Annotation of src/usr.bin/ssh/auth2.c, Revision 1.56.2.5
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: */
1.14 deraadt 24:
1.1 markus 25: #include "includes.h"
1.56.2.5! miod 26: RCSID("$OpenBSD: auth2.c,v 1.91 2002/05/13 02:37:39 itojun Exp $");
1.1 markus 27:
28: #include <openssl/evp.h>
29:
1.32 markus 30: #include "ssh2.h"
1.1 markus 31: #include "xmalloc.h"
32: #include "rsa.h"
1.45 djm 33: #include "sshpty.h"
1.1 markus 34: #include "packet.h"
35: #include "buffer.h"
1.32 markus 36: #include "log.h"
1.1 markus 37: #include "servconf.h"
38: #include "compat.h"
39: #include "channels.h"
40: #include "bufaux.h"
41: #include "auth.h"
42: #include "session.h"
43: #include "dispatch.h"
44: #include "key.h"
1.32 markus 45: #include "cipher.h"
46: #include "kex.h"
1.29 markus 47: #include "pathnames.h"
1.1 markus 48: #include "uidswap.h"
1.10 markus 49: #include "auth-options.h"
1.52 markus 50: #include "hostfile.h"
51: #include "canohost.h"
1.56.2.1 jason 52: #include "match.h"
1.56.2.5! miod 53: #include "monitor_wrap.h"
! 54: #include "atomicio.h"
1.1 markus 55:
56: /* import */
57: extern ServerOptions options;
1.23 markus 58: extern u_char *session_id2;
1.1 markus 59: extern int session_id2_len;
60:
1.56.2.5! miod 61: Authctxt *x_authctxt = NULL;
1.18 markus 62: static int one = 1;
63:
64: typedef struct Authmethod Authmethod;
65: struct Authmethod {
66: char *name;
67: int (*userauth)(Authctxt *authctxt);
68: int *enabled;
69: };
70:
1.1 markus 71: /* protocol */
72:
1.56.2.4 miod 73: static void input_service_request(int, u_int32_t, void *);
74: static void input_userauth_request(int, u_int32_t, void *);
1.1 markus 75:
76: /* helper */
1.56.2.1 jason 77: static Authmethod *authmethod_lookup(const char *);
78: static char *authmethods_get(void);
1.56.2.5! miod 79: int user_key_allowed(struct passwd *, Key *);
! 80: int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
1.1 markus 81:
1.18 markus 82: /* auth */
1.56.2.1 jason 83: static void userauth_banner(void);
84: static int userauth_none(Authctxt *);
85: static int userauth_passwd(Authctxt *);
86: static int userauth_pubkey(Authctxt *);
87: static int userauth_hostbased(Authctxt *);
88: static int userauth_kbdint(Authctxt *);
1.18 markus 89:
90: Authmethod authmethods[] = {
91: {"none",
92: userauth_none,
93: &one},
94: {"publickey",
95: userauth_pubkey,
1.21 markus 96: &options.pubkey_authentication},
1.40 markus 97: {"password",
98: userauth_passwd,
99: &options.password_authentication},
1.18 markus 100: {"keyboard-interactive",
101: userauth_kbdint,
102: &options.kbd_interactive_authentication},
1.52 markus 103: {"hostbased",
104: userauth_hostbased,
105: &options.hostbased_authentication},
1.18 markus 106: {NULL, NULL, NULL}
1.1 markus 107: };
108:
109: /*
1.18 markus 110: * loop until authctxt->success == TRUE
1.1 markus 111: */
112:
1.56.2.5! miod 113: Authctxt *
1.56.2.4 miod 114: do_authentication2(void)
1.1 markus 115: {
1.28 markus 116: Authctxt *authctxt = authctxt_new();
117:
1.18 markus 118: x_authctxt = authctxt; /*XXX*/
119:
1.56.2.2 miod 120: /* challenge-response is implemented via keyboard interactive */
1.56.2.1 jason 121: if (options.challenge_response_authentication)
1.34 markus 122: options.kbd_interactive_authentication = 1;
123:
1.56.2.4 miod 124: dispatch_init(&dispatch_protocol_error);
1.1 markus 125: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 126: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.56.2.5! miod 127:
! 128: return (authctxt);
1.1 markus 129: }
130:
1.56.2.1 jason 131: static void
1.56.2.4 miod 132: input_service_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 133: {
1.18 markus 134: Authctxt *authctxt = ctxt;
1.23 markus 135: u_int len;
1.1 markus 136: int accept = 0;
137: char *service = packet_get_string(&len);
1.56.2.4 miod 138: packet_check_eom();
1.1 markus 139:
1.18 markus 140: if (authctxt == NULL)
141: fatal("input_service_request: no authctxt");
142:
1.1 markus 143: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 144: if (!authctxt->success) {
1.1 markus 145: accept = 1;
146: /* now we can handle user-auth requests */
147: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
148: }
149: }
150: /* XXX all other service requests are denied */
151:
152: if (accept) {
153: packet_start(SSH2_MSG_SERVICE_ACCEPT);
154: packet_put_cstring(service);
155: packet_send();
156: packet_write_wait();
157: } else {
158: debug("bad service request %s", service);
159: packet_disconnect("bad service request %s", service);
160: }
161: xfree(service);
162: }
163:
1.56.2.1 jason 164: static void
1.56.2.4 miod 165: input_userauth_request(int type, u_int32_t seq, void *ctxt)
1.1 markus 166: {
1.18 markus 167: Authctxt *authctxt = ctxt;
168: Authmethod *m = NULL;
1.28 markus 169: char *user, *service, *method, *style = NULL;
1.1 markus 170: int authenticated = 0;
171:
1.18 markus 172: if (authctxt == NULL)
173: fatal("input_userauth_request: no authctxt");
1.1 markus 174:
1.18 markus 175: user = packet_get_string(NULL);
176: service = packet_get_string(NULL);
177: method = packet_get_string(NULL);
1.1 markus 178: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 179: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 180:
1.28 markus 181: if ((style = strchr(user, ':')) != NULL)
182: *style++ = 0;
183:
1.36 stevesk 184: if (authctxt->attempt++ == 0) {
1.18 markus 185: /* setup auth context */
1.56.2.5! miod 186: authctxt->pw = PRIVSEP(getpwnamallow(user));
! 187: if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
1.18 markus 188: authctxt->valid = 1;
189: debug2("input_userauth_request: setting up authctxt for %s", user);
190: } else {
191: log("input_userauth_request: illegal user %s", user);
192: }
1.56.2.5! miod 193: setproctitle("%s%s", authctxt->pw ? user : "unknown",
! 194: use_privsep ? " [net]" : "");
1.18 markus 195: authctxt->user = xstrdup(user);
196: authctxt->service = xstrdup(service);
1.56.2.1 jason 197: authctxt->style = style ? xstrdup(style) : NULL;
1.56.2.5! miod 198: if (use_privsep)
! 199: mm_inform_authserv(service, style);
1.56.2.1 jason 200: } else if (strcmp(user, authctxt->user) != 0 ||
201: strcmp(service, authctxt->service) != 0) {
202: packet_disconnect("Change of username or service not allowed: "
203: "(%s,%s) -> (%s,%s)",
204: authctxt->user, authctxt->service, user, service);
1.1 markus 205: }
1.28 markus 206: /* reset state */
1.56.2.4 miod 207: auth2_challenge_stop(authctxt);
1.28 markus 208: authctxt->postponed = 0;
1.18 markus 209:
1.28 markus 210: /* try to authenticate user */
1.18 markus 211: m = authmethod_lookup(method);
212: if (m != NULL) {
213: debug2("input_userauth_request: try method %s", method);
214: authenticated = m->userauth(authctxt);
215: }
1.49 markus 216: userauth_finish(authctxt, authenticated, method);
217:
218: xfree(service);
219: xfree(user);
220: xfree(method);
221: }
222:
223: void
224: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
225: {
1.56.2.1 jason 226: char *methods;
227:
1.28 markus 228: if (!authctxt->valid && authenticated)
229: fatal("INTERNAL ERROR: authenticated invalid user %s",
230: authctxt->user);
1.18 markus 231:
232: /* Special handling for root */
1.41 markus 233: if (authenticated && authctxt->pw->pw_uid == 0 &&
234: !auth_root_allowed(method))
1.3 markus 235: authenticated = 0;
236:
1.18 markus 237: /* Log before sending the reply */
1.28 markus 238: auth_log(authctxt, authenticated, method, " ssh2");
239:
1.56.2.1 jason 240: if (authctxt->postponed)
241: return;
242:
243: /* XXX todo: check if multiple auth methods are needed */
244: if (authenticated == 1) {
245: /* turn off userauth */
1.56.2.4 miod 246: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
1.56.2.1 jason 247: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
248: packet_send();
249: packet_write_wait();
250: /* now we can break out */
251: authctxt->success = 1;
252: } else {
253: if (authctxt->failures++ > AUTH_FAIL_MAX)
254: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
255: methods = authmethods_get();
256: packet_start(SSH2_MSG_USERAUTH_FAILURE);
257: packet_put_cstring(methods);
258: packet_put_char(0); /* XXX partial success, unused */
259: packet_send();
260: packet_write_wait();
261: xfree(methods);
262: }
1.18 markus 263: }
264:
1.56.2.5! miod 265: char *
! 266: auth2_read_banner(void)
1.25 markus 267: {
268: struct stat st;
269: char *banner = NULL;
270: off_t len, n;
271: int fd;
272:
1.56.2.5! miod 273: if ((fd = open(options.banner, O_RDONLY)) == -1)
! 274: return (NULL);
! 275: if (fstat(fd, &st) == -1) {
! 276: close(fd);
! 277: return (NULL);
! 278: }
1.25 markus 279: len = st.st_size;
280: banner = xmalloc(len + 1);
1.56.2.5! miod 281: n = atomicio(read, fd, banner, len);
! 282: close(fd);
! 283:
! 284: if (n != len) {
! 285: free(banner);
! 286: return (NULL);
! 287: }
1.25 markus 288: banner[n] = '\0';
1.56.2.5! miod 289:
! 290: return (banner);
! 291: }
! 292:
! 293: static void
! 294: userauth_banner(void)
! 295: {
! 296: char *banner = NULL;
! 297:
! 298: if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
! 299: return;
! 300:
! 301: if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
! 302: goto done;
! 303:
1.25 markus 304: packet_start(SSH2_MSG_USERAUTH_BANNER);
305: packet_put_cstring(banner);
306: packet_put_cstring(""); /* language, unused */
307: packet_send();
308: debug("userauth_banner: sent");
309: done:
310: if (banner)
311: xfree(banner);
312: return;
313: }
1.18 markus 314:
1.56.2.1 jason 315: static int
1.18 markus 316: userauth_none(Authctxt *authctxt)
1.1 markus 317: {
1.18 markus 318: /* disable method "none", only allowed one time */
319: Authmethod *m = authmethod_lookup("none");
320: if (m != NULL)
321: m->enabled = NULL;
1.56.2.4 miod 322: packet_check_eom();
1.25 markus 323: userauth_banner();
1.56.2.5! miod 324: return (authctxt->valid ? PRIVSEP(auth_password(authctxt, "")) : 0);
1.1 markus 325: }
1.18 markus 326:
1.56.2.1 jason 327: static int
1.18 markus 328: userauth_passwd(Authctxt *authctxt)
1.1 markus 329: {
330: char *password;
331: int authenticated = 0;
332: int change;
1.23 markus 333: u_int len;
1.1 markus 334: change = packet_get_char();
335: if (change)
336: log("password change not supported");
337: password = packet_get_string(&len);
1.56.2.4 miod 338: packet_check_eom();
1.18 markus 339: if (authctxt->valid &&
1.56.2.5! miod 340: PRIVSEP(auth_password(authctxt, password)) == 1)
1.1 markus 341: authenticated = 1;
342: memset(password, 0, len);
343: xfree(password);
344: return authenticated;
345: }
1.18 markus 346:
1.56.2.1 jason 347: static int
1.18 markus 348: userauth_kbdint(Authctxt *authctxt)
349: {
350: int authenticated = 0;
1.56.2.1 jason 351: char *lang, *devs;
1.56.2.4 miod 352:
1.18 markus 353: lang = packet_get_string(NULL);
354: devs = packet_get_string(NULL);
1.56.2.4 miod 355: packet_check_eom();
1.18 markus 356:
1.56.2.1 jason 357: debug("keyboard-interactive devs %s", devs);
1.28 markus 358:
1.56.2.1 jason 359: if (options.challenge_response_authentication)
1.34 markus 360: authenticated = auth2_challenge(authctxt, devs);
1.28 markus 361:
1.18 markus 362: xfree(devs);
1.56.2.1 jason 363: xfree(lang);
1.18 markus 364: return authenticated;
365: }
366:
1.56.2.1 jason 367: static int
1.18 markus 368: userauth_pubkey(Authctxt *authctxt)
1.1 markus 369: {
370: Buffer b;
1.56.2.4 miod 371: Key *key = NULL;
372: char *pkalg;
373: u_char *pkblob, *sig;
1.23 markus 374: u_int alen, blen, slen;
1.21 markus 375: int have_sig, pktype;
1.1 markus 376: int authenticated = 0;
377:
1.18 markus 378: if (!authctxt->valid) {
379: debug2("userauth_pubkey: disabled because of invalid user");
1.8 markus 380: return 0;
381: }
1.1 markus 382: have_sig = packet_get_char();
1.22 markus 383: if (datafellows & SSH_BUG_PKAUTH) {
384: debug2("userauth_pubkey: SSH_BUG_PKAUTH");
385: /* no explicit pkalg given */
386: pkblob = packet_get_string(&blen);
387: buffer_init(&b);
388: buffer_append(&b, pkblob, blen);
389: /* so we have to extract the pkalg from the pkblob */
390: pkalg = buffer_get_string(&b, &alen);
391: buffer_free(&b);
392: } else {
393: pkalg = packet_get_string(&alen);
394: pkblob = packet_get_string(&blen);
395: }
1.21 markus 396: pktype = key_type_from_name(pkalg);
397: if (pktype == KEY_UNSPEC) {
1.22 markus 398: /* this is perfectly legal */
1.56.2.4 miod 399: log("userauth_pubkey: unsupported public key algorithm: %s",
400: pkalg);
401: goto done;
1.1 markus 402: }
1.21 markus 403: key = key_from_blob(pkblob, blen);
1.56.2.4 miod 404: if (key == NULL) {
405: error("userauth_pubkey: cannot decode key: %s", pkalg);
406: goto done;
407: }
408: if (key->type != pktype) {
409: error("userauth_pubkey: type mismatch for decoded key "
410: "(received %d, expected %d)", key->type, pktype);
411: goto done;
412: }
413: if (have_sig) {
414: sig = packet_get_string(&slen);
415: packet_check_eom();
416: buffer_init(&b);
417: if (datafellows & SSH_OLD_SESSIONID) {
418: buffer_append(&b, session_id2, session_id2_len);
419: } else {
420: buffer_put_string(&b, session_id2, session_id2_len);
421: }
422: /* reconstruct packet */
423: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
424: buffer_put_cstring(&b, authctxt->user);
425: buffer_put_cstring(&b,
426: datafellows & SSH_BUG_PKSERVICE ?
427: "ssh-userauth" :
428: authctxt->service);
429: if (datafellows & SSH_BUG_PKAUTH) {
430: buffer_put_char(&b, have_sig);
431: } else {
432: buffer_put_cstring(&b, "publickey");
433: buffer_put_char(&b, have_sig);
434: buffer_put_cstring(&b, pkalg);
435: }
436: buffer_put_string(&b, pkblob, blen);
1.21 markus 437: #ifdef DEBUG_PK
1.56.2.4 miod 438: buffer_dump(&b);
1.1 markus 439: #endif
1.56.2.4 miod 440: /* test for correct signature */
1.56.2.5! miod 441: authenticated = 0;
! 442: if (PRIVSEP(user_key_allowed(authctxt->pw, key)) &&
! 443: PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
! 444: buffer_len(&b))) == 1)
1.56.2.4 miod 445: authenticated = 1;
446: buffer_clear(&b);
447: xfree(sig);
448: } else {
449: debug("test whether pkalg/pkblob are acceptable");
450: packet_check_eom();
1.18 markus 451:
1.56.2.4 miod 452: /* XXX fake reply and always send PK_OK ? */
453: /*
454: * XXX this allows testing whether a user is allowed
455: * to login: if you happen to have a valid pubkey this
456: * message is sent. the message is NEVER sent at all
457: * if a user is not allowed to login. is this an
458: * issue? -markus
459: */
1.56.2.5! miod 460: if (PRIVSEP(user_key_allowed(authctxt->pw, key))) {
1.56.2.4 miod 461: packet_start(SSH2_MSG_USERAUTH_PK_OK);
462: packet_put_string(pkalg, alen);
463: packet_put_string(pkblob, blen);
464: packet_send();
465: packet_write_wait();
466: authctxt->postponed = 1;
1.1 markus 467: }
468: }
1.56.2.4 miod 469: if (authenticated != 1)
470: auth_clear_options();
471: done:
1.21 markus 472: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1.56.2.4 miod 473: if (key != NULL)
474: key_free(key);
1.1 markus 475: xfree(pkalg);
476: xfree(pkblob);
477: return authenticated;
478: }
479:
1.56.2.1 jason 480: static int
1.52 markus 481: userauth_hostbased(Authctxt *authctxt)
482: {
483: Buffer b;
1.56.2.4 miod 484: Key *key = NULL;
485: char *pkalg, *cuser, *chost, *service;
486: u_char *pkblob, *sig;
1.52 markus 487: u_int alen, blen, slen;
488: int pktype;
489: int authenticated = 0;
490:
491: if (!authctxt->valid) {
492: debug2("userauth_hostbased: disabled because of invalid user");
493: return 0;
494: }
495: pkalg = packet_get_string(&alen);
496: pkblob = packet_get_string(&blen);
497: chost = packet_get_string(NULL);
498: cuser = packet_get_string(NULL);
499: sig = packet_get_string(&slen);
500:
501: debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
502: cuser, chost, pkalg, slen);
503: #ifdef DEBUG_PK
504: debug("signature:");
505: buffer_init(&b);
506: buffer_append(&b, sig, slen);
507: buffer_dump(&b);
508: buffer_free(&b);
509: #endif
510: pktype = key_type_from_name(pkalg);
511: if (pktype == KEY_UNSPEC) {
512: /* this is perfectly legal */
513: log("userauth_hostbased: unsupported "
514: "public key algorithm: %s", pkalg);
515: goto done;
516: }
517: key = key_from_blob(pkblob, blen);
518: if (key == NULL) {
1.56.2.4 miod 519: error("userauth_hostbased: cannot decode key: %s", pkalg);
520: goto done;
521: }
522: if (key->type != pktype) {
523: error("userauth_hostbased: type mismatch for decoded key "
524: "(received %d, expected %d)", key->type, pktype);
1.52 markus 525: goto done;
526: }
1.55 markus 527: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
528: authctxt->service;
1.52 markus 529: buffer_init(&b);
1.55 markus 530: buffer_put_string(&b, session_id2, session_id2_len);
1.52 markus 531: /* reconstruct packet */
532: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
533: buffer_put_cstring(&b, authctxt->user);
1.55 markus 534: buffer_put_cstring(&b, service);
1.52 markus 535: buffer_put_cstring(&b, "hostbased");
536: buffer_put_string(&b, pkalg, alen);
537: buffer_put_string(&b, pkblob, blen);
538: buffer_put_cstring(&b, chost);
539: buffer_put_cstring(&b, cuser);
540: #ifdef DEBUG_PK
541: buffer_dump(&b);
542: #endif
543: /* test for allowed key and correct signature */
1.56.2.5! miod 544: authenticated = 0;
! 545: if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
! 546: PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
! 547: buffer_len(&b))) == 1)
1.52 markus 548: authenticated = 1;
549:
550: buffer_clear(&b);
551: done:
552: debug2("userauth_hostbased: authenticated %d", authenticated);
1.56.2.4 miod 553: if (key != NULL)
554: key_free(key);
1.52 markus 555: xfree(pkalg);
556: xfree(pkblob);
557: xfree(cuser);
558: xfree(chost);
559: xfree(sig);
560: return authenticated;
561: }
562:
1.18 markus 563: /* get current user */
1.1 markus 564:
565: struct passwd*
566: auth_get_user(void)
567: {
1.18 markus 568: return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
1.1 markus 569: }
570:
1.18 markus 571: #define DELIM ","
572:
1.56.2.1 jason 573: static char *
1.18 markus 574: authmethods_get(void)
1.1 markus 575: {
1.18 markus 576: Authmethod *method = NULL;
1.56.2.4 miod 577: Buffer b;
1.18 markus 578: char *list;
1.1 markus 579:
1.56.2.4 miod 580: buffer_init(&b);
1.18 markus 581: for (method = authmethods; method->name != NULL; method++) {
582: if (strcmp(method->name, "none") == 0)
583: continue;
584: if (method->enabled != NULL && *(method->enabled) != 0) {
1.56.2.4 miod 585: if (buffer_len(&b) > 0)
586: buffer_append(&b, ",", 1);
587: buffer_append(&b, method->name, strlen(method->name));
1.1 markus 588: }
589: }
1.56.2.4 miod 590: buffer_append(&b, "\0", 1);
591: list = xstrdup(buffer_ptr(&b));
592: buffer_free(&b);
1.18 markus 593: return list;
594: }
595:
1.56.2.1 jason 596: static Authmethod *
1.18 markus 597: authmethod_lookup(const char *name)
598: {
599: Authmethod *method = NULL;
600: if (name != NULL)
601: for (method = authmethods; method->name != NULL; method++)
602: if (method->enabled != NULL &&
603: *(method->enabled) != 0 &&
604: strcmp(name, method->name) == 0)
605: return method;
606: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
607: return NULL;
1.1 markus 608: }
609:
610: /* return 1 if user allows given key */
1.56.2.1 jason 611: static int
612: user_key_allowed2(struct passwd *pw, Key *key, char *file)
1.1 markus 613: {
1.56.2.1 jason 614: char line[8192];
1.1 markus 615: int found_key = 0;
616: FILE *f;
1.23 markus 617: u_long linenum = 0;
1.1 markus 618: struct stat st;
619: Key *found;
1.56.2.4 miod 620: char *fp;
1.1 markus 621:
1.18 markus 622: if (pw == NULL)
623: return 0;
624:
1.1 markus 625: /* Temporarily use the user's uid. */
1.51 markus 626: temporarily_use_uid(pw);
1.1 markus 627:
1.56.2.1 jason 628: debug("trying public key file %s", file);
1.1 markus 629:
630: /* Fail quietly if file does not exist */
631: if (stat(file, &st) < 0) {
632: /* Restore the privileged uid. */
633: restore_uid();
634: return 0;
635: }
636: /* Open the file containing the authorized keys. */
637: f = fopen(file, "r");
638: if (!f) {
639: /* Restore the privileged uid. */
640: restore_uid();
641: return 0;
642: }
1.56.2.1 jason 643: if (options.strict_modes &&
644: secure_filename(f, file, pw, line, sizeof(line)) != 0) {
645: fclose(f);
646: log("Authentication refused: %s", line);
647: restore_uid();
648: return 0;
1.1 markus 649: }
1.56.2.1 jason 650:
1.1 markus 651: found_key = 0;
1.16 markus 652: found = key_new(key->type);
1.1 markus 653:
654: while (fgets(line, sizeof(line), f)) {
1.10 markus 655: char *cp, *options = NULL;
1.1 markus 656: linenum++;
657: /* Skip leading whitespace, empty and comment lines. */
658: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
659: ;
660: if (!*cp || *cp == '\n' || *cp == '#')
661: continue;
1.10 markus 662:
1.56.2.1 jason 663: if (key_read(found, &cp) != 1) {
1.10 markus 664: /* no key? check if there are options for this key */
665: int quoted = 0;
1.21 markus 666: debug2("user_key_allowed: check options: '%s'", cp);
1.10 markus 667: options = cp;
668: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
669: if (*cp == '\\' && cp[1] == '"')
670: cp++; /* Skip both */
671: else if (*cp == '"')
672: quoted = !quoted;
673: }
674: /* Skip remaining whitespace. */
675: for (; *cp == ' ' || *cp == '\t'; cp++)
676: ;
1.56.2.1 jason 677: if (key_read(found, &cp) != 1) {
1.21 markus 678: debug2("user_key_allowed: advance: '%s'", cp);
1.10 markus 679: /* still no key? advance to next line*/
680: continue;
681: }
682: }
683: if (key_equal(found, key) &&
1.30 markus 684: auth_parse_options(pw, options, file, linenum) == 1) {
1.1 markus 685: found_key = 1;
1.56.2.1 jason 686: debug("matching key found: file %s, line %lu",
1.1 markus 687: file, linenum);
1.56.2.4 miod 688: fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
689: verbose("Found matching %s key: %s",
690: key_type(found), fp);
691: xfree(fp);
1.1 markus 692: break;
693: }
694: }
695: restore_uid();
696: fclose(f);
697: key_free(found);
1.46 markus 698: if (!found_key)
699: debug2("key not found");
1.1 markus 700: return found_key;
1.52 markus 701: }
702:
1.56.2.1 jason 703: /* check whether given key is in .ssh/authorized_keys* */
1.56.2.5! miod 704: int
1.56.2.1 jason 705: user_key_allowed(struct passwd *pw, Key *key)
706: {
707: int success;
708: char *file;
709:
710: file = authorized_keys_file(pw);
711: success = user_key_allowed2(pw, key, file);
712: xfree(file);
713: if (success)
714: return success;
715:
716: /* try suffix "2" for backward compat, too */
717: file = authorized_keys_file2(pw);
718: success = user_key_allowed2(pw, key, file);
719: xfree(file);
720: return success;
721: }
722:
1.52 markus 723: /* return 1 if given hostkey is allowed */
1.56.2.5! miod 724: int
1.54 markus 725: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 726: Key *key)
727: {
728: const char *resolvedname, *ipaddr, *lookup;
1.56.2.4 miod 729: HostStatus host_status;
730: int len;
1.52 markus 731:
1.56.2.4 miod 732: resolvedname = get_canonical_hostname(options.verify_reverse_mapping);
1.52 markus 733: ipaddr = get_remote_ipaddr();
734:
1.53 markus 735: debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
736: chost, resolvedname, ipaddr);
1.52 markus 737:
738: if (options.hostbased_uses_name_from_packet_only) {
739: if (auth_rhosts2(pw, cuser, chost, chost) == 0)
740: return 0;
741: lookup = chost;
742: } else {
1.53 markus 743: if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
744: debug2("stripping trailing dot from chost %s", chost);
745: chost[len - 1] = '\0';
746: }
1.52 markus 747: if (strcasecmp(resolvedname, chost) != 0)
748: log("userauth_hostbased mismatch: "
749: "client sends %s, but we resolve %s to %s",
750: chost, ipaddr, resolvedname);
751: if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
752: return 0;
753: lookup = resolvedname;
754: }
755: debug2("userauth_hostbased: access allowed by auth_rhosts2");
756:
1.56.2.1 jason 757: host_status = check_key_in_hostfiles(pw, key, lookup,
758: _PATH_SSH_SYSTEM_HOSTFILE,
759: options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
760:
761: /* backward compat if no key has been found. */
762: if (host_status == HOST_NEW)
763: host_status = check_key_in_hostfiles(pw, key, lookup,
764: _PATH_SSH_SYSTEM_HOSTFILE2,
765: options.ignore_user_known_hosts ? NULL :
766: _PATH_SSH_USER_HOSTFILE2);
1.52 markus 767:
768: return (host_status == HOST_OK);
1.1 markus 769: }
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