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 1.15 2004/01/19 21:25:15 markus Exp $");
27 #include <openssl/evp.h>
28 #include <openssl/rand.h>
29 #include <openssl/rsa.h>
42 #include "pathnames.h"
45 /* XXX readconf.c needs these */
46 uid_t original_real_uid
;
48 #ifdef HAVE___PROGNAME
49 extern char *__progname
;
55 valid_request(struct passwd
*pw
, char *host
, Key
**ret
, u_char
*data
,
68 buffer_append(&b
, data
, datalen
);
70 /* session id, currently limited to SHA1 (20 bytes) */
71 p
= buffer_get_string(&b
, &len
);
76 if (buffer_get_char(&b
) != SSH2_MSG_USERAUTH_REQUEST
)
80 buffer_skip_string(&b
);
83 p
= buffer_get_string(&b
, NULL
);
84 if (strcmp("ssh-connection", p
) != 0)
89 p
= buffer_get_string(&b
, NULL
);
90 if (strcmp("hostbased", p
) != 0)
95 pkalg
= buffer_get_string(&b
, NULL
);
96 pkblob
= buffer_get_string(&b
, &blen
);
98 pktype
= key_type_from_name(pkalg
);
99 if (pktype
== KEY_UNSPEC
)
101 else if ((key
= key_from_blob(pkblob
, blen
)) == NULL
)
103 else if (key
->type
!= pktype
)
108 /* client host name, handle trailing dot */
109 p
= buffer_get_string(&b
, &len
);
110 debug2("valid_request: check expect chost %s got %s", host
, p
);
111 if (strlen(host
) != len
- 1)
113 else if (p
[len
- 1] != '.')
115 else if (strncasecmp(host
, p
, len
- 1) != 0)
120 p
= buffer_get_string(&b
, NULL
);
122 if (strcmp(pw
->pw_name
, p
) != 0)
127 if (buffer_len(&b
) != 0)
131 debug3("valid_request: fail %d", fail
);
133 if (fail
&& key
!= NULL
)
138 return (fail
? -1 : 0);
142 main(int argc
, char **argv
)
148 int key_fd
[2], i
, found
, version
= 2, fd
;
149 u_char
*signature
, *data
;
154 key_fd
[0] = open(_PATH_HOST_RSA_KEY_FILE
, O_RDONLY
);
155 key_fd
[1] = open(_PATH_HOST_DSA_KEY_FILE
, O_RDONLY
);
164 #ifdef DEBUG_SSH_KEYSIGN
165 log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3
, SYSLOG_FACILITY_AUTH
, 0);
168 /* verify that ssh-keysign is enabled by the admin */
169 original_real_uid
= getuid(); /* XXX readconf.c needs this */
170 initialize_options(&options
);
171 (void)read_config_file(_PATH_HOST_CONFIG_FILE
, "", &options
);
172 fill_default_options(&options
);
173 if (options
.enable_ssh_keysign
!= 1)
174 fatal("ssh-keysign not enabled in %s",
175 _PATH_HOST_CONFIG_FILE
);
177 if (key_fd
[0] == -1 && key_fd
[1] == -1)
178 fatal("could not open any host key");
180 if ((pw
= getpwuid(getuid())) == NULL
)
181 fatal("getpwuid failed");
184 SSLeay_add_all_algorithms();
185 for (i
= 0; i
< 256; i
++)
186 rnd
[i
] = arc4random();
187 RAND_seed(rnd
, sizeof(rnd
));
190 for (i
= 0; i
< 2; i
++) {
194 keys
[i
] = key_load_private_pem(key_fd
[i
], KEY_UNSPEC
,
201 fatal("no hostkey found");
204 if (ssh_msg_recv(STDIN_FILENO
, &b
) < 0)
205 fatal("ssh_msg_recv failed");
206 if (buffer_get_char(&b
) != version
)
207 fatal("bad version");
208 fd
= buffer_get_int(&b
);
209 if ((fd
== STDIN_FILENO
) || (fd
== STDOUT_FILENO
))
211 if ((host
= get_local_name(fd
)) == NULL
)
212 fatal("cannot get sockname for fd");
214 data
= buffer_get_string(&b
, &dlen
);
215 if (valid_request(pw
, host
, &key
, data
, dlen
) < 0)
216 fatal("not a valid request");
220 for (i
= 0; i
< 2; i
++) {
221 if (keys
[i
] != NULL
&&
222 key_equal(key
, keys
[i
])) {
228 fatal("no matching hostkey found");
230 if (key_sign(keys
[i
], &signature
, &slen
, data
, dlen
) != 0)
231 fatal("key_sign failed");
236 buffer_put_string(&b
, signature
, slen
);
237 if (ssh_msg_send(STDOUT_FILENO
, version
, &b
) == -1)
238 fatal("ssh_msg_send failed");