[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 1.2 2002/05/31 10:30:33 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 */
	buffer_skip_string(&b);
	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"
	25	RCSID("$OpenBSD: ssh-keysign.c,v 1.2 2002/05/31 10:30:33 markus Exp $");
	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
	63	/* session id */
	64	buffer_skip_string(&b);
	65	if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
	66	fail++;
	67
	68	/* server user */
	69	buffer_skip_string(&b);
	70
	71	/* service */
	72	p = buffer_get_string(&b, NULL);
	73	if (strcmp("ssh-connection", p) != 0)
	74	fail++;
	75	xfree(p);
	76
	77	/* method */
	78	p = buffer_get_string(&b, NULL);
	79	if (strcmp("hostbased", p) != 0)
	80	fail++;
	81	xfree(p);
	82
	83	/* pubkey */
	84	pkalg = buffer_get_string(&b, NULL);
	85	pkblob = buffer_get_string(&b, &blen);
	86
	87	pktype = key_type_from_name(pkalg);
	88	if (pktype == KEY_UNSPEC)
	89	fail++;
	90	else if ((key = key_from_blob(pkblob, blen)) == NULL)
	91	fail++;
	92	else if (key->type != pktype)
	93	fail++;
	94	xfree(pkalg);
	95	xfree(pkblob);
	96
	97	/* client host name, handle trailing dot */
	98	p = buffer_get_string(&b, &len);
	99	debug2("valid_request: check expect chost %s got %s", host, p);
	100	if (strlen(host) != len - 1)
	101	fail++;
	102	else if (p[len - 1] != '.')
	103	fail++;
	104	else if (strncasecmp(host, p, len - 1) != 0)
	105	fail++;
	106	xfree(p);
	107
	108	/* local user */
	109	p = buffer_get_string(&b, NULL);
	110
111	if (strcmp(pw->pw_name, p) != 0)
112	fail++;
113	xfree(p);
114
115	/* end of message */
116	if (buffer_len(&b) != 0)
117	fail++;
118
119	debug3("valid_request: fail %d", fail);
120
121	if (fail && key != NULL)
122	key_free(key);
123	else
124	*ret = key;
125
126	return (fail ? -1 : 0);
127	}
128
129	int
130	main(int argc, char **argv)
131	{
132	Buffer b;
133	Key keys[2], key;
134	struct passwd *pw;
135	int key_fd[2], i, found, version = 2, fd;
136	u_char signature, data;
137	char *host;
138	u_int slen, dlen;
139
140	key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
141	key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
142
143	seteuid(getuid());
144	setuid(getuid());
145
875ec275	146	init_rng();
	147	seed_rng();
	148	arc4random_stir();
04eb391d	149
39c00dc2	150	#ifdef DEBUG_SSH_KEYSIGN
	151	log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
	152	#endif
	153
	154	if (key_fd[0] == -1 && key_fd[1] == -1)
	155	fatal("could not open any host key");
	156
	157	if ((pw = getpwuid(getuid())) == NULL)
	158	fatal("getpwuid failed");
	159	pw = pwcopy(pw);
	160
	161	SSLeay_add_all_algorithms();
	162
	163	found = 0;
	164	for (i = 0; i < 2; i++) {
	165	keys[i] = NULL;
	166	if (key_fd[i] == -1)
	167	continue;
	168	keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
	169	NULL, NULL);
	170	close(key_fd[i]);
	171	if (keys[i] != NULL)
	172	found = 1;
	173	}
	174	if (!found)
	175	fatal("no hostkey found");
	176
	177	buffer_init(&b);
	178	if (msg_recv(STDIN_FILENO, &b) < 0)
	179	fatal("msg_recv failed");
	180	if (buffer_get_char(&b) != version)
	181	fatal("bad version");
	182	fd = buffer_get_int(&b);
	183	if ((fd == STDIN_FILENO) \|\| (fd == STDOUT_FILENO))
	184	fatal("bad fd");
	185	if ((host = get_local_name(fd)) == NULL)
	186	fatal("cannot get sockname for fd");
	187
	188	data = buffer_get_string(&b, &dlen);
	189	if (valid_request(pw, host, &key, data, dlen) < 0)
	190	fatal("not a valid request");
	191	xfree(data);
	192	xfree(host);
	193
	194	found = 0;
	195	for (i = 0; i < 2; i++) {
	196	if (keys[i] != NULL &&
	197	key_equal(key, keys[i])) {
	198	found = 1;
	199	break;
	200	}
	201	}
	202	if (!found)
	203	fatal("no matching hostkey found");
	204
	205	if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
	206	fatal("key_sign failed");
	207
	208	/* send reply */
	209	buffer_clear(&b);
	210	buffer_put_string(&b, signature, slen);
	211	msg_send(STDOUT_FILENO, version, &b);
	212
	213	return (0);
214	}