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deraadt@openbsd.org087266e2015-01-20 23:14:00 +00001/* $OpenBSD: ssh-pkcs11-helper.c,v 1.10 2015/01/20 23:14:00 deraadt Exp $ */
Damien Miller7ea845e2010-02-12 09:21:02 +11002/*
3 * Copyright (c) 2010 Markus Friedl. All rights reserved.
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
Damien Miller8ad0fbd2010-02-12 09:49:06 +110018#include "includes.h"
19
Damien Miller7ea845e2010-02-12 09:21:02 +110020#include <sys/types.h>
Damien Miller8ad0fbd2010-02-12 09:49:06 +110021#ifdef HAVE_SYS_TIME_H
22# include <sys/time.h>
23#endif
24
25#include "openbsd-compat/sys-queue.h"
Damien Miller7ea845e2010-02-12 09:21:02 +110026
27#include <stdarg.h>
28#include <string.h>
29#include <unistd.h>
30#include <errno.h>
31
32#include "xmalloc.h"
33#include "buffer.h"
34#include "log.h"
35#include "misc.h"
36#include "key.h"
37#include "authfd.h"
38#include "ssh-pkcs11.h"
39
Damien Miller47f9a412010-03-14 08:37:49 +110040#ifdef ENABLE_PKCS11
41
Damien Miller7ea845e2010-02-12 09:21:02 +110042/* borrows code from sftp-server and ssh-agent */
43
44struct pkcs11_keyinfo {
45 Key *key;
46 char *providername;
47 TAILQ_ENTRY(pkcs11_keyinfo) next;
48};
49
50TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
51
52#define MAX_MSG_LENGTH 10240 /*XXX*/
53
54/* helper */
55#define get_int() buffer_get_int(&iqueue);
56#define get_string(lenp) buffer_get_string(&iqueue, lenp);
57
58/* input and output queue */
59Buffer iqueue;
60Buffer oqueue;
61
62static void
63add_key(Key *k, char *name)
64{
65 struct pkcs11_keyinfo *ki;
66
67 ki = xcalloc(1, sizeof(*ki));
68 ki->providername = xstrdup(name);
69 ki->key = k;
70 TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
71}
72
73static void
74del_keys_by_name(char *name)
75{
76 struct pkcs11_keyinfo *ki, *nxt;
77
78 for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
79 nxt = TAILQ_NEXT(ki, next);
80 if (!strcmp(ki->providername, name)) {
81 TAILQ_REMOVE(&pkcs11_keylist, ki, next);
Darren Tuckera627d422013-06-02 07:31:17 +100082 free(ki->providername);
Damien Miller7ea845e2010-02-12 09:21:02 +110083 key_free(ki->key);
84 free(ki);
85 }
86 }
87}
88
89/* lookup matching 'private' key */
90static Key *
91lookup_key(Key *k)
92{
93 struct pkcs11_keyinfo *ki;
94
95 TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
96 debug("check %p %s", ki, ki->providername);
97 if (key_equal(k, ki->key))
98 return (ki->key);
99 }
100 return (NULL);
101}
102
103static void
104send_msg(Buffer *m)
105{
106 int mlen = buffer_len(m);
107
108 buffer_put_int(&oqueue, mlen);
109 buffer_append(&oqueue, buffer_ptr(m), mlen);
110 buffer_consume(m, mlen);
111}
112
113static void
114process_add(void)
115{
116 char *name, *pin;
117 Key **keys;
118 int i, nkeys;
119 u_char *blob;
120 u_int blen;
121 Buffer msg;
122
123 buffer_init(&msg);
124 name = get_string(NULL);
125 pin = get_string(NULL);
126 if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
127 buffer_put_char(&msg, SSH2_AGENT_IDENTITIES_ANSWER);
128 buffer_put_int(&msg, nkeys);
129 for (i = 0; i < nkeys; i++) {
Damien Millerf1e44ea2013-12-05 10:23:21 +1100130 if (key_to_blob(keys[i], &blob, &blen) == 0)
131 continue;
Damien Miller7ea845e2010-02-12 09:21:02 +1100132 buffer_put_string(&msg, blob, blen);
133 buffer_put_cstring(&msg, name);
Darren Tuckera627d422013-06-02 07:31:17 +1000134 free(blob);
Damien Miller7ea845e2010-02-12 09:21:02 +1100135 add_key(keys[i], name);
136 }
Darren Tuckera627d422013-06-02 07:31:17 +1000137 free(keys);
Damien Miller7ea845e2010-02-12 09:21:02 +1100138 } else {
139 buffer_put_char(&msg, SSH_AGENT_FAILURE);
140 }
Darren Tuckera627d422013-06-02 07:31:17 +1000141 free(pin);
142 free(name);
Damien Miller7ea845e2010-02-12 09:21:02 +1100143 send_msg(&msg);
144 buffer_free(&msg);
145}
146
147static void
148process_del(void)
149{
150 char *name, *pin;
151 Buffer msg;
152
153 buffer_init(&msg);
154 name = get_string(NULL);
155 pin = get_string(NULL);
156 del_keys_by_name(name);
157 if (pkcs11_del_provider(name) == 0)
158 buffer_put_char(&msg, SSH_AGENT_SUCCESS);
159 else
160 buffer_put_char(&msg, SSH_AGENT_FAILURE);
Darren Tuckera627d422013-06-02 07:31:17 +1000161 free(pin);
162 free(name);
Damien Miller7ea845e2010-02-12 09:21:02 +1100163 send_msg(&msg);
164 buffer_free(&msg);
165}
166
167static void
168process_sign(void)
169{
170 u_char *blob, *data, *signature = NULL;
171 u_int blen, dlen, slen = 0;
Damien Miller86687062014-07-02 15:28:02 +1000172 int ok = -1;
Damien Miller7ea845e2010-02-12 09:21:02 +1100173 Key *key, *found;
174 Buffer msg;
175
176 blob = get_string(&blen);
177 data = get_string(&dlen);
Darren Tucker4908d442012-07-02 22:15:38 +1000178 (void)get_int(); /* XXX ignore flags */
Damien Miller7ea845e2010-02-12 09:21:02 +1100179
180 if ((key = key_from_blob(blob, blen)) != NULL) {
181 if ((found = lookup_key(key)) != NULL) {
Damien Miller86687062014-07-02 15:28:02 +1000182#ifdef WITH_OPENSSL
183 int ret;
184
Damien Miller7ea845e2010-02-12 09:21:02 +1100185 slen = RSA_size(key->rsa);
186 signature = xmalloc(slen);
187 if ((ret = RSA_private_encrypt(dlen, data, signature,
188 found->rsa, RSA_PKCS1_PADDING)) != -1) {
189 slen = ret;
190 ok = 0;
191 }
Damien Miller86687062014-07-02 15:28:02 +1000192#endif /* WITH_OPENSSL */
Damien Miller7ea845e2010-02-12 09:21:02 +1100193 }
194 key_free(key);
195 }
196 buffer_init(&msg);
197 if (ok == 0) {
198 buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
199 buffer_put_string(&msg, signature, slen);
200 } else {
201 buffer_put_char(&msg, SSH_AGENT_FAILURE);
202 }
Darren Tuckera627d422013-06-02 07:31:17 +1000203 free(data);
204 free(blob);
205 free(signature);
Damien Miller7ea845e2010-02-12 09:21:02 +1100206 send_msg(&msg);
207 buffer_free(&msg);
208}
209
210static void
211process(void)
212{
213 u_int msg_len;
214 u_int buf_len;
215 u_int consumed;
216 u_int type;
217 u_char *cp;
218
219 buf_len = buffer_len(&iqueue);
220 if (buf_len < 5)
221 return; /* Incomplete message. */
222 cp = buffer_ptr(&iqueue);
223 msg_len = get_u32(cp);
224 if (msg_len > MAX_MSG_LENGTH) {
225 error("bad message len %d", msg_len);
226 cleanup_exit(11);
227 }
228 if (buf_len < msg_len + 4)
229 return;
230 buffer_consume(&iqueue, 4);
231 buf_len -= 4;
232 type = buffer_get_char(&iqueue);
233 switch (type) {
234 case SSH_AGENTC_ADD_SMARTCARD_KEY:
235 debug("process_add");
236 process_add();
237 break;
238 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
239 debug("process_del");
240 process_del();
241 break;
242 case SSH2_AGENTC_SIGN_REQUEST:
243 debug("process_sign");
244 process_sign();
245 break;
246 default:
247 error("Unknown message %d", type);
248 break;
249 }
250 /* discard the remaining bytes from the current packet */
251 if (buf_len < buffer_len(&iqueue)) {
252 error("iqueue grew unexpectedly");
253 cleanup_exit(255);
254 }
255 consumed = buf_len - buffer_len(&iqueue);
256 if (msg_len < consumed) {
257 error("msg_len %d < consumed %d", msg_len, consumed);
258 cleanup_exit(255);
259 }
260 if (msg_len > consumed)
261 buffer_consume(&iqueue, msg_len - consumed);
262}
263
264void
265cleanup_exit(int i)
266{
267 /* XXX */
268 _exit(i);
269}
270
271int
272main(int argc, char **argv)
273{
274 fd_set *rset, *wset;
275 int in, out, max, log_stderr = 0;
276 ssize_t len, olen, set_size;
277 SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
278 LogLevel log_level = SYSLOG_LEVEL_ERROR;
279 char buf[4*4096];
280
Damien Miller7ea845e2010-02-12 09:21:02 +1100281 extern char *__progname;
282
Tim Ricebff24b82010-02-28 14:51:56 -0800283 TAILQ_INIT(&pkcs11_keylist);
284 pkcs11_init(0);
285
Damien Miller09a24db2010-02-28 03:28:05 +1100286 seed_rng();
Damien Millerdfa41562010-02-12 10:06:28 +1100287 __progname = ssh_get_progname(argv[0]);
288
Damien Miller7ea845e2010-02-12 09:21:02 +1100289 log_init(__progname, log_level, log_facility, log_stderr);
290
291 in = STDIN_FILENO;
292 out = STDOUT_FILENO;
293
294 max = 0;
295 if (in > max)
296 max = in;
297 if (out > max)
298 max = out;
299
300 buffer_init(&iqueue);
301 buffer_init(&oqueue);
302
303 set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
304 rset = (fd_set *)xmalloc(set_size);
305 wset = (fd_set *)xmalloc(set_size);
306
307 for (;;) {
308 memset(rset, 0, set_size);
309 memset(wset, 0, set_size);
310
311 /*
312 * Ensure that we can read a full buffer and handle
313 * the worst-case length packet it can generate,
314 * otherwise apply backpressure by stopping reads.
315 */
316 if (buffer_check_alloc(&iqueue, sizeof(buf)) &&
317 buffer_check_alloc(&oqueue, MAX_MSG_LENGTH))
318 FD_SET(in, rset);
319
320 olen = buffer_len(&oqueue);
321 if (olen > 0)
322 FD_SET(out, wset);
323
324 if (select(max+1, rset, wset, NULL, NULL) < 0) {
325 if (errno == EINTR)
326 continue;
327 error("select: %s", strerror(errno));
328 cleanup_exit(2);
329 }
330
331 /* copy stdin to iqueue */
332 if (FD_ISSET(in, rset)) {
333 len = read(in, buf, sizeof buf);
334 if (len == 0) {
335 debug("read eof");
336 cleanup_exit(0);
337 } else if (len < 0) {
338 error("read: %s", strerror(errno));
339 cleanup_exit(1);
340 } else {
341 buffer_append(&iqueue, buf, len);
342 }
343 }
344 /* send oqueue to stdout */
345 if (FD_ISSET(out, wset)) {
346 len = write(out, buffer_ptr(&oqueue), olen);
347 if (len < 0) {
348 error("write: %s", strerror(errno));
349 cleanup_exit(1);
350 } else {
351 buffer_consume(&oqueue, len);
352 }
353 }
354
355 /*
356 * Process requests from client if we can fit the results
357 * into the output buffer, otherwise stop processing input
358 * and let the output queue drain.
359 */
360 if (buffer_check_alloc(&oqueue, MAX_MSG_LENGTH))
361 process();
362 }
363}
Damien Millerdfa41562010-02-12 10:06:28 +1100364#else /* ENABLE_PKCS11 */
365int
366main(int argc, char **argv)
367{
368 extern char *__progname;
369
370 __progname = ssh_get_progname(argv[0]);
371 log_init(__progname, SYSLOG_LEVEL_ERROR, SYSLOG_FACILITY_AUTH, 0);
372 fatal("PKCS#11 support disabled at compile time");
373}
374#endif /* ENABLE_PKCS11 */