[openssh.git] / ssh-keysign.c

/*
 * Copyright (c) 2002 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.
 *
 * 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: ssh-keysign.c,v 1.3 2002/06/08 05:07:09 markus Exp $");

#include <openssl/evp.h>

#include "log.h"
#include "key.h"
#include "ssh2.h"
#include "misc.h"
#include "xmalloc.h"
#include "buffer.h"
#include "bufaux.h"
#include "authfile.h"
#include "msg.h"
#include "canohost.h"
#include "pathnames.h"

#ifdef HAVE___PROGNAME
extern char *__progname;
#else
char *__progname;
#endif

static int
valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
    u_int datalen)
{
	Buffer b;
	Key *key;
	u_char *pkblob;
	u_int blen, len;
	char *pkalg, *p;
	int pktype, fail;

	fail = 0;

	buffer_init(&b);
	buffer_append(&b, data, datalen);
 
	/* session id, currently limited to SHA1 (20 bytes) */
	p = buffer_get_string(&b, &len);
	if (len != 20)
		fail++;
	xfree(p);

	if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
		fail++;

	/* server user */
	buffer_skip_string(&b);

	/* service */
	p = buffer_get_string(&b, NULL);
	if (strcmp("ssh-connection", p) != 0)
		fail++;
	xfree(p);

	/* method */
	p = buffer_get_string(&b, NULL);
	if (strcmp("hostbased", p) != 0)
		fail++;
	xfree(p);

	/* pubkey */
	pkalg = buffer_get_string(&b, NULL);
	pkblob = buffer_get_string(&b, &blen);

	pktype = key_type_from_name(pkalg);
	if (pktype == KEY_UNSPEC)
		fail++;
	else if ((key = key_from_blob(pkblob, blen)) == NULL)
		fail++;
	else if (key->type != pktype)
		fail++;
	xfree(pkalg);
	xfree(pkblob);

	/* client host name, handle trailing dot */
	p = buffer_get_string(&b, &len);
	debug2("valid_request: check expect chost %s got %s", host, p);
	if (strlen(host) != len - 1)
		fail++;
	else if (p[len - 1] != '.')
	      fail++;
	else if (strncasecmp(host, p, len - 1) != 0)
	      fail++;
	xfree(p);

	/* local user */
	p = buffer_get_string(&b, NULL);

	if (strcmp(pw->pw_name, p) != 0)
		fail++;
	xfree(p);

	/* end of message */
	if (buffer_len(&b) != 0)
		fail++;

	debug3("valid_request: fail %d", fail);

	if (fail && key != NULL)
		key_free(key);
	else
		*ret = key;

	return (fail ? -1 : 0);
}

int
main(int argc, char **argv)
{
	Buffer b;
	Key *keys[2], *key;
	struct passwd *pw;
	int key_fd[2], i, found, version = 2, fd;
	u_char *signature, *data;
	char *host;
	u_int slen, dlen;

	key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
	key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);

	seteuid(getuid());
	setuid(getuid());

	init_rng();
	seed_rng();
	arc4random_stir();

#ifdef DEBUG_SSH_KEYSIGN
	log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
#endif  

	if (key_fd[0] == -1 && key_fd[1] == -1)
		fatal("could not open any host key");

	if ((pw = getpwuid(getuid())) == NULL)
		fatal("getpwuid failed");
	pw = pwcopy(pw); 

	SSLeay_add_all_algorithms();

	found = 0;
	for (i = 0; i < 2; i++) {
		keys[i] = NULL;
		if (key_fd[i] == -1)
			continue;
		keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
		    NULL, NULL);
		close(key_fd[i]);
		if (keys[i] != NULL)
			found = 1;
	}
	if (!found)
		fatal("no hostkey found");

	buffer_init(&b);
	if (msg_recv(STDIN_FILENO, &b) < 0)
		fatal("msg_recv failed");
	if (buffer_get_char(&b) != version)
		fatal("bad version");
	fd = buffer_get_int(&b);
	if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
		fatal("bad fd");
	if ((host = get_local_name(fd)) == NULL)
		fatal("cannot get sockname for fd");
	
	data = buffer_get_string(&b, &dlen);
	if (valid_request(pw, host, &key, data, dlen) < 0)
		fatal("not a valid request");
	xfree(data);
	xfree(host);

	found = 0;
	for (i = 0; i < 2; i++) {
		if (keys[i] != NULL &&
		    key_equal(key, keys[i])) {
			found = 1;
			break;
		}
	}
	if (!found)
		fatal("no matching hostkey found");

	if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
		fatal("key_sign failed");
	
	/* send reply */
	buffer_clear(&b);
	buffer_put_string(&b, signature, slen);
	msg_send(STDOUT_FILENO, version, &b);

	return (0);
}
Commit	Line	Data
39c00dc2	1	/*
	2	* Copyright (c) 2002 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	*
	13	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	15	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	16	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	17	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	18	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	19	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	20	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	21	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	22	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	23	*/
	24	#include "includes.h"
1f143cf2	25	RCSID("$OpenBSD: ssh-keysign.c,v 1.3 2002/06/08 05:07:09 markus Exp $");
39c00dc2	26
	27	#include <openssl/evp.h>
	28
	29	#include "log.h"
	30	#include "key.h"
	31	#include "ssh2.h"
	32	#include "misc.h"
	33	#include "xmalloc.h"
	34	#include "buffer.h"
	35	#include "bufaux.h"
	36	#include "authfile.h"
	37	#include "msg.h"
	38	#include "canohost.h"
	39	#include "pathnames.h"
	40
95d5ebf7	41	#ifdef HAVE___PROGNAME
	42	extern char *__progname;
	43	#else
	44	char *__progname;
	45	#endif
	46
39c00dc2	47	static int
	48	valid_request(struct passwd pw, char host, Key *ret, u_char data,
	49	u_int datalen)
	50	{
	51	Buffer b;
	52	Key *key;
	53	u_char *pkblob;
	54	u_int blen, len;
	55	char pkalg, p;
	56	int pktype, fail;
	57
	58	fail = 0;
	59
	60	buffer_init(&b);
	61	buffer_append(&b, data, datalen);
	62
1f143cf2	63	/* session id, currently limited to SHA1 (20 bytes) */
	64	p = buffer_get_string(&b, &len);
	65	if (len != 20)
	66	fail++;
	67	xfree(p);
	68
39c00dc2	69	if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
	70	fail++;
	71
	72	/* server user */
	73	buffer_skip_string(&b);
	74
	75	/* service */
	76	p = buffer_get_string(&b, NULL);
	77	if (strcmp("ssh-connection", p) != 0)
	78	fail++;
	79	xfree(p);
	80
	81	/* method */
	82	p = buffer_get_string(&b, NULL);
	83	if (strcmp("hostbased", p) != 0)
	84	fail++;
	85	xfree(p);
	86
	87	/* pubkey */
	88	pkalg = buffer_get_string(&b, NULL);
	89	pkblob = buffer_get_string(&b, &blen);
	90
	91	pktype = key_type_from_name(pkalg);
	92	if (pktype == KEY_UNSPEC)
	93	fail++;
	94	else if ((key = key_from_blob(pkblob, blen)) == NULL)
	95	fail++;
	96	else if (key->type != pktype)
	97	fail++;
	98	xfree(pkalg);
	99	xfree(pkblob);
	100
	101	/* client host name, handle trailing dot */
	102	p = buffer_get_string(&b, &len);
	103	debug2("valid_request: check expect chost %s got %s", host, p);
	104	if (strlen(host) != len - 1)
	105	fail++;
	106	else if (p[len - 1] != '.')
	107	fail++;
	108	else if (strncasecmp(host, p, len - 1) != 0)
	109	fail++;
	110	xfree(p);
	111
	112	/* local user */
	113	p = buffer_get_string(&b, NULL);
	114
	115	if (strcmp(pw->pw_name, p) != 0)
	116	fail++;
	117	xfree(p);
	118
	119	/* end of message */
	120	if (buffer_len(&b) != 0)
	121	fail++;
	122
	123	debug3("valid_request: fail %d", fail);
	124
	125	if (fail && key != NULL)
	126	key_free(key);
	127	else
	128	*ret = key;
	129
	130	return (fail ? -1 : 0);
	131	}
	132
133	int
134	main(int argc, char **argv)
135	{
136	Buffer b;
137	Key keys[2], key;
138	struct passwd *pw;
139	int key_fd[2], i, found, version = 2, fd;
140	u_char signature, data;
141	char *host;
142	u_int slen, dlen;
143
144	key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
145	key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
146
147	seteuid(getuid());
148	setuid(getuid());
149
875ec275	150	init_rng();
	151	seed_rng();
	152	arc4random_stir();
04eb391d	153
39c00dc2	154	#ifdef DEBUG_SSH_KEYSIGN
	155	log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
	156	#endif
	157
	158	if (key_fd[0] == -1 && key_fd[1] == -1)
	159	fatal("could not open any host key");
	160
	161	if ((pw = getpwuid(getuid())) == NULL)
	162	fatal("getpwuid failed");
	163	pw = pwcopy(pw);
	164
	165	SSLeay_add_all_algorithms();
	166
	167	found = 0;
	168	for (i = 0; i < 2; i++) {
	169	keys[i] = NULL;
	170	if (key_fd[i] == -1)
	171	continue;
	172	keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
	173	NULL, NULL);
	174	close(key_fd[i]);
	175	if (keys[i] != NULL)
	176	found = 1;
	177	}
	178	if (!found)
	179	fatal("no hostkey found");
	180
	181	buffer_init(&b);
	182	if (msg_recv(STDIN_FILENO, &b) < 0)
	183	fatal("msg_recv failed");
	184	if (buffer_get_char(&b) != version)
	185	fatal("bad version");
	186	fd = buffer_get_int(&b);
	187	if ((fd == STDIN_FILENO) \|\| (fd == STDOUT_FILENO))
	188	fatal("bad fd");
	189	if ((host = get_local_name(fd)) == NULL)
	190	fatal("cannot get sockname for fd");
	191
	192	data = buffer_get_string(&b, &dlen);
	193	if (valid_request(pw, host, &key, data, dlen) < 0)
	194	fatal("not a valid request");
	195	xfree(data);
	196	xfree(host);
	197
	198	found = 0;
	199	for (i = 0; i < 2; i++) {
	200	if (keys[i] != NULL &&
	201	key_equal(key, keys[i])) {
	202	found = 1;
	203	break;
	204	}
	205	}
	206	if (!found)
	207	fatal("no matching hostkey found");
	208
	209	if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
	210	fatal("key_sign failed");
	211
	212	/* send reply */
	213	buffer_clear(&b);
	214	buffer_put_string(&b, signature, slen);
	215	msg_send(STDOUT_FILENO, version, &b);
	216
	217	return (0);
218	}