Annotation of src/usr.bin/ssh/ssh-agent.c, Revision 1.34
1.34 ! markus 1: /* $OpenBSD: ssh-agent.c,v 1.33 2000/08/19 21:34:43 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: * Created: Wed Mar 29 03:46:59 1995 ylo
8: * The authentication agent program.
1.33 markus 9: *
10: * SSH2 implementation,
11: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.22 deraadt 12: */
1.1 deraadt 13:
14: #include "includes.h"
1.34 ! markus 15: RCSID("$OpenBSD: ssh-agent.c,v 1.33 2000/08/19 21:34:43 markus Exp $");
1.1 deraadt 16:
17: #include "ssh.h"
18: #include "rsa.h"
19: #include "buffer.h"
20: #include "bufaux.h"
21: #include "xmalloc.h"
22: #include "packet.h"
23: #include "getput.h"
24: #include "mpaux.h"
25:
1.33 markus 26: #include <openssl/evp.h>
1.27 markus 27: #include <openssl/md5.h>
1.32 markus 28: #include <openssl/dsa.h>
29: #include <openssl/rsa.h>
30: #include "key.h"
31: #include "authfd.h"
1.33 markus 32: #include "dsa.h"
33: #include "kex.h"
1.7 deraadt 34:
1.21 markus 35: typedef struct {
36: int fd;
37: enum {
38: AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION
39: } type;
40: Buffer input;
41: Buffer output;
1.1 deraadt 42: } SocketEntry;
43:
44: unsigned int sockets_alloc = 0;
45: SocketEntry *sockets = NULL;
46:
1.21 markus 47: typedef struct {
1.33 markus 48: Key *key;
1.21 markus 49: char *comment;
1.1 deraadt 50: } Identity;
51:
1.33 markus 52: typedef struct {
53: int nentries;
54: Identity *identities;
55: } Idtab;
56:
57: /* private key table, one per protocol version */
58: Idtab idtable[3];
1.1 deraadt 59:
60: int max_fd = 0;
61:
1.11 markus 62: /* pid of shell == parent of agent */
1.29 deraadt 63: pid_t parent_pid = -1;
1.10 markus 64:
65: /* pathname and directory for AUTH_SOCKET */
66: char socket_name[1024];
67: char socket_dir[1024];
68:
1.20 markus 69: extern char *__progname;
70:
1.2 provos 71: void
1.33 markus 72: idtab_init(void)
1.1 deraadt 73: {
1.33 markus 74: int i;
75: for (i = 0; i <=2; i++){
76: idtable[i].identities = NULL;
77: idtable[i].nentries = 0;
78: }
79: }
80:
81: /* return private key table for requested protocol version */
82: Idtab *
83: idtab_lookup(int version)
84: {
85: if (version < 1 || version > 2)
86: fatal("internal error, bad protocol version %d", version);
87: return &idtable[version];
88: }
89:
90: /* return matching private key for given public key */
91: Key *
92: lookup_private_key(Key *key, int *idx, int version)
93: {
94: int i;
95: Idtab *tab = idtab_lookup(version);
96: for (i = 0; i < tab->nentries; i++) {
97: if (key_equal(key, tab->identities[i].key)) {
98: if (idx != NULL)
99: *idx = i;
100: return tab->identities[i].key;
101: }
102: }
103: return NULL;
104: }
105:
106: /* send list of supported public keys to 'client' */
107: void
108: process_request_identities(SocketEntry *e, int version)
109: {
110: Idtab *tab = idtab_lookup(version);
1.21 markus 111: Buffer msg;
112: int i;
1.1 deraadt 113:
1.21 markus 114: buffer_init(&msg);
1.33 markus 115: buffer_put_char(&msg, (version == 1) ?
116: SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER);
117: buffer_put_int(&msg, tab->nentries);
118: for (i = 0; i < tab->nentries; i++) {
119: Identity *id = &tab->identities[i];
120: if (id->key->type == KEY_RSA) {
121: buffer_put_int(&msg, BN_num_bits(id->key->rsa->n));
122: buffer_put_bignum(&msg, id->key->rsa->e);
123: buffer_put_bignum(&msg, id->key->rsa->n);
124: } else {
125: unsigned char *blob;
126: unsigned int blen;
127: dsa_make_key_blob(id->key, &blob, &blen);
128: buffer_put_string(&msg, blob, blen);
129: xfree(blob);
130: }
131: buffer_put_cstring(&msg, id->comment);
1.21 markus 132: }
133: buffer_put_int(&e->output, buffer_len(&msg));
134: buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
135: buffer_free(&msg);
1.1 deraadt 136: }
137:
1.33 markus 138: /* ssh1 only */
1.2 provos 139: void
1.33 markus 140: process_authentication_challenge1(SocketEntry *e)
1.1 deraadt 141: {
1.33 markus 142: Key *key, *private;
143: BIGNUM *challenge;
144: int i, len;
1.21 markus 145: Buffer msg;
146: MD5_CTX md;
147: unsigned char buf[32], mdbuf[16], session_id[16];
148: unsigned int response_type;
149:
150: buffer_init(&msg);
1.33 markus 151: key = key_new(KEY_RSA);
1.21 markus 152: challenge = BN_new();
1.33 markus 153:
154: buffer_get_int(&e->input); /* ignored */
155: buffer_get_bignum(&e->input, key->rsa->e);
156: buffer_get_bignum(&e->input, key->rsa->n);
1.21 markus 157: buffer_get_bignum(&e->input, challenge);
158:
1.33 markus 159: /* Only protocol 1.1 is supported */
160: if (buffer_len(&e->input) == 0)
161: goto failure;
162: buffer_get(&e->input, (char *) session_id, 16);
163: response_type = buffer_get_int(&e->input);
164: if (response_type != 1)
165: goto failure;
166:
167: private = lookup_private_key(key, NULL, 1);
168: if (private != NULL) {
169: /* Decrypt the challenge using the private key. */
170: rsa_private_decrypt(challenge, challenge, private->rsa);
171:
172: /* The response is MD5 of decrypted challenge plus session id. */
173: len = BN_num_bytes(challenge);
174: if (len <= 0 || len > 32) {
175: log("process_authentication_challenge: bad challenge length %d", len);
176: goto failure;
177: }
178: memset(buf, 0, 32);
179: BN_bn2bin(challenge, buf + 32 - len);
180: MD5_Init(&md);
181: MD5_Update(&md, buf, 32);
182: MD5_Update(&md, session_id, 16);
183: MD5_Final(mdbuf, &md);
184:
185: /* Send the response. */
186: buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE);
187: for (i = 0; i < 16; i++)
188: buffer_put_char(&msg, mdbuf[i]);
189: goto send;
190: }
1.21 markus 191:
1.33 markus 192: failure:
193: /* Unknown identity or protocol error. Send failure. */
1.21 markus 194: buffer_put_char(&msg, SSH_AGENT_FAILURE);
195: send:
196: buffer_put_int(&e->output, buffer_len(&msg));
1.33 markus 197: buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg));
198: key_free(key);
199: BN_clear_free(challenge);
200: buffer_free(&msg);
201: }
202:
203: /* ssh2 only */
204: void
205: process_sign_request2(SocketEntry *e)
206: {
207: extern int datafellows;
208: Key *key, *private;
209: unsigned char *blob, *data, *signature = NULL;
210: unsigned int blen, dlen, slen = 0;
211: Buffer msg;
212: int ok = -1;
213:
214: datafellows = 0;
215:
216: blob = buffer_get_string(&e->input, &blen);
217: data = buffer_get_string(&e->input, &dlen);
1.34 ! markus 218: buffer_get_int(&e->input); /* flags, unused */
1.33 markus 219:
220: key = dsa_key_from_blob(blob, blen);
221: if (key != NULL) {
222: private = lookup_private_key(key, NULL, 2);
223: if (private != NULL)
224: ok = dsa_sign(private, &signature, &slen, data, dlen);
225: }
226: key_free(key);
227: buffer_init(&msg);
228: if (ok == 0) {
229: buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
230: buffer_put_string(&msg, signature, slen);
231: } else {
232: buffer_put_char(&msg, SSH_AGENT_FAILURE);
233: }
234: buffer_put_int(&e->output, buffer_len(&msg));
1.21 markus 235: buffer_append(&e->output, buffer_ptr(&msg),
1.33 markus 236: buffer_len(&msg));
1.21 markus 237: buffer_free(&msg);
1.33 markus 238: xfree(data);
239: xfree(blob);
240: if (signature != NULL)
241: xfree(signature);
1.1 deraadt 242: }
243:
1.33 markus 244: /* shared */
1.2 provos 245: void
1.33 markus 246: process_remove_identity(SocketEntry *e, int version)
1.1 deraadt 247: {
1.33 markus 248: Key *key = NULL, *private;
249: unsigned char *blob;
250: unsigned int blen;
1.21 markus 251: unsigned int bits;
1.33 markus 252: int success = 0;
1.21 markus 253:
1.33 markus 254: switch(version){
255: case 1:
256: key = key_new(KEY_RSA);
257: bits = buffer_get_int(&e->input);
258: buffer_get_bignum(&e->input, key->rsa->e);
259: buffer_get_bignum(&e->input, key->rsa->n);
260:
261: if (bits != key_size(key))
262: log("Warning: identity keysize mismatch: actual %d, announced %d",
263: key_size(key), bits);
264: break;
265: case 2:
266: blob = buffer_get_string(&e->input, &blen);
267: key = dsa_key_from_blob(blob, blen);
268: xfree(blob);
269: break;
270: }
271: if (key != NULL) {
272: int idx;
273: private = lookup_private_key(key, &idx, version);
274: if (private != NULL) {
1.23 markus 275: /*
276: * We have this key. Free the old key. Since we
277: * don\'t want to leave empty slots in the middle of
278: * the array, we actually free the key there and copy
279: * data from the last entry.
280: */
1.33 markus 281: Idtab *tab = idtab_lookup(version);
282: key_free(tab->identities[idx].key);
283: xfree(tab->identities[idx].comment);
284: if (idx != tab->nentries)
285: tab->identities[idx] = tab->identities[tab->nentries];
286: tab->nentries--;
287: success = 1;
1.21 markus 288: }
1.33 markus 289: key_free(key);
290: }
1.1 deraadt 291: buffer_put_int(&e->output, 1);
1.33 markus 292: buffer_put_char(&e->output,
293: success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
1.1 deraadt 294: }
295:
1.2 provos 296: void
1.33 markus 297: process_remove_all_identities(SocketEntry *e, int version)
1.1 deraadt 298: {
1.21 markus 299: unsigned int i;
1.33 markus 300: Idtab *tab = idtab_lookup(version);
1.21 markus 301:
302: /* Loop over all identities and clear the keys. */
1.33 markus 303: for (i = 0; i < tab->nentries; i++) {
304: key_free(tab->identities[i].key);
305: xfree(tab->identities[i].comment);
1.21 markus 306: }
307:
308: /* Mark that there are no identities. */
1.33 markus 309: tab->nentries = 0;
1.21 markus 310:
311: /* Send success. */
312: buffer_put_int(&e->output, 1);
313: buffer_put_char(&e->output, SSH_AGENT_SUCCESS);
314: return;
1.1 deraadt 315: }
316:
1.2 provos 317: void
1.33 markus 318: process_add_identity(SocketEntry *e, int version)
1.1 deraadt 319: {
1.33 markus 320: Key *k = NULL;
321: RSA *rsa;
1.21 markus 322: BIGNUM *aux;
323: BN_CTX *ctx;
1.33 markus 324: char *type;
325: char *comment;
326: int success = 0;
327: Idtab *tab = idtab_lookup(version);
328:
329: switch (version) {
330: case 1:
331: k = key_new(KEY_RSA);
332: rsa = k->rsa;
333:
334: /* allocate mem for private key */
335: /* XXX rsa->n and rsa->e are already allocated */
336: rsa->d = BN_new();
337: rsa->iqmp = BN_new();
338: rsa->q = BN_new();
339: rsa->p = BN_new();
340: rsa->dmq1 = BN_new();
341: rsa->dmp1 = BN_new();
342:
343: buffer_get_int(&e->input); /* ignored */
344:
345: buffer_get_bignum(&e->input, rsa->n);
346: buffer_get_bignum(&e->input, rsa->e);
347: buffer_get_bignum(&e->input, rsa->d);
348: buffer_get_bignum(&e->input, rsa->iqmp);
349:
350: /* SSH and SSL have p and q swapped */
351: buffer_get_bignum(&e->input, rsa->q); /* p */
352: buffer_get_bignum(&e->input, rsa->p); /* q */
353:
354: /* Generate additional parameters */
355: aux = BN_new();
356: ctx = BN_CTX_new();
1.21 markus 357:
1.33 markus 358: BN_sub(aux, rsa->q, BN_value_one());
359: BN_mod(rsa->dmq1, rsa->d, aux, ctx);
360:
361: BN_sub(aux, rsa->p, BN_value_one());
362: BN_mod(rsa->dmp1, rsa->d, aux, ctx);
1.21 markus 363:
1.33 markus 364: BN_clear_free(aux);
365: BN_CTX_free(ctx);
1.21 markus 366:
1.33 markus 367: break;
368: case 2:
369: type = buffer_get_string(&e->input, NULL);
370: if (strcmp(type, KEX_DSS)) {
371: buffer_clear(&e->input);
372: xfree(type);
373: goto send;
1.21 markus 374: }
1.33 markus 375: xfree(type);
1.1 deraadt 376:
1.33 markus 377: k = key_new(KEY_DSA);
378:
379: /* allocate mem for private key */
380: k->dsa->priv_key = BN_new();
381:
382: buffer_get_bignum2(&e->input, k->dsa->p);
383: buffer_get_bignum2(&e->input, k->dsa->q);
384: buffer_get_bignum2(&e->input, k->dsa->g);
385: buffer_get_bignum2(&e->input, k->dsa->pub_key);
386: buffer_get_bignum2(&e->input, k->dsa->priv_key);
387:
388: break;
389: }
390:
391: comment = buffer_get_string(&e->input, NULL);
392: if (k == NULL) {
393: xfree(comment);
394: goto send;
395: }
396: success = 1;
397: if (lookup_private_key(k, NULL, version) == NULL) {
398: if (tab->nentries == 0)
399: tab->identities = xmalloc(sizeof(Identity));
400: else
401: tab->identities = xrealloc(tab->identities,
402: (tab->nentries + 1) * sizeof(Identity));
403: tab->identities[tab->nentries].key = k;
404: tab->identities[tab->nentries].comment = comment;
405: /* Increment the number of identities. */
406: tab->nentries++;
407: } else {
408: key_free(k);
409: xfree(comment);
410: }
411: send:
1.1 deraadt 412: buffer_put_int(&e->output, 1);
1.33 markus 413: buffer_put_char(&e->output,
414: success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE);
1.1 deraadt 415: }
416:
1.33 markus 417: /* dispatch incoming messages */
418:
1.2 provos 419: void
420: process_message(SocketEntry *e)
1.1 deraadt 421: {
1.21 markus 422: unsigned int msg_len;
423: unsigned int type;
424: unsigned char *cp;
425: if (buffer_len(&e->input) < 5)
426: return; /* Incomplete message. */
427: cp = (unsigned char *) buffer_ptr(&e->input);
428: msg_len = GET_32BIT(cp);
429: if (msg_len > 256 * 1024) {
430: shutdown(e->fd, SHUT_RDWR);
431: close(e->fd);
432: e->type = AUTH_UNUSED;
433: return;
434: }
435: if (buffer_len(&e->input) < msg_len + 4)
436: return;
437: buffer_consume(&e->input, 4);
438: type = buffer_get_char(&e->input);
439:
440: switch (type) {
1.33 markus 441: /* ssh1 */
442: case SSH_AGENTC_RSA_CHALLENGE:
443: process_authentication_challenge1(e);
444: break;
1.21 markus 445: case SSH_AGENTC_REQUEST_RSA_IDENTITIES:
1.33 markus 446: process_request_identities(e, 1);
1.21 markus 447: break;
448: case SSH_AGENTC_ADD_RSA_IDENTITY:
1.33 markus 449: process_add_identity(e, 1);
1.21 markus 450: break;
451: case SSH_AGENTC_REMOVE_RSA_IDENTITY:
1.33 markus 452: process_remove_identity(e, 1);
1.21 markus 453: break;
454: case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
1.33 markus 455: process_remove_all_identities(e, 1);
456: break;
457: /* ssh2 */
458: case SSH2_AGENTC_SIGN_REQUEST:
459: process_sign_request2(e);
460: break;
461: case SSH2_AGENTC_REQUEST_IDENTITIES:
462: process_request_identities(e, 2);
463: break;
464: case SSH2_AGENTC_ADD_IDENTITY:
465: process_add_identity(e, 2);
466: break;
467: case SSH2_AGENTC_REMOVE_IDENTITY:
468: process_remove_identity(e, 2);
469: break;
470: case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
471: process_remove_all_identities(e, 2);
1.21 markus 472: break;
473: default:
474: /* Unknown message. Respond with failure. */
475: error("Unknown message %d", type);
476: buffer_clear(&e->input);
477: buffer_put_int(&e->output, 1);
478: buffer_put_char(&e->output, SSH_AGENT_FAILURE);
479: break;
480: }
1.1 deraadt 481: }
482:
1.2 provos 483: void
484: new_socket(int type, int fd)
1.1 deraadt 485: {
1.21 markus 486: unsigned int i, old_alloc;
487: if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
488: error("fcntl O_NONBLOCK: %s", strerror(errno));
489:
490: if (fd > max_fd)
491: max_fd = fd;
492:
493: for (i = 0; i < sockets_alloc; i++)
494: if (sockets[i].type == AUTH_UNUSED) {
495: sockets[i].fd = fd;
496: sockets[i].type = type;
497: buffer_init(&sockets[i].input);
498: buffer_init(&sockets[i].output);
499: return;
500: }
501: old_alloc = sockets_alloc;
502: sockets_alloc += 10;
503: if (sockets)
504: sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0]));
505: else
506: sockets = xmalloc(sockets_alloc * sizeof(sockets[0]));
507: for (i = old_alloc; i < sockets_alloc; i++)
508: sockets[i].type = AUTH_UNUSED;
509: sockets[old_alloc].type = type;
510: sockets[old_alloc].fd = fd;
511: buffer_init(&sockets[old_alloc].input);
512: buffer_init(&sockets[old_alloc].output);
1.1 deraadt 513: }
514:
1.2 provos 515: void
516: prepare_select(fd_set *readset, fd_set *writeset)
1.1 deraadt 517: {
1.21 markus 518: unsigned int i;
519: for (i = 0; i < sockets_alloc; i++)
520: switch (sockets[i].type) {
521: case AUTH_SOCKET:
522: case AUTH_CONNECTION:
523: FD_SET(sockets[i].fd, readset);
524: if (buffer_len(&sockets[i].output) > 0)
525: FD_SET(sockets[i].fd, writeset);
526: break;
527: case AUTH_UNUSED:
528: break;
529: default:
530: fatal("Unknown socket type %d", sockets[i].type);
531: break;
532: }
533: }
534:
1.28 markus 535: void
1.21 markus 536: after_select(fd_set *readset, fd_set *writeset)
537: {
538: unsigned int i;
539: int len, sock;
1.26 markus 540: socklen_t slen;
1.21 markus 541: char buf[1024];
542: struct sockaddr_un sunaddr;
543:
544: for (i = 0; i < sockets_alloc; i++)
545: switch (sockets[i].type) {
546: case AUTH_UNUSED:
547: break;
548: case AUTH_SOCKET:
549: if (FD_ISSET(sockets[i].fd, readset)) {
1.26 markus 550: slen = sizeof(sunaddr);
551: sock = accept(sockets[i].fd, (struct sockaddr *) & sunaddr, &slen);
1.21 markus 552: if (sock < 0) {
553: perror("accept from AUTH_SOCKET");
554: break;
555: }
556: new_socket(AUTH_CONNECTION, sock);
557: }
558: break;
559: case AUTH_CONNECTION:
560: if (buffer_len(&sockets[i].output) > 0 &&
561: FD_ISSET(sockets[i].fd, writeset)) {
562: len = write(sockets[i].fd, buffer_ptr(&sockets[i].output),
563: buffer_len(&sockets[i].output));
564: if (len <= 0) {
565: shutdown(sockets[i].fd, SHUT_RDWR);
566: close(sockets[i].fd);
567: sockets[i].type = AUTH_UNUSED;
1.30 djm 568: buffer_free(&sockets[i].input);
569: buffer_free(&sockets[i].output);
1.21 markus 570: break;
571: }
572: buffer_consume(&sockets[i].output, len);
573: }
574: if (FD_ISSET(sockets[i].fd, readset)) {
575: len = read(sockets[i].fd, buf, sizeof(buf));
576: if (len <= 0) {
577: shutdown(sockets[i].fd, SHUT_RDWR);
578: close(sockets[i].fd);
579: sockets[i].type = AUTH_UNUSED;
1.30 djm 580: buffer_free(&sockets[i].input);
581: buffer_free(&sockets[i].output);
1.21 markus 582: break;
583: }
584: buffer_append(&sockets[i].input, buf, len);
585: process_message(&sockets[i]);
586: }
587: break;
588: default:
589: fatal("Unknown type %d", sockets[i].type);
590: }
1.1 deraadt 591: }
592:
1.6 deraadt 593: void
1.2 provos 594: check_parent_exists(int sig)
1.1 deraadt 595: {
1.29 deraadt 596: if (parent_pid != -1 && kill(parent_pid, 0) < 0) {
1.21 markus 597: /* printf("Parent has died - Authentication agent exiting.\n"); */
598: exit(1);
599: }
600: signal(SIGALRM, check_parent_exists);
601: alarm(10);
1.1 deraadt 602: }
603:
1.15 markus 604: void
605: cleanup_socket(void)
606: {
1.21 markus 607: remove(socket_name);
608: rmdir(socket_dir);
1.10 markus 609: }
610:
1.15 markus 611: void
612: cleanup_exit(int i)
613: {
1.21 markus 614: cleanup_socket();
615: exit(i);
1.15 markus 616: }
617:
618: void
619: usage()
620: {
1.21 markus 621: fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION);
622: fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n",
623: __progname);
624: exit(1);
1.15 markus 625: }
626:
1.2 provos 627: int
628: main(int ac, char **av)
1.1 deraadt 629: {
1.21 markus 630: fd_set readset, writeset;
631: int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch;
632: struct sockaddr_un sunaddr;
633: pid_t pid;
634: char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid];
635:
636: /* check if RSA support exists */
637: if (rsa_alive() == 0) {
638: fprintf(stderr,
639: "%s: no RSA support in libssl and libcrypto. See ssl(8).\n",
640: __progname);
641: exit(1);
642: }
643: while ((ch = getopt(ac, av, "cks")) != -1) {
644: switch (ch) {
645: case 'c':
646: if (s_flag)
647: usage();
648: c_flag++;
649: break;
650: case 'k':
651: k_flag++;
652: break;
653: case 's':
654: if (c_flag)
655: usage();
656: s_flag++;
657: break;
658: default:
659: usage();
660: }
661: }
662: ac -= optind;
663: av += optind;
664:
665: if (ac > 0 && (c_flag || k_flag || s_flag))
666: usage();
667:
668: if (ac == 0 && !c_flag && !k_flag && !s_flag) {
669: shell = getenv("SHELL");
670: if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0)
671: c_flag = 1;
672: }
673: if (k_flag) {
674: pidstr = getenv(SSH_AGENTPID_ENV_NAME);
675: if (pidstr == NULL) {
676: fprintf(stderr, "%s not set, cannot kill agent\n",
677: SSH_AGENTPID_ENV_NAME);
678: exit(1);
679: }
680: pid = atoi(pidstr);
681: if (pid < 1) { /* XXX PID_MAX check too */
1.29 deraadt 682: /* Yes, PID_MAX check please */
1.21 markus 683: fprintf(stderr, "%s=\"%s\", which is not a good PID\n",
684: SSH_AGENTPID_ENV_NAME, pidstr);
685: exit(1);
686: }
687: if (kill(pid, SIGTERM) == -1) {
688: perror("kill");
689: exit(1);
690: }
691: format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
692: printf(format, SSH_AUTHSOCKET_ENV_NAME);
693: printf(format, SSH_AGENTPID_ENV_NAME);
694: printf("echo Agent pid %d killed;\n", pid);
695: exit(0);
696: }
697: parent_pid = getpid();
698:
699: /* Create private directory for agent socket */
700: strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir);
701: if (mkdtemp(socket_dir) == NULL) {
702: perror("mkdtemp: private socket dir");
703: exit(1);
704: }
705: snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir,
706: parent_pid);
707:
1.23 markus 708: /*
709: * Create socket early so it will exist before command gets run from
710: * the parent.
711: */
1.21 markus 712: sock = socket(AF_UNIX, SOCK_STREAM, 0);
713: if (sock < 0) {
714: perror("socket");
715: cleanup_exit(1);
716: }
717: memset(&sunaddr, 0, sizeof(sunaddr));
718: sunaddr.sun_family = AF_UNIX;
719: strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path));
720: if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) {
721: perror("bind");
722: cleanup_exit(1);
723: }
724: if (listen(sock, 5) < 0) {
725: perror("listen");
726: cleanup_exit(1);
727: }
1.23 markus 728: /*
729: * Fork, and have the parent execute the command, if any, or present
730: * the socket data. The child continues as the authentication agent.
731: */
1.21 markus 732: pid = fork();
733: if (pid == -1) {
734: perror("fork");
735: exit(1);
736: }
737: if (pid != 0) { /* Parent - execute the given command. */
738: close(sock);
739: snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid);
740: if (ac == 0) {
741: format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
742: printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
743: SSH_AUTHSOCKET_ENV_NAME);
744: printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
745: SSH_AGENTPID_ENV_NAME);
746: printf("echo Agent pid %d;\n", pid);
747: exit(0);
748: }
749: setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1);
750: setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1);
751: execvp(av[0], av);
752: perror(av[0]);
753: exit(1);
754: }
755: close(0);
756: close(1);
757: close(2);
758:
759: if (setsid() == -1) {
760: perror("setsid");
761: cleanup_exit(1);
762: }
763: if (atexit(cleanup_socket) < 0) {
764: perror("atexit");
765: cleanup_exit(1);
766: }
767: new_socket(AUTH_SOCKET, sock);
768: if (ac > 0) {
769: signal(SIGALRM, check_parent_exists);
770: alarm(10);
771: }
1.33 markus 772: idtab_init();
1.21 markus 773: signal(SIGINT, SIG_IGN);
774: signal(SIGPIPE, SIG_IGN);
1.28 markus 775: signal(SIGHUP, cleanup_exit);
776: signal(SIGTERM, cleanup_exit);
1.21 markus 777: while (1) {
778: FD_ZERO(&readset);
779: FD_ZERO(&writeset);
780: prepare_select(&readset, &writeset);
781: if (select(max_fd + 1, &readset, &writeset, NULL, NULL) < 0) {
782: if (errno == EINTR)
783: continue;
784: exit(1);
785: }
786: after_select(&readset, &writeset);
1.15 markus 787: }
1.21 markus 788: /* NOTREACHED */
1.1 deraadt 789: }
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