Annotation of src/usr.bin/ssh/ssh-keysign.c, Revision 1.4.2.1
1.1 markus 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"
1.4.2.1 ! miod 25: RCSID("$OpenBSD: ssh-keysign.c,v 1.4 2002/06/19 00:27:55 deraadt Exp $");
1.1 markus 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"
1.2 markus 38: #include "canohost.h"
1.1 markus 39: #include "pathnames.h"
40:
41: static int
1.2 markus 42: valid_request(struct passwd *pw, char *host, Key **ret, u_char *data,
43: u_int datalen)
1.1 markus 44: {
45: Buffer b;
46: Key *key;
1.2 markus 47: u_char *pkblob;
48: u_int blen, len;
49: char *pkalg, *p;
1.1 markus 50: int pktype, fail;
51:
52: fail = 0;
53:
54: buffer_init(&b);
55: buffer_append(&b, data, datalen);
1.4 deraadt 56:
1.3 markus 57: /* session id, currently limited to SHA1 (20 bytes) */
58: p = buffer_get_string(&b, &len);
59: if (len != 20)
60: fail++;
61: xfree(p);
62:
1.1 markus 63: if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
64: fail++;
65:
66: /* server user */
67: buffer_skip_string(&b);
68:
69: /* service */
70: p = buffer_get_string(&b, NULL);
71: if (strcmp("ssh-connection", p) != 0)
72: fail++;
73: xfree(p);
74:
75: /* method */
76: p = buffer_get_string(&b, NULL);
77: if (strcmp("hostbased", p) != 0)
78: fail++;
79: xfree(p);
80:
81: /* pubkey */
82: pkalg = buffer_get_string(&b, NULL);
83: pkblob = buffer_get_string(&b, &blen);
84:
85: pktype = key_type_from_name(pkalg);
86: if (pktype == KEY_UNSPEC)
87: fail++;
88: else if ((key = key_from_blob(pkblob, blen)) == NULL)
89: fail++;
90: else if (key->type != pktype)
91: fail++;
92: xfree(pkalg);
93: xfree(pkblob);
94:
1.2 markus 95: /* client host name, handle trailing dot */
96: p = buffer_get_string(&b, &len);
97: debug2("valid_request: check expect chost %s got %s", host, p);
98: if (strlen(host) != len - 1)
99: fail++;
100: else if (p[len - 1] != '.')
1.4 deraadt 101: fail++;
1.2 markus 102: else if (strncasecmp(host, p, len - 1) != 0)
1.4 deraadt 103: fail++;
1.2 markus 104: xfree(p);
1.1 markus 105:
106: /* local user */
107: p = buffer_get_string(&b, NULL);
1.2 markus 108:
1.1 markus 109: if (strcmp(pw->pw_name, p) != 0)
110: fail++;
111: xfree(p);
112:
113: /* end of message */
114: if (buffer_len(&b) != 0)
115: fail++;
116:
117: debug3("valid_request: fail %d", fail);
118:
119: if (fail && key != NULL)
120: key_free(key);
121: else
122: *ret = key;
123:
124: return (fail ? -1 : 0);
125: }
126:
127: int
128: main(int argc, char **argv)
129: {
130: Buffer b;
131: Key *keys[2], *key;
132: struct passwd *pw;
1.2 markus 133: int key_fd[2], i, found, version = 2, fd;
1.1 markus 134: u_char *signature, *data;
1.2 markus 135: char *host;
1.1 markus 136: u_int slen, dlen;
137:
138: key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
139: key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
140:
141: seteuid(getuid());
142: setuid(getuid());
143:
144: #ifdef DEBUG_SSH_KEYSIGN
145: log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
1.4 deraadt 146: #endif
1.1 markus 147:
148: if (key_fd[0] == -1 && key_fd[1] == -1)
149: fatal("could not open any host key");
150:
151: if ((pw = getpwuid(getuid())) == NULL)
152: fatal("getpwuid failed");
1.4 deraadt 153: pw = pwcopy(pw);
1.1 markus 154:
155: SSLeay_add_all_algorithms();
156:
157: found = 0;
158: for (i = 0; i < 2; i++) {
159: keys[i] = NULL;
160: if (key_fd[i] == -1)
161: continue;
162: keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
163: NULL, NULL);
164: close(key_fd[i]);
165: if (keys[i] != NULL)
166: found = 1;
167: }
168: if (!found)
169: fatal("no hostkey found");
170:
171: buffer_init(&b);
172: if (msg_recv(STDIN_FILENO, &b) < 0)
173: fatal("msg_recv failed");
174: if (buffer_get_char(&b) != version)
175: fatal("bad version");
1.2 markus 176: fd = buffer_get_int(&b);
177: if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
178: fatal("bad fd");
179: if ((host = get_local_name(fd)) == NULL)
180: fatal("cannot get sockname for fd");
1.4 deraadt 181:
1.1 markus 182: data = buffer_get_string(&b, &dlen);
1.2 markus 183: if (valid_request(pw, host, &key, data, dlen) < 0)
1.1 markus 184: fatal("not a valid request");
185: xfree(data);
1.2 markus 186: xfree(host);
1.1 markus 187:
188: found = 0;
189: for (i = 0; i < 2; i++) {
190: if (keys[i] != NULL &&
191: key_equal(key, keys[i])) {
192: found = 1;
193: break;
194: }
195: }
196: if (!found)
197: fatal("no matching hostkey found");
198:
199: if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
200: fatal("key_sign failed");
1.4 deraadt 201:
1.1 markus 202: /* send reply */
203: buffer_clear(&b);
204: buffer_put_string(&b, signature, slen);
205: msg_send(STDOUT_FILENO, version, &b);
206:
207: return (0);
208: }
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