Annotation of src/usr.bin/ssh/ssh-pkcs11-helper.c, Revision 1.18
1.18 ! dtucker 1: /* $OpenBSD: ssh-pkcs11-helper.c,v 1.17 2019/01/23 02:01:10 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:
1.17 djm 22: #include <errno.h>
23: #include <poll.h>
1.1 markus 24: #include <stdarg.h>
25: #include <string.h>
26: #include <unistd.h>
27:
28: #include "xmalloc.h"
1.14 markus 29: #include "sshbuf.h"
1.1 markus 30: #include "log.h"
31: #include "misc.h"
1.14 markus 32: #include "sshkey.h"
1.1 markus 33: #include "authfd.h"
34: #include "ssh-pkcs11.h"
1.14 markus 35: #include "ssherr.h"
1.1 markus 36:
37: /* borrows code from sftp-server and ssh-agent */
38:
39: struct pkcs11_keyinfo {
1.13 markus 40: struct sshkey *key;
1.1 markus 41: char *providername;
42: TAILQ_ENTRY(pkcs11_keyinfo) next;
43: };
44:
45: TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
46:
47: #define MAX_MSG_LENGTH 10240 /*XXX*/
48:
49: /* input and output queue */
1.14 markus 50: struct sshbuf *iqueue;
51: struct sshbuf *oqueue;
1.1 markus 52:
53: static void
1.13 markus 54: add_key(struct sshkey *k, char *name)
1.1 markus 55: {
56: struct pkcs11_keyinfo *ki;
57:
58: ki = xcalloc(1, sizeof(*ki));
59: ki->providername = xstrdup(name);
60: ki->key = k;
61: TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
62: }
63:
64: static void
65: del_keys_by_name(char *name)
66: {
67: struct pkcs11_keyinfo *ki, *nxt;
68:
69: for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
70: nxt = TAILQ_NEXT(ki, next);
71: if (!strcmp(ki->providername, name)) {
72: TAILQ_REMOVE(&pkcs11_keylist, ki, next);
1.6 djm 73: free(ki->providername);
1.14 markus 74: sshkey_free(ki->key);
1.1 markus 75: free(ki);
76: }
77: }
78: }
79:
80: /* lookup matching 'private' key */
1.13 markus 81: static struct sshkey *
82: lookup_key(struct sshkey *k)
1.1 markus 83: {
84: struct pkcs11_keyinfo *ki;
85:
86: TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
87: debug("check %p %s", ki, ki->providername);
1.14 markus 88: if (sshkey_equal(k, ki->key))
1.1 markus 89: return (ki->key);
90: }
91: return (NULL);
92: }
93:
94: static void
1.14 markus 95: send_msg(struct sshbuf *m)
1.1 markus 96: {
1.14 markus 97: int r;
1.1 markus 98:
1.14 markus 99: if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
100: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 101: }
102:
103: static void
104: process_add(void)
105: {
106: char *name, *pin;
1.15 djm 107: struct sshkey **keys = NULL;
1.14 markus 108: int r, i, nkeys;
1.1 markus 109: u_char *blob;
1.14 markus 110: size_t blen;
111: struct sshbuf *msg;
1.1 markus 112:
1.14 markus 113: if ((msg = sshbuf_new()) == NULL)
114: fatal("%s: sshbuf_new failed", __func__);
115: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
116: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
117: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 118: if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
1.14 markus 119: if ((r = sshbuf_put_u8(msg,
120: SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
121: (r = sshbuf_put_u32(msg, nkeys)) != 0)
122: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 123: for (i = 0; i < nkeys; i++) {
1.14 markus 124: if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
125: debug("%s: sshkey_to_blob: %s",
126: __func__, ssh_err(r));
1.7 djm 127: continue;
1.14 markus 128: }
129: if ((r = sshbuf_put_string(msg, blob, blen)) != 0 ||
130: (r = sshbuf_put_cstring(msg, name)) != 0)
131: fatal("%s: buffer error: %s",
132: __func__, ssh_err(r));
1.6 djm 133: free(blob);
1.1 markus 134: add_key(keys[i], name);
135: }
136: } else {
1.14 markus 137: if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
138: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.15 djm 139: if ((r = sshbuf_put_u32(msg, -nkeys)) != 0)
140: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 141: }
1.15 djm 142: free(keys);
1.6 djm 143: free(pin);
144: free(name);
1.14 markus 145: send_msg(msg);
146: sshbuf_free(msg);
1.1 markus 147: }
148:
149: static void
150: process_del(void)
151: {
152: char *name, *pin;
1.14 markus 153: struct sshbuf *msg;
154: int r;
1.1 markus 155:
1.14 markus 156: if ((msg = sshbuf_new()) == NULL)
157: fatal("%s: sshbuf_new failed", __func__);
158: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
159: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
160: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 161: del_keys_by_name(name);
1.14 markus 162: if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
163: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
164: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.6 djm 165: free(pin);
166: free(name);
1.14 markus 167: send_msg(msg);
168: sshbuf_free(msg);
1.1 markus 169: }
170:
171: static void
172: process_sign(void)
173: {
174: u_char *blob, *data, *signature = NULL;
1.14 markus 175: size_t blen, dlen, slen = 0;
176: int r, ok = -1;
1.13 markus 177: struct sshkey *key, *found;
1.14 markus 178: struct sshbuf *msg;
1.1 markus 179:
1.14 markus 180: /* XXX support SHA2 signature flags */
181: if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
182: (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
183: (r = sshbuf_get_u32(iqueue, NULL)) != 0)
184: fatal("%s: buffer error: %s", __func__, ssh_err(r));
185:
186: if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
187: error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
188: else {
1.1 markus 189: if ((found = lookup_key(key)) != NULL) {
1.8 djm 190: #ifdef WITH_OPENSSL
191: int ret;
192:
1.15 djm 193: if (key->type == KEY_RSA) {
194: slen = RSA_size(key->rsa);
195: signature = xmalloc(slen);
196: ret = RSA_private_encrypt(dlen, data, signature,
197: found->rsa, RSA_PKCS1_PADDING);
198: if (ret != -1) {
199: slen = ret;
200: ok = 0;
201: }
202: } else if (key->type == KEY_ECDSA) {
1.18 ! dtucker 203: u_int xslen = ECDSA_size(key->ecdsa);
! 204:
1.15 djm 205: signature = xmalloc(xslen);
206: /* "The parameter type is ignored." */
207: ret = ECDSA_sign(-1, data, dlen, signature,
208: &xslen, found->ecdsa);
209: if (ret != 0)
210: ok = 0;
211: else
212: error("%s: ECDSA_sign"
213: " returns %d", __func__, ret);
214: slen = xslen;
215: } else
216: error("%s: don't know how to sign with key "
217: "type %d", __func__, (int)key->type);
1.8 djm 218: #endif /* WITH_OPENSSL */
1.1 markus 219: }
1.14 markus 220: sshkey_free(key);
1.1 markus 221: }
1.14 markus 222: if ((msg = sshbuf_new()) == NULL)
223: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 224: if (ok == 0) {
1.14 markus 225: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
226: (r = sshbuf_put_string(msg, signature, slen)) != 0)
227: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 228: } else {
1.14 markus 229: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
230: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 231: }
1.6 djm 232: free(data);
233: free(blob);
234: free(signature);
1.14 markus 235: send_msg(msg);
236: sshbuf_free(msg);
1.1 markus 237: }
238:
239: static void
240: process(void)
241: {
242: u_int msg_len;
243: u_int buf_len;
244: u_int consumed;
1.14 markus 245: u_char type;
246: const u_char *cp;
247: int r;
1.1 markus 248:
1.14 markus 249: buf_len = sshbuf_len(iqueue);
1.1 markus 250: if (buf_len < 5)
251: return; /* Incomplete message. */
1.14 markus 252: cp = sshbuf_ptr(iqueue);
1.1 markus 253: msg_len = get_u32(cp);
254: if (msg_len > MAX_MSG_LENGTH) {
255: error("bad message len %d", msg_len);
256: cleanup_exit(11);
257: }
258: if (buf_len < msg_len + 4)
259: return;
1.14 markus 260: if ((r = sshbuf_consume(iqueue, 4)) != 0 ||
261: (r = sshbuf_get_u8(iqueue, &type)) != 0)
262: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 263: buf_len -= 4;
264: switch (type) {
265: case SSH_AGENTC_ADD_SMARTCARD_KEY:
266: debug("process_add");
267: process_add();
268: break;
269: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
270: debug("process_del");
271: process_del();
272: break;
273: case SSH2_AGENTC_SIGN_REQUEST:
274: debug("process_sign");
275: process_sign();
276: break;
277: default:
278: error("Unknown message %d", type);
279: break;
280: }
281: /* discard the remaining bytes from the current packet */
1.14 markus 282: if (buf_len < sshbuf_len(iqueue)) {
1.1 markus 283: error("iqueue grew unexpectedly");
284: cleanup_exit(255);
285: }
1.14 markus 286: consumed = buf_len - sshbuf_len(iqueue);
1.1 markus 287: if (msg_len < consumed) {
288: error("msg_len %d < consumed %d", msg_len, consumed);
289: cleanup_exit(255);
290: }
1.14 markus 291: if (msg_len > consumed) {
292: if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
293: fatal("%s: buffer error: %s", __func__, ssh_err(r));
294: }
1.1 markus 295: }
296:
297: void
298: cleanup_exit(int i)
299: {
300: /* XXX */
301: _exit(i);
302: }
303:
1.16 djm 304:
1.1 markus 305: int
306: main(int argc, char **argv)
307: {
1.16 djm 308: int r, ch, in, out, max, log_stderr = 0;
1.17 djm 309: ssize_t len;
1.1 markus 310: SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
311: LogLevel log_level = SYSLOG_LEVEL_ERROR;
312: char buf[4*4096];
1.2 deraadt 313: extern char *__progname;
1.17 djm 314: struct pollfd pfd[2];
1.1 markus 315:
1.12 dtucker 316: ssh_malloc_init(); /* must be called before any mallocs */
1.1 markus 317: TAILQ_INIT(&pkcs11_keylist);
318:
319: log_init(__progname, log_level, log_facility, log_stderr);
320:
1.16 djm 321: while ((ch = getopt(argc, argv, "v")) != -1) {
322: switch (ch) {
323: case 'v':
324: log_stderr = 1;
325: if (log_level == SYSLOG_LEVEL_ERROR)
326: log_level = SYSLOG_LEVEL_DEBUG1;
327: else if (log_level < SYSLOG_LEVEL_DEBUG3)
328: log_level++;
329: break;
330: default:
331: fprintf(stderr, "usage: %s [-v]\n", __progname);
332: exit(1);
333: }
334: }
335:
336: log_init(__progname, log_level, log_facility, log_stderr);
337:
338: pkcs11_init(0);
1.1 markus 339: in = STDIN_FILENO;
340: out = STDOUT_FILENO;
341:
342: max = 0;
343: if (in > max)
344: max = in;
345: if (out > max)
346: max = out;
347:
1.14 markus 348: if ((iqueue = sshbuf_new()) == NULL)
349: fatal("%s: sshbuf_new failed", __func__);
350: if ((oqueue = sshbuf_new()) == NULL)
351: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 352:
1.17 djm 353: while (1) {
354: memset(pfd, 0, sizeof(pfd));
355: pfd[0].fd = in;
356: pfd[1].fd = out;
1.1 markus 357:
358: /*
359: * Ensure that we can read a full buffer and handle
360: * the worst-case length packet it can generate,
361: * otherwise apply backpressure by stopping reads.
362: */
1.14 markus 363: if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
364: (r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.17 djm 365: pfd[0].events = POLLIN;
1.14 markus 366: else if (r != SSH_ERR_NO_BUFFER_SPACE)
367: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 368:
1.17 djm 369: if (sshbuf_len(oqueue) > 0)
370: pfd[1].events = POLLOUT;
1.1 markus 371:
1.17 djm 372: if ((r = poll(pfd, 2, -1 /* INFTIM */)) <= 0) {
373: if (r == 0 || errno == EINTR)
1.1 markus 374: continue;
1.17 djm 375: fatal("poll: %s", strerror(errno));
1.1 markus 376: }
377:
378: /* copy stdin to iqueue */
1.17 djm 379: if ((pfd[0].revents & (POLLIN|POLLERR)) != 0) {
1.1 markus 380: len = read(in, buf, sizeof buf);
381: if (len == 0) {
382: debug("read eof");
383: cleanup_exit(0);
384: } else if (len < 0) {
385: error("read: %s", strerror(errno));
386: cleanup_exit(1);
1.14 markus 387: } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
388: fatal("%s: buffer error: %s",
389: __func__, ssh_err(r));
1.1 markus 390: }
391: }
392: /* send oqueue to stdout */
1.17 djm 393: if ((pfd[1].revents & (POLLOUT|POLLHUP)) != 0) {
394: len = write(out, sshbuf_ptr(oqueue),
395: sshbuf_len(oqueue));
1.1 markus 396: if (len < 0) {
397: error("write: %s", strerror(errno));
398: cleanup_exit(1);
1.14 markus 399: } else if ((r = sshbuf_consume(oqueue, len)) != 0) {
400: fatal("%s: buffer error: %s",
401: __func__, ssh_err(r));
1.1 markus 402: }
403: }
404:
405: /*
406: * Process requests from client if we can fit the results
407: * into the output buffer, otherwise stop processing input
408: * and let the output queue drain.
409: */
1.14 markus 410: if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.1 markus 411: process();
1.14 markus 412: else if (r != SSH_ERR_NO_BUFFER_SPACE)
413: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 414: }
415: }
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