deSDag-Erling Smørgrav {
524bc5531deSDag-Erling Smørgrav 	struct key_entry *k;
525bc5531deSDag-Erling Smørgrav 	char *orig, *avail, *oavail = NULL, *alg, *replace = NULL;
526bc5531deSDag-Erling Smørgrav 	char **proposal;
527bc5531deSDag-Erling Smørgrav 	size_t maxlen;
528bc5531deSDag-Erling Smørgrav 	int ktype, r;
529bc5531deSDag-Erling Smørgrav 
530bc5531deSDag-Erling Smørgrav 	/* XXX we de-serialize ssh->kex->my, modify it, and change it */
531bc5531deSDag-Erling Smørgrav 	if ((r = kex_buf2prop(ssh->kex->my, NULL, &proposal)) != 0)
532bc5531deSDag-Erling Smørgrav 		return r;
533bc5531deSDag-Erling Smørgrav 	orig = proposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
534bc5531deSDag-Erling Smørgrav 	if ((oavail = avail = strdup(orig)) == NULL) {
535bc5531deSDag-Erling Smørgrav 		r = SSH_ERR_ALLOC_FAIL;
536bc5531deSDag-Erling Smørgrav 		goto out;
537bc5531deSDag-Erling Smørgrav 	}
538bc5531deSDag-Erling Smørgrav 	maxlen = strlen(avail) + 1;
539bc5531deSDag-Erling Smørgrav 	if ((replace = calloc(1, maxlen)) == NULL) {
540bc5531deSDag-Erling Smørgrav 		r = SSH_ERR_ALLOC_FAIL;
541bc5531deSDag-Erling Smørgrav 		goto out;
542bc5531deSDag-Erling Smørgrav 	}
543bc5531deSDag-Erling Smørgrav 	*replace = '\0';
544bc5531deSDag-Erling Smørgrav 	while ((alg = strsep(&avail, ",")) && *alg != '\0') {
545bc5531deSDag-Erling Smørgrav 		if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC)
546bc5531deSDag-Erling Smørgrav 			continue;
547bc5531deSDag-Erling Smørgrav 		TAILQ_FOREACH(k, &ssh->public_keys, next) {
548bc5531deSDag-Erling Smørgrav 			if (k->key->type == ktype ||
549bc5531deSDag-Erling Smørgrav 			    (sshkey_is_cert(k->key) && k->key->type ==
550bc5531deSDag-Erling Smørgrav 			    sshkey_type_plain(ktype))) {
551bc5531deSDag-Erling Smørgrav 				if (*replace != '\0')
552bc5531deSDag-Erling Smørgrav 					strlcat(replace, ",", maxlen);
553bc5531deSDag-Erling Smørgrav 				strlcat(replace, alg, maxlen);
554bc5531deSDag-Erling Smørgrav 				break;
555bc5531deSDag-Erling Smørgrav 			}
556bc5531deSDag-Erling Smørgrav 		}
557bc5531deSDag-Erling Smørgrav 	}
558bc5531deSDag-Erling Smørgrav 	if (*replace != '\0') {
55919261079SEd Maste 		debug2_f("orig/%d    %s", ssh->kex->server, orig);
56019261079SEd Maste 		debug2_f("replace/%d %s", ssh->kex->server, replace);
561bc5531deSDag-Erling Smørgrav 		free(orig);
562bc5531deSDag-Erling Smørgrav 		proposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = replace;
563bc5531deSDag-Erling Smørgrav 		replace = NULL;	/* owned by proposal */
564bc5531deSDag-Erling Smørgrav 		r = kex_prop2buf(ssh->kex->my, proposal);
565bc5531deSDag-Erling Smørgrav 	}
566bc5531deSDag-Erling Smørgrav  out:
567bc5531deSDag-Erling Smørgrav 	free(oavail);
568bc5531deSDag-Erling Smørgrav 	free(replace);
569bc5531deSDag-Erling Smørgrav 	kex_prop_free(proposal);
570bc5531deSDag-Erling Smørgrav 	return r;
571bc5531deSDag-Erling Smørgrav }
572bc5531deSDag-Erling Smørgrav 
573bc5531deSDag-Erling Smørgrav int
_ssh_host_key_sign(struct ssh * ssh,struct sshkey * privkey,struct sshkey * pubkey,u_char ** signature,size_t * slen,const u_char * data,size_t dlen,const char * alg)57419261079SEd Maste _ssh_host_key_sign(struct ssh *ssh, struct sshkey *privkey,
57519261079SEd Maste     struct sshkey *pubkey, u_char **signature, size_t *slen,
57619261079SEd Maste     const u_char *data, size_t dlen, const char *alg)
577bc5531deSDag-Erling Smørgrav {
57819261079SEd Maste 	return sshkey_sign(privkey, signature, slen, data, dlen,
57919261079SEd Maste 	    alg, NULL, NULL, ssh->compat);
580bc5531deSDag-Erling Smørgrav }
581