Annotation of src/usr.bin/ssh/auth2.c, Revision 1.61
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"
1.61 ! markus 26: RCSID("$OpenBSD: auth2.c,v 1.60 2001/05/30 23:31:14 markus 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"
1.61 ! markus 39: #include "channels.h"
1.1 markus 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"
1.43 markus 50: #include "misc.h"
1.52 markus 51: #include "hostfile.h"
52: #include "canohost.h"
53: #include "tildexpand.h"
1.57 markus 54: #include "match.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:
1.18 markus 61: static Authctxt *x_authctxt = NULL;
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:
1.15 markus 73: void input_service_request(int type, int plen, void *ctxt);
74: void input_userauth_request(int type, int plen, void *ctxt);
75: void protocol_error(int type, int plen, void *ctxt);
1.1 markus 76:
77: /* helper */
1.18 markus 78: Authmethod *authmethod_lookup(const char *name);
1.52 markus 79: char *authmethods_get(void);
1.21 markus 80: int user_key_allowed(struct passwd *pw, Key *key);
1.52 markus 81: int
1.54 markus 82: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 83: Key *key);
1.1 markus 84:
1.18 markus 85: /* auth */
1.25 markus 86: void userauth_banner(void);
1.49 markus 87: void userauth_reply(Authctxt *authctxt, int authenticated);
1.18 markus 88: int userauth_none(Authctxt *authctxt);
89: int userauth_passwd(Authctxt *authctxt);
90: int userauth_pubkey(Authctxt *authctxt);
1.52 markus 91: int userauth_hostbased(Authctxt *authctxt);
1.18 markus 92: int userauth_kbdint(Authctxt *authctxt);
93:
94: Authmethod authmethods[] = {
95: {"none",
96: userauth_none,
97: &one},
98: {"publickey",
99: userauth_pubkey,
1.21 markus 100: &options.pubkey_authentication},
1.40 markus 101: {"password",
102: userauth_passwd,
103: &options.password_authentication},
1.18 markus 104: {"keyboard-interactive",
105: userauth_kbdint,
106: &options.kbd_interactive_authentication},
1.52 markus 107: {"hostbased",
108: userauth_hostbased,
109: &options.hostbased_authentication},
1.18 markus 110: {NULL, NULL, NULL}
1.1 markus 111: };
112:
113: /*
1.18 markus 114: * loop until authctxt->success == TRUE
1.1 markus 115: */
116:
117: void
118: do_authentication2()
119: {
1.28 markus 120: Authctxt *authctxt = authctxt_new();
121:
1.18 markus 122: x_authctxt = authctxt; /*XXX*/
123:
1.34 markus 124: /* challenge-reponse is implemented via keyboard interactive */
1.57 markus 125: if (options.challenge_response_authentication)
1.34 markus 126: options.kbd_interactive_authentication = 1;
127:
1.1 markus 128: dispatch_init(&protocol_error);
129: dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
1.18 markus 130: dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
1.48 markus 131: do_authenticated(authctxt);
1.1 markus 132: }
133:
134: void
1.15 markus 135: protocol_error(int type, int plen, void *ctxt)
1.1 markus 136: {
137: log("auth: protocol error: type %d plen %d", type, plen);
138: packet_start(SSH2_MSG_UNIMPLEMENTED);
139: packet_put_int(0);
140: packet_send();
141: packet_write_wait();
142: }
143:
144: void
1.15 markus 145: input_service_request(int type, int plen, void *ctxt)
1.1 markus 146: {
1.18 markus 147: Authctxt *authctxt = ctxt;
1.23 markus 148: u_int len;
1.1 markus 149: int accept = 0;
150: char *service = packet_get_string(&len);
151: packet_done();
152:
1.18 markus 153: if (authctxt == NULL)
154: fatal("input_service_request: no authctxt");
155:
1.1 markus 156: if (strcmp(service, "ssh-userauth") == 0) {
1.18 markus 157: if (!authctxt->success) {
1.1 markus 158: accept = 1;
159: /* now we can handle user-auth requests */
160: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
161: }
162: }
163: /* XXX all other service requests are denied */
164:
165: if (accept) {
166: packet_start(SSH2_MSG_SERVICE_ACCEPT);
167: packet_put_cstring(service);
168: packet_send();
169: packet_write_wait();
170: } else {
171: debug("bad service request %s", service);
172: packet_disconnect("bad service request %s", service);
173: }
174: xfree(service);
175: }
176:
177: void
1.15 markus 178: input_userauth_request(int type, int plen, void *ctxt)
1.1 markus 179: {
1.18 markus 180: Authctxt *authctxt = ctxt;
181: Authmethod *m = NULL;
1.28 markus 182: char *user, *service, *method, *style = NULL;
1.1 markus 183: int authenticated = 0;
184:
1.18 markus 185: if (authctxt == NULL)
186: fatal("input_userauth_request: no authctxt");
1.1 markus 187:
1.18 markus 188: user = packet_get_string(NULL);
189: service = packet_get_string(NULL);
190: method = packet_get_string(NULL);
1.1 markus 191: debug("userauth-request for user %s service %s method %s", user, service, method);
1.24 markus 192: debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
1.1 markus 193:
1.28 markus 194: if ((style = strchr(user, ':')) != NULL)
195: *style++ = 0;
196:
1.36 stevesk 197: if (authctxt->attempt++ == 0) {
1.18 markus 198: /* setup auth context */
199: struct passwd *pw = NULL;
200: pw = getpwnam(user);
201: if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
202: authctxt->pw = pwcopy(pw);
203: authctxt->valid = 1;
204: debug2("input_userauth_request: setting up authctxt for %s", user);
205: } else {
206: log("input_userauth_request: illegal user %s", user);
207: }
1.42 markus 208: setproctitle("%s", pw ? user : "unknown");
1.18 markus 209: authctxt->user = xstrdup(user);
210: authctxt->service = xstrdup(service);
1.28 markus 211: authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */
1.18 markus 212: } else if (authctxt->valid) {
213: if (strcmp(user, authctxt->user) != 0 ||
214: strcmp(service, authctxt->service) != 0) {
1.52 markus 215: log("input_userauth_request: mismatch: (%s,%s)!=(%s,%s)",
1.18 markus 216: user, service, authctxt->user, authctxt->service);
217: authctxt->valid = 0;
1.1 markus 218: }
219: }
1.28 markus 220: /* reset state */
221: dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error);
222: authctxt->postponed = 0;
1.47 markus 223: #ifdef BSD_AUTH
224: if (authctxt->as) {
225: auth_close(authctxt->as);
226: authctxt->as = NULL;
227: }
228: #endif
1.18 markus 229:
1.28 markus 230: /* try to authenticate user */
1.18 markus 231: m = authmethod_lookup(method);
232: if (m != NULL) {
233: debug2("input_userauth_request: try method %s", method);
234: authenticated = m->userauth(authctxt);
235: }
1.49 markus 236: userauth_finish(authctxt, authenticated, method);
237:
238: xfree(service);
239: xfree(user);
240: xfree(method);
241: }
242:
243: void
244: userauth_finish(Authctxt *authctxt, int authenticated, char *method)
245: {
1.60 markus 246: char *methods;
247:
1.28 markus 248: if (!authctxt->valid && authenticated)
249: fatal("INTERNAL ERROR: authenticated invalid user %s",
250: authctxt->user);
1.18 markus 251:
252: /* Special handling for root */
1.41 markus 253: if (authenticated && authctxt->pw->pw_uid == 0 &&
254: !auth_root_allowed(method))
1.3 markus 255: authenticated = 0;
256:
1.18 markus 257: /* Log before sending the reply */
1.28 markus 258: auth_log(authctxt, authenticated, method, " ssh2");
259:
1.60 markus 260: if (authctxt->postponed)
261: return;
262:
263: /* XXX todo: check if multiple auth methods are needed */
264: if (authenticated == 1) {
265: /* turn off userauth */
266: dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
267: packet_start(SSH2_MSG_USERAUTH_SUCCESS);
268: packet_send();
269: packet_write_wait();
270: /* now we can break out */
271: authctxt->success = 1;
272: } else {
273: if (authctxt->failures++ > AUTH_FAIL_MAX)
274: packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
275: methods = authmethods_get();
276: packet_start(SSH2_MSG_USERAUTH_FAILURE);
277: packet_put_cstring(methods);
278: packet_put_char(0); /* XXX partial success, unused */
279: packet_send();
280: packet_write_wait();
281: xfree(methods);
282: }
1.18 markus 283: }
284:
1.25 markus 285: void
286: userauth_banner(void)
287: {
288: struct stat st;
289: char *banner = NULL;
290: off_t len, n;
291: int fd;
292:
293: if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
294: return;
1.50 markus 295: if ((fd = open(options.banner, O_RDONLY)) < 0)
1.25 markus 296: return;
297: if (fstat(fd, &st) < 0)
298: goto done;
299: len = st.st_size;
300: banner = xmalloc(len + 1);
301: if ((n = read(fd, banner, len)) < 0)
302: goto done;
303: banner[n] = '\0';
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: close(fd);
313: return;
1.1 markus 314: }
315:
316: int
1.18 markus 317: userauth_none(Authctxt *authctxt)
1.1 markus 318: {
1.18 markus 319: /* disable method "none", only allowed one time */
320: Authmethod *m = authmethod_lookup("none");
321: if (m != NULL)
322: m->enabled = NULL;
1.1 markus 323: packet_done();
1.25 markus 324: userauth_banner();
1.47 markus 325: return authctxt->valid ? auth_password(authctxt, "") : 0;
1.1 markus 326: }
1.18 markus 327:
1.1 markus 328: int
1.18 markus 329: userauth_passwd(Authctxt *authctxt)
1.1 markus 330: {
331: char *password;
332: int authenticated = 0;
333: int change;
1.23 markus 334: u_int len;
1.1 markus 335: change = packet_get_char();
336: if (change)
337: log("password change not supported");
338: password = packet_get_string(&len);
339: packet_done();
1.18 markus 340: if (authctxt->valid &&
1.47 markus 341: auth_password(authctxt, password) == 1)
1.1 markus 342: authenticated = 1;
343: memset(password, 0, len);
344: xfree(password);
345: return authenticated;
346: }
1.18 markus 347:
348: int
349: userauth_kbdint(Authctxt *authctxt)
350: {
351: int authenticated = 0;
1.57 markus 352: char *lang, *devs;
353:
1.18 markus 354: lang = packet_get_string(NULL);
355: devs = packet_get_string(NULL);
356: packet_done();
357:
1.57 markus 358: debug("keyboard-interactive devs %s", devs);
1.28 markus 359:
1.57 markus 360: if (options.challenge_response_authentication)
1.34 markus 361: authenticated = auth2_challenge(authctxt, devs);
1.28 markus 362:
1.57 markus 363: xfree(devs);
1.18 markus 364: xfree(lang);
365: return authenticated;
366: }
367:
1.1 markus 368: int
1.18 markus 369: userauth_pubkey(Authctxt *authctxt)
1.1 markus 370: {
371: Buffer b;
372: Key *key;
373: char *pkalg, *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 */
399: log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
1.1 markus 400: xfree(pkalg);
1.22 markus 401: xfree(pkblob);
1.1 markus 402: return 0;
403: }
1.21 markus 404: key = key_from_blob(pkblob, blen);
1.2 markus 405: if (key != NULL) {
406: if (have_sig) {
407: sig = packet_get_string(&slen);
408: packet_done();
409: buffer_init(&b);
1.20 markus 410: if (datafellows & SSH_OLD_SESSIONID) {
411: buffer_append(&b, session_id2, session_id2_len);
412: } else {
1.11 markus 413: buffer_put_string(&b, session_id2, session_id2_len);
414: }
1.9 markus 415: /* reconstruct packet */
1.2 markus 416: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1.18 markus 417: buffer_put_cstring(&b, authctxt->user);
1.9 markus 418: buffer_put_cstring(&b,
1.22 markus 419: datafellows & SSH_BUG_PKSERVICE ?
1.9 markus 420: "ssh-userauth" :
1.18 markus 421: authctxt->service);
1.22 markus 422: if (datafellows & SSH_BUG_PKAUTH) {
423: buffer_put_char(&b, have_sig);
424: } else {
425: buffer_put_cstring(&b, "publickey");
426: buffer_put_char(&b, have_sig);
1.56 markus 427: buffer_put_cstring(&b, pkalg);
1.22 markus 428: }
1.9 markus 429: buffer_put_string(&b, pkblob, blen);
1.21 markus 430: #ifdef DEBUG_PK
1.2 markus 431: buffer_dump(&b);
1.1 markus 432: #endif
1.2 markus 433: /* test for correct signature */
1.21 markus 434: if (user_key_allowed(authctxt->pw, key) &&
435: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
1.2 markus 436: authenticated = 1;
437: buffer_clear(&b);
438: xfree(sig);
439: } else {
1.18 markus 440: debug("test whether pkalg/pkblob are acceptable");
1.2 markus 441: packet_done();
1.18 markus 442:
1.2 markus 443: /* XXX fake reply and always send PK_OK ? */
1.6 markus 444: /*
445: * XXX this allows testing whether a user is allowed
446: * to login: if you happen to have a valid pubkey this
447: * message is sent. the message is NEVER sent at all
448: * if a user is not allowed to login. is this an
449: * issue? -markus
450: */
1.21 markus 451: if (user_key_allowed(authctxt->pw, key)) {
1.2 markus 452: packet_start(SSH2_MSG_USERAUTH_PK_OK);
453: packet_put_string(pkalg, alen);
454: packet_put_string(pkblob, blen);
455: packet_send();
456: packet_write_wait();
1.38 markus 457: authctxt->postponed = 1;
1.2 markus 458: }
1.1 markus 459: }
1.17 markus 460: if (authenticated != 1)
461: auth_clear_options();
1.2 markus 462: key_free(key);
1.1 markus 463: }
1.21 markus 464: debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
1.1 markus 465: xfree(pkalg);
466: xfree(pkblob);
467: return authenticated;
468: }
469:
1.52 markus 470: int
471: userauth_hostbased(Authctxt *authctxt)
472: {
473: Buffer b;
474: Key *key;
1.55 markus 475: char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
1.52 markus 476: u_int alen, blen, slen;
477: int pktype;
478: int authenticated = 0;
479:
480: if (!authctxt->valid) {
481: debug2("userauth_hostbased: disabled because of invalid user");
482: return 0;
483: }
484: pkalg = packet_get_string(&alen);
485: pkblob = packet_get_string(&blen);
486: chost = packet_get_string(NULL);
487: cuser = packet_get_string(NULL);
488: sig = packet_get_string(&slen);
489:
490: debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
491: cuser, chost, pkalg, slen);
492: #ifdef DEBUG_PK
493: debug("signature:");
494: buffer_init(&b);
495: buffer_append(&b, sig, slen);
496: buffer_dump(&b);
497: buffer_free(&b);
498: #endif
499: pktype = key_type_from_name(pkalg);
500: if (pktype == KEY_UNSPEC) {
501: /* this is perfectly legal */
502: log("userauth_hostbased: unsupported "
503: "public key algorithm: %s", pkalg);
504: goto done;
505: }
506: key = key_from_blob(pkblob, blen);
507: if (key == NULL) {
508: debug("userauth_hostbased: cannot decode key: %s", pkalg);
509: goto done;
510: }
1.55 markus 511: service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
512: authctxt->service;
1.52 markus 513: buffer_init(&b);
1.55 markus 514: buffer_put_string(&b, session_id2, session_id2_len);
1.52 markus 515: /* reconstruct packet */
516: buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
517: buffer_put_cstring(&b, authctxt->user);
1.55 markus 518: buffer_put_cstring(&b, service);
1.52 markus 519: buffer_put_cstring(&b, "hostbased");
520: buffer_put_string(&b, pkalg, alen);
521: buffer_put_string(&b, pkblob, blen);
522: buffer_put_cstring(&b, chost);
523: buffer_put_cstring(&b, cuser);
524: #ifdef DEBUG_PK
525: buffer_dump(&b);
526: #endif
527: /* test for allowed key and correct signature */
528: if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
529: key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
530: authenticated = 1;
531:
532: buffer_clear(&b);
533: key_free(key);
534:
535: done:
536: debug2("userauth_hostbased: authenticated %d", authenticated);
537: xfree(pkalg);
538: xfree(pkblob);
539: xfree(cuser);
540: xfree(chost);
541: xfree(sig);
542: return authenticated;
543: }
544:
1.18 markus 545: /* get current user */
1.1 markus 546:
547: struct passwd*
548: auth_get_user(void)
549: {
1.18 markus 550: return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
1.1 markus 551: }
552:
1.18 markus 553: #define DELIM ","
554:
555: char *
556: authmethods_get(void)
1.1 markus 557: {
1.18 markus 558: Authmethod *method = NULL;
1.23 markus 559: u_int size = 0;
1.18 markus 560: char *list;
1.1 markus 561:
1.18 markus 562: for (method = authmethods; method->name != NULL; method++) {
563: if (strcmp(method->name, "none") == 0)
564: continue;
565: if (method->enabled != NULL && *(method->enabled) != 0) {
566: if (size != 0)
567: size += strlen(DELIM);
568: size += strlen(method->name);
1.1 markus 569: }
1.18 markus 570: }
571: size++; /* trailing '\0' */
572: list = xmalloc(size);
573: list[0] = '\0';
574:
575: for (method = authmethods; method->name != NULL; method++) {
576: if (strcmp(method->name, "none") == 0)
577: continue;
578: if (method->enabled != NULL && *(method->enabled) != 0) {
579: if (list[0] != '\0')
580: strlcat(list, DELIM, size);
581: strlcat(list, method->name, size);
1.1 markus 582: }
583: }
1.18 markus 584: return list;
585: }
586:
587: Authmethod *
588: authmethod_lookup(const char *name)
589: {
590: Authmethod *method = NULL;
591: if (name != NULL)
592: for (method = authmethods; method->name != NULL; method++)
593: if (method->enabled != NULL &&
594: *(method->enabled) != 0 &&
595: strcmp(name, method->name) == 0)
596: return method;
597: debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
598: return NULL;
1.1 markus 599: }
600:
601: /* return 1 if user allows given key */
602: int
1.21 markus 603: user_key_allowed(struct passwd *pw, Key *key)
1.1 markus 604: {
1.58 markus 605: char line[8192], *file;
1.1 markus 606: int found_key = 0;
607: FILE *f;
1.23 markus 608: u_long linenum = 0;
1.1 markus 609: struct stat st;
610: Key *found;
611:
1.18 markus 612: if (pw == NULL)
613: return 0;
614:
1.1 markus 615: /* Temporarily use the user's uid. */
1.51 markus 616: temporarily_use_uid(pw);
1.1 markus 617:
618: /* The authorized keys. */
1.58 markus 619: file = authorized_keys_file2(pw);
620: debug("trying public key file %s", file);
1.1 markus 621:
622: /* Fail quietly if file does not exist */
623: if (stat(file, &st) < 0) {
624: /* Restore the privileged uid. */
625: restore_uid();
1.58 markus 626: xfree(file);
1.1 markus 627: return 0;
628: }
629: /* Open the file containing the authorized keys. */
630: f = fopen(file, "r");
631: if (!f) {
632: /* Restore the privileged uid. */
633: restore_uid();
1.58 markus 634: xfree(file);
1.1 markus 635: return 0;
636: }
1.58 markus 637: if (options.strict_modes &&
638: secure_filename(f, file, pw->pw_uid, line, sizeof(line)) != 0) {
639: xfree(file);
640: fclose(f);
641: log("Authentication refused: %s", line);
642: restore_uid();
643: return 0;
1.1 markus 644: }
1.58 markus 645:
1.1 markus 646: found_key = 0;
1.16 markus 647: found = key_new(key->type);
1.1 markus 648:
649: while (fgets(line, sizeof(line), f)) {
1.10 markus 650: char *cp, *options = NULL;
1.1 markus 651: linenum++;
652: /* Skip leading whitespace, empty and comment lines. */
653: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
654: ;
655: if (!*cp || *cp == '\n' || *cp == '#')
656: continue;
1.10 markus 657:
1.21 markus 658: if (key_read(found, &cp) == -1) {
1.10 markus 659: /* no key? check if there are options for this key */
660: int quoted = 0;
1.21 markus 661: debug2("user_key_allowed: check options: '%s'", cp);
1.10 markus 662: options = cp;
663: for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
664: if (*cp == '\\' && cp[1] == '"')
665: cp++; /* Skip both */
666: else if (*cp == '"')
667: quoted = !quoted;
668: }
669: /* Skip remaining whitespace. */
670: for (; *cp == ' ' || *cp == '\t'; cp++)
671: ;
1.21 markus 672: if (key_read(found, &cp) == -1) {
673: debug2("user_key_allowed: advance: '%s'", cp);
1.10 markus 674: /* still no key? advance to next line*/
675: continue;
676: }
677: }
678: if (key_equal(found, key) &&
1.30 markus 679: auth_parse_options(pw, options, file, linenum) == 1) {
1.1 markus 680: found_key = 1;
681: debug("matching key found: file %s, line %ld",
682: file, linenum);
683: break;
684: }
685: }
686: restore_uid();
687: fclose(f);
1.58 markus 688: xfree(file);
1.1 markus 689: key_free(found);
1.46 markus 690: if (!found_key)
691: debug2("key not found");
1.1 markus 692: return found_key;
1.52 markus 693: }
694:
695: /* return 1 if given hostkey is allowed */
696: int
1.54 markus 697: hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
1.52 markus 698: Key *key)
699: {
700: Key *found;
701: const char *resolvedname, *ipaddr, *lookup;
702: struct stat st;
703: char *user_hostfile;
1.53 markus 704: int host_status, len;
1.52 markus 705:
706: resolvedname = get_canonical_hostname(options.reverse_mapping_check);
707: ipaddr = get_remote_ipaddr();
708:
1.53 markus 709: debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
710: chost, resolvedname, ipaddr);
1.52 markus 711:
712: if (options.hostbased_uses_name_from_packet_only) {
713: if (auth_rhosts2(pw, cuser, chost, chost) == 0)
714: return 0;
715: lookup = chost;
716: } else {
1.53 markus 717: if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
718: debug2("stripping trailing dot from chost %s", chost);
719: chost[len - 1] = '\0';
720: }
1.52 markus 721: if (strcasecmp(resolvedname, chost) != 0)
722: log("userauth_hostbased mismatch: "
723: "client sends %s, but we resolve %s to %s",
724: chost, ipaddr, resolvedname);
725: if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
726: return 0;
727: lookup = resolvedname;
728: }
729: debug2("userauth_hostbased: access allowed by auth_rhosts2");
730:
731: /* XXX this is copied from auth-rh-rsa.c and should be shared */
732: found = key_new(key->type);
733: host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE2, lookup,
734: key, found, NULL);
735:
736: if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
737: user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE2,
738: pw->pw_uid);
739: if (options.strict_modes &&
740: (stat(user_hostfile, &st) == 0) &&
741: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
742: (st.st_mode & 022) != 0)) {
743: log("Hostbased authentication refused for %.100s: "
744: "bad owner or modes for %.200s",
745: pw->pw_name, user_hostfile);
746: } else {
747: temporarily_use_uid(pw);
748: host_status = check_host_in_hostfile(user_hostfile,
749: lookup, key, found, NULL);
750: restore_uid();
751: }
752: xfree(user_hostfile);
753: }
754: key_free(found);
755:
756: debug2("userauth_hostbased: key %s for %s", host_status == HOST_OK ?
757: "ok" : "not found", lookup);
758: return (host_status == HOST_OK);
1.1 markus 759: }
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