1 /* $OpenBSD: ssh-pkcs11-helper.c,v 1.23 2020/03/06 18:26:21 markus Exp $ */
3 * Copyright (c) 2010 Markus Friedl. All rights reserved.
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.
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.
20 #include <sys/types.h>
21 #ifdef HAVE_SYS_TIME_H
22 # include <sys/time.h>
25 #include "openbsd-compat/sys-queue.h"
42 #include "ssh-pkcs11.h"
49 /* borrows code from sftp-server and ssh-agent */
51 struct pkcs11_keyinfo {
53 char *providername, *label;
54 TAILQ_ENTRY(pkcs11_keyinfo) next;
57 TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
59 #define MAX_MSG_LENGTH 10240 /*XXX*/
61 /* input and output queue */
62 struct sshbuf *iqueue;
63 struct sshbuf *oqueue;
66 add_key(struct sshkey *k, char *name, char *label)
68 struct pkcs11_keyinfo *ki;
70 ki = xcalloc(1, sizeof(*ki));
71 ki->providername = xstrdup(name);
73 ki->label = xstrdup(label);
74 TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
78 del_keys_by_name(char *name)
80 struct pkcs11_keyinfo *ki, *nxt;
82 for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
83 nxt = TAILQ_NEXT(ki, next);
84 if (!strcmp(ki->providername, name)) {
85 TAILQ_REMOVE(&pkcs11_keylist, ki, next);
86 free(ki->providername);
94 /* lookup matching 'private' key */
95 static struct sshkey *
96 lookup_key(struct sshkey *k)
98 struct pkcs11_keyinfo *ki;
100 TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
101 debug("check %p %s %s", ki, ki->providername, ki->label);
102 if (sshkey_equal(k, ki->key))
109 send_msg(struct sshbuf *m)
113 if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
114 fatal("%s: buffer error: %s", __func__, ssh_err(r));
121 struct sshkey **keys = NULL;
126 char **labels = NULL;
128 if ((msg = sshbuf_new()) == NULL)
129 fatal("%s: sshbuf_new failed", __func__);
130 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
131 (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
132 fatal("%s: buffer error: %s", __func__, ssh_err(r));
133 if ((nkeys = pkcs11_add_provider(name, pin, &keys, &labels)) > 0) {
134 if ((r = sshbuf_put_u8(msg,
135 SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
136 (r = sshbuf_put_u32(msg, nkeys)) != 0)
137 fatal("%s: buffer error: %s", __func__, ssh_err(r));
138 for (i = 0; i < nkeys; i++) {
139 if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
140 debug("%s: sshkey_to_blob: %s",
141 __func__, ssh_err(r));
144 if ((r = sshbuf_put_string(msg, blob, blen)) != 0 ||
145 (r = sshbuf_put_cstring(msg, labels[i])) != 0)
146 fatal("%s: buffer error: %s",
147 __func__, ssh_err(r));
149 add_key(keys[i], name, labels[i]);
153 if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
154 fatal("%s: buffer error: %s", __func__, ssh_err(r));
155 if ((r = sshbuf_put_u32(msg, -nkeys)) != 0)
156 fatal("%s: buffer error: %s", __func__, ssh_err(r));
159 free(keys); /* keys themselves are transferred to pkcs11_keylist */
173 if ((msg = sshbuf_new()) == NULL)
174 fatal("%s: sshbuf_new failed", __func__);
175 if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
176 (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
177 fatal("%s: buffer error: %s", __func__, ssh_err(r));
178 del_keys_by_name(name);
179 if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
180 SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
181 fatal("%s: buffer error: %s", __func__, ssh_err(r));
191 u_char *blob, *data, *signature = NULL;
192 size_t blen, dlen, slen = 0;
194 struct sshkey *key, *found;
197 /* XXX support SHA2 signature flags */
198 if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
199 (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
200 (r = sshbuf_get_u32(iqueue, NULL)) != 0)
201 fatal("%s: buffer error: %s", __func__, ssh_err(r));
203 if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
204 error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
206 if ((found = lookup_key(key)) != NULL) {
210 if (key->type == KEY_RSA) {
211 slen = RSA_size(key->rsa);
212 signature = xmalloc(slen);
213 ret = RSA_private_encrypt(dlen, data, signature,
214 found->rsa, RSA_PKCS1_PADDING);
219 #ifdef OPENSSL_HAS_ECC
220 } else if (key->type == KEY_ECDSA) {
221 u_int xslen = ECDSA_size(key->ecdsa);
223 signature = xmalloc(xslen);
224 /* "The parameter type is ignored." */
225 ret = ECDSA_sign(-1, data, dlen, signature,
226 &xslen, found->ecdsa);
230 error("%s: ECDSA_sign"
231 " returns %d", __func__, ret);
233 #endif /* OPENSSL_HAS_ECC */
235 error("%s: don't know how to sign with key "
236 "type %d", __func__, (int)key->type);
237 #endif /* WITH_OPENSSL */
241 if ((msg = sshbuf_new()) == NULL)
242 fatal("%s: sshbuf_new failed", __func__);
244 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
245 (r = sshbuf_put_string(msg, signature, slen)) != 0)
246 fatal("%s: buffer error: %s", __func__, ssh_err(r));
248 if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
249 fatal("%s: buffer error: %s", __func__, ssh_err(r));
268 buf_len = sshbuf_len(iqueue);
270 return; /* Incomplete message. */
271 cp = sshbuf_ptr(iqueue);
272 msg_len = get_u32(cp);
273 if (msg_len > MAX_MSG_LENGTH) {
274 error("bad message len %d", msg_len);
277 if (buf_len < msg_len + 4)
279 if ((r = sshbuf_consume(iqueue, 4)) != 0 ||
280 (r = sshbuf_get_u8(iqueue, &type)) != 0)
281 fatal("%s: buffer error: %s", __func__, ssh_err(r));
284 case SSH_AGENTC_ADD_SMARTCARD_KEY:
285 debug("process_add");
288 case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
289 debug("process_del");
292 case SSH2_AGENTC_SIGN_REQUEST:
293 debug("process_sign");
297 error("Unknown message %d", type);
300 /* discard the remaining bytes from the current packet */
301 if (buf_len < sshbuf_len(iqueue)) {
302 error("iqueue grew unexpectedly");
305 consumed = buf_len - sshbuf_len(iqueue);
306 if (msg_len < consumed) {
307 error("msg_len %d < consumed %d", msg_len, consumed);
310 if (msg_len > consumed) {
311 if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
312 fatal("%s: buffer error: %s", __func__, ssh_err(r));
325 main(int argc, char **argv)
327 int r, ch, in, out, log_stderr = 0;
329 SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
330 LogLevel log_level = SYSLOG_LEVEL_ERROR;
332 extern char *__progname;
333 struct pollfd pfd[2];
335 __progname = ssh_get_progname(argv[0]);
337 TAILQ_INIT(&pkcs11_keylist);
339 log_init(__progname, log_level, log_facility, log_stderr);
341 while ((ch = getopt(argc, argv, "v")) != -1) {
345 if (log_level == SYSLOG_LEVEL_ERROR)
346 log_level = SYSLOG_LEVEL_DEBUG1;
347 else if (log_level < SYSLOG_LEVEL_DEBUG3)
351 fprintf(stderr, "usage: %s [-v]\n", __progname);
356 log_init(__progname, log_level, log_facility, log_stderr);
363 if ((iqueue = sshbuf_new()) == NULL)
364 fatal("%s: sshbuf_new failed", __func__);
365 if ((oqueue = sshbuf_new()) == NULL)
366 fatal("%s: sshbuf_new failed", __func__);
369 memset(pfd, 0, sizeof(pfd));
374 * Ensure that we can read a full buffer and handle
375 * the worst-case length packet it can generate,
376 * otherwise apply backpressure by stopping reads.
378 if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
379 (r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
380 pfd[0].events = POLLIN;
381 else if (r != SSH_ERR_NO_BUFFER_SPACE)
382 fatal("%s: buffer error: %s", __func__, ssh_err(r));
384 if (sshbuf_len(oqueue) > 0)
385 pfd[1].events = POLLOUT;
387 if ((r = poll(pfd, 2, -1 /* INFTIM */)) <= 0) {
388 if (r == 0 || errno == EINTR)
390 fatal("poll: %s", strerror(errno));
393 /* copy stdin to iqueue */
394 if ((pfd[0].revents & (POLLIN|POLLERR)) != 0) {
395 len = read(in, buf, sizeof buf);
399 } else if (len < 0) {
400 error("read: %s", strerror(errno));
402 } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
403 fatal("%s: buffer error: %s",
404 __func__, ssh_err(r));
407 /* send oqueue to stdout */
408 if ((pfd[1].revents & (POLLOUT|POLLHUP)) != 0) {
409 len = write(out, sshbuf_ptr(oqueue),
412 error("write: %s", strerror(errno));
414 } else if ((r = sshbuf_consume(oqueue, len)) != 0) {
415 fatal("%s: buffer error: %s",
416 __func__, ssh_err(r));
421 * Process requests from client if we can fit the results
422 * into the output buffer, otherwise stop processing input
423 * and let the output queue drain.
425 if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
427 else if (r != SSH_ERR_NO_BUFFER_SPACE)
428 fatal("%s: buffer error: %s", __func__, ssh_err(r));
432 #else /* WITH_OPENSSL */
440 main(int argc, char **argv)
442 fprintf(stderr, "PKCS#11 code is not enabled\n");
445 #endif /* WITH_OPENSSL */
446 #else /* ENABLE_PKCS11 */
448 main(int argc, char **argv)
450 extern char *__progname;
452 __progname = ssh_get_progname(argv[0]);
453 log_init(__progname, SYSLOG_LEVEL_ERROR, SYSLOG_FACILITY_AUTH, 0);
454 fatal("PKCS#11 support disabled at compile time");
456 #endif /* ENABLE_PKCS11 */