2 * Copyright (c) 2002 Markus Friedl. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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.
25 RCSID("$OpenBSD: ssh-keysign.c,v 1.7 2002/07/03 14:21:05 markus Exp $");
27 #include <openssl/evp.h>
28 #include <openssl/rand.h>
29 #include <openssl/rsa.h>
42 #include "pathnames.h"
45 uid_t original_real_uid; /* XXX readconf.c needs this */
47 #ifdef HAVE___PROGNAME
48 extern char *__progname;
54 valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
67 buffer_append(&b, data, datalen);
69 /* session id, currently limited to SHA1 (20 bytes) */
70 p = buffer_get_string(&b, &len);
75 if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
79 buffer_skip_string(&b);
82 p = buffer_get_string(&b, NULL);
83 if (strcmp("ssh-connection", p) != 0)
88 p = buffer_get_string(&b, NULL);
89 if (strcmp("hostbased", p) != 0)
94 pkalg = buffer_get_string(&b, NULL);
95 pkblob = buffer_get_string(&b, &blen);
97 pktype = key_type_from_name(pkalg);
98 if (pktype == KEY_UNSPEC)
100 else if ((key = key_from_blob(pkblob, blen)) == NULL)
102 else if (key->type != pktype)
107 /* client host name, handle trailing dot */
108 p = buffer_get_string(&b, &len);
109 debug2("valid_request: check expect chost %s got %s", host, p);
110 if (strlen(host) != len - 1)
112 else if (p[len - 1] != '.')
114 else if (strncasecmp(host, p, len - 1) != 0)
119 p = buffer_get_string(&b, NULL);
121 if (strcmp(pw->pw_name, p) != 0)
126 if (buffer_len(&b) != 0)
129 debug3("valid_request: fail %d", fail);
131 if (fail && key != NULL)
136 return (fail ? -1 : 0);
140 main(int argc, char **argv)
146 int key_fd[2], i, found, version = 2, fd;
147 u_char *signature, *data;
152 key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
153 key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
162 #ifdef DEBUG_SSH_KEYSIGN
163 log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
166 /* verify that ssh-keysign is enabled by the admin */
167 original_real_uid = getuid(); /* XXX readconf.c needs this */
168 initialize_options(&options);
169 (void)read_config_file(_PATH_HOST_CONFIG_FILE, "", &options);
170 fill_default_options(&options);
171 if (options.hostbased_authentication != 1)
172 fatal("Hostbased authentication not enabled in %s",
173 _PATH_HOST_CONFIG_FILE);
175 if (key_fd[0] == -1 && key_fd[1] == -1)
176 fatal("could not open any host key");
178 if ((pw = getpwuid(getuid())) == NULL)
179 fatal("getpwuid failed");
182 SSLeay_add_all_algorithms();
183 for (i = 0; i < 256; i++)
184 rnd[i] = arc4random();
185 RAND_seed(rnd, sizeof(rnd));
188 for (i = 0; i < 2; i++) {
192 keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
195 if (keys[i] != NULL && keys[i]->type == KEY_RSA) {
196 if (RSA_blinding_on(keys[i]->rsa, NULL) != 1) {
197 error("RSA_blinding_on failed");
206 fatal("no hostkey found");
209 if (ssh_msg_recv(STDIN_FILENO, &b) < 0)
210 fatal("ssh_msg_recv failed");
211 if (buffer_get_char(&b) != version)
212 fatal("bad version");
213 fd = buffer_get_int(&b);
214 if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
216 if ((host = get_local_name(fd)) == NULL)
217 fatal("cannot get sockname for fd");
219 data = buffer_get_string(&b, &dlen);
220 if (valid_request(pw, host, &key, data, dlen) < 0)
221 fatal("not a valid request");
225 for (i = 0; i < 2; i++) {
226 if (keys[i] != NULL &&
227 key_equal(key, keys[i])) {
233 fatal("no matching hostkey found");
235 if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
236 fatal("key_sign failed");
241 buffer_put_string(&b, signature, slen);
242 ssh_msg_send(STDOUT_FILENO, version, &b);