Annotation of src/usr.bin/ssh/ssh-pkcs11-helper.c, Revision 1.21
1.21 ! djm 1: /* $OpenBSD: ssh-pkcs11-helper.c,v 1.20 2019/09/06 04:53:27 djm Exp $ */
1.1 markus 2: /*
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:
1.9 djm 18: #include <sys/types.h>
1.1 markus 19: #include <sys/queue.h>
20: #include <sys/time.h>
21:
1.20 djm 22: #include <stdlib.h>
1.17 djm 23: #include <errno.h>
24: #include <poll.h>
1.1 markus 25: #include <stdarg.h>
26: #include <string.h>
27: #include <unistd.h>
28:
29: #include "xmalloc.h"
1.14 markus 30: #include "sshbuf.h"
1.1 markus 31: #include "log.h"
32: #include "misc.h"
1.14 markus 33: #include "sshkey.h"
1.1 markus 34: #include "authfd.h"
35: #include "ssh-pkcs11.h"
1.14 markus 36: #include "ssherr.h"
1.1 markus 37:
1.21 ! djm 38: #ifdef WITH_OPENSSL
! 39:
1.1 markus 40: /* borrows code from sftp-server and ssh-agent */
41:
42: struct pkcs11_keyinfo {
1.13 markus 43: struct sshkey *key;
1.1 markus 44: char *providername;
45: TAILQ_ENTRY(pkcs11_keyinfo) next;
46: };
47:
48: TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
49:
50: #define MAX_MSG_LENGTH 10240 /*XXX*/
51:
52: /* input and output queue */
1.14 markus 53: struct sshbuf *iqueue;
54: struct sshbuf *oqueue;
1.1 markus 55:
56: static void
1.13 markus 57: add_key(struct sshkey *k, char *name)
1.1 markus 58: {
59: struct pkcs11_keyinfo *ki;
60:
61: ki = xcalloc(1, sizeof(*ki));
62: ki->providername = xstrdup(name);
63: ki->key = k;
64: TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
65: }
66:
67: static void
68: del_keys_by_name(char *name)
69: {
70: struct pkcs11_keyinfo *ki, *nxt;
71:
72: for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
73: nxt = TAILQ_NEXT(ki, next);
74: if (!strcmp(ki->providername, name)) {
75: TAILQ_REMOVE(&pkcs11_keylist, ki, next);
1.6 djm 76: free(ki->providername);
1.14 markus 77: sshkey_free(ki->key);
1.1 markus 78: free(ki);
79: }
80: }
81: }
82:
83: /* lookup matching 'private' key */
1.13 markus 84: static struct sshkey *
85: lookup_key(struct sshkey *k)
1.1 markus 86: {
87: struct pkcs11_keyinfo *ki;
88:
89: TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
90: debug("check %p %s", ki, ki->providername);
1.14 markus 91: if (sshkey_equal(k, ki->key))
1.1 markus 92: return (ki->key);
93: }
94: return (NULL);
95: }
96:
97: static void
1.14 markus 98: send_msg(struct sshbuf *m)
1.1 markus 99: {
1.14 markus 100: int r;
1.1 markus 101:
1.14 markus 102: if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
103: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 104: }
105:
106: static void
107: process_add(void)
108: {
109: char *name, *pin;
1.15 djm 110: struct sshkey **keys = NULL;
1.14 markus 111: int r, i, nkeys;
1.1 markus 112: u_char *blob;
1.14 markus 113: size_t blen;
114: struct sshbuf *msg;
1.1 markus 115:
1.14 markus 116: if ((msg = sshbuf_new()) == NULL)
117: fatal("%s: sshbuf_new failed", __func__);
118: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
119: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
120: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 121: if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
1.14 markus 122: if ((r = sshbuf_put_u8(msg,
123: SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
124: (r = sshbuf_put_u32(msg, nkeys)) != 0)
125: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 126: for (i = 0; i < nkeys; i++) {
1.14 markus 127: if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
128: debug("%s: sshkey_to_blob: %s",
129: __func__, ssh_err(r));
1.7 djm 130: continue;
1.14 markus 131: }
132: if ((r = sshbuf_put_string(msg, blob, blen)) != 0 ||
133: (r = sshbuf_put_cstring(msg, name)) != 0)
134: fatal("%s: buffer error: %s",
135: __func__, ssh_err(r));
1.6 djm 136: free(blob);
1.1 markus 137: add_key(keys[i], name);
138: }
139: } else {
1.14 markus 140: if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
141: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.15 djm 142: if ((r = sshbuf_put_u32(msg, -nkeys)) != 0)
143: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 144: }
1.15 djm 145: free(keys);
1.6 djm 146: free(pin);
147: free(name);
1.14 markus 148: send_msg(msg);
149: sshbuf_free(msg);
1.1 markus 150: }
151:
152: static void
153: process_del(void)
154: {
155: char *name, *pin;
1.14 markus 156: struct sshbuf *msg;
157: int r;
1.1 markus 158:
1.14 markus 159: if ((msg = sshbuf_new()) == NULL)
160: fatal("%s: sshbuf_new failed", __func__);
161: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
162: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
163: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 164: del_keys_by_name(name);
1.14 markus 165: if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
166: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
167: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.6 djm 168: free(pin);
169: free(name);
1.14 markus 170: send_msg(msg);
171: sshbuf_free(msg);
1.1 markus 172: }
173:
174: static void
175: process_sign(void)
176: {
177: u_char *blob, *data, *signature = NULL;
1.14 markus 178: size_t blen, dlen, slen = 0;
179: int r, ok = -1;
1.13 markus 180: struct sshkey *key, *found;
1.14 markus 181: struct sshbuf *msg;
1.1 markus 182:
1.14 markus 183: /* XXX support SHA2 signature flags */
184: if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
185: (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
186: (r = sshbuf_get_u32(iqueue, NULL)) != 0)
187: fatal("%s: buffer error: %s", __func__, ssh_err(r));
188:
189: if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
190: error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
191: else {
1.1 markus 192: if ((found = lookup_key(key)) != NULL) {
1.8 djm 193: #ifdef WITH_OPENSSL
194: int ret;
195:
1.15 djm 196: if (key->type == KEY_RSA) {
197: slen = RSA_size(key->rsa);
198: signature = xmalloc(slen);
199: ret = RSA_private_encrypt(dlen, data, signature,
200: found->rsa, RSA_PKCS1_PADDING);
201: if (ret != -1) {
202: slen = ret;
203: ok = 0;
204: }
205: } else if (key->type == KEY_ECDSA) {
1.18 dtucker 206: u_int xslen = ECDSA_size(key->ecdsa);
207:
1.15 djm 208: signature = xmalloc(xslen);
209: /* "The parameter type is ignored." */
210: ret = ECDSA_sign(-1, data, dlen, signature,
211: &xslen, found->ecdsa);
212: if (ret != 0)
213: ok = 0;
214: else
215: error("%s: ECDSA_sign"
216: " returns %d", __func__, ret);
217: slen = xslen;
218: } else
219: error("%s: don't know how to sign with key "
220: "type %d", __func__, (int)key->type);
1.8 djm 221: #endif /* WITH_OPENSSL */
1.1 markus 222: }
1.14 markus 223: sshkey_free(key);
1.1 markus 224: }
1.14 markus 225: if ((msg = sshbuf_new()) == NULL)
226: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 227: if (ok == 0) {
1.14 markus 228: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
229: (r = sshbuf_put_string(msg, signature, slen)) != 0)
230: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 231: } else {
1.14 markus 232: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
233: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 234: }
1.6 djm 235: free(data);
236: free(blob);
237: free(signature);
1.14 markus 238: send_msg(msg);
239: sshbuf_free(msg);
1.1 markus 240: }
241:
242: static void
243: process(void)
244: {
245: u_int msg_len;
246: u_int buf_len;
247: u_int consumed;
1.14 markus 248: u_char type;
249: const u_char *cp;
250: int r;
1.1 markus 251:
1.14 markus 252: buf_len = sshbuf_len(iqueue);
1.1 markus 253: if (buf_len < 5)
254: return; /* Incomplete message. */
1.14 markus 255: cp = sshbuf_ptr(iqueue);
1.1 markus 256: msg_len = get_u32(cp);
257: if (msg_len > MAX_MSG_LENGTH) {
258: error("bad message len %d", msg_len);
259: cleanup_exit(11);
260: }
261: if (buf_len < msg_len + 4)
262: return;
1.14 markus 263: if ((r = sshbuf_consume(iqueue, 4)) != 0 ||
264: (r = sshbuf_get_u8(iqueue, &type)) != 0)
265: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 266: buf_len -= 4;
267: switch (type) {
268: case SSH_AGENTC_ADD_SMARTCARD_KEY:
269: debug("process_add");
270: process_add();
271: break;
272: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
273: debug("process_del");
274: process_del();
275: break;
276: case SSH2_AGENTC_SIGN_REQUEST:
277: debug("process_sign");
278: process_sign();
279: break;
280: default:
281: error("Unknown message %d", type);
282: break;
283: }
284: /* discard the remaining bytes from the current packet */
1.14 markus 285: if (buf_len < sshbuf_len(iqueue)) {
1.1 markus 286: error("iqueue grew unexpectedly");
287: cleanup_exit(255);
288: }
1.14 markus 289: consumed = buf_len - sshbuf_len(iqueue);
1.1 markus 290: if (msg_len < consumed) {
291: error("msg_len %d < consumed %d", msg_len, consumed);
292: cleanup_exit(255);
293: }
1.14 markus 294: if (msg_len > consumed) {
295: if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
296: fatal("%s: buffer error: %s", __func__, ssh_err(r));
297: }
1.1 markus 298: }
299:
300: void
301: cleanup_exit(int i)
302: {
303: /* XXX */
304: _exit(i);
305: }
306:
1.16 djm 307:
1.1 markus 308: int
309: main(int argc, char **argv)
310: {
1.16 djm 311: int r, ch, in, out, max, log_stderr = 0;
1.17 djm 312: ssize_t len;
1.1 markus 313: SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
314: LogLevel log_level = SYSLOG_LEVEL_ERROR;
315: char buf[4*4096];
1.2 deraadt 316: extern char *__progname;
1.17 djm 317: struct pollfd pfd[2];
1.1 markus 318:
319: TAILQ_INIT(&pkcs11_keylist);
320:
321: log_init(__progname, log_level, log_facility, log_stderr);
322:
1.16 djm 323: while ((ch = getopt(argc, argv, "v")) != -1) {
324: switch (ch) {
325: case 'v':
326: log_stderr = 1;
327: if (log_level == SYSLOG_LEVEL_ERROR)
328: log_level = SYSLOG_LEVEL_DEBUG1;
329: else if (log_level < SYSLOG_LEVEL_DEBUG3)
330: log_level++;
331: break;
332: default:
333: fprintf(stderr, "usage: %s [-v]\n", __progname);
334: exit(1);
335: }
336: }
337:
338: log_init(__progname, log_level, log_facility, log_stderr);
339:
340: pkcs11_init(0);
1.1 markus 341: in = STDIN_FILENO;
342: out = STDOUT_FILENO;
343:
344: max = 0;
345: if (in > max)
346: max = in;
347: if (out > max)
348: max = out;
349:
1.14 markus 350: if ((iqueue = sshbuf_new()) == NULL)
351: fatal("%s: sshbuf_new failed", __func__);
352: if ((oqueue = sshbuf_new()) == NULL)
353: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 354:
1.17 djm 355: while (1) {
356: memset(pfd, 0, sizeof(pfd));
357: pfd[0].fd = in;
358: pfd[1].fd = out;
1.1 markus 359:
360: /*
361: * Ensure that we can read a full buffer and handle
362: * the worst-case length packet it can generate,
363: * otherwise apply backpressure by stopping reads.
364: */
1.14 markus 365: if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
366: (r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.17 djm 367: pfd[0].events = POLLIN;
1.14 markus 368: else if (r != SSH_ERR_NO_BUFFER_SPACE)
369: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 370:
1.17 djm 371: if (sshbuf_len(oqueue) > 0)
372: pfd[1].events = POLLOUT;
1.1 markus 373:
1.17 djm 374: if ((r = poll(pfd, 2, -1 /* INFTIM */)) <= 0) {
375: if (r == 0 || errno == EINTR)
1.1 markus 376: continue;
1.17 djm 377: fatal("poll: %s", strerror(errno));
1.1 markus 378: }
379:
380: /* copy stdin to iqueue */
1.17 djm 381: if ((pfd[0].revents & (POLLIN|POLLERR)) != 0) {
1.1 markus 382: len = read(in, buf, sizeof buf);
383: if (len == 0) {
384: debug("read eof");
385: cleanup_exit(0);
386: } else if (len < 0) {
387: error("read: %s", strerror(errno));
388: cleanup_exit(1);
1.14 markus 389: } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
390: fatal("%s: buffer error: %s",
391: __func__, ssh_err(r));
1.1 markus 392: }
393: }
394: /* send oqueue to stdout */
1.17 djm 395: if ((pfd[1].revents & (POLLOUT|POLLHUP)) != 0) {
396: len = write(out, sshbuf_ptr(oqueue),
397: sshbuf_len(oqueue));
1.1 markus 398: if (len < 0) {
399: error("write: %s", strerror(errno));
400: cleanup_exit(1);
1.14 markus 401: } else if ((r = sshbuf_consume(oqueue, len)) != 0) {
402: fatal("%s: buffer error: %s",
403: __func__, ssh_err(r));
1.1 markus 404: }
405: }
406:
407: /*
408: * Process requests from client if we can fit the results
409: * into the output buffer, otherwise stop processing input
410: * and let the output queue drain.
411: */
1.14 markus 412: if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.1 markus 413: process();
1.14 markus 414: else if (r != SSH_ERR_NO_BUFFER_SPACE)
415: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 416: }
417: }
1.21 ! djm 418:
! 419: #else /* WITH_OPENSSL */
! 420: void
! 421: cleanup_exit(int i)
! 422: {
! 423: _exit(i);
! 424: }
! 425:
! 426: int
! 427: main(int argc, char **argv)
! 428: {
! 429: fprintf(stderr, "PKCS#11 code is not enabled\n");
! 430: return 1;
! 431: }
! 432: #endif /* WITH_OPENSSL */
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