Annotation of src/usr.bin/ssh/ssh-pkcs11-helper.c, Revision 1.8
1.8 ! djm 1: /* $OpenBSD: ssh-pkcs11-helper.c,v 1.7 2013/12/02 02:56:17 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:
18: #include <sys/queue.h>
19: #include <sys/types.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"
28: #include "buffer.h"
29: #include "log.h"
30: #include "misc.h"
31: #include "key.h"
32: #include "authfd.h"
33: #include "ssh-pkcs11.h"
34:
35: /* borrows code from sftp-server and ssh-agent */
36:
37: struct pkcs11_keyinfo {
38: Key *key;
39: char *providername;
40: TAILQ_ENTRY(pkcs11_keyinfo) next;
41: };
42:
43: TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
44:
45: #define MAX_MSG_LENGTH 10240 /*XXX*/
46:
47: /* helper */
48: #define get_int() buffer_get_int(&iqueue);
49: #define get_string(lenp) buffer_get_string(&iqueue, lenp);
50:
51: /* input and output queue */
52: Buffer iqueue;
53: Buffer oqueue;
54:
55: static void
56: add_key(Key *k, char *name)
57: {
58: struct pkcs11_keyinfo *ki;
59:
60: ki = xcalloc(1, sizeof(*ki));
61: ki->providername = xstrdup(name);
62: ki->key = k;
63: TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
64: }
65:
66: static void
67: del_keys_by_name(char *name)
68: {
69: struct pkcs11_keyinfo *ki, *nxt;
70:
71: for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
72: nxt = TAILQ_NEXT(ki, next);
73: if (!strcmp(ki->providername, name)) {
74: TAILQ_REMOVE(&pkcs11_keylist, ki, next);
1.6 djm 75: free(ki->providername);
1.1 markus 76: key_free(ki->key);
77: free(ki);
78: }
79: }
80: }
81:
82: /* lookup matching 'private' key */
83: static Key *
84: lookup_key(Key *k)
85: {
86: struct pkcs11_keyinfo *ki;
87:
88: TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
89: debug("check %p %s", ki, ki->providername);
90: if (key_equal(k, ki->key))
91: return (ki->key);
92: }
93: return (NULL);
94: }
95:
96: static void
97: send_msg(Buffer *m)
98: {
99: int mlen = buffer_len(m);
100:
101: buffer_put_int(&oqueue, mlen);
102: buffer_append(&oqueue, buffer_ptr(m), mlen);
103: buffer_consume(m, mlen);
104: }
105:
106: static void
107: process_add(void)
108: {
109: char *name, *pin;
110: Key **keys;
111: int i, nkeys;
112: u_char *blob;
113: u_int blen;
114: Buffer msg;
115:
116: buffer_init(&msg);
117: name = get_string(NULL);
118: pin = get_string(NULL);
119: if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
120: buffer_put_char(&msg, SSH2_AGENT_IDENTITIES_ANSWER);
121: buffer_put_int(&msg, nkeys);
122: for (i = 0; i < nkeys; i++) {
1.7 djm 123: if (key_to_blob(keys[i], &blob, &blen) == 0)
124: continue;
1.1 markus 125: buffer_put_string(&msg, blob, blen);
126: buffer_put_cstring(&msg, name);
1.6 djm 127: free(blob);
1.1 markus 128: add_key(keys[i], name);
129: }
1.6 djm 130: free(keys);
1.1 markus 131: } else {
132: buffer_put_char(&msg, SSH_AGENT_FAILURE);
133: }
1.6 djm 134: free(pin);
135: free(name);
1.1 markus 136: send_msg(&msg);
137: buffer_free(&msg);
138: }
139:
140: static void
141: process_del(void)
142: {
143: char *name, *pin;
144: Buffer msg;
145:
146: buffer_init(&msg);
147: name = get_string(NULL);
148: pin = get_string(NULL);
149: del_keys_by_name(name);
150: if (pkcs11_del_provider(name) == 0)
151: buffer_put_char(&msg, SSH_AGENT_SUCCESS);
152: else
153: buffer_put_char(&msg, SSH_AGENT_FAILURE);
1.6 djm 154: free(pin);
155: free(name);
1.1 markus 156: send_msg(&msg);
157: buffer_free(&msg);
158: }
159:
160: static void
161: process_sign(void)
162: {
163: u_char *blob, *data, *signature = NULL;
164: u_int blen, dlen, slen = 0;
1.8 ! djm 165: int ok = -1;
1.1 markus 166: Key *key, *found;
167: Buffer msg;
168:
169: blob = get_string(&blen);
170: data = get_string(&dlen);
1.4 dtucker 171: (void)get_int(); /* XXX ignore flags */
1.1 markus 172:
173: if ((key = key_from_blob(blob, blen)) != NULL) {
174: if ((found = lookup_key(key)) != NULL) {
1.8 ! djm 175: #ifdef WITH_OPENSSL
! 176: int ret;
! 177:
1.1 markus 178: slen = RSA_size(key->rsa);
179: signature = xmalloc(slen);
180: if ((ret = RSA_private_encrypt(dlen, data, signature,
181: found->rsa, RSA_PKCS1_PADDING)) != -1) {
182: slen = ret;
183: ok = 0;
184: }
1.8 ! djm 185: #endif /* WITH_OPENSSL */
1.1 markus 186: }
187: key_free(key);
188: }
189: buffer_init(&msg);
190: if (ok == 0) {
191: buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
192: buffer_put_string(&msg, signature, slen);
193: } else {
194: buffer_put_char(&msg, SSH_AGENT_FAILURE);
195: }
1.6 djm 196: free(data);
197: free(blob);
198: free(signature);
1.1 markus 199: send_msg(&msg);
200: buffer_free(&msg);
201: }
202:
203: static void
204: process(void)
205: {
206: u_int msg_len;
207: u_int buf_len;
208: u_int consumed;
209: u_int type;
210: u_char *cp;
211:
212: buf_len = buffer_len(&iqueue);
213: if (buf_len < 5)
214: return; /* Incomplete message. */
215: cp = buffer_ptr(&iqueue);
216: msg_len = get_u32(cp);
217: if (msg_len > MAX_MSG_LENGTH) {
218: error("bad message len %d", msg_len);
219: cleanup_exit(11);
220: }
221: if (buf_len < msg_len + 4)
222: return;
223: buffer_consume(&iqueue, 4);
224: buf_len -= 4;
225: type = buffer_get_char(&iqueue);
226: switch (type) {
227: case SSH_AGENTC_ADD_SMARTCARD_KEY:
228: debug("process_add");
229: process_add();
230: break;
231: case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
232: debug("process_del");
233: process_del();
234: break;
235: case SSH2_AGENTC_SIGN_REQUEST:
236: debug("process_sign");
237: process_sign();
238: break;
239: default:
240: error("Unknown message %d", type);
241: break;
242: }
243: /* discard the remaining bytes from the current packet */
244: if (buf_len < buffer_len(&iqueue)) {
245: error("iqueue grew unexpectedly");
246: cleanup_exit(255);
247: }
248: consumed = buf_len - buffer_len(&iqueue);
249: if (msg_len < consumed) {
250: error("msg_len %d < consumed %d", msg_len, consumed);
251: cleanup_exit(255);
252: }
253: if (msg_len > consumed)
254: buffer_consume(&iqueue, msg_len - consumed);
255: }
256:
257: void
258: cleanup_exit(int i)
259: {
260: /* XXX */
261: _exit(i);
262: }
263:
264: int
265: main(int argc, char **argv)
266: {
267: fd_set *rset, *wset;
268: int in, out, max, log_stderr = 0;
269: ssize_t len, olen, set_size;
270: SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
271: LogLevel log_level = SYSLOG_LEVEL_ERROR;
272: char buf[4*4096];
1.2 deraadt 273: extern char *__progname;
1.1 markus 274:
275: TAILQ_INIT(&pkcs11_keylist);
276: pkcs11_init(0);
277:
278: log_init(__progname, log_level, log_facility, log_stderr);
279:
280: in = STDIN_FILENO;
281: out = STDOUT_FILENO;
282:
283: max = 0;
284: if (in > max)
285: max = in;
286: if (out > max)
287: max = out;
288:
289: buffer_init(&iqueue);
290: buffer_init(&oqueue);
291:
292: set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
293: rset = (fd_set *)xmalloc(set_size);
294: wset = (fd_set *)xmalloc(set_size);
295:
296: for (;;) {
297: memset(rset, 0, set_size);
298: memset(wset, 0, set_size);
299:
300: /*
301: * Ensure that we can read a full buffer and handle
302: * the worst-case length packet it can generate,
303: * otherwise apply backpressure by stopping reads.
304: */
305: if (buffer_check_alloc(&iqueue, sizeof(buf)) &&
306: buffer_check_alloc(&oqueue, MAX_MSG_LENGTH))
307: FD_SET(in, rset);
308:
309: olen = buffer_len(&oqueue);
310: if (olen > 0)
311: FD_SET(out, wset);
312:
313: if (select(max+1, rset, wset, NULL, NULL) < 0) {
314: if (errno == EINTR)
315: continue;
316: error("select: %s", strerror(errno));
317: cleanup_exit(2);
318: }
319:
320: /* copy stdin to iqueue */
321: if (FD_ISSET(in, rset)) {
322: len = read(in, buf, sizeof buf);
323: if (len == 0) {
324: debug("read eof");
325: cleanup_exit(0);
326: } else if (len < 0) {
327: error("read: %s", strerror(errno));
328: cleanup_exit(1);
329: } else {
330: buffer_append(&iqueue, buf, len);
331: }
332: }
333: /* send oqueue to stdout */
334: if (FD_ISSET(out, wset)) {
335: len = write(out, buffer_ptr(&oqueue), olen);
336: if (len < 0) {
337: error("write: %s", strerror(errno));
338: cleanup_exit(1);
339: } else {
340: buffer_consume(&oqueue, len);
341: }
342: }
343:
344: /*
345: * Process requests from client if we can fit the results
346: * into the output buffer, otherwise stop processing input
347: * and let the output queue drain.
348: */
349: if (buffer_check_alloc(&oqueue, MAX_MSG_LENGTH))
350: process();
351: }
352: }