Annotation of src/usr.bin/ssh/ssh-keysign.c, Revision 1.2
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"
1.2 ! markus 25: RCSID("$OpenBSD: ssh-keysign.c,v 1.1 2002/05/23 19:24:30 markus 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);
56:
57: /* session id */
58: buffer_skip_string(&b);
59: if (buffer_get_char(&b) != SSH2_MSG_USERAUTH_REQUEST)
60: fail++;
61:
62: /* server user */
63: buffer_skip_string(&b);
64:
65: /* service */
66: p = buffer_get_string(&b, NULL);
67: if (strcmp("ssh-connection", p) != 0)
68: fail++;
69: xfree(p);
70:
71: /* method */
72: p = buffer_get_string(&b, NULL);
73: if (strcmp("hostbased", p) != 0)
74: fail++;
75: xfree(p);
76:
77: /* pubkey */
78: pkalg = buffer_get_string(&b, NULL);
79: pkblob = buffer_get_string(&b, &blen);
80:
81: pktype = key_type_from_name(pkalg);
82: if (pktype == KEY_UNSPEC)
83: fail++;
84: else if ((key = key_from_blob(pkblob, blen)) == NULL)
85: fail++;
86: else if (key->type != pktype)
87: fail++;
88: xfree(pkalg);
89: xfree(pkblob);
90:
1.2 ! markus 91: /* client host name, handle trailing dot */
! 92: p = buffer_get_string(&b, &len);
! 93: debug2("valid_request: check expect chost %s got %s", host, p);
! 94: if (strlen(host) != len - 1)
! 95: fail++;
! 96: else if (p[len - 1] != '.')
! 97: fail++;
! 98: else if (strncasecmp(host, p, len - 1) != 0)
! 99: fail++;
! 100: xfree(p);
1.1 markus 101:
102: /* local user */
103: p = buffer_get_string(&b, NULL);
1.2 ! markus 104:
1.1 markus 105: if (strcmp(pw->pw_name, p) != 0)
106: fail++;
107: xfree(p);
108:
109: /* end of message */
110: if (buffer_len(&b) != 0)
111: fail++;
112:
113: debug3("valid_request: fail %d", fail);
114:
115: if (fail && key != NULL)
116: key_free(key);
117: else
118: *ret = key;
119:
120: return (fail ? -1 : 0);
121: }
122:
123: int
124: main(int argc, char **argv)
125: {
126: Buffer b;
127: Key *keys[2], *key;
128: struct passwd *pw;
1.2 ! markus 129: int key_fd[2], i, found, version = 2, fd;
1.1 markus 130: u_char *signature, *data;
1.2 ! markus 131: char *host;
1.1 markus 132: u_int slen, dlen;
133:
134: key_fd[0] = open(_PATH_HOST_RSA_KEY_FILE, O_RDONLY);
135: key_fd[1] = open(_PATH_HOST_DSA_KEY_FILE, O_RDONLY);
136:
137: seteuid(getuid());
138: setuid(getuid());
139:
140: #ifdef DEBUG_SSH_KEYSIGN
141: log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0);
142: #endif
143:
144: if (key_fd[0] == -1 && key_fd[1] == -1)
145: fatal("could not open any host key");
146:
147: if ((pw = getpwuid(getuid())) == NULL)
148: fatal("getpwuid failed");
149: pw = pwcopy(pw);
150:
151: SSLeay_add_all_algorithms();
152:
153: found = 0;
154: for (i = 0; i < 2; i++) {
155: keys[i] = NULL;
156: if (key_fd[i] == -1)
157: continue;
158: keys[i] = key_load_private_pem(key_fd[i], KEY_UNSPEC,
159: NULL, NULL);
160: close(key_fd[i]);
161: if (keys[i] != NULL)
162: found = 1;
163: }
164: if (!found)
165: fatal("no hostkey found");
166:
167: buffer_init(&b);
168: if (msg_recv(STDIN_FILENO, &b) < 0)
169: fatal("msg_recv failed");
170: if (buffer_get_char(&b) != version)
171: fatal("bad version");
1.2 ! markus 172: fd = buffer_get_int(&b);
! 173: if ((fd == STDIN_FILENO) || (fd == STDOUT_FILENO))
! 174: fatal("bad fd");
! 175: if ((host = get_local_name(fd)) == NULL)
! 176: fatal("cannot get sockname for fd");
! 177:
1.1 markus 178: data = buffer_get_string(&b, &dlen);
1.2 ! markus 179: if (valid_request(pw, host, &key, data, dlen) < 0)
1.1 markus 180: fatal("not a valid request");
181: xfree(data);
1.2 ! markus 182: xfree(host);
1.1 markus 183:
184: found = 0;
185: for (i = 0; i < 2; i++) {
186: if (keys[i] != NULL &&
187: key_equal(key, keys[i])) {
188: found = 1;
189: break;
190: }
191: }
192: if (!found)
193: fatal("no matching hostkey found");
194:
195: if (key_sign(keys[i], &signature, &slen, data, dlen) != 0)
196: fatal("key_sign failed");
197:
198: /* send reply */
199: buffer_clear(&b);
200: buffer_put_string(&b, signature, slen);
201: msg_send(STDOUT_FILENO, version, &b);
202:
203: return (0);
204: }
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