Annotation of src/usr.bin/ssh/ssh-pkcs11-helper.c, Revision 1.16
1.16 ! djm 1: /* $OpenBSD: ssh-pkcs11-helper.c,v 1.15 2019/01/20 22:51:37 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:
22: #include <stdarg.h>
23: #include <string.h>
24: #include <unistd.h>
25: #include <errno.h>
26:
27: #include "xmalloc.h"
1.14 markus 28: #include "sshbuf.h"
1.1 markus 29: #include "log.h"
30: #include "misc.h"
1.14 markus 31: #include "sshkey.h"
1.1 markus 32: #include "authfd.h"
33: #include "ssh-pkcs11.h"
1.14 markus 34: #include "ssherr.h"
1.1 markus 35:
36: /* borrows code from sftp-server and ssh-agent */
37:
38: struct pkcs11_keyinfo {
1.13 markus 39: struct sshkey *key;
1.1 markus 40: char *providername;
41: TAILQ_ENTRY(pkcs11_keyinfo) next;
42: };
43:
44: TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
45:
46: #define MAX_MSG_LENGTH 10240 /*XXX*/
47:
48: /* input and output queue */
1.14 markus 49: struct sshbuf *iqueue;
50: struct sshbuf *oqueue;
1.1 markus 51:
52: static void
1.13 markus 53: add_key(struct sshkey *k, char *name)
1.1 markus 54: {
55: struct pkcs11_keyinfo *ki;
56:
57: ki = xcalloc(1, sizeof(*ki));
58: ki->providername = xstrdup(name);
59: ki->key = k;
60: TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
61: }
62:
63: static void
64: del_keys_by_name(char *name)
65: {
66: struct pkcs11_keyinfo *ki, *nxt;
67:
68: for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
69: nxt = TAILQ_NEXT(ki, next);
70: if (!strcmp(ki->providername, name)) {
71: TAILQ_REMOVE(&pkcs11_keylist, ki, next);
1.6 djm 72: free(ki->providername);
1.14 markus 73: sshkey_free(ki->key);
1.1 markus 74: free(ki);
75: }
76: }
77: }
78:
79: /* lookup matching 'private' key */
1.13 markus 80: static struct sshkey *
81: lookup_key(struct sshkey *k)
1.1 markus 82: {
83: struct pkcs11_keyinfo *ki;
84:
85: TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
86: debug("check %p %s", ki, ki->providername);
1.14 markus 87: if (sshkey_equal(k, ki->key))
1.1 markus 88: return (ki->key);
89: }
90: return (NULL);
91: }
92:
93: static void
1.14 markus 94: send_msg(struct sshbuf *m)
1.1 markus 95: {
1.14 markus 96: int r;
1.1 markus 97:
1.14 markus 98: if ((r = sshbuf_put_stringb(oqueue, m)) != 0)
99: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 100: }
101:
102: static void
103: process_add(void)
104: {
105: char *name, *pin;
1.15 djm 106: struct sshkey **keys = NULL;
1.14 markus 107: int r, i, nkeys;
1.1 markus 108: u_char *blob;
1.14 markus 109: size_t blen;
110: struct sshbuf *msg;
1.1 markus 111:
1.14 markus 112: if ((msg = sshbuf_new()) == NULL)
113: fatal("%s: sshbuf_new failed", __func__);
114: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
115: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
116: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 117: if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
1.14 markus 118: if ((r = sshbuf_put_u8(msg,
119: SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
120: (r = sshbuf_put_u32(msg, nkeys)) != 0)
121: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 122: for (i = 0; i < nkeys; i++) {
1.14 markus 123: if ((r = sshkey_to_blob(keys[i], &blob, &blen)) != 0) {
124: debug("%s: sshkey_to_blob: %s",
125: __func__, ssh_err(r));
1.7 djm 126: continue;
1.14 markus 127: }
128: if ((r = sshbuf_put_string(msg, blob, blen)) != 0 ||
129: (r = sshbuf_put_cstring(msg, name)) != 0)
130: fatal("%s: buffer error: %s",
131: __func__, ssh_err(r));
1.6 djm 132: free(blob);
1.1 markus 133: add_key(keys[i], name);
134: }
135: } else {
1.14 markus 136: if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
137: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.15 djm 138: if ((r = sshbuf_put_u32(msg, -nkeys)) != 0)
139: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 140: }
1.15 djm 141: free(keys);
1.6 djm 142: free(pin);
143: free(name);
1.14 markus 144: send_msg(msg);
145: sshbuf_free(msg);
1.1 markus 146: }
147:
148: static void
149: process_del(void)
150: {
151: char *name, *pin;
1.14 markus 152: struct sshbuf *msg;
153: int r;
1.1 markus 154:
1.14 markus 155: if ((msg = sshbuf_new()) == NULL)
156: fatal("%s: sshbuf_new failed", __func__);
157: if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
158: (r = sshbuf_get_cstring(iqueue, &pin, NULL)) != 0)
159: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 160: del_keys_by_name(name);
1.14 markus 161: if ((r = sshbuf_put_u8(msg, pkcs11_del_provider(name) == 0 ?
162: SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
163: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.6 djm 164: free(pin);
165: free(name);
1.14 markus 166: send_msg(msg);
167: sshbuf_free(msg);
1.1 markus 168: }
169:
170: static void
171: process_sign(void)
172: {
173: u_char *blob, *data, *signature = NULL;
1.14 markus 174: size_t blen, dlen, slen = 0;
175: int r, ok = -1;
1.13 markus 176: struct sshkey *key, *found;
1.14 markus 177: struct sshbuf *msg;
1.1 markus 178:
1.14 markus 179: /* XXX support SHA2 signature flags */
180: if ((r = sshbuf_get_string(iqueue, &blob, &blen)) != 0 ||
181: (r = sshbuf_get_string(iqueue, &data, &dlen)) != 0 ||
182: (r = sshbuf_get_u32(iqueue, NULL)) != 0)
183: fatal("%s: buffer error: %s", __func__, ssh_err(r));
184:
185: if ((r = sshkey_from_blob(blob, blen, &key)) != 0)
186: error("%s: sshkey_from_blob: %s", __func__, ssh_err(r));
187: else {
1.1 markus 188: if ((found = lookup_key(key)) != NULL) {
1.8 djm 189: #ifdef WITH_OPENSSL
1.15 djm 190: u_int xslen;
1.8 djm 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) {
203: xslen = ECDSA_size(key->ecdsa);
204: signature = xmalloc(xslen);
205: /* "The parameter type is ignored." */
206: ret = ECDSA_sign(-1, data, dlen, signature,
207: &xslen, found->ecdsa);
208: if (ret != 0)
209: ok = 0;
210: else
211: error("%s: ECDSA_sign"
212: " returns %d", __func__, ret);
213: slen = xslen;
214: } else
215: error("%s: don't know how to sign with key "
216: "type %d", __func__, (int)key->type);
1.8 djm 217: #endif /* WITH_OPENSSL */
1.1 markus 218: }
1.14 markus 219: sshkey_free(key);
1.1 markus 220: }
1.14 markus 221: if ((msg = sshbuf_new()) == NULL)
222: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 223: if (ok == 0) {
1.14 markus 224: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
225: (r = sshbuf_put_string(msg, signature, slen)) != 0)
226: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 227: } else {
1.14 markus 228: if ((r = sshbuf_put_u8(msg, SSH2_AGENT_FAILURE)) != 0)
229: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 230: }
1.6 djm 231: free(data);
232: free(blob);
233: free(signature);
1.14 markus 234: send_msg(msg);
235: sshbuf_free(msg);
1.1 markus 236: }
237:
238: static void
239: process(void)
240: {
241: u_int msg_len;
242: u_int buf_len;
243: u_int consumed;
1.14 markus 244: u_char type;
245: const u_char *cp;
246: int r;
1.1 markus 247:
1.14 markus 248: buf_len = sshbuf_len(iqueue);
1.1 markus 249: if (buf_len < 5)
250: return; /* Incomplete message. */
1.14 markus 251: cp = sshbuf_ptr(iqueue);
1.1 markus 252: msg_len = get_u32(cp);
253: if (msg_len > MAX_MSG_LENGTH) {
254: error("bad message len %d", msg_len);
255: cleanup_exit(11);
256: }
257: if (buf_len < msg_len + 4)
258: return;
1.14 markus 259: if ((r = sshbuf_consume(iqueue, 4)) != 0 ||
260: (r = sshbuf_get_u8(iqueue, &type)) != 0)
261: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 262: buf_len -= 4;
263: switch (type) {
264: case SSH_AGENTC_ADD_SMARTCARD_KEY:
265: debug("process_add");
266: process_add();
267: break;
268: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
269: debug("process_del");
270: process_del();
271: break;
272: case SSH2_AGENTC_SIGN_REQUEST:
273: debug("process_sign");
274: process_sign();
275: break;
276: default:
277: error("Unknown message %d", type);
278: break;
279: }
280: /* discard the remaining bytes from the current packet */
1.14 markus 281: if (buf_len < sshbuf_len(iqueue)) {
1.1 markus 282: error("iqueue grew unexpectedly");
283: cleanup_exit(255);
284: }
1.14 markus 285: consumed = buf_len - sshbuf_len(iqueue);
1.1 markus 286: if (msg_len < consumed) {
287: error("msg_len %d < consumed %d", msg_len, consumed);
288: cleanup_exit(255);
289: }
1.14 markus 290: if (msg_len > consumed) {
291: if ((r = sshbuf_consume(iqueue, msg_len - consumed)) != 0)
292: fatal("%s: buffer error: %s", __func__, ssh_err(r));
293: }
1.1 markus 294: }
295:
296: void
297: cleanup_exit(int i)
298: {
299: /* XXX */
300: _exit(i);
301: }
302:
1.16 ! djm 303:
1.1 markus 304: int
305: main(int argc, char **argv)
306: {
307: fd_set *rset, *wset;
1.16 ! djm 308: int r, ch, in, out, max, log_stderr = 0;
1.1 markus 309: ssize_t len, olen, set_size;
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;
1.1 markus 314:
1.12 dtucker 315: ssh_malloc_init(); /* must be called before any mallocs */
1.1 markus 316: TAILQ_INIT(&pkcs11_keylist);
317:
318: log_init(__progname, log_level, log_facility, log_stderr);
319:
1.16 ! djm 320: while ((ch = getopt(argc, argv, "v")) != -1) {
! 321: switch (ch) {
! 322: case 'v':
! 323: log_stderr = 1;
! 324: if (log_level == SYSLOG_LEVEL_ERROR)
! 325: log_level = SYSLOG_LEVEL_DEBUG1;
! 326: else if (log_level < SYSLOG_LEVEL_DEBUG3)
! 327: log_level++;
! 328: break;
! 329: default:
! 330: fprintf(stderr, "usage: %s [-v]\n", __progname);
! 331: exit(1);
! 332: }
! 333: }
! 334:
! 335: log_init(__progname, log_level, log_facility, log_stderr);
! 336:
! 337: pkcs11_init(0);
1.1 markus 338: in = STDIN_FILENO;
339: out = STDOUT_FILENO;
340:
341: max = 0;
342: if (in > max)
343: max = in;
344: if (out > max)
345: max = out;
346:
1.14 markus 347: if ((iqueue = sshbuf_new()) == NULL)
348: fatal("%s: sshbuf_new failed", __func__);
349: if ((oqueue = sshbuf_new()) == NULL)
350: fatal("%s: sshbuf_new failed", __func__);
1.1 markus 351:
352: set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
1.11 deraadt 353: rset = xmalloc(set_size);
354: wset = xmalloc(set_size);
1.1 markus 355:
356: for (;;) {
357: memset(rset, 0, set_size);
358: memset(wset, 0, set_size);
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)
1.1 markus 367: FD_SET(in, rset);
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:
1.14 markus 371: olen = sshbuf_len(oqueue);
1.1 markus 372: if (olen > 0)
373: FD_SET(out, wset);
374:
375: if (select(max+1, rset, wset, NULL, NULL) < 0) {
376: if (errno == EINTR)
377: continue;
378: error("select: %s", strerror(errno));
379: cleanup_exit(2);
380: }
381:
382: /* copy stdin to iqueue */
383: if (FD_ISSET(in, rset)) {
384: len = read(in, buf, sizeof buf);
385: if (len == 0) {
386: debug("read eof");
387: cleanup_exit(0);
388: } else if (len < 0) {
389: error("read: %s", strerror(errno));
390: cleanup_exit(1);
1.14 markus 391: } else if ((r = sshbuf_put(iqueue, buf, len)) != 0) {
392: fatal("%s: buffer error: %s",
393: __func__, ssh_err(r));
1.1 markus 394: }
395: }
396: /* send oqueue to stdout */
397: if (FD_ISSET(out, wset)) {
1.14 markus 398: len = write(out, sshbuf_ptr(oqueue), olen);
1.1 markus 399: if (len < 0) {
400: error("write: %s", strerror(errno));
401: cleanup_exit(1);
1.14 markus 402: } else if ((r = sshbuf_consume(oqueue, len)) != 0) {
403: fatal("%s: buffer error: %s",
404: __func__, ssh_err(r));
1.1 markus 405: }
406: }
407:
408: /*
409: * Process requests from client if we can fit the results
410: * into the output buffer, otherwise stop processing input
411: * and let the output queue drain.
412: */
1.14 markus 413: if ((r = sshbuf_check_reserve(oqueue, MAX_MSG_LENGTH)) == 0)
1.1 markus 414: process();
1.14 markus 415: else if (r != SSH_ERR_NO_BUFFER_SPACE)
416: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 417: }
418: }
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