Annotation of src/usr.bin/ssh/ssh-agent.c, Revision 1.38
1.38 ! markus 1: /* $OpenBSD: ssh-agent.c,v 1.37 2000/09/21 11:07:51 markus Exp $ */
1.15 markus 2:
1.1 deraadt 3: /*
1.22 deraadt 4: * Author: Tatu Ylonen <ylo@cs.hut.fi>
5: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6: * All rights reserved
7: * The authentication agent program.
1.33 markus 8: *
1.35 deraadt 9: * As far as I am concerned, the code I have written for this software
10: * can be used freely for any purpose. Any derived versions of this
11: * software must be clearly marked as such, and if the derived work is
12: * incompatible with the protocol description in the RFC file, it must be
13: * called by a name other than "ssh" or "Secure Shell".
14: *
1.33 markus 15: * SSH2 implementation,
16: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.35 deraadt 17: *
18: * Redistribution and use in source and binary forms, with or without
19: * modification, are permitted provided that the following conditions
20: * are met:
21: * 1. Redistributions of source code must retain the above copyright
22: * notice, this list of conditions and the following disclaimer.
23: * 2. Redistributions in binary form must reproduce the above copyright
24: * notice, this list of conditions and the following disclaimer in the
25: * documentation and/or other materials provided with the distribution.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.22 deraadt 37: */
1.1 deraadt 38:
39: #include "includes.h"
1.38 ! markus 40: RCSID("$OpenBSD: ssh-agent.c,v 1.37 2000/09/21 11:07:51 markus Exp $");
1.1 deraadt 41:
42: #include "ssh.h"
43: #include "rsa.h"
44: #include "buffer.h"
45: #include "bufaux.h"
46: #include "xmalloc.h"
47: #include "packet.h"
48: #include "getput.h"
49: #include "mpaux.h"
50:
1.33 markus 51: #include <openssl/evp.h>
1.27 markus 52: #include <openssl/md5.h>
1.32 markus 53: #include <openssl/dsa.h>
54: #include <openssl/rsa.h>
55: #include "key.h"
56: #include "authfd.h"
1.33 markus 57: #include "dsa.h"
58: #include "kex.h"
1.37 markus 59: #include "compat.h"
1.7 deraadt 60:
1.21 markus 61: typedef struct {
62: int fd;
63: enum {
64: AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION
65: } type;
66: Buffer input;
67: Buffer output;
1.1 deraadt 68: } SocketEntry;
69:
70: unsigned int sockets_alloc = 0;
71: SocketEntry *sockets = NULL;
72:
1.21 markus 73: typedef struct {
1.33 markus 74: Key *key;
1.21 markus 75: char *comment;
1.1 deraadt 76: } Identity;
77:
1.33 markus 78: typedef struct {
79: int nentries;
80: Identity *identities;
81: } Idtab;
82:
83: /* private key table, one per protocol version */
84: Idtab idtable[3];
1.1 deraadt 85:
86: int max_fd = 0;
87:
1.11 markus 88: /* pid of shell == parent of agent */
1.29 deraadt 89: pid_t parent_pid = -1;
1.10 markus 90:
91: /* pathname and directory for AUTH_SOCKET */
92: char socket_name[1024];
93: char socket_dir[1024];
94:
1.20 markus 95: extern char *__progname;
96:
1.2 provos 97: void
1.33 markus 98: idtab_init(void)
1.1 deraadt 99: {
1.33 markus 100: int i;
101: for (i = 0; i <=2; i++){
102: idtable[i].identities = NULL;
103: idtable[i].nentries = 0;
104: }
105: }
106:
107: /* return private key table for requested protocol version */
108: Idtab *
109: idtab_lookup(int version)
110: {
111: if (version < 1 || version > 2)
112: fatal("internal error, bad protocol version %d", version);
113: return &idtable[version];
114: }
115:
116: /* return matching private key for given public key */
117: Key *
118: lookup_private_key(Key *key, int *idx, int version)
119: {
120: int i;
121: Idtab *tab = idtab_lookup(version);
122: for (i = 0; i < tab->nentries; i++) {
123: if (key_equal(key, tab->identities[i].key)) {
124: if (idx != NULL)
125: *idx = i;
126: return tab->identities[i].key;
127: }
128: }
129: return NULL;
130: }
131:
132: /* send list of supported public keys to 'client' */
133: void
134: process_request_identities(SocketEntry *e, int version)
135: {
136: Idtab *tab = idtab_lookup(version);
1.21 markus 137: Buffer msg;
138: int i;
1.1 deraadt 139:
1.21 markus 140: buffer_init(&msg);
1.33 markus 141: buffer_put_char(&msg, (version == 1) ?
142: SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
143: buffer_put_int(&msg, tab->nentries);
144: for (i = 0; i < tab->nentries; i++) {
145: Identity *id = &tab->identities[i];
146: if (id->key->type == KEY_RSA) {
147: buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
148: buffer_put_bignum(&msg, id->key->rsa->e);
149: buffer_put_bignum(&msg, id->key->rsa->n);
150: } else {
151: unsigned char *blob;
152: unsigned int blen;
153: dsa_make_key_blob(id->key, &blob, &blen);
154: buffer_put_string(&msg, blob, blen);
155: xfree(blob);
156: }
157: buffer_put_cstring(&msg, id->comment);
1.21 markus 158: }
159: buffer_put_int(&e->output, buffer_len(&msg));
160: buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
161: buffer_free(&msg);
1.1 deraadt 162: }
163:
1.33 markus 164: /* ssh1 only */
1.2 provos 165: void
1.33 markus 166: process_authentication_challenge1(SocketEntry *e)
1.1 deraadt 167: {
1.33 markus 168: Key *key, *private;
169: BIGNUM *challenge;
170: int i, len;
1.21 markus 171: Buffer msg;
172: MD5_CTX md;
173: unsigned char buf[32], mdbuf[16], session_id[16];
174: unsigned int response_type;
175:
176: buffer_init(&msg);
1.33 markus 177: key = key_new(KEY_RSA);
1.21 markus 178: challenge = BN_new();
1.33 markus 179:
180: buffer_get_int(&e->input); /* ignored */
181: buffer_get_bignum(&e->input, key->rsa->e);
182: buffer_get_bignum(&e->input, key->rsa->n);
1.21 markus 183: buffer_get_bignum(&e->input, challenge);
184:
1.33 markus 185: /* Only protocol 1.1 is supported */
186: if (buffer_len(&e->input) == 0)
187: goto failure;
188: buffer_get(&e->input, (char *) session_id, 16);
189: response_type = buffer_get_int(&e->input);
190: if (response_type != 1)
191: goto failure;
192:
193: private = lookup_private_key(key, NULL, 1);
194: if (private != NULL) {
195: /* Decrypt the challenge using the private key. */
196: rsa_private_decrypt(challenge, challenge, private->rsa);
197:
198: /* The response is MD5 of decrypted challenge plus session id. */
199: len = BN_num_bytes(challenge);
200: if (len <= 0 || len > 32) {
201: log("process_authentication_challenge: bad challenge length %d", len);
202: goto failure;
203: }
204: memset(buf, 0, 32);
205: BN_bn2bin(challenge, buf + 32 - len);
206: MD5_Init(&md);
207: MD5_Update(&md, buf, 32);
208: MD5_Update(&md, session_id, 16);
209: MD5_Final(mdbuf, &md);
210:
211: /* Send the response. */
212: buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
213: for (i = 0; i < 16; i++)
214: buffer_put_char(&msg, mdbuf[i]);
215: goto send;
216: }
1.21 markus 217:
1.33 markus 218: failure:
219: /* Unknown identity or protocol error. Send failure. */
1.21 markus 220: buffer_put_char(&msg, SSH_AGENT_FAILURE);
221: send:
222: buffer_put_int(&e->output, buffer_len(&msg));
1.33 markus 223: buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
224: key_free(key);
225: BN_clear_free(challenge);
226: buffer_free(&msg);
227: }
228:
229: /* ssh2 only */
230: void
231: process_sign_request2(SocketEntry *e)
232: {
233: extern int datafellows;
234: Key *key, *private;
235: unsigned char *blob, *data, *signature = NULL;
236: unsigned int blen, dlen, slen = 0;
1.37 markus 237: int flags;
1.33 markus 238: Buffer msg;
239: int ok = -1;
240:
241: datafellows = 0;
242:
243: blob = buffer_get_string(&e->input, &blen);
244: data = buffer_get_string(&e->input, &dlen);
1.37 markus 245:
246: flags = buffer_get_int(&e->input);
247: if (flags & SSH_AGENT_OLD_SIGNATURE)
248: datafellows = SSH_BUG_SIGBLOB;
1.33 markus 249:
250: key = dsa_key_from_blob(blob, blen);
251: if (key != NULL) {
252: private = lookup_private_key(key, NULL, 2);
253: if (private != NULL)
254: ok = dsa_sign(private, &signature, &slen, data, dlen);
255: }
256: key_free(key);
257: buffer_init(&msg);
258: if (ok == 0) {
259: buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
260: buffer_put_string(&msg, signature, slen);
261: } else {
262: buffer_put_char(&msg, SSH_AGENT_FAILURE);
263: }
264: buffer_put_int(&e->output, buffer_len(&msg));
1.21 markus 265: buffer_append(&e->output, buffer_ptr(&msg),
1.33 markus 266: buffer_len(&msg));
1.21 markus 267: buffer_free(&msg);
1.33 markus 268: xfree(data);
269: xfree(blob);
270: if (signature != NULL)
271: xfree(signature);
1.1 deraadt 272: }
273:
1.33 markus 274: /* shared */
1.2 provos 275: void
1.33 markus 276: process_remove_identity(SocketEntry *e, int version)
1.1 deraadt 277: {
1.33 markus 278: Key *key = NULL, *private;
279: unsigned char *blob;
280: unsigned int blen;
1.21 markus 281: unsigned int bits;
1.33 markus 282: int success = 0;
1.21 markus 283:
1.33 markus 284: switch(version){
285: case 1:
286: key = key_new(KEY_RSA);
287: bits = buffer_get_int(&e->input);
288: buffer_get_bignum(&e->input, key->rsa->e);
289: buffer_get_bignum(&e->input, key->rsa->n);
290:
291: if (bits != key_size(key))
292: log("Warning: identity keysize mismatch: actual %d, announced %d",
293: key_size(key), bits);
294: break;
295: case 2:
296: blob = buffer_get_string(&e->input, &blen);
297: key = dsa_key_from_blob(blob, blen);
298: xfree(blob);
299: break;
300: }
301: if (key != NULL) {
302: int idx;
303: private = lookup_private_key(key, &idx, version);
304: if (private != NULL) {
1.23 markus 305: /*
306: * We have this key. Free the old key. Since we
307: * don\'t want to leave empty slots in the middle of
308: * the array, we actually free the key there and copy
309: * data from the last entry.
310: */
1.33 markus 311: Idtab *tab = idtab_lookup(version);
312: key_free(tab->identities[idx].key);
313: xfree(tab->identities[idx].comment);
1.38 ! markus 314: if (tab->nentries < 1)
! 315: fatal("process_remove_identity: "
! 316: "internal error: tab->nentries %d",
! 317: tab->nentries);
! 318: if (idx != tab->nentries - 1)
! 319: tab->identities[idx] = tab->identities[tab->nentries - 1];
1.33 markus 320: tab->nentries--;
321: success = 1;
1.21 markus 322: }
1.33 markus 323: key_free(key);
324: }
1.1 deraadt 325: buffer_put_int(&e->output, 1);
1.33 markus 326: buffer_put_char(&e->output,
327: success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
1.1 deraadt 328: }
329:
1.2 provos 330: void
1.33 markus 331: process_remove_all_identities(SocketEntry *e, int version)
1.1 deraadt 332: {
1.21 markus 333: unsigned int i;
1.33 markus 334: Idtab *tab = idtab_lookup(version);
1.21 markus 335:
336: /* Loop over all identities and clear the keys. */
1.33 markus 337: for (i = 0; i < tab->nentries; i++) {
338: key_free(tab->identities[i].key);
339: xfree(tab->identities[i].comment);
1.21 markus 340: }
341:
342: /* Mark that there are no identities. */
1.33 markus 343: tab->nentries = 0;
1.21 markus 344:
345: /* Send success. */
346: buffer_put_int(&e->output, 1);
347: buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
348: return;
1.1 deraadt 349: }
350:
1.2 provos 351: void
1.33 markus 352: process_add_identity(SocketEntry *e, int version)
1.1 deraadt 353: {
1.33 markus 354: Key *k = NULL;
355: RSA *rsa;
1.21 markus 356: BIGNUM *aux;
357: BN_CTX *ctx;
1.33 markus 358: char *type;
359: char *comment;
360: int success = 0;
361: Idtab *tab = idtab_lookup(version);
362:
363: switch (version) {
364: case 1:
365: k = key_new(KEY_RSA);
366: rsa = k->rsa;
367:
368: /* allocate mem for private key */
369: /* XXX rsa->n and rsa->e are already allocated */
370: rsa->d = BN_new();
371: rsa->iqmp = BN_new();
372: rsa->q = BN_new();
373: rsa->p = BN_new();
374: rsa->dmq1 = BN_new();
375: rsa->dmp1 = BN_new();
376:
377: buffer_get_int(&e->input); /* ignored */
378:
379: buffer_get_bignum(&e->input, rsa->n);
380: buffer_get_bignum(&e->input, rsa->e);
381: buffer_get_bignum(&e->input, rsa->d);
382: buffer_get_bignum(&e->input, rsa->iqmp);
383:
384: /* SSH and SSL have p and q swapped */
385: buffer_get_bignum(&e->input, rsa->q); /* p */
386: buffer_get_bignum(&e->input, rsa->p); /* q */
387:
388: /* Generate additional parameters */
389: aux = BN_new();
390: ctx = BN_CTX_new();
1.21 markus 391:
1.33 markus 392: BN_sub(aux, rsa->q, BN_value_one());
393: BN_mod(rsa->dmq1, rsa->d, aux, ctx);
394:
395: BN_sub(aux, rsa->p, BN_value_one());
396: BN_mod(rsa->dmp1, rsa->d, aux, ctx);
1.21 markus 397:
1.33 markus 398: BN_clear_free(aux);
399: BN_CTX_free(ctx);
1.21 markus 400:
1.33 markus 401: break;
402: case 2:
403: type = buffer_get_string(&e->input, NULL);
404: if (strcmp(type, KEX_DSS)) {
405: buffer_clear(&e->input);
406: xfree(type);
407: goto send;
1.21 markus 408: }
1.33 markus 409: xfree(type);
1.1 deraadt 410:
1.33 markus 411: k = key_new(KEY_DSA);
412:
413: /* allocate mem for private key */
414: k->dsa->priv_key = BN_new();
415:
416: buffer_get_bignum2(&e->input, k->dsa->p);
417: buffer_get_bignum2(&e->input, k->dsa->q);
418: buffer_get_bignum2(&e->input, k->dsa->g);
419: buffer_get_bignum2(&e->input, k->dsa->pub_key);
420: buffer_get_bignum2(&e->input, k->dsa->priv_key);
421:
422: break;
423: }
424:
425: comment = buffer_get_string(&e->input, NULL);
426: if (k == NULL) {
427: xfree(comment);
428: goto send;
429: }
430: success = 1;
431: if (lookup_private_key(k, NULL, version) == NULL) {
432: if (tab->nentries == 0)
433: tab->identities = xmalloc(sizeof(Identity));
434: else
435: tab->identities = xrealloc(tab->identities,
436: (tab->nentries + 1) * sizeof(Identity));
437: tab->identities[tab->nentries].key = k;
438: tab->identities[tab->nentries].comment = comment;
439: /* Increment the number of identities. */
440: tab->nentries++;
441: } else {
442: key_free(k);
443: xfree(comment);
444: }
445: send:
1.1 deraadt 446: buffer_put_int(&e->output, 1);
1.33 markus 447: buffer_put_char(&e->output,
448: success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
1.1 deraadt 449: }
450:
1.33 markus 451: /* dispatch incoming messages */
452:
1.2 provos 453: void
454: process_message(SocketEntry *e)
1.1 deraadt 455: {
1.21 markus 456: unsigned int msg_len;
457: unsigned int type;
458: unsigned char *cp;
459: if (buffer_len(&e->input) < 5)
460: return; /* Incomplete message. */
461: cp = (unsigned char *) buffer_ptr(&e->input);
462: msg_len = GET_32BIT(cp);
463: if (msg_len > 256 * 1024) {
464: shutdown(e->fd, SHUT_RDWR);
465: close(e->fd);
466: e->type = AUTH_UNUSED;
467: return;
468: }
469: if (buffer_len(&e->input) < msg_len + 4)
470: return;
471: buffer_consume(&e->input, 4);
472: type = buffer_get_char(&e->input);
473:
474: switch (type) {
1.33 markus 475: /* ssh1 */
476: case SSH_AGENTC_RSA_CHALLENGE:
477: process_authentication_challenge1(e);
478: break;
1.21 markus 479: case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
1.33 markus 480: process_request_identities(e, 1);
1.21 markus 481: break;
482: case SSH_AGENTC_ADD_RSA_IDENTITY:
1.33 markus 483: process_add_identity(e, 1);
1.21 markus 484: break;
485: case SSH_AGENTC_REMOVE_RSA_IDENTITY:
1.33 markus 486: process_remove_identity(e, 1);
1.21 markus 487: break;
488: case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
1.33 markus 489: process_remove_all_identities(e, 1);
490: break;
491: /* ssh2 */
492: case SSH2_AGENTC_SIGN_REQUEST:
493: process_sign_request2(e);
494: break;
495: case SSH2_AGENTC_REQUEST_IDENTITIES:
496: process_request_identities(e, 2);
497: break;
498: case SSH2_AGENTC_ADD_IDENTITY:
499: process_add_identity(e, 2);
500: break;
501: case SSH2_AGENTC_REMOVE_IDENTITY:
502: process_remove_identity(e, 2);
503: break;
504: case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
505: process_remove_all_identities(e, 2);
1.21 markus 506: break;
507: default:
508: /* Unknown message. Respond with failure. */
509: error("Unknown message %d", type);
510: buffer_clear(&e->input);
511: buffer_put_int(&e->output, 1);
512: buffer_put_char(&e->output, SSH_AGENT_FAILURE);
513: break;
514: }
1.1 deraadt 515: }
516:
1.2 provos 517: void
518: new_socket(int type, int fd)
1.1 deraadt 519: {
1.21 markus 520: unsigned int i, old_alloc;
521: if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
522: error("fcntl O_NONBLOCK: %s", strerror(errno));
523:
524: if (fd > max_fd)
525: max_fd = fd;
526:
527: for (i = 0; i < sockets_alloc; i++)
528: if (sockets[i].type == AUTH_UNUSED) {
529: sockets[i].fd = fd;
530: sockets[i].type = type;
531: buffer_init(&sockets[i].input);
532: buffer_init(&sockets[i].output);
533: return;
534: }
535: old_alloc = sockets_alloc;
536: sockets_alloc += 10;
537: if (sockets)
538: sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0]));
539: else
540: sockets = xmalloc(sockets_alloc * sizeof(sockets[0]));
541: for (i = old_alloc; i < sockets_alloc; i++)
542: sockets[i].type = AUTH_UNUSED;
543: sockets[old_alloc].type = type;
544: sockets[old_alloc].fd = fd;
545: buffer_init(&sockets[old_alloc].input);
546: buffer_init(&sockets[old_alloc].output);
1.1 deraadt 547: }
548:
1.2 provos 549: void
550: prepare_select(fd_set *readset, fd_set *writeset)
1.1 deraadt 551: {
1.21 markus 552: unsigned int i;
553: for (i = 0; i < sockets_alloc; i++)
554: switch (sockets[i].type) {
555: case AUTH_SOCKET:
556: case AUTH_CONNECTION:
557: FD_SET(sockets[i].fd, readset);
558: if (buffer_len(&sockets[i].output) > 0)
559: FD_SET(sockets[i].fd, writeset);
560: break;
561: case AUTH_UNUSED:
562: break;
563: default:
564: fatal("Unknown socket type %d", sockets[i].type);
565: break;
566: }
567: }
568:
1.28 markus 569: void
1.21 markus 570: after_select(fd_set *readset, fd_set *writeset)
571: {
572: unsigned int i;
573: int len, sock;
1.26 markus 574: socklen_t slen;
1.21 markus 575: char buf[1024];
576: struct sockaddr_un sunaddr;
577:
578: for (i = 0; i < sockets_alloc; i++)
579: switch (sockets[i].type) {
580: case AUTH_UNUSED:
581: break;
582: case AUTH_SOCKET:
583: if (FD_ISSET(sockets[i].fd, readset)) {
1.26 markus 584: slen = sizeof(sunaddr);
585: sock = accept(sockets[i].fd, (struct sockaddr *) & sunaddr, &slen);
1.21 markus 586: if (sock < 0) {
587: perror("accept from AUTH_SOCKET");
588: break;
589: }
590: new_socket(AUTH_CONNECTION, sock);
591: }
592: break;
593: case AUTH_CONNECTION:
594: if (buffer_len(&sockets[i].output) > 0 &&
595: FD_ISSET(sockets[i].fd, writeset)) {
596: len = write(sockets[i].fd, buffer_ptr(&sockets[i].output),
597: buffer_len(&sockets[i].output));
598: if (len <= 0) {
599: shutdown(sockets[i].fd, SHUT_RDWR);
600: close(sockets[i].fd);
601: sockets[i].type = AUTH_UNUSED;
1.30 djm 602: buffer_free(&sockets[i].input);
603: buffer_free(&sockets[i].output);
1.21 markus 604: break;
605: }
606: buffer_consume(&sockets[i].output, len);
607: }
608: if (FD_ISSET(sockets[i].fd, readset)) {
609: len = read(sockets[i].fd, buf, sizeof(buf));
610: if (len <= 0) {
611: shutdown(sockets[i].fd, SHUT_RDWR);
612: close(sockets[i].fd);
613: sockets[i].type = AUTH_UNUSED;
1.30 djm 614: buffer_free(&sockets[i].input);
615: buffer_free(&sockets[i].output);
1.21 markus 616: break;
617: }
618: buffer_append(&sockets[i].input, buf, len);
619: process_message(&sockets[i]);
620: }
621: break;
622: default:
623: fatal("Unknown type %d", sockets[i].type);
624: }
1.1 deraadt 625: }
626:
1.6 deraadt 627: void
1.2 provos 628: check_parent_exists(int sig)
1.1 deraadt 629: {
1.29 deraadt 630: if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1.21 markus 631: /* printf("Parent has died - Authentication agent exiting.\n"); */
632: exit(1);
633: }
634: signal(SIGALRM, check_parent_exists);
635: alarm(10);
1.1 deraadt 636: }
637:
1.15 markus 638: void
639: cleanup_socket(void)
640: {
1.21 markus 641: remove(socket_name);
642: rmdir(socket_dir);
1.10 markus 643: }
644:
1.15 markus 645: void
646: cleanup_exit(int i)
647: {
1.21 markus 648: cleanup_socket();
649: exit(i);
1.15 markus 650: }
651:
652: void
653: usage()
654: {
1.21 markus 655: fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION);
656: fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n",
657: __progname);
658: exit(1);
1.15 markus 659: }
660:
1.2 provos 661: int
662: main(int ac, char **av)
1.1 deraadt 663: {
1.21 markus 664: fd_set readset, writeset;
665: int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch;
666: struct sockaddr_un sunaddr;
667: pid_t pid;
668: char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid];
669:
670: /* check if RSA support exists */
671: if (rsa_alive() == 0) {
672: fprintf(stderr,
673: "%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
674: __progname);
675: exit(1);
676: }
677: while ((ch = getopt(ac, av, "cks")) != -1) {
678: switch (ch) {
679: case 'c':
680: if (s_flag)
681: usage();
682: c_flag++;
683: break;
684: case 'k':
685: k_flag++;
686: break;
687: case 's':
688: if (c_flag)
689: usage();
690: s_flag++;
691: break;
692: default:
693: usage();
694: }
695: }
696: ac -= optind;
697: av += optind;
698:
699: if (ac > 0 && (c_flag || k_flag || s_flag))
700: usage();
701:
702: if (ac == 0 && !c_flag && !k_flag && !s_flag) {
703: shell = getenv("SHELL");
704: if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
705: c_flag = 1;
706: }
707: if (k_flag) {
708: pidstr = getenv(SSH_AGENTPID_ENV_NAME);
709: if (pidstr == NULL) {
710: fprintf(stderr, "%s not set, cannot kill agent\n",
711: SSH_AGENTPID_ENV_NAME);
712: exit(1);
713: }
714: pid = atoi(pidstr);
715: if (pid < 1) { /* XXX PID_MAX check too */
1.29 deraadt 716: /* Yes, PID_MAX check please */
1.21 markus 717: fprintf(stderr, "%s=\"%s\", which is not a good PID\n",
718: SSH_AGENTPID_ENV_NAME, pidstr);
719: exit(1);
720: }
721: if (kill(pid, SIGTERM) == -1) {
722: perror("kill");
723: exit(1);
724: }
725: format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
726: printf(format, SSH_AUTHSOCKET_ENV_NAME);
727: printf(format, SSH_AGENTPID_ENV_NAME);
728: printf("echo Agent pid %d killed;\n", pid);
729: exit(0);
730: }
731: parent_pid = getpid();
732:
733: /* Create private directory for agent socket */
734: strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir);
735: if (mkdtemp(socket_dir) == NULL) {
736: perror("mkdtemp: private socket dir");
737: exit(1);
738: }
739: snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir,
740: parent_pid);
741:
1.23 markus 742: /*
743: * Create socket early so it will exist before command gets run from
744: * the parent.
745: */
1.21 markus 746: sock = socket(AF_UNIX, SOCK_STREAM, 0);
747: if (sock < 0) {
748: perror("socket");
749: cleanup_exit(1);
750: }
751: memset(&sunaddr, 0, sizeof(sunaddr));
752: sunaddr.sun_family = AF_UNIX;
753: strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
754: if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
755: perror("bind");
756: cleanup_exit(1);
757: }
758: if (listen(sock, 5) < 0) {
759: perror("listen");
760: cleanup_exit(1);
761: }
1.23 markus 762: /*
763: * Fork, and have the parent execute the command, if any, or present
764: * the socket data. The child continues as the authentication agent.
765: */
1.21 markus 766: pid = fork();
767: if (pid == -1) {
768: perror("fork");
769: exit(1);
770: }
771: if (pid != 0) { /* Parent - execute the given command. */
772: close(sock);
773: snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid);
774: if (ac == 0) {
775: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
776: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
777: SSH_AUTHSOCKET_ENV_NAME);
778: printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
779: SSH_AGENTPID_ENV_NAME);
780: printf("echo Agent pid %d;\n", pid);
781: exit(0);
782: }
1.36 deraadt 783: if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
784: setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
785: perror("setenv");
786: exit(1);
787: }
1.21 markus 788: execvp(av[0], av);
789: perror(av[0]);
790: exit(1);
791: }
792: close(0);
793: close(1);
794: close(2);
795:
796: if (setsid() == -1) {
797: perror("setsid");
798: cleanup_exit(1);
799: }
800: if (atexit(cleanup_socket) < 0) {
801: perror("atexit");
802: cleanup_exit(1);
803: }
804: new_socket(AUTH_SOCKET, sock);
805: if (ac > 0) {
806: signal(SIGALRM, check_parent_exists);
807: alarm(10);
808: }
1.33 markus 809: idtab_init();
1.21 markus 810: signal(SIGINT, SIG_IGN);
811: signal(SIGPIPE, SIG_IGN);
1.28 markus 812: signal(SIGHUP, cleanup_exit);
813: signal(SIGTERM, cleanup_exit);
1.21 markus 814: while (1) {
815: FD_ZERO(&readset);
816: FD_ZERO(&writeset);
817: prepare_select(&readset, &writeset);
818: if (select(max_fd + 1, &readset, &writeset, NULL, NULL) < 0) {
819: if (errno == EINTR)
820: continue;
821: exit(1);
822: }
823: after_select(&readset, &writeset);
1.15 markus 824: }
1.21 markus 825: /* NOTREACHED */
1.1 deraadt 826: }
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