Annotation of src/usr.bin/ssh/sshconnect2.c, Revision 1.102
1.1 markus 1: /*
2: * Copyright (c) 2000 Markus Friedl. All rights reserved.
3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
7: * 1. Redistributions of source code must retain the above copyright
8: * notice, this list of conditions and the following disclaimer.
9: * 2. Redistributions in binary form must reproduce the above copyright
10: * notice, this list of conditions and the following disclaimer in the
11: * documentation and/or other materials provided with the distribution.
12: *
13: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: */
24:
25: #include "includes.h"
1.102 ! markus 26: RCSID("$OpenBSD: sshconnect2.c,v 1.101 2002/05/24 08:45:14 markus Exp $");
1.1 markus 27:
28: #include "ssh.h"
1.37 markus 29: #include "ssh2.h"
1.1 markus 30: #include "xmalloc.h"
31: #include "buffer.h"
32: #include "packet.h"
33: #include "compat.h"
34: #include "bufaux.h"
1.37 markus 35: #include "cipher.h"
1.1 markus 36: #include "kex.h"
37: #include "myproposal.h"
38: #include "sshconnect.h"
39: #include "authfile.h"
1.57 provos 40: #include "dh.h"
1.17 markus 41: #include "authfd.h"
1.37 markus 42: #include "log.h"
43: #include "readconf.h"
44: #include "readpass.h"
1.53 markus 45: #include "match.h"
1.61 markus 46: #include "dispatch.h"
1.68 markus 47: #include "canohost.h"
1.100 markus 48: #include "msg.h"
49: #include "pathnames.h"
1.22 provos 50:
1.1 markus 51: /* import */
52: extern char *client_version_string;
53: extern char *server_version_string;
54: extern Options options;
55:
56: /*
57: * SSH2 key exchange
58: */
59:
1.32 markus 60: u_char *session_id2 = NULL;
1.1 markus 61: int session_id2_len = 0;
62:
1.61 markus 63: char *xxx_host;
64: struct sockaddr *xxx_hostaddr;
65:
1.63 markus 66: Kex *xxx_kex = NULL;
67:
1.76 itojun 68: static int
1.75 markus 69: verify_host_key_callback(Key *hostkey)
1.61 markus 70: {
1.75 markus 71: if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
1.83 markus 72: fatal("Host key verification failed.");
1.61 markus 73: return 0;
74: }
75:
1.1 markus 76: void
1.22 provos 77: ssh_kex2(char *host, struct sockaddr *hostaddr)
78: {
79: Kex *kex;
1.61 markus 80:
81: xxx_host = host;
82: xxx_hostaddr = hostaddr;
1.22 provos 83:
1.29 markus 84: if (options.ciphers == (char *)-1) {
85: log("No valid ciphers for protocol version 2 given, using defaults.");
86: options.ciphers = NULL;
1.24 markus 87: }
1.22 provos 88: if (options.ciphers != NULL) {
89: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
90: myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
91: }
1.60 stevesk 92: myproposal[PROPOSAL_ENC_ALGS_CTOS] =
93: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
94: myproposal[PROPOSAL_ENC_ALGS_STOC] =
95: compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1.22 provos 96: if (options.compression) {
1.47 markus 97: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 98: myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
99: } else {
1.47 markus 100: myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1.22 provos 101: myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1.47 markus 102: }
103: if (options.macs != NULL) {
104: myproposal[PROPOSAL_MAC_ALGS_CTOS] =
105: myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1.22 provos 106: }
1.70 markus 107: if (options.hostkeyalgorithms != NULL)
1.88 deraadt 108: myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
1.70 markus 109: options.hostkeyalgorithms;
1.22 provos 110:
1.65 markus 111: /* start key exchange */
1.64 markus 112: kex = kex_setup(myproposal);
1.61 markus 113: kex->client_version_string=client_version_string;
114: kex->server_version_string=server_version_string;
1.75 markus 115: kex->verify_host_key=&verify_host_key_callback;
1.63 markus 116:
117: xxx_kex = kex;
1.22 provos 118:
1.66 markus 119: dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1.62 markus 120:
121: session_id2 = kex->session_id;
122: session_id2_len = kex->session_id_len;
1.22 provos 123:
124: #ifdef DEBUG_KEXDH
125: /* send 1st encrypted/maced/compressed message */
126: packet_start(SSH2_MSG_IGNORE);
127: packet_put_cstring("markus");
128: packet_send();
129: packet_write_wait();
130: #endif
1.61 markus 131: debug("done: ssh_kex2.");
1.1 markus 132: }
1.11 markus 133:
1.1 markus 134: /*
135: * Authenticate user
136: */
1.20 markus 137:
138: typedef struct Authctxt Authctxt;
139: typedef struct Authmethod Authmethod;
140:
141: typedef int sign_cb_fn(
142: Authctxt *authctxt, Key *key,
1.96 markus 143: u_char **sigp, u_int *lenp, u_char *data, u_int datalen);
1.20 markus 144:
145: struct Authctxt {
146: const char *server_user;
1.68 markus 147: const char *local_user;
1.20 markus 148: const char *host;
149: const char *service;
1.23 markus 150: Authmethod *method;
1.20 markus 151: int success;
1.51 markus 152: char *authlist;
1.68 markus 153: /* pubkey */
1.51 markus 154: Key *last_key;
155: sign_cb_fn *last_key_sign;
156: int last_key_hint;
1.68 markus 157: AuthenticationConnection *agent;
158: /* hostbased */
1.100 markus 159: Sensitive *sensitive;
1.82 markus 160: /* kbd-interactive */
161: int info_req_seen;
1.20 markus 162: };
163: struct Authmethod {
164: char *name; /* string to compare against server's list */
165: int (*userauth)(Authctxt *authctxt);
166: int *enabled; /* flag in option struct that enables method */
167: int *batch_flag; /* flag in option struct that disables method */
168: };
169:
1.92 markus 170: void input_userauth_success(int, u_int32_t, void *);
171: void input_userauth_failure(int, u_int32_t, void *);
172: void input_userauth_banner(int, u_int32_t, void *);
173: void input_userauth_error(int, u_int32_t, void *);
174: void input_userauth_info_req(int, u_int32_t, void *);
175: void input_userauth_pk_ok(int, u_int32_t, void *);
1.99 markus 176: void input_userauth_passwd_changereq(int, u_int32_t, void *);
1.86 itojun 177:
178: int userauth_none(Authctxt *);
179: int userauth_pubkey(Authctxt *);
180: int userauth_passwd(Authctxt *);
181: int userauth_kbdint(Authctxt *);
182: int userauth_hostbased(Authctxt *);
1.20 markus 183:
1.86 itojun 184: void userauth(Authctxt *, char *);
1.51 markus 185:
1.76 itojun 186: static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
187: static void clear_auth_state(Authctxt *);
188:
189: static Authmethod *authmethod_get(char *authlist);
190: static Authmethod *authmethod_lookup(const char *name);
191: static char *authmethods_get(void);
1.20 markus 192:
193: Authmethod authmethods[] = {
1.81 markus 194: {"hostbased",
195: userauth_hostbased,
196: &options.hostbased_authentication,
197: NULL},
1.20 markus 198: {"publickey",
199: userauth_pubkey,
1.28 markus 200: &options.pubkey_authentication,
1.20 markus 201: NULL},
1.81 markus 202: {"keyboard-interactive",
203: userauth_kbdint,
204: &options.kbd_interactive_authentication,
205: &options.batch_mode},
1.20 markus 206: {"password",
207: userauth_passwd,
208: &options.password_authentication,
1.23 markus 209: &options.batch_mode},
210: {"none",
211: userauth_none,
212: NULL,
213: NULL},
1.20 markus 214: {NULL, NULL, NULL, NULL}
215: };
216:
217: void
1.68 markus 218: ssh_userauth2(const char *local_user, const char *server_user, char *host,
1.100 markus 219: Sensitive *sensitive)
1.20 markus 220: {
221: Authctxt authctxt;
222: int type;
1.39 markus 223:
1.73 markus 224: if (options.challenge_response_authentication)
1.39 markus 225: options.kbd_interactive_authentication = 1;
1.20 markus 226:
227: debug("send SSH2_MSG_SERVICE_REQUEST");
228: packet_start(SSH2_MSG_SERVICE_REQUEST);
229: packet_put_cstring("ssh-userauth");
230: packet_send();
231: packet_write_wait();
1.91 markus 232: type = packet_read();
1.20 markus 233: if (type != SSH2_MSG_SERVICE_ACCEPT) {
234: fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
235: }
236: if (packet_remaining() > 0) {
1.91 markus 237: char *reply = packet_get_string(NULL);
1.20 markus 238: debug("service_accept: %s", reply);
239: xfree(reply);
240: } else {
241: debug("buggy server: service_accept w/o service");
242: }
1.90 markus 243: packet_check_eom();
1.20 markus 244: debug("got SSH2_MSG_SERVICE_ACCEPT");
245:
1.53 markus 246: if (options.preferred_authentications == NULL)
247: options.preferred_authentications = authmethods_get();
248:
1.20 markus 249: /* setup authentication context */
1.82 markus 250: memset(&authctxt, 0, sizeof(authctxt));
1.20 markus 251: authctxt.agent = ssh_get_authentication_connection();
252: authctxt.server_user = server_user;
1.68 markus 253: authctxt.local_user = local_user;
1.20 markus 254: authctxt.host = host;
255: authctxt.service = "ssh-connection"; /* service name */
256: authctxt.success = 0;
1.23 markus 257: authctxt.method = authmethod_lookup("none");
1.51 markus 258: authctxt.authlist = NULL;
1.100 markus 259: authctxt.sensitive = sensitive;
1.82 markus 260: authctxt.info_req_seen = 0;
1.23 markus 261: if (authctxt.method == NULL)
262: fatal("ssh_userauth2: internal error: cannot send userauth none request");
1.20 markus 263:
264: /* initial userauth request */
1.23 markus 265: userauth_none(&authctxt);
1.20 markus 266:
1.65 markus 267: dispatch_init(&input_userauth_error);
1.20 markus 268: dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
269: dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
1.35 markus 270: dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
1.20 markus 271: dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
272:
273: if (authctxt.agent != NULL)
274: ssh_close_authentication_connection(authctxt.agent);
275:
1.34 markus 276: debug("ssh-userauth2 successful: method %s", authctxt.method->name);
1.20 markus 277: }
278: void
1.51 markus 279: userauth(Authctxt *authctxt, char *authlist)
280: {
281: if (authlist == NULL) {
282: authlist = authctxt->authlist;
283: } else {
284: if (authctxt->authlist)
285: xfree(authctxt->authlist);
286: authctxt->authlist = authlist;
287: }
288: for (;;) {
289: Authmethod *method = authmethod_get(authlist);
290: if (method == NULL)
291: fatal("Permission denied (%s).", authlist);
292: authctxt->method = method;
293: if (method->userauth(authctxt) != 0) {
294: debug2("we sent a %s packet, wait for reply", method->name);
295: break;
296: } else {
297: debug2("we did not send a packet, disable method");
298: method->enabled = NULL;
299: }
300: }
301: }
302: void
1.92 markus 303: input_userauth_error(int type, u_int32_t seq, void *ctxt)
1.20 markus 304: {
1.35 markus 305: fatal("input_userauth_error: bad message during authentication: "
306: "type %d", type);
307: }
308: void
1.92 markus 309: input_userauth_banner(int type, u_int32_t seq, void *ctxt)
1.35 markus 310: {
311: char *msg, *lang;
312: debug3("input_userauth_banner");
313: msg = packet_get_string(NULL);
314: lang = packet_get_string(NULL);
315: fprintf(stderr, "%s", msg);
316: xfree(msg);
317: xfree(lang);
1.20 markus 318: }
319: void
1.92 markus 320: input_userauth_success(int type, u_int32_t seq, void *ctxt)
1.20 markus 321: {
322: Authctxt *authctxt = ctxt;
323: if (authctxt == NULL)
324: fatal("input_userauth_success: no authentication context");
1.51 markus 325: if (authctxt->authlist)
326: xfree(authctxt->authlist);
327: clear_auth_state(authctxt);
1.20 markus 328: authctxt->success = 1; /* break out */
329: }
330: void
1.92 markus 331: input_userauth_failure(int type, u_int32_t seq, void *ctxt)
1.20 markus 332: {
333: Authctxt *authctxt = ctxt;
334: char *authlist = NULL;
335: int partial;
336:
337: if (authctxt == NULL)
338: fatal("input_userauth_failure: no authentication context");
339:
1.23 markus 340: authlist = packet_get_string(NULL);
1.20 markus 341: partial = packet_get_char();
1.90 markus 342: packet_check_eom();
1.20 markus 343:
344: if (partial != 0)
1.45 markus 345: log("Authenticated with partial success.");
1.20 markus 346: debug("authentications that can continue: %s", authlist);
347:
1.51 markus 348: clear_auth_state(authctxt);
349: userauth(authctxt, authlist);
350: }
351: void
1.92 markus 352: input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
1.51 markus 353: {
354: Authctxt *authctxt = ctxt;
355: Key *key = NULL;
356: Buffer b;
1.96 markus 357: int pktype, sent = 0;
358: u_int alen, blen;
359: char *pkalg, *fp;
360: u_char *pkblob;
1.51 markus 361:
362: if (authctxt == NULL)
363: fatal("input_userauth_pk_ok: no authentication context");
364: if (datafellows & SSH_BUG_PKOK) {
365: /* this is similar to SSH_BUG_PKAUTH */
366: debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
367: pkblob = packet_get_string(&blen);
368: buffer_init(&b);
369: buffer_append(&b, pkblob, blen);
370: pkalg = buffer_get_string(&b, &alen);
371: buffer_free(&b);
372: } else {
373: pkalg = packet_get_string(&alen);
374: pkblob = packet_get_string(&blen);
375: }
1.90 markus 376: packet_check_eom();
1.51 markus 377:
378: debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
379: pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
380:
381: do {
382: if (authctxt->last_key == NULL ||
383: authctxt->last_key_sign == NULL) {
384: debug("no last key or no sign cb");
385: break;
386: }
1.95 markus 387: if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
1.51 markus 388: debug("unknown pkalg %s", pkalg);
389: break;
390: }
391: if ((key = key_from_blob(pkblob, blen)) == NULL) {
392: debug("no key from blob. pkalg %s", pkalg);
1.95 markus 393: break;
394: }
1.98 markus 395: if (key->type != pktype) {
1.95 markus 396: error("input_userauth_pk_ok: type mismatch "
397: "for decoded key (received %d, expected %d)",
398: key->type, pktype);
1.51 markus 399: break;
400: }
1.54 markus 401: fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
402: debug2("input_userauth_pk_ok: fp %s", fp);
403: xfree(fp);
1.51 markus 404: if (!key_equal(key, authctxt->last_key)) {
405: debug("key != last_key");
1.20 markus 406: break;
407: }
1.51 markus 408: sent = sign_and_send_pubkey(authctxt, key,
409: authctxt->last_key_sign);
1.87 deraadt 410: } while (0);
1.51 markus 411:
412: if (key != NULL)
413: key_free(key);
414: xfree(pkalg);
415: xfree(pkblob);
416:
417: /* unregister */
418: clear_auth_state(authctxt);
419: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
420:
421: /* try another method if we did not send a packet*/
422: if (sent == 0)
423: userauth(authctxt, NULL);
424:
1.20 markus 425: }
426:
1.1 markus 427: int
1.23 markus 428: userauth_none(Authctxt *authctxt)
429: {
430: /* initial userauth request */
431: packet_start(SSH2_MSG_USERAUTH_REQUEST);
432: packet_put_cstring(authctxt->server_user);
433: packet_put_cstring(authctxt->service);
434: packet_put_cstring(authctxt->method->name);
435: packet_send();
436: return 1;
437: }
438:
439: int
1.20 markus 440: userauth_passwd(Authctxt *authctxt)
1.1 markus 441: {
1.6 markus 442: static int attempt = 0;
1.99 markus 443: char prompt[150];
1.1 markus 444: char *password;
1.6 markus 445:
1.13 todd 446: if (attempt++ >= options.number_of_password_prompts)
1.6 markus 447: return 0;
1.13 todd 448:
1.87 deraadt 449: if (attempt != 1)
1.13 todd 450: error("Permission denied, please try again.");
1.1 markus 451:
1.43 itojun 452: snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
1.20 markus 453: authctxt->server_user, authctxt->host);
1.1 markus 454: password = read_passphrase(prompt, 0);
455: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 456: packet_put_cstring(authctxt->server_user);
457: packet_put_cstring(authctxt->service);
1.23 markus 458: packet_put_cstring(authctxt->method->name);
1.1 markus 459: packet_put_char(0);
1.49 markus 460: packet_put_cstring(password);
1.1 markus 461: memset(password, 0, strlen(password));
462: xfree(password);
1.85 markus 463: packet_add_padding(64);
1.1 markus 464: packet_send();
1.99 markus 465:
466: dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
467: &input_userauth_passwd_changereq);
468:
1.1 markus 469: return 1;
470: }
1.99 markus 471: /*
472: * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
473: */
474: void
475: input_userauth_passwd_changereq(int type, uint32_t seqnr, void *ctxt)
476: {
477: Authctxt *authctxt = ctxt;
478: char *info, *lang, *password = NULL, *retype = NULL;
479: char prompt[150];
480:
481: debug2("input_userauth_passwd_changereq");
482:
483: if (authctxt == NULL)
484: fatal("input_userauth_passwd_changereq: "
485: "no authentication context");
486:
487: info = packet_get_string(NULL);
488: lang = packet_get_string(NULL);
489: if (strlen(info) > 0)
490: log("%s", info);
491: xfree(info);
492: xfree(lang);
493: packet_start(SSH2_MSG_USERAUTH_REQUEST);
494: packet_put_cstring(authctxt->server_user);
495: packet_put_cstring(authctxt->service);
496: packet_put_cstring(authctxt->method->name);
497: packet_put_char(1); /* additional info */
498: snprintf(prompt, sizeof(prompt),
499: "Enter %.30s@%.128s's old password: ",
500: authctxt->server_user, authctxt->host);
501: password = read_passphrase(prompt, 0);
502: packet_put_cstring(password);
503: memset(password, 0, strlen(password));
504: xfree(password);
505: password = NULL;
506: while (password == NULL) {
507: snprintf(prompt, sizeof(prompt),
508: "Enter %.30s@%.128s's new password: ",
509: authctxt->server_user, authctxt->host);
510: password = read_passphrase(prompt, RP_ALLOW_EOF);
511: if (password == NULL) {
512: /* bail out */
513: return;
514: }
515: snprintf(prompt, sizeof(prompt),
516: "Retype %.30s@%.128s's new password: ",
517: authctxt->server_user, authctxt->host);
518: retype = read_passphrase(prompt, 0);
519: if (strcmp(password, retype) != 0) {
520: memset(password, 0, strlen(password));
521: xfree(password);
522: log("Mismatch; try again, EOF to quit.");
523: password = NULL;
524: }
525: memset(retype, 0, strlen(retype));
526: xfree(retype);
527: }
528: packet_put_cstring(password);
529: memset(password, 0, strlen(password));
530: xfree(password);
531: packet_add_padding(64);
532: packet_send();
533:
534: dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
535: &input_userauth_passwd_changereq);
536: }
1.1 markus 537:
1.79 stevesk 538: static void
1.51 markus 539: clear_auth_state(Authctxt *authctxt)
540: {
541: /* XXX clear authentication state */
1.99 markus 542: dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
543:
1.51 markus 544: if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
545: debug3("clear_auth_state: key_free %p", authctxt->last_key);
546: key_free(authctxt->last_key);
547: }
548: authctxt->last_key = NULL;
549: authctxt->last_key_hint = -2;
550: authctxt->last_key_sign = NULL;
551: }
552:
1.76 itojun 553: static int
1.20 markus 554: sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
1.1 markus 555: {
556: Buffer b;
1.32 markus 557: u_char *blob, *signature;
1.96 markus 558: u_int bloblen, slen;
1.14 markus 559: int skip = 0;
1.17 markus 560: int ret = -1;
1.23 markus 561: int have_sig = 1;
1.1 markus 562:
1.30 markus 563: debug3("sign_and_send_pubkey");
1.51 markus 564:
1.28 markus 565: if (key_to_blob(k, &blob, &bloblen) == 0) {
566: /* we cannot handle this key */
1.30 markus 567: debug3("sign_and_send_pubkey: cannot handle key");
1.28 markus 568: return 0;
569: }
1.1 markus 570: /* data to be signed */
571: buffer_init(&b);
1.26 markus 572: if (datafellows & SSH_OLD_SESSIONID) {
573: buffer_append(&b, session_id2, session_id2_len);
1.41 stevesk 574: skip = session_id2_len;
1.26 markus 575: } else {
1.14 markus 576: buffer_put_string(&b, session_id2, session_id2_len);
577: skip = buffer_len(&b);
578: }
1.1 markus 579: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 580: buffer_put_cstring(&b, authctxt->server_user);
1.10 markus 581: buffer_put_cstring(&b,
1.30 markus 582: datafellows & SSH_BUG_PKSERVICE ?
1.10 markus 583: "ssh-userauth" :
1.20 markus 584: authctxt->service);
1.30 markus 585: if (datafellows & SSH_BUG_PKAUTH) {
586: buffer_put_char(&b, have_sig);
587: } else {
588: buffer_put_cstring(&b, authctxt->method->name);
589: buffer_put_char(&b, have_sig);
1.41 stevesk 590: buffer_put_cstring(&b, key_ssh_name(k));
1.30 markus 591: }
1.1 markus 592: buffer_put_string(&b, blob, bloblen);
593:
594: /* generate signature */
1.51 markus 595: ret = (*sign_callback)(authctxt, k, &signature, &slen,
596: buffer_ptr(&b), buffer_len(&b));
1.17 markus 597: if (ret == -1) {
598: xfree(blob);
599: buffer_free(&b);
600: return 0;
601: }
1.28 markus 602: #ifdef DEBUG_PK
1.1 markus 603: buffer_dump(&b);
604: #endif
1.30 markus 605: if (datafellows & SSH_BUG_PKSERVICE) {
1.10 markus 606: buffer_clear(&b);
607: buffer_append(&b, session_id2, session_id2_len);
1.51 markus 608: skip = session_id2_len;
1.10 markus 609: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.20 markus 610: buffer_put_cstring(&b, authctxt->server_user);
611: buffer_put_cstring(&b, authctxt->service);
1.23 markus 612: buffer_put_cstring(&b, authctxt->method->name);
613: buffer_put_char(&b, have_sig);
1.30 markus 614: if (!(datafellows & SSH_BUG_PKAUTH))
1.41 stevesk 615: buffer_put_cstring(&b, key_ssh_name(k));
1.10 markus 616: buffer_put_string(&b, blob, bloblen);
617: }
618: xfree(blob);
1.51 markus 619:
1.1 markus 620: /* append signature */
621: buffer_put_string(&b, signature, slen);
622: xfree(signature);
623:
624: /* skip session id and packet type */
1.14 markus 625: if (buffer_len(&b) < skip + 1)
1.20 markus 626: fatal("userauth_pubkey: internal error");
1.14 markus 627: buffer_consume(&b, skip + 1);
1.1 markus 628:
629: /* put remaining data from buffer into packet */
630: packet_start(SSH2_MSG_USERAUTH_REQUEST);
631: packet_put_raw(buffer_ptr(&b), buffer_len(&b));
632: buffer_free(&b);
633: packet_send();
1.17 markus 634:
635: return 1;
1.16 markus 636: }
637:
1.76 itojun 638: static int
1.51 markus 639: send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
640: int hint)
1.20 markus 641: {
1.51 markus 642: u_char *blob;
1.97 markus 643: u_int bloblen, have_sig = 0;
1.20 markus 644:
1.51 markus 645: debug3("send_pubkey_test");
1.16 markus 646:
1.51 markus 647: if (key_to_blob(k, &blob, &bloblen) == 0) {
648: /* we cannot handle this key */
649: debug3("send_pubkey_test: cannot handle key");
1.16 markus 650: return 0;
651: }
1.51 markus 652: /* register callback for USERAUTH_PK_OK message */
653: authctxt->last_key_sign = sign_callback;
654: authctxt->last_key_hint = hint;
655: authctxt->last_key = k;
656: dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
657:
658: packet_start(SSH2_MSG_USERAUTH_REQUEST);
659: packet_put_cstring(authctxt->server_user);
660: packet_put_cstring(authctxt->service);
661: packet_put_cstring(authctxt->method->name);
662: packet_put_char(have_sig);
663: if (!(datafellows & SSH_BUG_PKAUTH))
664: packet_put_cstring(key_ssh_name(k));
665: packet_put_string(blob, bloblen);
666: xfree(blob);
667: packet_send();
668: return 1;
669: }
670:
1.76 itojun 671: static Key *
1.51 markus 672: load_identity_file(char *filename)
673: {
674: Key *private;
675: char prompt[300], *passphrase;
1.56 markus 676: int quit, i;
1.52 markus 677: struct stat st;
1.16 markus 678:
1.52 markus 679: if (stat(filename, &st) < 0) {
680: debug3("no such identity: %s", filename);
681: return NULL;
682: }
1.56 markus 683: private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
684: if (private == NULL) {
685: if (options.batch_mode)
1.51 markus 686: return NULL;
1.16 markus 687: snprintf(prompt, sizeof prompt,
1.88 deraadt 688: "Enter passphrase for key '%.100s': ", filename);
1.20 markus 689: for (i = 0; i < options.number_of_password_prompts; i++) {
690: passphrase = read_passphrase(prompt, 0);
691: if (strcmp(passphrase, "") != 0) {
1.56 markus 692: private = key_load_private_type(KEY_UNSPEC, filename,
693: passphrase, NULL);
1.51 markus 694: quit = 0;
1.20 markus 695: } else {
696: debug2("no passphrase given, try next key");
1.51 markus 697: quit = 1;
1.20 markus 698: }
699: memset(passphrase, 0, strlen(passphrase));
700: xfree(passphrase);
1.56 markus 701: if (private != NULL || quit)
1.20 markus 702: break;
703: debug2("bad passphrase given, try again...");
1.16 markus 704: }
705: }
1.51 markus 706: return private;
707: }
708:
1.76 itojun 709: static int
1.96 markus 710: identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
711: u_char *data, u_int datalen)
1.51 markus 712: {
713: Key *private;
714: int idx, ret;
715:
716: idx = authctxt->last_key_hint;
717: if (idx < 0)
718: return -1;
1.80 markus 719:
720: /* private key is stored in external hardware */
1.88 deraadt 721: if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
1.80 markus 722: return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
723:
1.51 markus 724: private = load_identity_file(options.identity_files[idx]);
725: if (private == NULL)
726: return -1;
727: ret = key_sign(private, sigp, lenp, data, datalen);
728: key_free(private);
1.17 markus 729: return ret;
730: }
731:
1.76 itojun 732: static int
1.96 markus 733: agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
734: u_char *data, u_int datalen)
1.17 markus 735: {
1.20 markus 736: return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1.17 markus 737: }
738:
1.76 itojun 739: static int
1.96 markus 740: key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
741: u_char *data, u_int datalen)
1.51 markus 742: {
1.67 markus 743: return key_sign(key, sigp, lenp, data, datalen);
1.51 markus 744: }
745:
1.76 itojun 746: static int
1.20 markus 747: userauth_pubkey_agent(Authctxt *authctxt)
1.17 markus 748: {
749: static int called = 0;
1.28 markus 750: int ret = 0;
1.17 markus 751: char *comment;
752: Key *k;
753:
754: if (called == 0) {
1.28 markus 755: if (ssh_get_num_identities(authctxt->agent, 2) == 0)
756: debug2("userauth_pubkey_agent: no keys at all");
1.20 markus 757: called = 1;
1.17 markus 758: }
1.28 markus 759: k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1.20 markus 760: if (k == NULL) {
1.28 markus 761: debug2("userauth_pubkey_agent: no more keys");
762: } else {
1.51 markus 763: debug("userauth_pubkey_agent: testing agent key %s", comment);
1.28 markus 764: xfree(comment);
1.51 markus 765: ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
766: if (ret == 0)
767: key_free(k);
1.20 markus 768: }
1.28 markus 769: if (ret == 0)
770: debug2("userauth_pubkey_agent: no message sent");
1.17 markus 771: return ret;
1.1 markus 772: }
773:
1.20 markus 774: int
775: userauth_pubkey(Authctxt *authctxt)
776: {
777: static int idx = 0;
778: int sent = 0;
1.51 markus 779: Key *key;
780: char *filename;
1.20 markus 781:
1.28 markus 782: if (authctxt->agent != NULL) {
783: do {
784: sent = userauth_pubkey_agent(authctxt);
1.87 deraadt 785: } while (!sent && authctxt->agent->howmany > 0);
1.28 markus 786: }
787: while (!sent && idx < options.num_identity_files) {
1.51 markus 788: key = options.identity_keys[idx];
789: filename = options.identity_files[idx];
790: if (key == NULL) {
791: debug("try privkey: %s", filename);
792: key = load_identity_file(filename);
793: if (key != NULL) {
794: sent = sign_and_send_pubkey(authctxt, key,
795: key_sign_cb);
796: key_free(key);
797: }
798: } else if (key->type != KEY_RSA1) {
799: debug("try pubkey: %s", filename);
800: sent = send_pubkey_test(authctxt, key,
801: identity_sign_cb, idx);
802: }
1.28 markus 803: idx++;
804: }
1.20 markus 805: return sent;
806: }
807:
1.23 markus 808: /*
809: * Send userauth request message specifying keyboard-interactive method.
810: */
811: int
812: userauth_kbdint(Authctxt *authctxt)
813: {
814: static int attempt = 0;
815:
816: if (attempt++ >= options.number_of_password_prompts)
817: return 0;
1.82 markus 818: /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
819: if (attempt > 1 && !authctxt->info_req_seen) {
820: debug3("userauth_kbdint: disable: no info_req_seen");
821: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
822: return 0;
823: }
1.23 markus 824:
825: debug2("userauth_kbdint");
826: packet_start(SSH2_MSG_USERAUTH_REQUEST);
827: packet_put_cstring(authctxt->server_user);
828: packet_put_cstring(authctxt->service);
829: packet_put_cstring(authctxt->method->name);
830: packet_put_cstring(""); /* lang */
831: packet_put_cstring(options.kbd_interactive_devices ?
832: options.kbd_interactive_devices : "");
833: packet_send();
834:
835: dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
836: return 1;
837: }
838:
839: /*
1.46 markus 840: * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1.23 markus 841: */
842: void
1.92 markus 843: input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1.23 markus 844: {
845: Authctxt *authctxt = ctxt;
1.46 markus 846: char *name, *inst, *lang, *prompt, *response;
1.32 markus 847: u_int num_prompts, i;
1.23 markus 848: int echo = 0;
849:
850: debug2("input_userauth_info_req");
851:
852: if (authctxt == NULL)
853: fatal("input_userauth_info_req: no authentication context");
1.82 markus 854:
855: authctxt->info_req_seen = 1;
1.23 markus 856:
857: name = packet_get_string(NULL);
858: inst = packet_get_string(NULL);
859: lang = packet_get_string(NULL);
860: if (strlen(name) > 0)
1.78 markus 861: log("%s", name);
1.23 markus 862: if (strlen(inst) > 0)
1.78 markus 863: log("%s", inst);
1.46 markus 864: xfree(name);
1.23 markus 865: xfree(inst);
1.46 markus 866: xfree(lang);
1.23 markus 867:
868: num_prompts = packet_get_int();
869: /*
870: * Begin to build info response packet based on prompts requested.
871: * We commit to providing the correct number of responses, so if
872: * further on we run into a problem that prevents this, we have to
873: * be sure and clean this up and send a correct error response.
874: */
875: packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
876: packet_put_int(num_prompts);
877:
1.73 markus 878: debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1.23 markus 879: for (i = 0; i < num_prompts; i++) {
880: prompt = packet_get_string(NULL);
881: echo = packet_get_char();
882:
1.77 markus 883: response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1.23 markus 884:
1.49 markus 885: packet_put_cstring(response);
1.23 markus 886: memset(response, 0, strlen(response));
887: xfree(response);
888: xfree(prompt);
889: }
1.90 markus 890: packet_check_eom(); /* done with parsing incoming message. */
1.23 markus 891:
1.85 markus 892: packet_add_padding(64);
1.23 markus 893: packet_send();
1.68 markus 894: }
895:
1.100 markus 896: static int
897: ssh_keysign(
898: Key *key,
899: u_char **sigp, u_int *lenp,
900: u_char *data, u_int datalen)
901: {
902: Buffer b;
1.101 markus 903: struct stat st;
1.100 markus 904: pid_t pid;
905: int to[2], from[2], status, version = 1;
906:
907: debug("ssh_keysign called");
908:
1.101 markus 909: if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
910: error("ssh_keysign: no installed: %s", strerror(errno));
911: return -1;
912: }
1.100 markus 913: if (fflush(stdout) != 0)
914: error("ssh_keysign: fflush: %s", strerror(errno));
915: if (pipe(to) < 0) {
916: error("ssh_keysign: pipe: %s", strerror(errno));
917: return -1;
918: }
919: if (pipe(from) < 0) {
920: error("ssh_keysign: pipe: %s", strerror(errno));
921: return -1;
922: }
923: if ((pid = fork()) < 0) {
924: error("ssh_keysign: fork: %s", strerror(errno));
925: return -1;
926: }
927: if (pid == 0) {
928: seteuid(getuid());
929: setuid(getuid());
930: close(from[0]);
931: if (dup2(from[1], STDOUT_FILENO) < 0)
932: fatal("ssh_keysign: dup2: %s", strerror(errno));
933: close(to[1]);
934: if (dup2(to[0], STDIN_FILENO) < 0)
935: fatal("ssh_keysign: dup2: %s", strerror(errno));
1.102 ! markus 936: execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1.100 markus 937: fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
938: strerror(errno));
939: }
940: close(from[1]);
941: close(to[0]);
942:
943: buffer_init(&b);
944: buffer_put_string(&b, data, datalen);
945: msg_send(to[1], version, &b);
946:
947: if (msg_recv(from[0], &b) < 0) {
1.101 markus 948: error("ssh_keysign: no reply");
1.100 markus 949: buffer_clear(&b);
950: return -1;
951: }
1.101 markus 952: close(from[0]);
953: close(to[1]);
954:
955: while (waitpid(pid, &status, 0) < 0)
956: if (errno != EINTR)
957: break;
958:
1.100 markus 959: if (buffer_get_char(&b) != version) {
1.101 markus 960: error("ssh_keysign: bad version");
1.100 markus 961: buffer_clear(&b);
962: return -1;
963: }
964: *sigp = buffer_get_string(&b, lenp);
965: buffer_clear(&b);
966:
967: return 0;
968: }
969:
1.68 markus 970: int
971: userauth_hostbased(Authctxt *authctxt)
972: {
973: Key *private = NULL;
1.100 markus 974: Sensitive *sensitive = authctxt->sensitive;
1.68 markus 975: Buffer b;
976: u_char *signature, *blob;
977: char *chost, *pkalg, *p;
1.72 markus 978: const char *service;
1.68 markus 979: u_int blen, slen;
1.71 markus 980: int ok, i, len, found = 0;
1.68 markus 981:
982: /* check for a useful key */
1.100 markus 983: for (i = 0; i < sensitive->nkeys; i++) {
984: private = sensitive->keys[i];
1.68 markus 985: if (private && private->type != KEY_RSA1) {
986: found = 1;
987: /* we take and free the key */
1.100 markus 988: sensitive->keys[i] = NULL;
1.68 markus 989: break;
990: }
991: }
992: if (!found) {
1.84 markus 993: debug("userauth_hostbased: no more client hostkeys");
1.68 markus 994: return 0;
995: }
996: if (key_to_blob(private, &blob, &blen) == 0) {
997: key_free(private);
998: return 0;
999: }
1.84 markus 1000: /* figure out a name for the client host */
1001: p = get_local_name(packet_get_connection_in());
1002: if (p == NULL) {
1003: error("userauth_hostbased: cannot get local ipaddr/name");
1004: key_free(private);
1005: return 0;
1006: }
1007: len = strlen(p) + 2;
1008: chost = xmalloc(len);
1009: strlcpy(chost, p, len);
1010: strlcat(chost, ".", len);
1011: debug2("userauth_hostbased: chost %s", chost);
1012:
1.72 markus 1013: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1014: authctxt->service;
1.68 markus 1015: pkalg = xstrdup(key_ssh_name(private));
1016: buffer_init(&b);
1017: /* construct data */
1.72 markus 1018: buffer_put_string(&b, session_id2, session_id2_len);
1.68 markus 1019: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1020: buffer_put_cstring(&b, authctxt->server_user);
1.72 markus 1021: buffer_put_cstring(&b, service);
1.68 markus 1022: buffer_put_cstring(&b, authctxt->method->name);
1023: buffer_put_cstring(&b, pkalg);
1024: buffer_put_string(&b, blob, blen);
1025: buffer_put_cstring(&b, chost);
1026: buffer_put_cstring(&b, authctxt->local_user);
1027: #ifdef DEBUG_PK
1028: buffer_dump(&b);
1029: #endif
1.100 markus 1030: if (sensitive->external_keysign)
1031: ok = ssh_keysign(private, &signature, &slen,
1032: buffer_ptr(&b), buffer_len(&b));
1033: else
1034: ok = key_sign(private, &signature, &slen,
1035: buffer_ptr(&b), buffer_len(&b));
1.68 markus 1036: key_free(private);
1037: buffer_free(&b);
1038: if (ok != 0) {
1039: error("key_sign failed");
1040: xfree(chost);
1041: xfree(pkalg);
1042: return 0;
1043: }
1044: packet_start(SSH2_MSG_USERAUTH_REQUEST);
1045: packet_put_cstring(authctxt->server_user);
1046: packet_put_cstring(authctxt->service);
1047: packet_put_cstring(authctxt->method->name);
1048: packet_put_cstring(pkalg);
1049: packet_put_string(blob, blen);
1050: packet_put_cstring(chost);
1051: packet_put_cstring(authctxt->local_user);
1052: packet_put_string(signature, slen);
1053: memset(signature, 's', slen);
1054: xfree(signature);
1055: xfree(chost);
1056: xfree(pkalg);
1057:
1058: packet_send();
1059: return 1;
1.23 markus 1060: }
1.20 markus 1061:
1062: /* find auth method */
1063:
1064: /*
1065: * given auth method name, if configurable options permit this method fill
1066: * in auth_ident field and return true, otherwise return false.
1067: */
1.76 itojun 1068: static int
1.20 markus 1069: authmethod_is_enabled(Authmethod *method)
1070: {
1071: if (method == NULL)
1072: return 0;
1073: /* return false if options indicate this method is disabled */
1074: if (method->enabled == NULL || *method->enabled == 0)
1075: return 0;
1076: /* return false if batch mode is enabled but method needs interactive mode */
1077: if (method->batch_flag != NULL && *method->batch_flag != 0)
1078: return 0;
1079: return 1;
1080: }
1081:
1.76 itojun 1082: static Authmethod *
1.20 markus 1083: authmethod_lookup(const char *name)
1.1 markus 1084: {
1.20 markus 1085: Authmethod *method = NULL;
1086: if (name != NULL)
1087: for (method = authmethods; method->name != NULL; method++)
1088: if (strcmp(name, method->name) == 0)
1089: return method;
1090: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1091: return NULL;
1092: }
1.1 markus 1093:
1.53 markus 1094: /* XXX internal state */
1095: static Authmethod *current = NULL;
1096: static char *supported = NULL;
1097: static char *preferred = NULL;
1.20 markus 1098: /*
1099: * Given the authentication method list sent by the server, return the
1100: * next method we should try. If the server initially sends a nil list,
1.67 markus 1101: * use a built-in default list.
1.41 stevesk 1102: */
1.76 itojun 1103: static Authmethod *
1.20 markus 1104: authmethod_get(char *authlist)
1105: {
1.53 markus 1106:
1107: char *name = NULL;
1.97 markus 1108: u_int next;
1.41 stevesk 1109:
1.20 markus 1110: /* Use a suitable default if we're passed a nil list. */
1111: if (authlist == NULL || strlen(authlist) == 0)
1.53 markus 1112: authlist = options.preferred_authentications;
1.20 markus 1113:
1.53 markus 1114: if (supported == NULL || strcmp(authlist, supported) != 0) {
1115: debug3("start over, passed a different list %s", authlist);
1116: if (supported != NULL)
1117: xfree(supported);
1118: supported = xstrdup(authlist);
1119: preferred = options.preferred_authentications;
1120: debug3("preferred %s", preferred);
1121: current = NULL;
1122: } else if (current != NULL && authmethod_is_enabled(current))
1123: return current;
1.20 markus 1124:
1.53 markus 1125: for (;;) {
1126: if ((name = match_list(preferred, supported, &next)) == NULL) {
1127: debug("no more auth methods to try");
1128: current = NULL;
1129: return NULL;
1130: }
1131: preferred += next;
1.23 markus 1132: debug3("authmethod_lookup %s", name);
1.53 markus 1133: debug3("remaining preferred: %s", preferred);
1134: if ((current = authmethod_lookup(name)) != NULL &&
1135: authmethod_is_enabled(current)) {
1.23 markus 1136: debug3("authmethod_is_enabled %s", name);
1.53 markus 1137: debug("next auth method to try is %s", name);
1138: return current;
1.23 markus 1139: }
1.1 markus 1140: }
1.53 markus 1141: }
1.1 markus 1142:
1.79 stevesk 1143: static char *
1.53 markus 1144: authmethods_get(void)
1145: {
1146: Authmethod *method = NULL;
1.93 markus 1147: Buffer b;
1148: char *list;
1.27 provos 1149:
1.93 markus 1150: buffer_init(&b);
1.53 markus 1151: for (method = authmethods; method->name != NULL; method++) {
1152: if (authmethod_is_enabled(method)) {
1.93 markus 1153: if (buffer_len(&b) > 0)
1154: buffer_append(&b, ",", 1);
1155: buffer_append(&b, method->name, strlen(method->name));
1.53 markus 1156: }
1157: }
1.93 markus 1158: buffer_append(&b, "\0", 1);
1159: list = xstrdup(buffer_ptr(&b));
1160: buffer_free(&b);
1161: return list;
1.1 markus 1162: }
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