Annotation of src/usr.bin/ssh/ssh-pkcs11-helper.c, Revision 1.23
1.23 ! markus 1: /* $OpenBSD: ssh-pkcs11-helper.c,v 1.22 2020/01/25 00:03:36 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;
1.22 djm 44: char *providername, *label;
1.1 markus 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
1.22 djm 57: add_key(struct sshkey *k, char *name, char *label)
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;
1.22 djm 64: ki->label = xstrdup(label);
1.1 markus 65: TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
66: }
67:
68: static void
69: del_keys_by_name(char *name)
70: {
71: struct pkcs11_keyinfo *ki, *nxt;
72:
73: for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
74: nxt = TAILQ_NEXT(ki, next);
75: if (!strcmp(ki->providername, name)) {
76: TAILQ_REMOVE(&pkcs11_keylist, ki, next);
1.6 djm 77: free(ki->providername);
1.22 djm 78: free(ki->label);
1.14 markus 79: sshkey_free(ki->key);
1.1 markus 80: free(ki);
81: }
82: }
83: }
84:
85: /* lookup matching 'private' key */
1.13 markus 86: static struct sshkey *
87: lookup_key(struct sshkey *k)
1.1 markus 88: {
89: struct pkcs11_keyinfo *ki;
90:
91: TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
1.22 djm 92: debug("check %p %s %s", ki, ki->providername, ki->label);
1.14 markus 93: if (sshkey_equal(k, ki->key))
1.1 markus 94: return (ki->key);
95: }
96: return (NULL);
97: }
98:
99: static void
1.14 markus 100: send_msg(struct sshbuf *m)
1.1 markus 101: {
1.14 markus 102: int r;
1.1 markus 103:
1.14 markus 104: if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
105: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 106: }
107:
108: static void
109: process_add(void)
110: {
111: char *name, *pin;
1.15 djm 112: struct sshkey **keys = NULL;
1.14 markus 113: int r, i, nkeys;
1.1 markus 114: u_char *blob;
1.14 markus 115: size_t blen;
116: struct sshbuf *msg;
1.22 djm 117: char **labels = NULL;
1.1 markus 118:
1.14 markus 119: if ((msg = sshbuf_new()) == NULL)
120: fatal("%s: sshbuf_new failed", __func__);
121: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
122: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
123: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.22 djm 124: if ((nkeys = pkcs11_add_provider(name, pin, &keys, &labels)) > 0) {
1.14 markus 125: if ((r = sshbuf_put_u8(msg,
126: SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
127: (r = sshbuf_put_u32(msg, nkeys)) != 0)
128: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 129: for (i = 0; i < nkeys; i++) {
1.14 markus 130: if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
131: debug("%s: sshkey_to_blob: %s",
132: __func__, ssh_err(r));
1.7 djm 133: continue;
1.14 markus 134: }
135: if ((r = sshbuf_put_string(msg, blob, blen)) != 0 ||
1.22 djm 136: (r = sshbuf_put_cstring(msg, labels[i])) != 0)
1.14 markus 137: fatal("%s: buffer error: %s",
138: __func__, ssh_err(r));
1.6 djm 139: free(blob);
1.22 djm 140: add_key(keys[i], name, labels[i]);
141: free(labels[i]);
1.1 markus 142: }
143: } else {
1.14 markus 144: if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
145: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.15 djm 146: if ((r = sshbuf_put_u32(msg, -nkeys)) != 0)
147: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 148: }
1.22 djm 149: free(labels);
150: free(keys); /* keys themselves are transferred to pkcs11_keylist */
1.6 djm 151: free(pin);
152: free(name);
1.14 markus 153: send_msg(msg);
154: sshbuf_free(msg);
1.1 markus 155: }
156:
157: static void
158: process_del(void)
159: {
160: char *name, *pin;
1.14 markus 161: struct sshbuf *msg;
162: int r;
1.1 markus 163:
1.14 markus 164: if ((msg = sshbuf_new()) == NULL)
165: fatal("%s: sshbuf_new failed", __func__);
166: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
167: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
168: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 169: del_keys_by_name(name);
1.14 markus 170: if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
171: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
172: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.6 djm 173: free(pin);
174: free(name);
1.14 markus 175: send_msg(msg);
176: sshbuf_free(msg);
1.1 markus 177: }
178:
179: static void
180: process_sign(void)
181: {
182: u_char *blob, *data, *signature = NULL;
1.14 markus 183: size_t blen, dlen, slen = 0;
184: int r, ok = -1;
1.13 markus 185: struct sshkey *key, *found;
1.14 markus 186: struct sshbuf *msg;
1.1 markus 187:
1.14 markus 188: /* XXX support SHA2 signature flags */
189: if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
190: (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
191: (r = sshbuf_get_u32(iqueue, NULL)) != 0)
192: fatal("%s: buffer error: %s", __func__, ssh_err(r));
193:
194: if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
195: error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
196: else {
1.1 markus 197: if ((found = lookup_key(key)) != NULL) {
1.8 djm 198: #ifdef WITH_OPENSSL
199: int ret;
200:
1.15 djm 201: if (key->type == KEY_RSA) {
202: slen = RSA_size(key->rsa);
203: signature = xmalloc(slen);
204: ret = RSA_private_encrypt(dlen, data, signature,
205: found->rsa, RSA_PKCS1_PADDING);
206: if (ret != -1) {
207: slen = ret;
208: ok = 0;
209: }
210: } else if (key->type == KEY_ECDSA) {
1.18 dtucker 211: u_int xslen = ECDSA_size(key->ecdsa);
212:
1.15 djm 213: signature = xmalloc(xslen);
214: /* "The parameter type is ignored." */
215: ret = ECDSA_sign(-1, data, dlen, signature,
216: &xslen, found->ecdsa);
217: if (ret != 0)
218: ok = 0;
219: else
220: error("%s: ECDSA_sign"
221: " returns %d", __func__, ret);
222: slen = xslen;
223: } else
224: error("%s: don't know how to sign with key "
225: "type %d", __func__, (int)key->type);
1.8 djm 226: #endif /* WITH_OPENSSL */
1.1 markus 227: }
1.14 markus 228: sshkey_free(key);
1.1 markus 229: }
1.14 markus 230: if ((msg = sshbuf_new()) == NULL)
231: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 232: if (ok == 0) {
1.14 markus 233: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
234: (r = sshbuf_put_string(msg, signature, slen)) != 0)
235: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 236: } else {
1.14 markus 237: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
238: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 239: }
1.6 djm 240: free(data);
241: free(blob);
242: free(signature);
1.14 markus 243: send_msg(msg);
244: sshbuf_free(msg);
1.1 markus 245: }
246:
247: static void
248: process(void)
249: {
250: u_int msg_len;
251: u_int buf_len;
252: u_int consumed;
1.14 markus 253: u_char type;
254: const u_char *cp;
255: int r;
1.1 markus 256:
1.14 markus 257: buf_len = sshbuf_len(iqueue);
1.1 markus 258: if (buf_len < 5)
259: return; /* Incomplete message. */
1.14 markus 260: cp = sshbuf_ptr(iqueue);
1.1 markus 261: msg_len = get_u32(cp);
262: if (msg_len > MAX_MSG_LENGTH) {
263: error("bad message len %d", msg_len);
264: cleanup_exit(11);
265: }
266: if (buf_len < msg_len + 4)
267: return;
1.14 markus 268: if ((r = sshbuf_consume(iqueue, 4)) != 0 ||
269: (r = sshbuf_get_u8(iqueue, &type)) != 0)
270: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 271: buf_len -= 4;
272: switch (type) {
273: case SSH_AGENTC_ADD_SMARTCARD_KEY:
274: debug("process_add");
275: process_add();
276: break;
277: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
278: debug("process_del");
279: process_del();
280: break;
281: case SSH2_AGENTC_SIGN_REQUEST:
282: debug("process_sign");
283: process_sign();
284: break;
285: default:
286: error("Unknown message %d", type);
287: break;
288: }
289: /* discard the remaining bytes from the current packet */
1.14 markus 290: if (buf_len < sshbuf_len(iqueue)) {
1.1 markus 291: error("iqueue grew unexpectedly");
292: cleanup_exit(255);
293: }
1.14 markus 294: consumed = buf_len - sshbuf_len(iqueue);
1.1 markus 295: if (msg_len < consumed) {
296: error("msg_len %d < consumed %d", msg_len, consumed);
297: cleanup_exit(255);
298: }
1.14 markus 299: if (msg_len > consumed) {
300: if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
301: fatal("%s: buffer error: %s", __func__, ssh_err(r));
302: }
1.1 markus 303: }
304:
305: void
306: cleanup_exit(int i)
307: {
308: /* XXX */
309: _exit(i);
310: }
311:
1.16 djm 312:
1.1 markus 313: int
314: main(int argc, char **argv)
315: {
1.23 ! markus 316: int r, ch, in, out, log_stderr = 0;
1.17 djm 317: ssize_t len;
1.1 markus 318: SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
319: LogLevel log_level = SYSLOG_LEVEL_ERROR;
320: char buf[4*4096];
1.2 deraadt 321: extern char *__progname;
1.17 djm 322: struct pollfd pfd[2];
1.1 markus 323:
324: TAILQ_INIT(&pkcs11_keylist);
325:
326: log_init(__progname, log_level, log_facility, log_stderr);
327:
1.16 djm 328: while ((ch = getopt(argc, argv, "v")) != -1) {
329: switch (ch) {
330: case 'v':
331: log_stderr = 1;
332: if (log_level == SYSLOG_LEVEL_ERROR)
333: log_level = SYSLOG_LEVEL_DEBUG1;
334: else if (log_level < SYSLOG_LEVEL_DEBUG3)
335: log_level++;
336: break;
337: default:
338: fprintf(stderr, "usage: %s [-v]\n", __progname);
339: exit(1);
340: }
341: }
342:
343: log_init(__progname, log_level, log_facility, log_stderr);
344:
345: pkcs11_init(0);
1.1 markus 346: in = STDIN_FILENO;
347: out = STDOUT_FILENO;
348:
1.14 markus 349: if ((iqueue = sshbuf_new()) == NULL)
350: fatal("%s: sshbuf_new failed", __func__);
351: if ((oqueue = sshbuf_new()) == NULL)
352: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 353:
1.17 djm 354: while (1) {
355: memset(pfd, 0, sizeof(pfd));
356: pfd[0].fd = in;
357: pfd[1].fd = out;
1.1 markus 358:
359: /*
360: * Ensure that we can read a full buffer and handle
361: * the worst-case length packet it can generate,
362: * otherwise apply backpressure by stopping reads.
363: */
1.14 markus 364: if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
365: (r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.17 djm 366: pfd[0].events = POLLIN;
1.14 markus 367: else if (r != SSH_ERR_NO_BUFFER_SPACE)
368: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 369:
1.17 djm 370: if (sshbuf_len(oqueue) > 0)
371: pfd[1].events = POLLOUT;
1.1 markus 372:
1.17 djm 373: if ((r = poll(pfd, 2, -1 /* INFTIM */)) <= 0) {
374: if (r == 0 || errno == EINTR)
1.1 markus 375: continue;
1.17 djm 376: fatal("poll: %s", strerror(errno));
1.1 markus 377: }
378:
379: /* copy stdin to iqueue */
1.17 djm 380: if ((pfd[0].revents & (POLLIN|POLLERR)) != 0) {
1.1 markus 381: len = read(in, buf, sizeof buf);
382: if (len == 0) {
383: debug("read eof");
384: cleanup_exit(0);
385: } else if (len < 0) {
386: error("read: %s", strerror(errno));
387: cleanup_exit(1);
1.14 markus 388: } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
389: fatal("%s: buffer error: %s",
390: __func__, ssh_err(r));
1.1 markus 391: }
392: }
393: /* send oqueue to stdout */
1.17 djm 394: if ((pfd[1].revents & (POLLOUT|POLLHUP)) != 0) {
395: len = write(out, sshbuf_ptr(oqueue),
396: sshbuf_len(oqueue));
1.1 markus 397: if (len < 0) {
398: error("write: %s", strerror(errno));
399: cleanup_exit(1);
1.14 markus 400: } else if ((r = sshbuf_consume(oqueue, len)) != 0) {
401: fatal("%s: buffer error: %s",
402: __func__, ssh_err(r));
1.1 markus 403: }
404: }
405:
406: /*
407: * Process requests from client if we can fit the results
408: * into the output buffer, otherwise stop processing input
409: * and let the output queue drain.
410: */
1.14 markus 411: if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.1 markus 412: process();
1.14 markus 413: else if (r != SSH_ERR_NO_BUFFER_SPACE)
414: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 415: }
416: }
1.21 djm 417:
418: #else /* WITH_OPENSSL */
419: void
420: cleanup_exit(int i)
421: {
422: _exit(i);
423: }
424:
425: int
426: main(int argc, char **argv)
427: {
428: fprintf(stderr, "PKCS#11 code is not enabled\n");
429: return 1;
430: }
431: #endif /* WITH_OPENSSL */
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