[openssh.git] / sshconnect2.c

/*
 * Copyright (c) 2000 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Markus Friedl.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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.
 */

#include "includes.h"
RCSID("$OpenBSD: sshconnect2.c,v 1.13 2000/06/02 02:00:19 todd Exp $");

#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/dsa.h>
#include <openssl/md5.h>
#include <openssl/dh.h>
#include <openssl/hmac.h>

#include "ssh.h"
#include "xmalloc.h"
#include "rsa.h"
#include "buffer.h"
#include "packet.h"
#include "cipher.h"
#include "uidswap.h"
#include "compat.h"
#include "readconf.h"
#include "bufaux.h"
#include "ssh2.h"
#include "kex.h"
#include "myproposal.h"
#include "key.h"
#include "dsa.h"
#include "sshconnect.h"
#include "authfile.h"

/* import */
extern char *client_version_string;
extern char *server_version_string;
extern Options options;

/*
 * SSH2 key exchange
 */

unsigned char *session_id2 = NULL;
int session_id2_len = 0;

void
ssh_kex_dh(Kex *kex, char *host, struct sockaddr *hostaddr,
    Buffer *client_kexinit, Buffer *server_kexinit)
{
	int plen, dlen;
	unsigned int klen, kout;
	char *signature = NULL;
	unsigned int slen;
	char *server_host_key_blob = NULL;
	Key *server_host_key;
	unsigned int sbloblen;
	DH *dh;
	BIGNUM *dh_server_pub = 0;
	BIGNUM *shared_secret = 0;
	unsigned char *kbuf;
	unsigned char *hash;

	debug("Sending SSH2_MSG_KEXDH_INIT.");
	/* generate and send 'e', client DH public key */
	dh = dh_new_group1();
	packet_start(SSH2_MSG_KEXDH_INIT);
	packet_put_bignum2(dh->pub_key);
	packet_send();
	packet_write_wait();

#ifdef DEBUG_KEXDH
	fprintf(stderr, "\np= ");
	bignum_print(dh->p);
	fprintf(stderr, "\ng= ");
	bignum_print(dh->g);
	fprintf(stderr, "\npub= ");
	bignum_print(dh->pub_key);
	fprintf(stderr, "\n");
	DHparams_print_fp(stderr, dh);
#endif

	debug("Wait SSH2_MSG_KEXDH_REPLY.");

	packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);

	debug("Got SSH2_MSG_KEXDH_REPLY.");

	/* key, cert */
	server_host_key_blob = packet_get_string(&sbloblen);
	server_host_key = dsa_key_from_blob(server_host_key_blob, sbloblen);
	if (server_host_key == NULL)
		fatal("cannot decode server_host_key_blob");

	check_host_key(host, hostaddr, server_host_key,
	    options.user_hostfile2, options.system_hostfile2);

	/* DH paramter f, server public DH key */
	dh_server_pub = BN_new();
	if (dh_server_pub == NULL)
		fatal("dh_server_pub == NULL");
	packet_get_bignum2(dh_server_pub, &dlen);

#ifdef DEBUG_KEXDH
	fprintf(stderr, "\ndh_server_pub= ");
	bignum_print(dh_server_pub);
	fprintf(stderr, "\n");
	debug("bits %d", BN_num_bits(dh_server_pub));
#endif

	/* signed H */
	signature = packet_get_string(&slen);
	packet_done();

	if (!dh_pub_is_valid(dh, dh_server_pub))
		packet_disconnect("bad server public DH value");

	klen = DH_size(dh);
	kbuf = xmalloc(klen);
	kout = DH_compute_key(kbuf, dh_server_pub, dh);
#ifdef DEBUG_KEXDH
	debug("shared secret: len %d/%d", klen, kout);
	fprintf(stderr, "shared secret == ");
	for (i = 0; i< kout; i++)
		fprintf(stderr, "%02x", (kbuf[i])&0xff);
	fprintf(stderr, "\n");
#endif
	shared_secret = BN_new();

	BN_bin2bn(kbuf, kout, shared_secret);
	memset(kbuf, 0, klen);
	xfree(kbuf);

	/* calc and verify H */
	hash = kex_hash(
	    client_version_string,
	    server_version_string,
	    buffer_ptr(client_kexinit), buffer_len(client_kexinit),
	    buffer_ptr(server_kexinit), buffer_len(server_kexinit),
	    server_host_key_blob, sbloblen,
	    dh->pub_key,
	    dh_server_pub,
	    shared_secret
	);
	xfree(server_host_key_blob);
	DH_free(dh);
#ifdef DEBUG_KEXDH
	fprintf(stderr, "hash == ");
	for (i = 0; i< 20; i++)
		fprintf(stderr, "%02x", (hash[i])&0xff);
	fprintf(stderr, "\n");
#endif
	if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1)
		fatal("dsa_verify failed for server_host_key");
	key_free(server_host_key);

	kex_derive_keys(kex, hash, shared_secret);
	packet_set_kex(kex);

	/* save session id */
	session_id2_len = 20;
	session_id2 = xmalloc(session_id2_len);
	memcpy(session_id2, hash, session_id2_len);
}

void
ssh_kex2(char *host, struct sockaddr *hostaddr)
{
	int i, plen;
	Kex *kex;
	Buffer *client_kexinit, *server_kexinit;
	char *sprop[PROPOSAL_MAX];

	if (options.ciphers != NULL) {
		myproposal[PROPOSAL_ENC_ALGS_CTOS] =
		myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
	} else if (options.cipher == SSH_CIPHER_3DES) {
		myproposal[PROPOSAL_ENC_ALGS_CTOS] =
		myproposal[PROPOSAL_ENC_ALGS_STOC] =
		    (char *) cipher_name(SSH_CIPHER_3DES_CBC);
	} else if (options.cipher == SSH_CIPHER_BLOWFISH) {
		myproposal[PROPOSAL_ENC_ALGS_CTOS] =
		myproposal[PROPOSAL_ENC_ALGS_STOC] =
		    (char *) cipher_name(SSH_CIPHER_BLOWFISH_CBC);
	}
	if (options.compression) {
		myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib";
		myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
	} else {
		myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none";
		myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
	}

	/* buffers with raw kexinit messages */
	server_kexinit = xmalloc(sizeof(*server_kexinit));
	buffer_init(server_kexinit);
	client_kexinit = kex_init(myproposal);

	/* algorithm negotiation */
	kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
	kex = kex_choose_conf(myproposal, sprop, 0);
	for (i = 0; i < PROPOSAL_MAX; i++)
		xfree(sprop[i]);

	/* server authentication and session key agreement */
	ssh_kex_dh(kex, host, hostaddr, client_kexinit, server_kexinit);

	buffer_free(client_kexinit);
	buffer_free(server_kexinit);
	xfree(client_kexinit);
	xfree(server_kexinit);

	debug("Wait SSH2_MSG_NEWKEYS.");
	packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
	packet_done();
	debug("GOT SSH2_MSG_NEWKEYS.");

	debug("send SSH2_MSG_NEWKEYS.");
	packet_start(SSH2_MSG_NEWKEYS);
	packet_send();
	packet_write_wait();
	debug("done: send SSH2_MSG_NEWKEYS.");

#ifdef DEBUG_KEXDH
	/* send 1st encrypted/maced/compressed message */
	packet_start(SSH2_MSG_IGNORE);
	packet_put_cstring("markus");
	packet_send();
	packet_write_wait();
#endif
	debug("done: KEX2.");
}

/*
 * Authenticate user
 */
int
ssh2_try_passwd(const char *server_user, const char *host, const char *service)
{
	static int attempt = 0;
	char prompt[80];
	char *password;

	if (attempt++ >= options.number_of_password_prompts)
		return 0;

	if(attempt != 1)
		error("Permission denied, please try again.");

	snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",
	    server_user, host);
	password = read_passphrase(prompt, 0);
	packet_start(SSH2_MSG_USERAUTH_REQUEST);
	packet_put_cstring(server_user);
	packet_put_cstring(service);
	packet_put_cstring("password");
	packet_put_char(0);
	packet_put_cstring(password);
	memset(password, 0, strlen(password));
	xfree(password);
	packet_send();
	packet_write_wait();
	return 1;
}

int
ssh2_try_pubkey(char *filename,
    const char *server_user, const char *host, const char *service)
{
	Buffer b;
	Key *k;
	unsigned char *blob, *signature;
	int bloblen, slen;
	struct stat st;

	if (stat(filename, &st) != 0) {
		debug("key does not exist: %s", filename);
		return 0;
	}
	debug("try pubkey: %s", filename);

	k = key_new(KEY_DSA);
	if (!load_private_key(filename, "", k, NULL)) {
		int success = 0;
		char *passphrase;
		char prompt[300];
		snprintf(prompt, sizeof prompt,
		     "Enter passphrase for DSA key '%.100s': ",
		     filename);
		passphrase = read_passphrase(prompt, 0);
		success = load_private_key(filename, passphrase, k, NULL);
		memset(passphrase, 0, strlen(passphrase));
		xfree(passphrase);
		if (!success)
			return 0;
	}
	dsa_make_key_blob(k, &blob, &bloblen);

	/* data to be signed */
	buffer_init(&b);
	buffer_append(&b, session_id2, session_id2_len);
	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
	buffer_put_cstring(&b, server_user);
	buffer_put_cstring(&b,
	    datafellows & SSH_BUG_PUBKEYAUTH ?
	    "ssh-userauth" :
	    service);
	buffer_put_cstring(&b, "publickey");
	buffer_put_char(&b, 1);
	buffer_put_cstring(&b, KEX_DSS); 
	buffer_put_string(&b, blob, bloblen);

	/* generate signature */
	dsa_sign(k, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
	key_free(k);
#ifdef DEBUG_DSS
	buffer_dump(&b);
#endif
	if (datafellows & SSH_BUG_PUBKEYAUTH) {
		/* e.g. ssh-2.0.13: data-to-be-signed != data-on-the-wire */
		buffer_clear(&b);
		buffer_append(&b, session_id2, session_id2_len);
		buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
		buffer_put_cstring(&b, server_user);
		buffer_put_cstring(&b, service);
		buffer_put_cstring(&b, "publickey");
		buffer_put_char(&b, 1);
		buffer_put_cstring(&b, KEX_DSS); 
		buffer_put_string(&b, blob, bloblen);
	}
	xfree(blob);
	/* append signature */
	buffer_put_string(&b, signature, slen);
	xfree(signature);

	/* skip session id and packet type */
	if (buffer_len(&b) < session_id2_len + 1)
		fatal("ssh2_try_pubkey: internal error");
	buffer_consume(&b, session_id2_len + 1);

	/* put remaining data from buffer into packet */
	packet_start(SSH2_MSG_USERAUTH_REQUEST);
	packet_put_raw(buffer_ptr(&b), buffer_len(&b));
	buffer_free(&b);

	/* send */
	packet_send();
	packet_write_wait();
	return 1;
}

void
ssh_userauth2(const char *server_user, char *host)
{
	int type;
	int plen;
	int sent;
	unsigned int dlen;
	int partial;
	int i = 0;
	char *auths;
	char *service = "ssh-connection";		/* service name */

	debug("send SSH2_MSG_SERVICE_REQUEST");
	packet_start(SSH2_MSG_SERVICE_REQUEST);
	packet_put_cstring("ssh-userauth");
	packet_send();
	packet_write_wait();

	type = packet_read(&plen);
	if (type != SSH2_MSG_SERVICE_ACCEPT) {
		fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
	}
	if (packet_remaining() > 0) {
		char *reply = packet_get_string(&plen);
		debug("service_accept: %s", reply);
		xfree(reply);
	} else {
		/* payload empty for ssh-2.0.13 ?? */
		debug("buggy server: service_accept w/o service");
	}
	packet_done();
	debug("got SSH2_MSG_SERVICE_ACCEPT");

	/* INITIAL request for auth */
	packet_start(SSH2_MSG_USERAUTH_REQUEST);
	packet_put_cstring(server_user);
	packet_put_cstring(service);
	packet_put_cstring("none");
	packet_send();
	packet_write_wait();

	for (;;) {
		sent = 0;
		type = packet_read(&plen);
		if (type == SSH2_MSG_USERAUTH_SUCCESS)
			break;
		if (type != SSH2_MSG_USERAUTH_FAILURE)
			fatal("access denied: %d", type);
		/* SSH2_MSG_USERAUTH_FAILURE means: try again */
		auths = packet_get_string(&dlen);
		debug("authentications that can continue: %s", auths);
		partial = packet_get_char();
		packet_done();
		if (partial)
			debug("partial success");
		if (options.dsa_authentication &&
		    strstr(auths, "publickey") != NULL) {
			while (i < options.num_identity_files2) {
				sent = ssh2_try_pubkey(
				    options.identity_files2[i++],
				    server_user, host, service);
				if (sent)
					break;
			}
		}
		if (!sent) {
			if (options.password_authentication &&
			    !options.batch_mode &&
			    strstr(auths, "password") != NULL) {
				sent = ssh2_try_passwd(server_user, host, service);
			}
		}
		if (!sent)
			fatal("Permission denied (%s).", auths);
		xfree(auths);
	}
	packet_done();
	debug("ssh-userauth2 successfull");
}
Commit	Line	Data
a306f2dd	1	/*
	2	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	* 3. All advertising materials mentioning features or use of this software
	13	* must display the following acknowledgement:
	14	* This product includes software developed by Markus Friedl.
	15	* 4. The name of the author may not be used to endorse or promote products
	16	* derived from this software without specific prior written permission.
	17	*
	18	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	19	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	20	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	21	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	22	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	23	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	24	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	25	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	26	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	27	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	28	*/
	29
	30	#include "includes.h"
fa649821	31	RCSID("$OpenBSD: sshconnect2.c,v 1.13 2000/06/02 02:00:19 todd Exp $");
a306f2dd	32
	33	#include <openssl/bn.h>
	34	#include <openssl/rsa.h>
	35	#include <openssl/dsa.h>
	36	#include <openssl/md5.h>
	37	#include <openssl/dh.h>
	38	#include <openssl/hmac.h>
	39
	40	#include "ssh.h"
	41	#include "xmalloc.h"
	42	#include "rsa.h"
	43	#include "buffer.h"
	44	#include "packet.h"
	45	#include "cipher.h"
	46	#include "uidswap.h"
	47	#include "compat.h"
	48	#include "readconf.h"
	49	#include "bufaux.h"
	50	#include "ssh2.h"
	51	#include "kex.h"
	52	#include "myproposal.h"
	53	#include "key.h"
	54	#include "dsa.h"
	55	#include "sshconnect.h"
	56	#include "authfile.h"
	57
	58	/* import */
	59	extern char *client_version_string;
	60	extern char *server_version_string;
	61	extern Options options;
	62
	63	/*
	64	* SSH2 key exchange
	65	*/
	66
	67	unsigned char *session_id2 = NULL;
	68	int session_id2_len = 0;
	69
	70	void
71276795	71	ssh_kex_dh(Kex kex, char host, struct sockaddr *hostaddr,
71276795	72	Buffer client_kexinit, Buffer server_kexinit)
a306f2dd	73	{
71276795	74	int plen, dlen;
a306f2dd	75	unsigned int klen, kout;
a306f2dd	76	char *signature = NULL;
	77	unsigned int slen;
	78	char *server_host_key_blob = NULL;
	79	Key *server_host_key;
	80	unsigned int sbloblen;
	81	DH *dh;
	82	BIGNUM *dh_server_pub = 0;
	83	BIGNUM *shared_secret = 0;
a306f2dd	84	unsigned char *kbuf;
	85	unsigned char *hash;
	86
a306f2dd	87	debug("Sending SSH2_MSG_KEXDH_INIT.");
a306f2dd	88	/* generate and send 'e', client DH public key */
	89	dh = dh_new_group1();
	90	packet_start(SSH2_MSG_KEXDH_INIT);
	91	packet_put_bignum2(dh->pub_key);
	92	packet_send();
	93	packet_write_wait();
	94
	95	#ifdef DEBUG_KEXDH
	96	fprintf(stderr, "\np= ");
	97	bignum_print(dh->p);
	98	fprintf(stderr, "\ng= ");
	99	bignum_print(dh->g);
	100	fprintf(stderr, "\npub= ");
	101	bignum_print(dh->pub_key);
	102	fprintf(stderr, "\n");
	103	DHparams_print_fp(stderr, dh);
	104	#endif
	105
	106	debug("Wait SSH2_MSG_KEXDH_REPLY.");
	107
71276795	108	packet_read_expect(&plen, SSH2_MSG_KEXDH_REPLY);
a306f2dd	109
	110	debug("Got SSH2_MSG_KEXDH_REPLY.");
	111
	112	/* key, cert */
	113	server_host_key_blob = packet_get_string(&sbloblen);
	114	server_host_key = dsa_key_from_blob(server_host_key_blob, sbloblen);
	115	if (server_host_key == NULL)
	116	fatal("cannot decode server_host_key_blob");
	117
	118	check_host_key(host, hostaddr, server_host_key,
	119	options.user_hostfile2, options.system_hostfile2);
	120
	121	/* DH paramter f, server public DH key */
	122	dh_server_pub = BN_new();
	123	if (dh_server_pub == NULL)
	124	fatal("dh_server_pub == NULL");
	125	packet_get_bignum2(dh_server_pub, &dlen);
	126
	127	#ifdef DEBUG_KEXDH
	128	fprintf(stderr, "\ndh_server_pub= ");
	129	bignum_print(dh_server_pub);
	130	fprintf(stderr, "\n");
	131	debug("bits %d", BN_num_bits(dh_server_pub));
	132	#endif
	133
	134	/* signed H */
	135	signature = packet_get_string(&slen);
	136	packet_done();
	137
	138	if (!dh_pub_is_valid(dh, dh_server_pub))
	139	packet_disconnect("bad server public DH value");
	140
	141	klen = DH_size(dh);
	142	kbuf = xmalloc(klen);
	143	kout = DH_compute_key(kbuf, dh_server_pub, dh);
	144	#ifdef DEBUG_KEXDH
	145	debug("shared secret: len %d/%d", klen, kout);
	146	fprintf(stderr, "shared secret == ");
	147	for (i = 0; i< kout; i++)
	148	fprintf(stderr, "%02x", (kbuf[i])&0xff);
	149	fprintf(stderr, "\n");
	150	#endif
	151	shared_secret = BN_new();
	152
	153	BN_bin2bn(kbuf, kout, shared_secret);
	154	memset(kbuf, 0, klen);
	155	xfree(kbuf);
	156
	157	/* calc and verify H */
	158	hash = kex_hash(
	159	client_version_string,
	160	server_version_string,
	161	buffer_ptr(client_kexinit), buffer_len(client_kexinit),
	162	buffer_ptr(server_kexinit), buffer_len(server_kexinit),
	163	server_host_key_blob, sbloblen,
	164	dh->pub_key,
	165	dh_server_pub,
	166	shared_secret
	167	);
	168	xfree(server_host_key_blob);
71276795	169	DH_free(dh);
a306f2dd	170	#ifdef DEBUG_KEXDH
	171	fprintf(stderr, "hash == ");
	172	for (i = 0; i< 20; i++)
	173	fprintf(stderr, "%02x", (hash[i])&0xff);
	174	fprintf(stderr, "\n");
	175	#endif
	176	if (dsa_verify(server_host_key, (unsigned char *)signature, slen, hash, 20) != 1)
	177	fatal("dsa_verify failed for server_host_key");
	178	key_free(server_host_key);
	179
	180	kex_derive_keys(kex, hash, shared_secret);
	181	packet_set_kex(kex);
	182
a306f2dd	183	/* save session id */
	184	session_id2_len = 20;
	185	session_id2 = xmalloc(session_id2_len);
	186	memcpy(session_id2, hash, session_id2_len);
71276795	187	}
	188
	189	void
	190	ssh_kex2(char host, struct sockaddr hostaddr)
	191	{
	192	int i, plen;
	193	Kex *kex;
	194	Buffer client_kexinit, server_kexinit;
	195	char *sprop[PROPOSAL_MAX];
	196
	197	if (options.ciphers != NULL) {
	198	myproposal[PROPOSAL_ENC_ALGS_CTOS] =
	199	myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
	200	} else if (options.cipher == SSH_CIPHER_3DES) {
	201	myproposal[PROPOSAL_ENC_ALGS_CTOS] =
	202	myproposal[PROPOSAL_ENC_ALGS_STOC] =
	203	(char *) cipher_name(SSH_CIPHER_3DES_CBC);
	204	} else if (options.cipher == SSH_CIPHER_BLOWFISH) {
	205	myproposal[PROPOSAL_ENC_ALGS_CTOS] =
	206	myproposal[PROPOSAL_ENC_ALGS_STOC] =
	207	(char *) cipher_name(SSH_CIPHER_BLOWFISH_CBC);
	208	}
	209	if (options.compression) {
	210	myproposal[PROPOSAL_COMP_ALGS_CTOS] = "zlib";
	211	myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
	212	} else {
	213	myproposal[PROPOSAL_COMP_ALGS_CTOS] = "none";
	214	myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
	215	}
	216
	217	/* buffers with raw kexinit messages */
	218	server_kexinit = xmalloc(sizeof(*server_kexinit));
	219	buffer_init(server_kexinit);
	220	client_kexinit = kex_init(myproposal);
	221
	222	/* algorithm negotiation */
	223	kex_exchange_kexinit(client_kexinit, server_kexinit, sprop);
	224	kex = kex_choose_conf(myproposal, sprop, 0);
	225	for (i = 0; i < PROPOSAL_MAX; i++)
	226	xfree(sprop[i]);
	227
	228	/* server authentication and session key agreement */
	229	ssh_kex_dh(kex, host, hostaddr, client_kexinit, server_kexinit);
	230
	231	buffer_free(client_kexinit);
	232	buffer_free(server_kexinit);
	233	xfree(client_kexinit);
	234	xfree(server_kexinit);
a306f2dd	235
a306f2dd	236	debug("Wait SSH2_MSG_NEWKEYS.");
71276795	237	packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
a306f2dd	238	packet_done();
	239	debug("GOT SSH2_MSG_NEWKEYS.");
	240
	241	debug("send SSH2_MSG_NEWKEYS.");
	242	packet_start(SSH2_MSG_NEWKEYS);
	243	packet_send();
	244	packet_write_wait();
	245	debug("done: send SSH2_MSG_NEWKEYS.");
	246
	247	#ifdef DEBUG_KEXDH
	248	/* send 1st encrypted/maced/compressed message */
	249	packet_start(SSH2_MSG_IGNORE);
	250	packet_put_cstring("markus");
	251	packet_send();
	252	packet_write_wait();
	253	#endif
	254	debug("done: KEX2.");
	255	}
71276795	256
a306f2dd	257	/*
	258	* Authenticate user
	259	*/
	260	int
	261	ssh2_try_passwd(const char server_user, const char host, const char *service)
	262	{
1d1ffb87	263	static int attempt = 0;
a306f2dd	264	char prompt[80];
	265	char *password;
	266
fa649821	267	if (attempt++ >= options.number_of_password_prompts)
1d1ffb87	268	return 0;
1d1ffb87	269
fa649821	270	if(attempt != 1)
	271	error("Permission denied, please try again.");
	272
a306f2dd	273	snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",
	274	server_user, host);
	275	password = read_passphrase(prompt, 0);
	276	packet_start(SSH2_MSG_USERAUTH_REQUEST);
	277	packet_put_cstring(server_user);
	278	packet_put_cstring(service);
	279	packet_put_cstring("password");
	280	packet_put_char(0);
	281	packet_put_cstring(password);
	282	memset(password, 0, strlen(password));
	283	xfree(password);
	284	packet_send();
	285	packet_write_wait();
	286	return 1;
	287	}
	288
	289	int
	290	ssh2_try_pubkey(char *filename,
	291	const char server_user, const char host, const char *service)
	292	{
	293	Buffer b;
	294	Key *k;
	295	unsigned char blob, signature;
	296	int bloblen, slen;
0fbe8c74	297	struct stat st;
a306f2dd	298
0fbe8c74	299	if (stat(filename, &st) != 0) {
	300	debug("key does not exist: %s", filename);
	301	return 0;
	302	}
a306f2dd	303	debug("try pubkey: %s", filename);
	304
	305	k = key_new(KEY_DSA);
	306	if (!load_private_key(filename, "", k, NULL)) {
	307	int success = 0;
	308	char *passphrase;
	309	char prompt[300];
0fbe8c74	310	snprintf(prompt, sizeof prompt,
a306f2dd	311	"Enter passphrase for DSA key '%.100s': ",
0fbe8c74	312	filename);
a306f2dd	313	passphrase = read_passphrase(prompt, 0);
	314	success = load_private_key(filename, passphrase, k, NULL);
	315	memset(passphrase, 0, strlen(passphrase));
	316	xfree(passphrase);
	317	if (!success)
	318	return 0;
	319	}
	320	dsa_make_key_blob(k, &blob, &bloblen);
	321
	322	/* data to be signed */
	323	buffer_init(&b);
	324	buffer_append(&b, session_id2, session_id2_len);
	325	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
	326	buffer_put_cstring(&b, server_user);
d0c832f3	327	buffer_put_cstring(&b,
	328	datafellows & SSH_BUG_PUBKEYAUTH ?
	329	"ssh-userauth" :
	330	service);
a306f2dd	331	buffer_put_cstring(&b, "publickey");
	332	buffer_put_char(&b, 1);
	333	buffer_put_cstring(&b, KEX_DSS);
	334	buffer_put_string(&b, blob, bloblen);
a306f2dd	335
	336	/* generate signature */
	337	dsa_sign(k, &signature, &slen, buffer_ptr(&b), buffer_len(&b));
	338	key_free(k);
	339	#ifdef DEBUG_DSS
	340	buffer_dump(&b);
	341	#endif
d0c832f3	342	if (datafellows & SSH_BUG_PUBKEYAUTH) {
	343	/* e.g. ssh-2.0.13: data-to-be-signed != data-on-the-wire */
	344	buffer_clear(&b);
	345	buffer_append(&b, session_id2, session_id2_len);
	346	buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
	347	buffer_put_cstring(&b, server_user);
	348	buffer_put_cstring(&b, service);
	349	buffer_put_cstring(&b, "publickey");
	350	buffer_put_char(&b, 1);
	351	buffer_put_cstring(&b, KEX_DSS);
	352	buffer_put_string(&b, blob, bloblen);
	353	}
	354	xfree(blob);
a306f2dd	355	/* append signature */
	356	buffer_put_string(&b, signature, slen);
	357	xfree(signature);
	358
	359	/* skip session id and packet type */
	360	if (buffer_len(&b) < session_id2_len + 1)
	361	fatal("ssh2_try_pubkey: internal error");
	362	buffer_consume(&b, session_id2_len + 1);
	363
	364	/* put remaining data from buffer into packet */
	365	packet_start(SSH2_MSG_USERAUTH_REQUEST);
	366	packet_put_raw(buffer_ptr(&b), buffer_len(&b));
	367	buffer_free(&b);
	368
	369	/* send */
	370	packet_send();
	371	packet_write_wait();
	372	return 1;
	373	}
	374
	375	void
	376	ssh_userauth2(const char server_user, char host)
	377	{
	378	int type;
	379	int plen;
	380	int sent;
	381	unsigned int dlen;
	382	int partial;
	383	int i = 0;
	384	char *auths;
	385	char service = "ssh-connection"; / service name */
	386
	387	debug("send SSH2_MSG_SERVICE_REQUEST");
	388	packet_start(SSH2_MSG_SERVICE_REQUEST);
	389	packet_put_cstring("ssh-userauth");
	390	packet_send();
	391	packet_write_wait();
	392
	393	type = packet_read(&plen);
	394	if (type != SSH2_MSG_SERVICE_ACCEPT) {
	395	fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
	396	}
	397	if (packet_remaining() > 0) {
	398	char *reply = packet_get_string(&plen);
	399	debug("service_accept: %s", reply);
	400	xfree(reply);
	401	} else {
	402	/* payload empty for ssh-2.0.13 ?? */
f6cde515	403	debug("buggy server: service_accept w/o service");
a306f2dd	404	}
	405	packet_done();
	406	debug("got SSH2_MSG_SERVICE_ACCEPT");
	407
	408	/* INITIAL request for auth */
	409	packet_start(SSH2_MSG_USERAUTH_REQUEST);
	410	packet_put_cstring(server_user);
	411	packet_put_cstring(service);
	412	packet_put_cstring("none");
	413	packet_send();
	414	packet_write_wait();
	415
	416	for (;;) {
	417	sent = 0;
	418	type = packet_read(&plen);
	419	if (type == SSH2_MSG_USERAUTH_SUCCESS)
	420	break;
	421	if (type != SSH2_MSG_USERAUTH_FAILURE)
	422	fatal("access denied: %d", type);
	423	/* SSH2_MSG_USERAUTH_FAILURE means: try again */
	424	auths = packet_get_string(&dlen);
	425	debug("authentications that can continue: %s", auths);
	426	partial = packet_get_char();
	427	packet_done();
	428	if (partial)
	429	debug("partial success");
1d1ffb87	430	if (options.dsa_authentication &&
a306f2dd	431	strstr(auths, "publickey") != NULL) {
	432	while (i < options.num_identity_files2) {
	433	sent = ssh2_try_pubkey(
	434	options.identity_files2[i++],
	435	server_user, host, service);
	436	if (sent)
	437	break;
	438	}
	439	}
	440	if (!sent) {
	441	if (options.password_authentication &&
	442	!options.batch_mode &&
	443	strstr(auths, "password") != NULL) {
	444	sent = ssh2_try_passwd(server_user, host, service);
	445	}
	446	}
	447	if (!sent)
	448	fatal("Permission denied (%s).", auths);
	449	xfree(auths);
	450	}
	451	packet_done();
	452	debug("ssh-userauth2 successfull");
	453	}