Annotation of src/usr.bin/ssh/ssh-pkcs11-helper.c, Revision 1.26
1.26 ! djm 1: /* $OpenBSD: ssh-pkcs11-helper.c,v 1.25 2021/08/11 05:20:17 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) {
1.25 djm 92: debug("check %s %s %s", sshkey_type(ki->key),
93: ki->providername, ki->label);
1.14 markus 94: if (sshkey_equal(k, ki->key))
1.1 markus 95: return (ki->key);
96: }
97: return (NULL);
98: }
99:
100: static void
1.14 markus 101: send_msg(struct sshbuf *m)
1.1 markus 102: {
1.14 markus 103: int r;
1.1 markus 104:
1.14 markus 105: if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
1.24 djm 106: fatal_fr(r, "enqueue");
1.1 markus 107: }
108:
109: static void
110: process_add(void)
111: {
112: char *name, *pin;
1.15 djm 113: struct sshkey **keys = NULL;
1.14 markus 114: int r, i, nkeys;
1.1 markus 115: u_char *blob;
1.14 markus 116: size_t blen;
117: struct sshbuf *msg;
1.22 djm 118: char **labels = NULL;
1.1 markus 119:
1.14 markus 120: if ((msg = sshbuf_new()) == NULL)
1.24 djm 121: fatal_f("sshbuf_new failed");
1.14 markus 122: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
123: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
1.24 djm 124: fatal_fr(r, "parse");
1.22 djm 125: if ((nkeys = pkcs11_add_provider(name, pin, &keys, &labels)) > 0) {
1.14 markus 126: if ((r = sshbuf_put_u8(msg,
127: SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
128: (r = sshbuf_put_u32(msg, nkeys)) != 0)
1.24 djm 129: fatal_fr(r, "compose");
1.1 markus 130: for (i = 0; i < nkeys; i++) {
1.14 markus 131: if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
1.24 djm 132: debug_fr(r, "encode key");
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)
1.24 djm 137: fatal_fr(r, "compose key");
1.6 djm 138: free(blob);
1.22 djm 139: add_key(keys[i], name, labels[i]);
140: free(labels[i]);
1.1 markus 141: }
1.24 djm 142: } else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0 ||
143: (r = sshbuf_put_u32(msg, -nkeys)) != 0)
144: fatal_fr(r, "compose");
1.22 djm 145: free(labels);
146: free(keys); /* keys themselves are transferred to pkcs11_keylist */
1.6 djm 147: free(pin);
148: free(name);
1.14 markus 149: send_msg(msg);
150: sshbuf_free(msg);
1.1 markus 151: }
152:
153: static void
154: process_del(void)
155: {
156: char *name, *pin;
1.14 markus 157: struct sshbuf *msg;
158: int r;
1.1 markus 159:
1.14 markus 160: if ((msg = sshbuf_new()) == NULL)
1.24 djm 161: fatal_f("sshbuf_new failed");
1.14 markus 162: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
163: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
1.24 djm 164: fatal_fr(r, "parse");
1.1 markus 165: del_keys_by_name(name);
1.14 markus 166: if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
167: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
1.24 djm 168: fatal_fr(r, "compose");
1.6 djm 169: free(pin);
170: free(name);
1.14 markus 171: send_msg(msg);
172: sshbuf_free(msg);
1.1 markus 173: }
174:
175: static void
176: process_sign(void)
177: {
178: u_char *blob, *data, *signature = NULL;
1.14 markus 179: size_t blen, dlen, slen = 0;
180: int r, ok = -1;
1.13 markus 181: struct sshkey *key, *found;
1.14 markus 182: struct sshbuf *msg;
1.1 markus 183:
1.14 markus 184: /* XXX support SHA2 signature flags */
185: if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
186: (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
187: (r = sshbuf_get_u32(iqueue, NULL)) != 0)
1.24 djm 188: fatal_fr(r, "parse");
1.14 markus 189:
190: if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
1.24 djm 191: fatal_fr(r, "decode key");
1.14 markus 192: else {
1.1 markus 193: if ((found = lookup_key(key)) != NULL) {
1.8 djm 194: #ifdef WITH_OPENSSL
195: int ret;
196:
1.15 djm 197: if (key->type == KEY_RSA) {
198: slen = RSA_size(key->rsa);
199: signature = xmalloc(slen);
200: ret = RSA_private_encrypt(dlen, data, signature,
201: found->rsa, RSA_PKCS1_PADDING);
202: if (ret != -1) {
203: slen = ret;
204: ok = 0;
205: }
206: } else if (key->type == KEY_ECDSA) {
1.18 dtucker 207: u_int xslen = ECDSA_size(key->ecdsa);
208:
1.15 djm 209: signature = xmalloc(xslen);
210: /* "The parameter type is ignored." */
211: ret = ECDSA_sign(-1, data, dlen, signature,
212: &xslen, found->ecdsa);
213: if (ret != 0)
214: ok = 0;
215: else
1.24 djm 216: error_f("ECDSA_sign returned %d", ret);
1.15 djm 217: slen = xslen;
218: } else
1.24 djm 219: error_f("don't know how to sign with key "
220: "type %d", (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)
1.24 djm 226: fatal_f("sshbuf_new failed");
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)
1.24 djm 230: fatal_fr(r, "compose response");
1.1 markus 231: } else {
1.14 markus 232: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
1.24 djm 233: fatal_fr(r, "compose failure response");
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)
1.24 djm 265: fatal_fr(r, "parse type/len");
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)
1.24 djm 296: fatal_fr(r, "consume");
1.14 markus 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: {
1.23 markus 311: int r, ch, in, out, 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:
1.14 markus 344: if ((iqueue = sshbuf_new()) == NULL)
1.24 djm 345: fatal_f("sshbuf_new failed");
1.14 markus 346: if ((oqueue = sshbuf_new()) == NULL)
1.24 djm 347: fatal_f("sshbuf_new failed");
1.1 markus 348:
1.17 djm 349: while (1) {
350: memset(pfd, 0, sizeof(pfd));
351: pfd[0].fd = in;
352: pfd[1].fd = out;
1.1 markus 353:
354: /*
355: * Ensure that we can read a full buffer and handle
356: * the worst-case length packet it can generate,
357: * otherwise apply backpressure by stopping reads.
358: */
1.14 markus 359: if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
360: (r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.17 djm 361: pfd[0].events = POLLIN;
1.14 markus 362: else if (r != SSH_ERR_NO_BUFFER_SPACE)
1.24 djm 363: fatal_fr(r, "reserve");
1.1 markus 364:
1.17 djm 365: if (sshbuf_len(oqueue) > 0)
366: pfd[1].events = POLLOUT;
1.1 markus 367:
1.17 djm 368: if ((r = poll(pfd, 2, -1 /* INFTIM */)) <= 0) {
369: if (r == 0 || errno == EINTR)
1.1 markus 370: continue;
1.17 djm 371: fatal("poll: %s", strerror(errno));
1.1 markus 372: }
373:
374: /* copy stdin to iqueue */
1.26 ! djm 375: if ((pfd[0].revents & (POLLIN|POLLHUP|POLLERR)) != 0) {
1.1 markus 376: len = read(in, buf, sizeof buf);
377: if (len == 0) {
378: debug("read eof");
379: cleanup_exit(0);
380: } else if (len < 0) {
381: error("read: %s", strerror(errno));
382: cleanup_exit(1);
1.24 djm 383: } else if ((r = sshbuf_put(iqueue, buf, len)) != 0)
384: fatal_fr(r, "sshbuf_put");
1.1 markus 385: }
386: /* send oqueue to stdout */
1.17 djm 387: if ((pfd[1].revents & (POLLOUT|POLLHUP)) != 0) {
388: len = write(out, sshbuf_ptr(oqueue),
389: sshbuf_len(oqueue));
1.1 markus 390: if (len < 0) {
391: error("write: %s", strerror(errno));
392: cleanup_exit(1);
1.24 djm 393: } else if ((r = sshbuf_consume(oqueue, len)) != 0)
394: fatal_fr(r, "consume");
1.1 markus 395: }
396:
397: /*
398: * Process requests from client if we can fit the results
399: * into the output buffer, otherwise stop processing input
400: * and let the output queue drain.
401: */
1.14 markus 402: if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.1 markus 403: process();
1.14 markus 404: else if (r != SSH_ERR_NO_BUFFER_SPACE)
1.24 djm 405: fatal_fr(r, "reserve");
1.1 markus 406: }
407: }
1.21 djm 408:
409: #else /* WITH_OPENSSL */
410: void
411: cleanup_exit(int i)
412: {
413: _exit(i);
414: }
415:
416: int
417: main(int argc, char **argv)
418: {
419: fprintf(stderr, "PKCS#11 code is not enabled\n");
420: return 1;
421: }
422: #endif /* WITH_OPENSSL */
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